In a VOIP system, where SIP is a signaling protocol , a SIP proxy never participates in the media flow, thus it is media agnostic.

SDP packets describing a session with codecs , open ports , media formats etc are embedded in a SIP request such as invite .
Post a SDP Offer/Answer flow , RTP and RTCP esnsure that mediastream flow between the endpoints .

RTP is the provides end-to-end network transport functions suitable for applications transmitting real-time data, such as audio, video or simulation data, over multicast or unicast network services.

RTCP is the control protocl which provides monitoring of the data delivery, qos in a manner scalable to large multicast networks, and to provide minimal control and identification functionality.

RTP

protocol framework
supports use of RTP-level translators and mixers.
independent of the underlying transport and network layers.
does not address resource reservation
does not guarantee quality-of-service for real-time services.
services like payload type identification, sequence numbering, timestamping and delivery monitoring.

The sequence numbers included in RTP allow the receiver to reconstruct the sender’s packet sequence,

Usage :
Multimedia Multi particpant conferences
Storage of continuous data
Interactive distributed simulation
active badge, control and measurement applications

UDP provides best-effort delivery of datagrams for point-to-point as well as for multicast communications.

SRTP

Provides confidentiality, message authentication, and replay protection for both unicast and multicast RTP and RTCP streams.
security layer which resides between the RTP/RTCP application layer and the transport layer
cryptographic context includes includes

• session key , used directly in encryption/message authentication
• master key ,a securely exchanged random bit string used to derive session keys
• other working session parameters ( master key lifetime, master key identifier and length, FEC parameters, etc)
  it must be maintained by both the sender and receiver of these streams.

RTP Session

In an RTP session, each particpant maintains a full, separate space of SSRC identifiers. The set of participants included in one RTP session consists of those that can receive an SSRC identifier transmitted by any one of the participants either in RTP as the SSRC or a CSRC or in RTCP.

Real-Time Transport Protocol
    [Stream setup by SDP (frame 554)]
        [Setup frame: 554]
        [Setup Method: SDP]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 .... = Extension: False
    .... 0000 = Contributing source identifiers count: 0
    0... .... = Marker: False
    Payload type: ITU-T G.711 PCMU (0)
    Sequence number: 39644
    [Extended sequence number: 39644]
    Timestamp: 2256601824
    Synchronization Source identifier: 0x78006c62 (2013293666)
    Payload: 7efefefe7efefe7e7efefe7e7efefe7e7efefe7e7efefe7e...

Synchronization source (SSRC)

32-bit numeric SSRC identifier for source of a stream of RTP packets.
All packets from a synchronization source form part of the same timing and sequence number space, so a receiver groups packets by synchronization source for playback.

the binding of the SSRC identifiers is provided through RTCP.
If a participant generates multiple streams in one RTP session, for example from separate video cameras, each MUST be identified as a different SSRC.

Contributing source (CSRC)

A source of a stream of RTP packets that has contributed to the combined stream produced by an RTP mixer.
The mixer inserts a list of the SSRC identifiers of the sources , called CSRC list, that contributed to the generation of a particular packet into the RTP header of that packet.

An example application is audio conferencing where a mixer indicates all the talkers whose speech was combined to produce the outgoing packet, allowing the receiver to indicate the current talker, even though all the audio packets contain the same SSRC identifier (that of the mixer).

RTSP (Real-Time Streaming Protocol)

network control protocol
TCP to maintain an end-to-end connection
control real-time streaming media applications such as live audio and HD video streaming
establishes a media session between RTSP end-points ( can be RTSP media servers too) and initiates RTP streams to deliver the audio and video payload from the RTSP media servers to the clients.

RTCP (Real-Time Transport Control Protocol )

periodic transmission of control packet
monitor data deliver on large multicast networks
underlying protocol must provide multiplexing of the data and control packets
-provide feedback on the quality of the data distribution , congestion control , fault dialoginis , control of adaptive encodings
-carries a persistent transport-level identifier for an RTP source called the canonical name or CNAME , which is used to keep track of each participant
-observer number of particpants to rate of senidng packets for scaling up
-convey minimal session control information

Exmample of RTCP sender and receiver reports on transmission and reception statistics

Real-time Transport Control Protocol (Receiver Report)
    [Stream setup by SDP (frame 4)]
        [Setup frame: 4]
        [Setup Method: SDP]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Receiver Report (201)
    Length: 7 (32 bytes)
    Sender SSRC: 0x796dd0d6 (2037240022)
    Source 1
        Identifier: 0x00000000 (0)
        SSRC contents
            Fraction lost: 0 / 256
            Cumulative number of packets lost: 1
        Extended highest sequence number received: 6534
            Sequence number cycles count: 0
            Highest sequence number received: 6534
        Interarrival jitter: 0
        Last SR timestamp: 0 (0x00000000)
        Delay since last SR timestamp: 0 (0 milliseconds)

Real-time Transport Control Protocol (Source description)
    [Stream setup by SDP (frame 4)]
        [Setup frame: 4]
        [Setup Method: SDP]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 6 (28 bytes)
    Chunk 1, SSRC/CSRC 0x796DD0D6
        Identifier: 0x796dd0d6 (2037240022)
        SDES items
            Type: CNAME (user and domain) (1)
            Length: 8
            Text: 796dd0d6
            Type: NOTE (note about source) (7)
            Length: 5
            Text: plivo
            Type: END (0)

Simulcast

client encodes the same audio/video stream twice in different resolutions and bitrates and sending these to a router who then decides who receives which of the streams.

Multicast Audio Conference

Assume obtaining a multicast group address and pair of ports. One port is used for audio data, and the other is used for control (RTCP) packets.
The audio conferencing application used by each conference participant sends audio data in small chunks of ms duration.
Each chunk of audio data is preceded by an RTP header; RTP header and data are in turn contained in a UDP packet.

The RTP header indicates what type of audio encoding (such as PCM, ADPCM or LPC) is contained in each packet so that senders can change the encoding during a conference, for example, to accommodate a new participant that is connected through a low-bandwidth link or react to indications of network congestion.

Every packet networks, occasionally loses and reorders packets and delays them by variable amounts of time. Thus RTP header contains timing information and a sequence number that allow the receivers to reconstruct the timing produced by the source.
The sequence number can also be used by the receiver to estimate how many packets are being lost.

For QoS, each instance of the audio application in the conference periodically multicasts a reception report plus the name of its user on the RTCP(control) port. The reception report indicates how well the current speaker is being received and may be used to control adaptive encodings. In addition to the user name, other identifying information may also be included subject to control bandwidth limits.

A site sends the RTCP BYE packet when it leaves the conference.

Audio and Video Conference

Audio and video media are transmitted as separate RTP sessions, separate RTP and RTCP packets are transmitted for each medium using two different UDP port pairs and/or multicast addresses. There is no direct coupling at the RTP level between the audio and video sessions, except that a user participating in both sessions should use the same distinguished (canonical) name in the RTCP packets for both so that the sessions can be associated.

Synchronized playback of a source’s audio and video is achieved using timing information carried in the RTCP packets

Layered Encodings

In conflicting bandwidth requirements of heterogeneous receivers, Multimedia applications should be able to adjust the transmission rate to match the capacity of the receiver or to adapt to network congestion.
Rate-adaptation should be done by a layered encoding with a layered transmission system.

In the context of RTP over IP multicast, the source can stripe the progressive layers of a hierarchically represented signal across multiple RTP sessions each carried on its own multicast group. Receivers can then adapt to network heterogeneity and control their reception bandwidth by joining only the appropriate subset of the multicast groups.

Mixers , Translators and Monitors

Mixer

An intermediate system that receives RTP packets from one or more sources, possibly changes the data format, combines the packets in some manner and then forwards a new RTP packet.

example of Mixer for hi-speed to low-speed packet stream conversion

In conference cases where few participants are connected through a low-speed link where other have hi-speed link, instead of forcing lower-bandwidth, reduced-quality audio encoding for all, an RTP-level relay called a mixer may be placed near the low-bandwidth area.
This mixer resynchronizes incoming audio packets to reconstruct the constant 20 ms spacing generated by the sender, mixes these reconstructed audio streams into a single stream, translates the audio encoding to a lower-bandwidth one and forwards the lower-bandwidth packet stream across the low-speed links.

All data packets originating from a mixer will be identified as having the mixer as their synchronization source.
The RTP header includes a means for mixers to identify the sources that contributed to a mixed packet so that correct talker indication can be provided at the receivers.

Translator

An intermediate system that forwards RTP packets with their synchronization source identifier intact.

Examples of translators include devices that convert encodings without mixing, replicators from multicast to unicast, and application-level filters in firewalls.

Tranasltor for Firewall Limiting IP packet pass

Some of the intended participants in the audio conference may be connected with high bandwidth links but might not be directly reachable via IP multicast, for reasons such as being behind an application-level firewall that will not let any IP packets pass. For these sites, mixing may not be necessary, in which case another type of RTP-level relay called a translator may be used.

Two translators are installed, one on either side of the firewall, with the outside one funneling all multicast packets received through asecure connection to the translator inside the firewall. The translator inside the firewall sends them again as multicast packets to a multicast group restricted to the site’s internal network.

Other cases :

video mixers can scales the images of individual people in separate video streams and composites them into one video stream to simulate a group scene.

Translator usage when connection of a group of hosts speaking only IP/UDP to a group of hosts that understand only ST-II, packet-by-packet encoding translation of video streams from individual sources without resynchronization or mixing.

Monitor

An application that receives RTCP packets sent by participants in an RTP session, in particular the reception reports, and estimates the current quality of service for distribution monitoring, fault diagnosis and long-term statistics.

Layered Encodings

In conflicting bandwidth requirements of heterogeneous receivers, Multimedia applications should be able to adjust the transmission rate to match the capacity of the receiver or to adapt to network congestion.
Rate-adaptation should be done by a layered encoding with a layered transmission system.

In the context of RTP over IP multicast, the source can stripe the progressive layers of a hierarchically represented signal across multiple RTP sessions each carried on its own multicast group. Receivers can then adapt to network heterogeneity and control their reception bandwidth by joining only the appropriate subset of the multicast groups.

RTP Session

In an RTP session, each particpant maintains a full, separate space of SSRC identifiers. The set of participants included in one RTP session consists of those that can receive an SSRC identifier transmitted by any one of the participants either in RTP as the SSRC or a CSRC or in RTCP.

Real-Time Transport Protocol
    [Stream setup by SDP (frame 554)]
        [Setup frame: 554]
        [Setup Method: SDP]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 .... = Extension: False
    .... 0000 = Contributing source identifiers count: 0
    0... .... = Marker: False
    Payload type: ITU-T G.711 PCMU (0)
    Sequence number: 39644
    [Extended sequence number: 39644]
    Timestamp: 2256601824
    Synchronization Source identifier: 0x78006c62 (2013293666)
    Payload: 7efefefe7efefe7e7efefe7e7efefe7e7efefe7e7efefe7e...

Synchronization source (SSRC)

32-bit numeric SSRC identifier for source of a stream of RTP packets.
All packets from a synchronization source form part of the same timing and sequence number space, so a receiver groups packets by synchronization source for playback.

the binding of the SSRC identifiers is provided through RTCP.
If a participant generates multiple streams in one RTP session, for example from separate video cameras, each MUST be identified as a different SSRC.

Contributing source (CSRC)

A source of a stream of RTP packets that has contributed to the combined stream produced by an RTP mixer.
The mixer inserts a list of the SSRC identifiers of the sources , called CSRC list, that contributed to the generation of a particular packet into the RTP header of that packet. An example application is audio conferencing where a mixer indicates all the talkers whose speech was combined to produce the outgoing packet, allowing the receiver to indicate the current talker, even though all the audio packets contain the same SSRC identifier (that of the mixer).

RTCP

periodic transmission of control packet
underlying protocol must provide multiplexing of the data and control packets
– provide feedback on the quality of the data distribution , congestion control , fault diagnosis, control of adaptive encodings
– carries a persistent transport-level identifier for an RTP source called the canonical name or CNAME , which is used to keep track of each participant
– observer number of participants to rate of sending packets for scaling up
– convey minimal session control information

Components of RTCP based feedback

Status reports

• contained in sender report (SR)/received report (RR) packets
• transmitted at regular intervals as part of compound RTCP packets, can also contain SDES
• overall indication for reception quality of media stream

FB messages

indicate loss or reception of particular pieces of a media stream

Example of RTCP sender and receiver reports on transmission and reception statistics

Real-time Transport Control Protocol (Receiver Report)
    [Stream setup by SDP (frame 4)]
        [Setup frame: 4]
        [Setup Method: SDP]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Receiver Report (201)
    Length: 7 (32 bytes)
    Sender SSRC: 0x796dd0d6 (2037240022)
    Source 1
        Identifier: 0x00000000 (0)
        SSRC contents
            Fraction lost: 0 / 256
            Cumulative number of packets lost: 1
        Extended highest sequence number received: 6534
            Sequence number cycles count: 0
            Highest sequence number received: 6534
        Interarrival jitter: 0
        Last SR timestamp: 0 (0x00000000)
        Delay since last SR timestamp: 0 (0 milliseconds)

Real-time Transport Control Protocol (Source description)
    [Stream setup by SDP (frame 4)]
        [Setup frame: 4]
        [Setup Method: SDP]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 6 (28 bytes)
    Chunk 1, SSRC/CSRC 0x796DD0D6
        Identifier: 0x796dd0d6 (2037240022)
        SDES items
            Type: CNAME (user and domain) (1)
            Length: 8
            Text: 796dd0d6
            Type: NOTE (note about source) (7)
            Length: 5
            Text: plivo
            Type: END (0)

RTCP operation modes

• Immediate Feedback mode
• Early RTCP mode
• Regular RTCP Mode

Multiplexing RTP Sessions

In RTP, multiplexing is provided by the destination transport address (network address and port number) which is different for each RTP session ( seprate for audio and video ). This helps in cases where there is chaneg in encodings , change of clockrates , detection of packet loss suffered and RTCP reporting .
Moreover RTP mixer would not be able to combine interleaved streams of incompatible media into one stream.

Interleaving packets with different RTP media types but using the same SSRC would introduce several problems.
But multiplexing multiple related sources of the same medium in one RTP session using different SSRC values is the norm for multicast sessions.

SDES (Session Description Protocol Security Descriptions)

way to negotiate the key/cryptographic parameters for SRTP
keys are transported in the SDP attachment of a SIP message using TLS transport layer (SSLv3/TLSv1) or other methods like S/MIME.
media attribute defined by SDES is “crypto”
a=crypto: inline: [session-parms]

3 commonly used crypto suites are
AES_CM_128_HMAC_SHA1_80
AES_CM_128_HMAC_SHA1_32
F8_128_HMAC_SHA1_32

Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)

RTP provides continuous feedback about the overall reception quality from all receivers — thereby allowing the sender(s) in the mid-term to adapt their coding scheme and transmission behavior to the observed network quality of service (QoS).

RTP makes no provision for timely feedback that would allow a sender to repair the media stream immediately: through retransmissions, retroactive Forward Error Correction (FEC) control, or media-specific mechanisms for some video codecs, such as reference picture selection.

REMB ( Receiver Estimated Maximum Bitrate)

RTCP message used to provide bandwidth estimation in order to avoid creating congestion in the network.
support for this message is negotiated in the Offer/Answer SDP Exchange.

contains total estimated available bitrate on the path to the receiving side of this RTP session (in mantissa + exponent format).
used by sender to configure the maximum bitrate of the video encoding.

also notify the available bandwidth in the network and by media servers to limit the amount of bitrate the sender is allowed to send.

In Chrome it is deprecated in favor of the new sender side bandwidth estimation based on RTCP Transport Feedback messages.

Session Description Protocol (SDP) Capability Negotiation

negotiate use of one out of several possible transport protocols. The offerer uses the expected least-common-denominator (plain RTP) as the actual configuration, and the alternative transport protocols as the potential configurations.

m=audio 53456 RTP/AVP 0 18
a=tcap:1 RTP/SAVPF RTP/SAVP RTP/AVPF

plain RTP (RTP/AVP)
Secure RTP (RTP/SAVP)
RTP with RTCP-based feedback (RTP/AVPF)
Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)

Technologies around RTP streaming

Adaptive bitrate control

Adapt the audio and video codec bitrates to the available bandwidth, and hence optimize audio & video quality
For video, since reslution is chosed at the start only , encoder use bitrate and framerate sttributes onlu dirng runtime to adapt

RTCP packet called TMMBR (Temporary Maximum Media Stream Bit Rate Request) is sent to the remote client

Ref:

RFC 3550 – RTP: A Transport Protocol for Real-Time Applications

RFC 4585 Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)

Continuous Integration and Delivery Automation using Jenkins

continous delivery hub
distribute work across multiple machines, helping drive builds, tests and deployments across multiple platforms
self-contained Java-based program
extensible using plugins

Jenkins pieline

orchestrate and automate building their project in Jenkins

Configuration management using chef cookbooks

Alternatives like puppet and Ansible, which are also a cross-platform configuration management platform

Compute virtualization and containerization using Docker

Docker containers can be used instead of virtual machines such as VirtualBox , to isolates applications and be OS and platform independent
Makes distributed development possible and automates the deployment possible

Usage: docker [OPTIONS] COMMAND

A self-sufficient runtime for containers

Options:
–config string Location of client config files (default “/root/.docker”)
-D, –debug Enable debug mode
-H, –host list Daemon socket(s) to connect to
-l, –log-level string Set the logging level (“debug”|”info”|”warn”|”error”|”fatal”) (default “info”)
–tls Use TLS; implied by –tlsverify
–tlscacert string Trust certs signed only by this CA (default “/root/.docker/ca.pem”)
–tlscert string Path to TLS certificate file (default “/root/.docker/cert.pem”)
–tlskey string Path to TLS key file (default “/root/.docker/key.pem”)
–tlsverify Use TLS and verify the remote
-v, –version Print version information and quit

Docker commands

Management Commands:
builder Manage builds
config Manage Docker configs
container Manage containers
engine Manage the docker engine
image Manage images
network Manage networks
node Manage Swarm nodes
plugin Manage plugins
secret Manage Docker secrets
service Manage services
stack Manage Docker stacks
swarm Manage Swarm
system Manage Docker
trust Manage trust on Docker images
volume Manage volumes

Commands:
attach Attach local standard input, output, and error streams to a running container
build Build an image from a Dockerfile
commit Create a new image from a container’s changes
cp Copy files/folders between a container and the local filesystem
create Create a new container
diff Inspect changes to files or directories on a container’s filesystem
events Get real time events from the server
exec Run a command in a running container
export Export a container’s filesystem as a tar archive
history Show the history of an image
images List images
import Import the contents from a tarball to create a filesystem image
info Display system-wide information
inspect Return low-level information on Docker objects
kill Kill one or more running containers
load Load an image from a tar archive or STDIN
login Log in to a Docker registry
logout Log out from a Docker registry
logs Fetch the logs of a container
pause Pause all processes within one or more containers
port List port mappings or a specific mapping for the container
ps List containers
pull Pull an image or a repository from a registry
push Push an image or a repository to a registry
rename Rename a container
restart Restart one or more containers
rm Remove one or more containers
rmi Remove one or more images
run Run a command in a new container
save Save one or more images to a tar archive (streamed to STDOUT by default)
search Search the Docker Hub for images
start Start one or more stopped containers
stats Display a live stream of container(s) resource usage statistics
stop Stop one or more running containers
tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
top Display the running processes of a container
unpause Unpause all processes within one or more containers
update Update configuration of one or more containers
version Show the Docker version information
wait Block until one or more containers stop, then print their exit codes

docker container commands

List all container

docker ps 

docker container COMMAND

attach Attach local standard input, output, and error streams to a running container
commit Create a new image from a container’s changes
cp Copy files/folders between a container and the local filesystem
create Create a new container
diff Inspect changes to files or directories on a container’s filesystem
exec Run a command in a running container
export Export a container’s filesystem as a tar archive
inspect Display detailed information on one or more containers
kill Kill one or more running containers
logs Fetch the logs of a container
ls List containers
pause Pause all processes within one or more containers
port List port mappings or a specific mapping for the container
prune Remove all stopped containers
rename Rename a container
restart Restart one or more containers
rm Remove one or more containers
run Run a command in a new container
start Start one or more stopped containers
stats Display a live stream of container(s) resource usage statistics
stop Stop one or more running containers
top Display the running processes of a container
unpause Unpause all processes within one or more containers
update Update configuration of one or more containers
wait Block until one or more containers stop, then print their exit codes

docker image commands

see all iamges

>docker images
REPOSITORY                  TAG                 IMAGE ID            CREATED             SIZE
sipcapture/homer-cron       latest              fb2243f90cde        3 hours ago         476MB
sipcapture/homer-kamailio   latest              f159d46a22f3        3 hours ago         338MB
sipcapture/heplify          latest              9f5280306809        21 hours ago        9.61MB
<none&gt;                      <none&gt;              edaa5c708b3a        21 hours ago        619MB
mysql                       5.6                 c30095c52827        36 hours ago        256MB
sipcapture/homer-app        master              1e883a8d88d4        2 days ago          454MB
postgres                    11-alpine           5239fade3a90        7 days ago          71.9MB
golang                      alpine              6b21b4c6e7a3        7 days ago          350MB
alpine                      latest              b7b28af77ffe        7 days ago          5.58MB
debian                      jessie              652b7a59e393        9 days ago          129MB
sipcapture/heplify-server   master              aa85bfa7cb3e        2 weeks ago         22.6MB
kapacitor                   1.5-alpine          2a63b9d348df        4 weeks ago         73.6MB
influxdb                    1.5-alpine          40e13f6ee02a        7 weeks ago         84MB
chronograf                  1.5-alpine          02ed2863e25b        7 weeks ago         44.5MB
sipcapture/hepsub           master              3ef6550c4bc6        2 months ago        90.6MB
hello-world                 latest              fce289e99eb9        6 months ago        1.84kB
sipcapture/homer-webapp     latest              75e5b5b7b33c        7 months ago        428MB
telegraf                    1.5-alpine          aa8daabb3b1c        10 months ago       42MB
stefanprodan/caddy          latest              655880563633        21 months ago       24.7MB

See all stats

>docker stats
CONTAINER ID        NAME                CPU %               MEM USAGE / LIMIT     MEM %               NET I/O             BLOCK I/O           PIDS
f42c71741107        homer-cron          0.00%               52KiB / 994.6MiB      0.01%               2.3kB / 0B          602MB / 0B          0
0111765091ae        mysql               0.04%               452.2MiB / 994.6MiB   45.46%              1.35kB / 0B         2.06GB / 49.2kB     22

Run command from with docker

docker exec -it bash

First see all processes

docker ps

select a process and enter its bash

docker exec -it 0472a5127fff bash

to edit or update a file inside docker either install vim everytime u login in resh docker conainer like

apt-get update
apt-get install vim

or add this to dockerfile

RUN [“apt-get”, “update”]
RUN [“apt-get”, “install”, “-y”, “vim”]

see if ngrep is install , if not then install and run ngrep to get sip logs isnode that docker container

apt update
apt install ngrep
ngrep -p "14795778704" -W byline -d any port 5060

docker volume

volumes are used for persisting data generated by and used by Docker containers.
docker volumes have advantages over blind mounts such as
easier to backup or migrate , managed by docker APIs, can be safely shared among multiple containers etc

Commands:
create Create a volume
inspect Display detailed information on one or more volumes
ls List volumes
prune Remove all unused local volumes
rm Remove one or more volumes

docker stack

Lets to manager a cluster of docker containers thorugh docker swarm
can be defined via docker-compose.yml file

Options:
–orchestrator string Orchestrator to use (swarm|kubernetes|all)

Commands:
deploy Deploy a new stack or update an existing stack
ls List stacks
ps List the tasks in the stack
rm Remove one or more stacks
services List the services in the stack

docker service

commands :
create Create a new service
inspect Display detailed information on one or more services
logs Fetch the logs of a service or task
ls List services
ps List the tasks of one or more services
rm Remove one or more services
rollback Revert changes to a service’s configuration
scale Scale one or multiple replicated services
update Update a service

Run docker ccontainers

Run a command in a new container

Options:
–add-host list Add a custom host-to-IP mapping (host:ip)
-a, –attach list Attach to STDIN, STDOUT or STDERR
–blkio-weight uint16 Block IO (relative weight), between 10 and 1000, or 0 to disable (default 0)
–blkio-weight-device list Block IO weight (relative device weight) (default [])
–cap-add list Add Linux capabilities
–cap-drop list Drop Linux capabilities
–cgroup-parent string Optional parent cgroup for the container
–cidfile string Write the container ID to the file
–cpu-period int Limit CPU CFS (Completely Fair Scheduler) period
–cpu-quota int Limit CPU CFS (Completely Fair Scheduler) quota
–cpu-rt-period int Limit CPU real-time period in microseconds
–cpu-rt-runtime int Limit CPU real-time runtime in microseconds
-c, –cpu-shares int CPU shares (relative weight)
–cpus decimal Number of CPUs
–cpuset-cpus string CPUs in which to allow execution (0-3, 0,1)
–cpuset-mems string MEMs in which to allow execution (0-3, 0,1)
-d, –detach Run container in background and print container ID
–detach-keys string Override the key sequence for detaching a container
–device list Add a host device to the container
–device-cgroup-rule list Add a rule to the cgroup allowed devices list
–device-read-bps list Limit read rate (bytes per second) from a device (default [])
–device-read-iops list Limit read rate (IO per second) from a device (default [])
–device-write-bps list Limit write rate (bytes per second) to a device (default [])
–device-write-iops list Limit write rate (IO per second) to a device (default [])
–disable-content-trust Skip image verification (default true)
–dns list Set custom DNS servers
–dns-option list Set DNS options
–dns-search list Set custom DNS search domains
–entrypoint string Overwrite the default ENTRYPOINT of the image
-e, –env list Set environment variables
–env-file list Read in a file of environment variables
–expose list Expose a port or a range of ports
–group-add list Add additional groups to join
–health-cmd string Command to run to check health
–health-interval duration Time between running the check (ms|s|m|h) (default 0s)
–health-retries int Consecutive failures needed to report unhealthy
–health-start-period duration Start period for the container to initialize before starting health-retries countdown (ms|s|m|h) (default 0s)
–health-timeout duration Maximum time to allow one check to run (ms|s|m|h) (default 0s)
–help Print usage
-h, –hostname string Container host name
–init Run an init inside the container that forwards signals and reaps processes
-i, –interactive Keep STDIN open even if not attached
–ip string IPv4 address (e.g., 172.30.100.104)
–ip6 string IPv6 address (e.g., 2001:db8::33)
–ipc string IPC mode to use
–isolation string Container isolation technology
–kernel-memory bytes Kernel memory limit
-l, –label list Set meta data on a container
–label-file list Read in a line delimited file of labels
–link list Add link to another container
–link-local-ip list Container IPv4/IPv6 link-local addresses
–log-driver string Logging driver for the container
–log-opt list Log driver options
–mac-address string Container MAC address (e.g., 92:d0:c6:0a:29:33)
-m, –memory bytes Memory limit
–memory-reservation bytes Memory soft limit
–memory-swap bytes Swap limit equal to memory plus swap: ‘-1’ to enable unlimited swap
–memory-swappiness int Tune container memory swappiness (0 to 100) (default -1)
–mount mount Attach a filesystem mount to the container
–name string Assign a name to the container
–network string Connect a container to a network (default “default”)
–network-alias list Add network-scoped alias for the container
–no-healthcheck Disable any container-specified HEALTHCHECK
–oom-kill-disable Disable OOM Killer
–oom-score-adj int Tune host’s OOM preferences (-1000 to 1000)
–pid string PID namespace to use
–pids-limit int Tune container pids limit (set -1 for unlimited)
–privileged Give extended privileges to this container
-p, –publish list Publish a container’s port(s) to the host
-P, –publish-all Publish all exposed ports to random ports
–read-only Mount the container’s root filesystem as read only
–restart string Restart policy to apply when a container exits (default “no”)
–rm Automatically remove the container when it exits
–runtime string Runtime to use for this container
–security-opt list Security Options
–shm-size bytes Size of /dev/shm
–sig-proxy Proxy received signals to the process (default true)
–stop-signal string Signal to stop a container (default “SIGTERM”)
–stop-timeout int Timeout (in seconds) to stop a container
–storage-opt list Storage driver options for the container
–sysctl map Sysctl options (default map[])
–tmpfs list Mount a tmpfs directory
-t, –tty Allocate a pseudo-TTY
–ulimit ulimit Ulimit options (default [])
-u, –user string Username or UID (format: [:])
–userns string User namespace to use
–uts string UTS namespace to use
-v, –volume list Bind mount a volume
–volume-driver string Optional volume driver for the container
–volumes-from list Mount volumes from the specified container(s)
-w, –workdir string Working directory inside the container

sample run command

docker run -it -d --name opensips -e ENV=dev imagename:2.2

-it flags attaches to an interactive tty in the container.
-e gives envrionment variables
-d runs it in background and prints container id

remove docker entities

To remove all stopped containers, all dangling images, and all unused networks:

docker system prune -a

To remove all unused volumes

docker system prune --volumes

To remove all stopped containers

docker container prune

sometimes docker images keep piling with stopped congainer such as 

REPOSITORY                                                             TAG                 IMAGE ID            CREATED             SIZE

                                                                               d1dcfe2438ae        15 minutes ago      753MB

                                                                               2d353828889b        16 hours ago        910MB

                                                                               fb16e1be51f3        16 hours ago        910MB

                                                                               3dc9b3fbe2fb        17 hours ago        910MB

                                                                               7d1e4f183d93        18 hours ago        910MB

                                                                               70fe962b9971        18 hours ago        910MB

                                                                               c349859656b5        18 hours ago        910MB

                                                                               5d4cbd1f4cbe        18 hours ago        910MB

                                                                               aef6e40820f2        18 hours ago        910MB

                                                                               4a4d3897f40e        18 hours ago        910MB

                                                                               46bca8b4b1c3        20 hours ago        910MB

                                                                               c172e5f24798        20 hours ago        910MB

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                        PORTS               NAMES

0dd6698a7517        2d353828889b        "/entrypoint.sh"         13 minutes ago      Exited (137) 13 minutes ago                       hardcore_wozniak

047a42f7a6cd        d1dcfe2438ae        "/bin/sh -c 'aws s3 …"   18 minutes ago      Exited (1) 18 minutes ago                         ecstatic_heisenberg

65b2305520e9        2d353828889b        "/entrypoint.sh"         27 minutes ago      Exited (137) 26 minutes ago                       mystifying_robinson

56841a6c8da4        2d353828889b        "/entrypoint.sh"         17 hours ago        Exited (137) 26 minutes ago                       compassionate_keldysh

c23f9399c53d        zt-voipmonitor      "/entrypoint.sh"         17 hours ago        Exited (7) 17 hours ago                           angry_zhukovsky

5a0f99b7485a        3dc9b3fbe2fb        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         elegant_haslett

f49a4305928a        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         boring_bose

53afb5633a60        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         suspicious_varahamihira

662f6a76ecb3        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         wizardly_booth

c5dd4e8e8a12        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         gracious_kapitsa

0d17dd07af57        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         upbeat_elbakyan

60b419a51099        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         dreamy_ptolemy

6f3a7ca0a2d4        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         stupefied_gauss

0acab30d0c33        7d1e4f183d93        "/entrypoint.sh"         17 hours ago        Exited (137) 17 hours ago                         reverent_varahamihira

b3414b91d718        7d1e4f183d93        "/entrypoint.sh"         18 hours ago        Exited (137) 17 hours ago                         blissful_goodall

to remove such images and their conainer , first stop and remove confainers

docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)

then remove all dangling images

docker rmi  $(docker images -aq --filter dangling=true)

Infrastructure management using terraform

building, changing, and versioning infrastructure
Infra as Code – can run single application to datacentres via configuration files which create execution plan
can manage low-level components such as compute instances, storage, and networking, as well as high-level components such as DNS entries, SaaS features, etc.
Resource Graph – builds a graph of all your resources

tfenv can be used to manage terraform versions

brew unlink terraform
tfenv install 0.11.14
tfenv list 

Terraform configuration language

used for decalring resoirces and descriptions of infrastructure
.tf or .tf.json file extension
group of resources can be gathered into a module
Terraform configuration consists of a root module, where evaluation begins, along with a tree of child modules created when one module calls another.

Exmaple : launch a single AWS EC2 instance , fle server1.tf

provider "aws" {
  profile    = "default"
  region     = "us-east-1"
}

resource "aws_instance" "server1" {
  ami           = "ami-2757f631"
  instance_type = "t2.micro"
}

note : AMI IDs are region specific.
profile attribute here refers to the AWS Config File in ~/.aws/credentials

Terraform command line interface (CLI)

engine for evaluating and applying Terraform configurations.
uses plugins called providers that each define and manage a set of resource types

Command Usage: terraform [-version] [-help] [args]

Common commands:
apply Builds or changes infrastructure
console Interactive console for Terraform interpolations
destroy Destroy Terraform-managed infrastructure
env Workspace management
fmt Rewrites config files to canonical format
get Download and install modules for the configuration
graph Create a visual graph of Terraform resources
import Import existing infrastructure into Terraform
init Initialize a Terraform working directory
output Read an output from a state file
plan Generate and show an execution plan
providers Prints a tree of the providers used in the configuration
refresh Update local state file against real resources
show Inspect Terraform state or plan
taint Manually mark a resource for recreation
untaint Manually unmark a resource as tainted
validate Validates the Terraform files
version Prints the Terraform version
workspace Workspace management

All other commands:
0.12upgrade Rewrites pre-0.12 module source code for v0.12
debug Debug output management (experimental)
force-unlock Manually unlock the terraform state
push Obsolete command for Terraform Enterprise legacy (v1)
state Advanced state management

terraform init
initialize a working directory containing Terraform configuration files.

terraform validate
checks that verify whether a configuration is internally-consistent, regardless of any provided variables or existing state.

Kubernetes

container orchestration platform , automating deployment, scaling, and management of containerized applications.
can deploy to cluster of computers, automating the distribution and scheduling as well

Service discovery and load balancing – gives Pods their own IP addresses and a single DNS name for a set of Pods, and can load-balance across them.
Automatic bin packing – Automatically places containers based on their resource requirements and other constraints, while not sacrificing availability. Mix critical and best-effort workloads in order to drive up utilization and save even more resources.
Storage orchestration
Automatically mount the storage system of your choice, whether from local storage, a public cloud provider such as GCP or AWS, or a network storage system such as NFS, iSCSI, Gluster, Ceph, Cinder, or Flocker.
Self-healing – Restarts containers that fail, replaces and reschedules containers when nodes die, kills containers that don’t respond to your user-defined health check, and doesn’t advertise them to clients until they are ready to serve.
Automated rollouts and rollbacks – progressively rolls out changes to your application or its configuration, while monitoring application health to ensure it doesn’t kill all your instances at the same time.
Secret and configuration management – Deploy and update secrets and application configuration without rebuilding your image and without exposing secrets in your stack configuration.
Batch execution- manage batch and CI workloads, replacing containers that fail, if desired.
Horizontal scaling – Scale application up and down with a simple command, with a UI, or automatically based on CPU usage.

DevOps monitoring tools nagios

Manage Docker configs

Commands:
create Create a config from a file or STDIN
inspect Display detailed information on one or more configs
ls List configs
rm Remove one or more configs

Manage containers

Commands:
attach Attach local standard input, output, and error streams to a running container
commit Create a new image from a container’s changes
cp Copy files/folders between a container and the local filesystem
create Create a new container
diff Inspect changes to files or directories on a container’s filesystem
exec Run a command in a running container
export Export a container’s filesystem as a tar archive
inspect Display detailed information on one or more containers
kill Kill one or more running containers
logs Fetch the logs of a container
ls List containers
pause Pause all processes within one or more containers
port List port mappings or a specific mapping for the container
prune Remove all stopped containers
rename Rename a container
restart Restart one or more containers
rm Remove one or more containers
run Run a command in a new container
start Start one or more stopped containers
stats Display a live stream of container(s) resource usage statistics
stop Stop one or more running containers
top Display the running processes of a container
unpause Unpause all processes within one or more containers
update Update configuration of one or more containers
wait Block until one or more containers stop, then print their exit codes

Alternatives, Senu multi-cloud monitoring or Raygun

Ref :

Terraform : https://www.terraform.io
Kubernetes : https://kubernetes.io/
Sensu : https://sensu.io/

Jenkisn – https://raygun.com/blog/best-devops-tools/

Ramudroid is an ingeniously build robot to clean outdoors and alleys inspired by Bharat Swachhata Abhiyaan . Read more

Prototype in Development

Frame and wheel

Algorithm Enhancements

Obstruction Detection

Stop Operation on Tray Weight reaching threshold

Pause operation and take Shelter in Rain

Equipment Cost

Power And Charge Devices

1. Solar Panel MicroSun MS 12v 60 WP – 2500 INR
2. Solar charger Controller – 600 INR
3. Battery 11.1 V 2200 mAh – 500 INR

Frame and Motion Assembly

1. Wheels 10 cm diameter – 50 INR x 4 ie 200 INR
2. Tray – 400 INR
3. Frame Assembly – 1000 INR
4. Arduino to control Motors Drivers – 500 INR
5. Motor Driver – 300 INR
6. LCD display – 200 INR

Electronics , Communicating modules and Sensors

1. Raspberry Pi Moddel B+/ 4 -2700 INR
2. GPS module – 700 INR
3. GSM module – 1400 INR
4. Camera 5 MP Board Module – 450 INR

Total Cost to Develop – 12000 INR

Working Principle

The robot is divided into 2 parts – Cleaning Unit and driving unit

Driving Unit

consists of 4 wheel to drive the setup . Wheels must be tightly fixed inot position to prevent them from tilting, spreading outwards and imbalancing the load. 2 rear controller by 12 V 1 amp DC motors with 300 RPM and 2 front free wheels. Motors are conneted to Arduino for receving command for start , stop , left or right navigation.

There are three input pins for each motor, including Input1 (IN1), Input2 (IN2), and Enable1 (EN1) for Motor1 and Input3, Input4, and Enable2 for Motor2.
IN1 IN2 MOTOR
0 0 BRAKE
1 0 FORWARD
0 1 BACKWARD
1 1 BRAKE

Cleaning Unit

Uses 3 tough bristled brushes controlled by 3 5V DC gear motors with 60 RPM. The arrangement of the brushes is such that the bottom 2 brushes use clockwise and anticlockwise motion outwards to pull in the litter and push up with the flow of the air and bristles of the brush. The third brush combs the collected into the collector tray. The tray is attached to weight control system to stop operations when critical weight is reached to prevent overloading the robot

Solar specification

Maximum Power (Pmax) – 60 Wp
Voltage at Maximum Power (Vmpp) – 18.1 V
Current at Maximum Power (Impp) – 3.32 A
Open Circuit Voltage (Voc) – 22.32 V
Short Circuit Current (Isc) – 3.63 A
Standard Test Conditions (STC): air mass AM 1.5, irradiance 1000W/m2, cell temperature 25°C
Maximum System Voltage 1000 V

Electrical Data at NOCT
Temperature – 47±2 °C
Nominal Operating Cell Temperature (NOCT): 800W/m2, AM 1.5, windspeed 1m/s,ambient temperature 20°C

Thermal Ratings
Operating Temperature Range -20~90 °C
Temperature Coefficient of Pmax -0.43 %/°C
Temperature Coefficient of Voc -0.36 %/°C
Temperature Coefficient of Isc 0.66 %/°C

Material Data
Panel Dimension (H/W/D) 705x655x35 mm
Weight 6 kg
Cell Type Polycrystalline
Cell Size 156×156 mm
Cell Number 36
Encapsulant Type – EVA ( Ethylene vinyl acetate)
Frame Type Anodized Aluminium Alloy

Physical
Dimentions – 70mm x 655mm x 35mm
cells per module – 36
cell type – poly crystalline sIlicon
fuel cell dimention – 156mm x 156mm
Encapsulation – EVA
back cover – PV sheet

Ref : https://www.enfsolar.com/pv/panel-datasheet/crystalline/20863

Load

Solar panel weight – 5kg with annodixed alumium frame , 3 kg without the frame with just the toughened texture glass on panel
Frame and wheels – 2kg
Accessories – 1 kg
garbage holding capacity – 2 kg
Total Weight of the Robot : maximum upto 10Kg

Scenarios

Good Sunlight scenario : This 12 Volt solar panel provide about 2.5 Amps of current on average during daytime. In such a situtaion it is directly used to drive the machine’s motors for wheels and brushes and electrical components such as PI and arduino. In no motion of rest conditions the genrated power is used to charge the attached backup battery.

Shady / evening / morning scenario : When the panel is not receiving direct or strong sunlight, the power generated is less hence not sufficient to take the load of driving the wheels for movement. Hence is the power falls below a certain prespecified threhold, the current is drawn from battery backup.

Night / No sunlight Scenario : battery is used to power the setup. panel can be dismounted to lower the load.

Contributing to Ramudroid Project or Reuse

It is deigned and developed as an MIT licensed Opensourced product by a bunch of developers and engineers in Bangalore for greater good.

Combination of opensips working scenarios scripts with code is at https://github.com/altanai/opensipsexamples.

Dispatcher Module

This modules implements a dispatcher for destination addresses. It computes hashes over parts of the request and selects an address from a destination set. The selected address is used then as outbound proxy.
The module can be used as a stateless load balancer, having no guarantee of fair distribution.

Exported Parameters

list_file (string) – Path to the file with destination sets. Default value is “/etc/opensips/dispatcher.list” or “/usr/local/etc/opensips/dispatcher.list”.

modparam("dispatcher", "list_file", "/var/run/opensips/dispatcher.list")

db_url (string) – load the sets of gateways from the database you must set this parameter. Default value is “NULL” (disable DB support).

modparam("dispatcher", "db_url", "mysql://user:passwb@localhost/database")

table_name (string) – load the sets of gateways from the database you must set this parameter as the database name.
Default value is “dispatcher”.

modparam("dispatcher", "table_name", "my_dispatcher")

setid_col (string) – storing the gateway’s group id. Default value is “setid”.

modparam("dispatcher", "setid_col", "groupid")

destination_col (string) – destination’s sip uri.

modparam("dispatcher", "destination_col", "uri")

flags_col (string) – The column’s name in the database storing the flags for destination uri.

modparam("dispatcher", "flags_col", "dstflags")

force_dst (int) – If set to 1, force overwriting of destination address when that is already set. Default value is “0”.

modparam("dispatcher", "force_dst", 1)

flags (int) – affect dispatcher’s behaviour, defined as a bitmask on an integer value. If flag 1 is set only the username part of the uri will be used when computing an uri based hash. If no flags are set the username, hostname and port will be used The port is used only if different from 5060 (normal sip uri) or 5061 (in the sips case). If flag 2 is set, then the failover support is enabled. The functions exported by the module will store the rest of addresses from the destination set in AVP, and use these AVPs to contact next address when the current-tried fails. Default value is “0”.

modparam("dispatcher", "flags", 3)

use_default (int) – If the parameter is set to 1, the last address in destination set is used as last option to send the message. For example, it is good when wanting to send the call to an anouncement server saying: “the gateways are full, try later”. Default value is “0”.

modparam("dispatcher", "use_default", 1)

dst_avp (str) – The name of the avp which will hold the list with addresses, in the order they have been selected by the chosen algorithm. If use_default is 1, the value of last dst_avp_id is the last address in destination set. The first dst_avp_id is the selected destinations. All the other addresses from the destination set will be added in the avp list to be able to implement serial forking.

modparam("dispatcher", "dst_avp", "$avp(i:271)")

grp_avp (str) – The name of the avp storing the group id of the destination set. Good to have it for later usage or checks. Default is null.

modparam("dispatcher", "grp_avp", "$avp(i:272)")

cnt_avp (str) – The name of the avp storing the number of destination addresses kept in dst_avp avps.

modparam("dispatcher", "cnt_avp", "$avp(i:273)")

hash_pvar (str) – String with PVs used for the hashing algorithm like to do hashing over custom message parts.Default value is “null” – disabled.

modparam("dispatcher", "hash_pvar", "$avp(i:273)")

setid_pvar (str) – name of the PV where to store the set ID (group ID) when calling ds_is_from_list() with no parameter.

modparam("dispatcher", "setid_pvar", "$var(setid)")

ds_ping_method (string) – With this Method you can define, with which method you want to probe the failed gateways. This method is only available, if compiled with the probing of failed gateways enabled. Default value is “OPTIONS”.

modparam("dispatcher", "ds_ping_method", "INFO")

ds_ping_from (string) – With this Method you can define the “From:”-Line for the request, sent to the failed gateways. This method is only available, if compiled with the probing of failed gateways enabled. Default value is “sip:dispatcher@localhost”.

modparam("dispatcher", "ds_ping_from", "sip:proxy@sip.somehost.com")

ds_ping_interval (int – With this Method you can define the interval for sending a request to a failed gateway. This parameter is only used, when the TM-Module is loaded. If set to “0”, the pinging of failed requests is disabled.Default value is “10”.

modparam("dispatcher", "ds_ping_interval", 30)

ds_probing_threshhold (int) – If you want to set a gateway into probing mode, you will need a specific number of requests until it will change from “active” to probing. The number of attempts can be set with this parameter. Default value is “3”.

modparam("dispatcher", "ds_probing_threshhold", 10)

ds_probing_mode (int) – Controls what gateways are tested to see if they are reachable. If set to 0, only the gateways with state PROBING are tested, if set to 1, all gateways are tested. If set to 1 and the response is 407 (timeout), an active gateway is set to PROBING state. Default value is “0”.

modparam("dispatcher", "ds_probing_mode", 1)

options_reply_codes (str) – This parameter must contain a list of SIP reply codes separated by comma. The codes defined here will be considered as valid reply codes for OPTIONS messages used for pinging, apart for 200. Default value is “NULL”.

modparam("dispatcher", "options_reply_codes", "501, 403")

Exported Functions

ds_select_dst(set, alg) – The method selects a destination from addresses set.Meaning of the parameters is as follows:
set – the id of the set from where to pick up destination address. It is the first column in destination list file.
alg – the algorithm used to select the destination address.
“0” – hash over callid
“1” – hash over from uri.
“2” – hash over to uri.
“3” – hash over request-uri.
“4” – round-robin (next destination).
“5” – hash over authorization-username (Proxy-Authorization or “normal” authorization). If no username is found, round robin is used.
“6” – random (using rand()).
“7” – hash over the content of PVs string. Note: This works only when the parameter hash_pvar is set.
“X” – if the algorithm is not implemented, the first entry in set is chosen.

If the bit 2 in ‘flags’ is set, the rest of the addresses from the destination set is stored in AVP list. You can use ‘ds_next_dst()’ to use next address to achieve serial forking to all possible destinations. This function can be used from REQUEST_ROUTE.

ds_select_dst("1", "0");

ds_select_domain(set, alg)
The method selects a destination from addresses set and rewrites the host and port from R-URI. This function can be used from REQUEST_ROUTE.

ds_next_dst() – Takes the next destination address from the AVPs with id ‘dst_avp_id’ and sets the dst_uri (outbound proxy address). This function can be used from FAILURE_ROUTE.

ds_next_domain() – Takes the next destination address from the AVPs with id ‘dst_avp_id’ and sets the domain part of the request uri. This function can be used from FAILURE_ROUTE.

ds_mark_dst() – Mark the last used address from destination set as inactive, in order to be ingnored in the future. In this way it can be implemented an automatic detection of failed gateways. When an address is marked as inactive, it will be ignored by ‘ds_select_dst’ and ‘ds_select_domain’. This function can be used from FAILURE_ROUTE.

ds_mark_dst(“s”) – Mark the last used address from destination set as inactive (“i”/”I”/”0”), active (“a”/”A”/”1”) or probing (“p”/”P”/”2”). With this function, an automatic detection of failed gateways can be implemented. When an address is marked as inactive or probing, it will be ignored by ‘ds_select_dst’ and ‘ds_select_domain’. possible parameters:
“i”, “I” or “0” – the last destination should be set to inactive and will be ignored in future requests.
“a”, “A” or “1” – the last destination should be set to active.
“p”, “P” or “2” – the last destination will be set to probing. Note: You will need to call this function “threshhold”-times, before it will be actually set to probing.This function can be used from FAILURE_ROUTE.

ds_is_from_list() – This function returns true, if the current request comes from a host from the dispatcher-list; otherwise false. This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and ONREPLY_ROUTE.

ds_is_from_list(“group”) – This function returns true, if the current request comes from a host in the given group of the dispatcher-list; otherwise false.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE and ONREPLY_ROUTE.

Exported MI Functions

ds_set_state – Sets the status for a destination address (can be use to mark the destination as active or inactive).
Parameters:
state : state of the destination address
“a”: active
“i”: inactive
“p”: probing
group: destination group id
address: address of the destination in the group

MI FIFO Command Format:
:ds_set_state:reply_fifo_file
state
group
address
empty_line

ds_list – It lists the groups and included destinations.

MI FIFO Command Format:
:ds_list:reply_fifo_file
empty_line

ds_reload – reloads the groups and included destinations.

MI DATAGRAM Command Format:

    ":ds_reload:\n."

Installation and Running

Destination List File – Each destination point must be on one line. First token is the set id, followed by destination address. Optionally, the third field can be flags value (1 – destination inactive, 2 – destination in probing mod — you can do bitwise OR to set both flags). The set id must be an integer value. Destination address must be a valid SIP URI. Empty lines or lines starting with “#” are ignored.

Exmaple of a dispatcher list file
line format
setit(integer) destination(sip uri) flags (integer, optional)

proxies
2 sip:127.0.0.1:5080
2 sip:127.0.0.1:5082

gateways
1 sip:127.0.0.1:7070
1 sip:127.0.0.1:7072
1 sip:127.0.0.1:7074

OpenSIPS config file

sample config file for dispatcher module

debug=9            debug level (cmd line: -dddddddddd)
fork=no
log_stderror=yes  (cmd line: -E)

children=2
check_via=no      (cmd. line: -v)
dns=off           (cmd. line: -r)
rev_dns=off       (cmd. line: -R)
port=5060

module loading

mpath="/usr/local/lib/opensips/modules/"
loadmodule "maxfwd.so"
loadmodule "sl.so"
loadmodule "dispatcher.so"

setting module-specific parameters

dispatcher params

modparam("dispatcher", "list_file", "../etc/dispatcher.list")
// modparam("dispatcher", "force_dst", 1)

route{
if ( !mf_process_maxfwd_header("10") )
{
sl_send_reply("483","To Many Hops");
drop();
};
ds_select_dst("2", "0");
forward();
// t_relay();
}

db_text Module

Implementation for a simplified database engine based on text files. It can be used by OpenSIPS DB interface instead of other database module (like MySQL). It keeps everything in memory.

The db_text database system architecture contains

• a database is represented by a directory in the local file system. NOTE: when you use db_text in OpenSIPS, the database URL for modules must be the path to the directory where the table-files are located, prefixed by “text://”,
  e.g., “text:///var/dbtext/opensips”.
• a table is represented by a text file inside database directory.

Internal format of a db_text table

column definition name(type,attr) where types can be int , double , str and attributes be auto , null ,
* each other line is a row with data. The line ends with “\n”.
* the fields are separated by “:”.
* no value between two ‘:’ (or between ‘:’ and start/end of a row) means “null” value.
* next characters must be escaped in strings: “\n”, “\r”, “\t”, “:”.
* 0 — the zero value must be escaped too.

Sample of a db_text table ,

id(int,auto) name(str) flag(double) desc(str,null)
1:nick:0.34:a\tgood\: friend
2:cole:-3.75:colleague
3:bob:2.50:

Minimal OpenSIPS location db_text table definition

username(str) contact(str) expires(int) q(double) callid(str) cseq(int)

Minimal OpenSIPS subscriber db_text table example

username(str) password(str) ha1(str) domain(str) ha1b(str)
suser:supasswd:xxx:alpha.org:xxx

This database interface don’t support the data insertion with default values. All such values specified in the database
template are ignored.

db_mode (integer) – Set caching mode (0 – default) or non-caching mode (1). In caching mode, data is loaded at startup. In non-caching mode, the module check every time a table is requested whether the correspondingfile on disk has changed, and if yes, will re-load table from file.

modparam("db_text", "db_mode", 1)

Exported MI Functions

dbt_dump – Write back to hard drive modified tables.

opensipsctl fifo dbt_dump

dbt_reload – Causes db_text module to reload cached tables from disk. Parameters:
1 db_name (optional) – database name to reload.
2 table_name (optional, but cannot be present without the
db_name parameter) – specific table to reload.

MI FIFO Command Format:
opensipsctl fifo dbt_reload
opensipsctl fifo dbt_reload /path/to/dbtext/database
opensipsctl fifo dbt_reload /path/to/dbtext/database table_name

Installation and Running

Compile the module and load it instead of mysql or other DB modules.

Load the db_text module

loadmodule "/path/to/opensips/modules/db_text.so"
modparam("module_name", "database_URL", "text:///path/to/dbtext/database
")

Using db_text with basic OpenSIPS configuration

Definition of ‘subscriber’ table (one line)

username(str) domain(str) password(str) first_name(str) last_name(str) phone(str) email_address(str) datetime_created(int) datetime_modified(int) confirmation(str) flag(str) sendnotification(str) greeting(str) ha1(str) ha1b(str) perms(str) allow_find(str) timezone(str,null) rpid(str,null)

Definition of ‘location’ and ‘aliases’ tables (one line)

username(str) domain(str,null) contact(str,null) received(str) expires(i
nt,null) q(double,null) callid(str,null) cseq(int,null) last_modified(st
r) flags(int) user_agent(str) socket(str)

Definition of ‘version’ table and sample records

table_name(str) table_version(int)
subscriber:3
location:6
aliases:6

Configuration file using dbtext databse for oersistant storage . Also using auth

<h1>debug_mode=yes</h1>
children=4

check_via=no    # (cmd. line: -v)
dns=no          # (cmd. line: -r)
rev_dns=no      # (cmd. line: -R)
listen=udp:10.100.100.1:5060

loadmodule "modules/dbtext/dbtext.so"
loadmodule "modules/sl/sl.so"
loadmodule "modules/tm/tm.so"
loadmodule "modules/rr/rr.so"
loadmodule "modules/maxfwd/maxfwd.so"
loadmodule "modules/usrloc/usrloc.so"
loadmodule "modules/registrar/registrar.so"
loadmodule "modules/textops/textops.so"
loadmodule "modules/textops/mi_fifo.so"
loadmodule "modules/auth/auth.so"
loadmodule "modules/auth_db/auth_db.so"

setting module-specific parameters

-- mi_fifo params --

modparam("mi_fifo", "fifo_name", "/tmp/opensips_fifo")

-- usrloc params --

modparam("usrloc", "db_mode", 2)
modparam("usrloc|auth_db", "db_url", "text:///tmp/opensipsdb")

modparam("auth_db", "calculate_ha1", 1)
modparam("auth_db", "password_column", "password")
modparam("auth_db", "user_column", "username")
modparam("auth_db", "domain_column", "domain")

route{
// initial sanity checks -- messages with max_forwards==0, or excessively long requests
if (!mf_process_maxfwd_header("10")) {
sl_send_reply("483","Too Many Hops");
exit;
};
if ($ml >=  65535 ) {
sl_send_reply("513", "Message too big");
exit;
};

// we record-route all messages -- to make sure that subsequent messages will go through this proxy;
if (!$rm=="REGISTER") record_route();
<pre><code>// subsequent messages withing a dialog should take the path determined by record-routing
if (loose_route()) {
    // mark routing logic in request
    append_hf("P-hint: rr-enforced\r\n");
    route(1);
    exit;
};

if (!is_myself("$rd")) {
    // mark routing logic in request
    append_hf("P-hint: outbound\r\n");
    route(1);
    exit;
};

//if the request is for other domain use UsrLoc 
if (is_myself("$rd")) {
    if ($rm=="REGISTER") {
        # digest authentication
        if (!www_authorize("", "subscriber")) {
            www_challenge("", "0");
            exit;
        };

        save("location");
        exit;
    };

    lookup("aliases");
    if (!is_myself("$rd")) {
        append_hf("P-hint: outbound alias\r\n");
        route(1);
        exit;
    };

    # native SIP destinations are handled using our USRLOC DB
    if (!lookup("location")) {
        sl_send_reply("404", "Not Found");
        exit;
    };
};
append_hf("P-hint: usrloc applied\r\n");
route(1);</code></pre>
}

route[1]
{
if (!t_relay()) {
sl_reply_error();
};
}

This article focuses on setting up sipwise rtpegine to proxy rtp traffic from kamailio app server. This is an updated version of the the old article .

RTPengine is a proxy for RTP traffic and other UDP based media traffic over either IPv4 or IPv6. It can even bridge between diff IP networks and interfaces . It can do TOS/QoS field setting. It is Multi-threaded , can advertise different addresses for operation behind NAT.

It bears in-kernel packet forwarding for low-latency and low-CPU performance .

When used with kamailio RTP engine module it adds more features . I wrote an article covering all relevant and important kamailio modules earlier including RTPProxy and RTP engine ;https://telecom.altanai.com/2014/11/18/kamailio-modules/.

• Full SDP parsing and rewriting
• Supports non-standard RTCP ports (RFC 3605)
• ICE (RFC 5245):
  • Bridging between ICE-enabled and ICE-unaware user agents
  • Optionally acting only as additional ICE relay/candidate
  • Optionally forcing relay of media streams by removing other ICE candidates
• SRTP (RFC 3711):
  • Support for SDES (RFC 4568) and DTLS-SRTP (RFC 5764)
  • AES-CM and AES-F8 ciphers, both in userspace and in kernel
  • HMAC-SHA1 packet authentication
  • Bridging between RTP and SRTP user agents
• RTCP profile with feedback extensions (RTP/AVPF, RFC 4585 and 5124)
• Arbitrary bridging between any of the supported RTP profiles (RTP/AVP, RTP/AVPF, RTP/SAVP, RTP/SAVPF)
• RTP/RTCP multiplexing (RFC 5761) and demultiplexing
• Breaking of BUNDLE’d media streams (draft-ietf-mmusic-sdp-bundle-negotiation)
• Recording of media streams, decrypted if possible
• Transcoding and repacketization
• Playback of pre-recorded streams/announcements

Sipwise NGCP RTP Engine Source Code

There are 3 parts of the source structure in sipwise NGCP ( Next Generation communication Platform) rtpengine :

1.daemon

The userspace daemon and workhorse, minimum requirement for anything to work. Running make will compile the binary, which will be called rtpengine.

Required packages including their development headers are required to compile the daemon:

• pkg-config
• GLib including GThread and GLib-JSON version 2.x
• zlib
• OpenSSL
• PCRE library
• XMLRPC-C version 1.16.08 or higher
• hiredis library
• gperf
• libcurl version 3.x or 4.x
• libevent version 2.x
• libpcap
• libsystemd
• MySQL or MariaDB client library (optional for media playback and call recording daemon)
• libiptc library for iptables management (optional)
• ffmpeg codec libraries for transcoding (optional) such as libavcodec, libavfilter, libswresample
• bcg729 for full G.729 transcoding support (optional)

options for make – with_iptables_option , with_transcoding

 with_transcoding=no make 

2.iptables-extension

Required for in-kernel packet forwarding. With the iptables development headers installed, issuing make will compile the plugin for iptables and ip6tables. The file will be called libxt_RTPENGINE.so and needs to be copied into the xtables module directory. The location of this directory can be determined through pkg-config xtables –variable=xtlibdir on newer systems, and/or is usually either /lib/xtables/ or /usr/lib/x86_64-linux-gnu/xtables/.

3.kernel-module

Required for in-kernel packet forwarding. Compilation of the kernel module requires the kernel development headers to be installed in/lib/modules/$VERSION/build/, where $VERSION is the output of the command uname -r.

Successful compilation of the module will produce the file xt_RTPENGINE.ko. The module can be inserted into the running kernel manually through insmod xt_RTPENGINE.ko

It is recommended to copy the module into /lib/modules/$VERSION/updates/, followed by running depmod -a.

After this, the module can be loaded by issuing modprobe xt_RTPENGINE.

Installation

Follow instructions on https://gist.github.com/altanai/0d8cadbe6876d545fd63d6b3e79dcf73

Requirements

sudo su 
apt-get install debhelper iptables-dev libcurl4-openssl-dev libglib2.0-dev  libjson-glib-dev libxmlrpc-core-c3-dev libhiredis-dev build-essential:native

for pcap

apt install ibpcap-dev

some ffmpeg pakages like

apt install libavcodec-dev libavfilter-dev libavformat-dev libavresample-dev  libavutil-dev

for dpkg

libcrypt-openssl-rsa-perl libdigest-crc-perl libio-multiplex-perl libnet-interface-perl libsystemd-dev markdown

for debhelper>10

vi /etc/apt/sources.list

add line

deb http://archive.ubuntu.com/ubuntu xenial-backports main restricted universe multiverse
sudo apt update

check version

apt-cache policy debhelper dh-autoreconf
  debhelper:
   Installed: 9.20160115ubuntu3
   Candidate: 9.20160115ubuntu3
   Version table:
      10.2.2ubuntu1~ubuntu16.04.1 100
         100 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
         100 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
  *** 9.20160115ubuntu3 500
         500 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
         100 /var/lib/dpkg/status
 dh-autoreconf:
   Installed: (none)
   Candidate: 11
   Version table:
      12~ubuntu16.04.1 100
         100 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
         100 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
      11 500
         500 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

Force installing the version from backports repo as it have low priority.

sudo apt install dh-autoreconf=12~ubuntu16.04.1 debhelper=10.2.2ubuntu1~ubuntu16.04.1

so now new priority will be

debhelper:

  Installed: 10.2.2ubuntu1~ubuntu16.04.1
  Candidate: 10.2.2ubuntu1~ubuntu16.04.1
  Version table:
 *** 10.2.2ubuntu1~ubuntu16.04.1 100
        100 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
        100 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
        100 /var/lib/dpkg/status
     9.20160115ubuntu3 500
        500 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
dh-autoreconf:
  Installed: 12~ubuntu16.04.1
  Candidate: 12~ubuntu16.04.1
  Version table:
 *** 12~ubuntu16.04.1 100
        100 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
        100 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages
        100 /var/lib/dpkg/status
     11 500
        500 http://us-east-1.ec2.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

ref :https://askubuntu.com/questions/863221/need-help-building-debhelper-10-2-2-bpo8-from-source

Get sourcecode

cd /usr/local/src
git clone https://github.com/sipwise/rtpengine.git

cd rtpengine
 ./debian/flavors/no_ngcp

use dpkg-checkbuilddeps to find any missing dependices

For missing dependencies

dpkg-checkbuilddeps: error: Unmet build dependencies: libbcg729-dev
remove the encoder for G.729 which is not supported by ffmoeg by exporting varible

export DEB_BUILD_PROFILES="pkg.ngcp-rtpengine.nobcg729"

Ref :ref : https://github.com/sipwise/rtpengine#g729-support

for defaultlibmysqlclient-dev and libiptc-dev

vi debian/control
change from default-libmysqlclient-dev to libmysqlclient-dev, change from libiptcdata-dev to libiptc-dev and install the alternatives such as

apt install libmysqlclient-dev libiptcdata-dev 

Generated deb files should be outside the rtpegine home folder

cd ..
dpkg -i ngcp-rtpengine-daemon_7.3.0.0+0~mr7.3.0.0_amd64.deb
dpkg -i ngcp-rtpengine-iptables_7.3.0.0+0~mr7.3.0.0_amd64.deb
dpkg -i ngcp-rtpengine-kernel-dkms_7.3.0.0+0~mr7.3.0.0_all.deb
dpkg -i ngcp-rtpengine-kernel-source_7.3.0.0+0~mr7.3.0.0_all.deb
dpkg -i ngcp-rtpengine-recording-daemon_7.3.0.0+0~mr7.3.0.0_amd64.deb
dpkg -i ngcp-rtpengine-utils_7.3.0.0+0~mr7.3.0.0_all.deb
dpkg -i ngcp-rtpengine_7.3.0.0+0~mr7.3.0.0_all.deb

Manual installation and running all test cases

cd rtpengine
make check

If you dont find a package you are looking for , some alternatives are to do apt-cache search like

apt-cache search libavfilter
libavfilter-dev - FFmpeg library containing media filters - development files
libavfilter-ffmpeg5 - FFmpeg library containing media filters - runtime files 

or to search in ubuntu packages web https://packages.ubuntu.com/

Running RTPEngine

rtpegine application options

• -v, –version Print build time and exit
• –config-file=FILE Load config from this file
• –config-section=STRING Config file section to use
• –log-facility=daemon|local0|…|local7 Syslog facility to use for logging
• -L, –log-level=INT Mask log priorities above this level
• -E, –log-stderr Log on stderr instead of syslog
• –no-log-timestamps Drop timestamps from log lines to stderr
• –log-mark-prefix Prefix for sensitive log info
• –log-mark-suffix Suffix for sensitive log info
• -p, –pidfile=FILE Write PID to file
• -f, –foreground Don’t fork to background
• -t, –table=INT Kernel table to use
• -F, –no-fallback Only start when kernel module is available
• -i, –interface=[NAME/]IP[!IP] Local interface for RTP
• -k, –subscribe-keyspace=INT INT … Subscription keyspace list
• -l, –listen-tcp=[IP:]PORT TCP port to listen on
• -u, –listen-udp=[IP46|HOSTNAME:]PORT UDP port to listen on
• -n, –listen-ng=[IP46|HOSTNAME:]PORT UDP port to listen on, NG protocol
• -c, –listen-cli=[IP46|HOSTNAME:]PORT UDP port to listen on, CLI
• -g, –graphite=IP46|HOSTNAME:PORT Address of the graphite server
• -G, –graphite-interval=INT Graphite send interval in seconds
• –graphite-prefix=STRING Prefix for graphite line
• -T, –tos=INT Default TOS value to set on streams
• –control-tos=INT Default TOS value to set on control-ng
• -o, –timeout=SECS RTP timeout
• -s, –silent-timeout=SECS RTP timeout for muted
• -a, –final-timeout=SECS Call timeout
• –offer-timeout=SECS Timeout for incomplete one-sided calls
• -m, –port-min=INT Lowest port to use for RTP
• -M, –port-max=INT Highest port to use for RTP
• -r, –redis=[PW@]IP:PORT/INT Connect to Redis database
• -w, –redis-write=[PW@]IP:PORT/INT Connect to Redis write database
• –redis-num-threads=INT Number of Redis restore threads
• –redis-expires=INT Expire time in seconds for redis keys
• -q, –no-redis-required Start no matter of redis connection state
• –redis-allowed-errors=INT Number of allowed errors before redis is temporarily disabled
• –redis-disable-time=INT Number of seconds redis communication is disabled because of errors
• –redis-cmd-timeout=INT Sets a timeout in milliseconds for redis commands
• –redis-connect-timeout=INT Sets a timeout in milliseconds for redis connections
• -b, –b2b-url=STRING XMLRPC URL of B2B UA
• –log-facility-cdr=daemon|local0|…|local7 Syslog facility to use for logging CDRs
• –log-facility-rtcp=daemon|local0|…|local7 Syslog facility to use for logging RTCP
• –log-facility-dtmf=daemon|local0|…|local7 Syslog facility to use for logging DTMF
• –log-format=default|parsable Log prefix format
• -x, –xmlrpc-format=INT XMLRPC timeout request format to use. 0: SEMS DI, 1: call-id only, 2: Kamailio
• –num-threads=INT Number of worker threads to create
• –media-num-threads=INT Number of worker threads for media playback
• -d, –delete-delay=INT Delay for deleting a session from memory.
• –sip-source Use SIP source address by default
• –dtls-passive Always prefer DTLS passive role
• –max-sessions=INT Limit of maximum number of sessions
• –max-load=FLOAT Reject new sessions if load averages exceeds this value
• –max-cpu=FLOAT Reject new sessions if CPU usage (in percent) exceeds this value
• –max-bandwidth=INT Reject new sessions if bandwidth usage (in bytes per second) exceeds this value
• –homer=IP46|HOSTNAME:PORT Address of Homer server for RTCP stats
• –homer-protocol=udp|tcp Transport protocol for Homer (default udp)
• –homer-id=INT ‘Capture ID’ to use within the HEP protocol
• –recording-dir=FILE Directory for storing pcap and metadata files
• –recording-method=pcap|proc Strategy for call recording
• –recording-format=raw|eth File format for stored pcap files
• –iptables-chain=STRING Add explicit firewall rules to this iptables chain
• –codecs Print a list of supported codecs and exit
• –scheduling=default|none|fifo|rr|other|batch|idle Thread scheduling policy
• –priority=INT Thread scheduling priority
• –idle-scheduling=default|none|fifo|rr|other|batch|idle Idle thread scheduling policy
• –idle-priority=INT Idle thread scheduling priority
• –log-srtp-keys Log SRTP keys to error log
• –mysql-host=HOST|IP MySQL host for stored media files
• –mysql-port=INT MySQL port
• –mysql-user=USERNAME MySQL connection credentials
• –mysql-pass=PASSWORD MySQL connection credentials
• –mysql-query=STRING MySQL select query

rtpengine --interface="10.10.10.10" --listen-ng=25061 --listen-cli=25062 --foreground --log-stderr --listen-udp=25060 --listen-tcp=25060

In-Kernal Packet Forwarding

To avoid the overhead involved in processing each individual RTP packet in userspace-only operation, especially as RTP traffic consists of many small packets at high rates, rtpengine provides a kernel module to offload the bulk of the packet forwarding duties from user space to kernel space. This also results in increasing the number of concurrent calls as CPU usage decreases.In-kernel packet forwarding is implemented as an iptables module (x_tables) and has 2 parts – xt_RTPENGINE and plugin to the iptables and ip6tables command-line utilities

Sequence of events for a newly established media stream is then:

1. Kamailio as SIP proxy controls rtpengine and signals it about a newly established call.
2. Rtpengine daemon allocates local UDP ports and sets up preliminary forward rules based on the info received from the SIP proxy.
3. An RTP packet is received on the local port.
4. It traverses the iptables chains and gets passed to the xt_RTPENGINE module.
5. The module doesn’t recognize it as belonging to an established stream and thus ignores it.
6. The packet continues normal processing and eventually ends up in the daemon’s receive queue.
7. The daemon reads it, processes it and forwards it. It also updates some internal data.
8. This userspace-only processing and forwarding continues for a little while, during which time information about additional streams and/or endpoints may be obtained from the SIP proxy.
9. After a few seconds, when the daemon is satisfied with what it has learned about the media endpoints, it pushes the forwarding rules to the kernel.
10. From this moment on, the kernel module will recognize incoming packets belonging to those streams and will forward them on its own. It will stop those packets from traversing the network stacks any further, so the daemon will not see them any more on its receive queues.
11. In-kernel forwarding is allowed to cease to work at any given time, either accidentally (e.g. by removal of the iptablesrule) or deliberatly (the daemon will do so in case of a re-invite), in which case forwarding falls back to userspace-only operation.

The Kernel Module

The kernel module supports multiple forwarding tables, identified through their ID number , bydefault 0 to 63

Each running instance of the rtpengine daemon controls one such table. To load use

modprobe xt_RTPENGINE and to unload rmmod xt_RTPENGINE,. With the module loaded, a new directory will appear in /proc/, namely /proc/rtpengine/ , containing pseudo-files, control ( to create and delete forwarding tables) and list ( list of currently active forwarding tables)

To manually create a forwarding table with ID 33, the following command can be used:

echo ‘add 43’ > /proc/rtpengine/control

The iptables module

In order for the kernel module to be able to actually forward packets, an iptables rule must be set up to send packets into the module. Each such rule is associated with one forwarding table. In the simplest case, for forwarding table 33, this can be done through:

iptables -I INPUT -p udp -j RTPENGINE –id 33

To restrict the rules to the UDP port range used by rtpengine, e.g. by supplying a parameter like –dport 30000:40000. If the kernel module receives a packet that it doesn’t recognize as belonging to an active media stream, it will simply ignore it and hand it back to the network stack for normal processing.

A typical start-up sequence including in-kernel forwarding might look like this:

modprobe xt_RTPENGINE
iptables -I INPUT -p udp -j RTPENGINE --id 0
ip6tables -I INPUT -p udp -j RTPENGINE --id 0

ensure that the table we want to use doesn’t exist – usually needed after a daemon restart, otherwise will error

echo 'del 0' > /proc/rtpengine/control

start daemon

/usr/sbin/rtpengine --table=0 --interface=10.64.73.31 --interface=2001:db8::4f3:3d \
--listen-ng=127.0.0.1:2223 --tos=184 --pidfile=/run/rtpengine.pid --no-fallback

Running Multiple Instances

To run multiple instances of rtpengine on the same machine run multiple instances of the daemon using different command-line options ( local addresses and listening ports), together with multiple different kernel forwarding tables.

For example, if one local network interface has address 10.64.73.31 and another has address 192.168.65.73, then the start-up sequence might look like this:

modprobe xt_RTPENGINE
iptables -I INPUT -p udp -d 10.64.73.31 -j RTPENGINE --id 0
iptables -I INPUT -p udp -d 192.168.65.73 -j RTPENGINE --id 1
echo 'del 0' > /proc/rtpengine/control
echo 'del 1' > /proc/rtpengine/control

/usr/sbin/rtpengine --table=0 --interface=<ip> \
--listen-ng=127.0.0.1:2223 --tos=184 --pidfile=/run/rtpengine-10.pid --no-fallback
/usr/sbin/rtpengine --table=1 --interface=<ip_pvy>\
--listen-ng=127.0.0.1:2224 --tos=184 --pidfile=/run/rtpengine-192.pid --no-fallback

With this setup, the SIP proxy can choose which instance of rtpengine to talk to and thus which local interface to use by sending its control messages to either port 2223 or port 2224.

Transcoding

Currently transcoding is supported for audio streams. Can we turned off with with_transcoding=no option in makeFile

Normally rtpengine leaves codec negotiation up to the clients involved in the call and does not interfere. In this case, if the clients fail to agree on a codec, the call will fail.

transcoding options in the ng control protocol,  transcode or ptime . If a codec is requested via the transcode option that was not originally offered, transcoding will be engaged for that call. With transcoding active for a call, all unsupported codecs will be removed from the SDP.

Transcoding happens in userspace only, so in-kernel packet forwarding will not be available for transcoded codecs. Codecs that are supported by both sides will simply be passed through transparently (unless repacketization is active). In-kernel packet forwarding will still be available for these codecs.

codecs supported by rtpengine can be shown with –codecs options

• rtpengine –codecs
• PCMA: fully supported
• PCMU: fully supported
• G723: fully supported
• G722: fully supported
• QCELP: supported for decoding only
• G729: supported for decoding only
• speex: fully supported
• GSM: fully supported
• iLBC: not supported
• opus: fully supported
• vorbis: codec supported but lacks RTP definition
• ac3: codec supported but lacks RTP definition
• eac3: codec supported but lacks RTP definition
• ATRAC3: supported for decoding only
• ATRAC-X: supported for decoding only
• AMR: supported for decoding only
• AMR-WB: supported for decoding only
• PCM-S16LE: codec supported but lacks RTP definition
• PCM-U8: codec supported but lacks RTP definition
• MP3: codec supported but lacks RTP definition

ng Control Protocol

advanced control protocol to pass SDP body from the SIP proxy to the rtpengine daemon, has the body rewritten in the daemon, and then pas back to the SIP proxy to embed into the SIP message. It is  based on the bencode standard and runs over UDP transport.

Each message passed between the SIP proxy and the media proxy contains of two parts: message cookie ( to match requests to responses, and retransmission detection) and bencoded dictionary

The dictionary of each request must contain at least one key called command and corresponding value must be a string and determines the type of message. Currently the following commands are defined:

• ping
• offer
• answer
• delete
• query
• start recording
• stop recording
• block DTMF
• unblock DTMF
• block media
• unblock media
• start forwarding
• stop forwarding
• play media
• stop media

The response dictionary must contain at least one key called result. The value can be either ok (optional key warning) or error( to be accompanied by error-reason ). For the ping command, the additional value pong is allowed.

rtpengine.sample.conf

[rtpengine]

table = 0
no-fallback = false
for userspace forwarding only:
table = -1

// separate multiple interfaces with semicolons:
interface = internal/12.23.34.45;external/23.34.45.54

listen-ng = 127.0.0.1:2223
listen-tcp = 25060
listen-udp = 12222

timeout = 60
silent-timeout = 3600
tos = 184
control-tos = 184
delete-delay = 30
final-timeout = 10800

foreground = false
pidfile = /run/ngcp-rtpengine-daemon.pid
num-threads = 16

port-min = 30000
port-max = 40000
max-sessions = 5000

recording-dir = /var/spool/rtpengine
recording-method = proc
recording-format = raw

redis = 127.0.0.1:6379/5
redis-write = password@x.x.x.x:6379/42
redis-num-threads = 8
no-redis-required = false
redis-expires = 86400
redis-allowed-errors = -1
redis-disable-time = 10
redis-cmd-timeout = 0
redis-connect-timeout = 1000

b2b-url = http://127.0.0.1:8090/
xmlrpc-format = 0

log-level = 6
log-stderr = false
log-facility = daemon
log-facility-cdr = local0
log-facility-rtcp = local1

graphite = 127.0.0.1:9006
graphite-interval = 60
graphite-prefix = foobar.

homer = 123.234.345.456:65432
homer-protocol = udp
homer-id = 2001

sip-source = false
dtls-passive = false

To start the ngcp-rtpengine-daemon service

/etc/init.d/ngcp-rtpengine-daemon start
[ ok ] Starting ngcp-rtpengine-daemon (via systemctl): ngcp-rtpengine-daemon.service.

checking status ngcp-rtpengine-daemonservice

# systemctl status ngcp-rtpengine-daemon.service

● ngcp-rtpengine-daemon.service - NGCP RTP/media Proxy Daemon
   Loaded: loaded (/lib/systemd/system/ngcp-rtpengine-daemon.service; disabled; vendor preset: enabled)
   Active: active (running) since Thu 2019-04-11 10:16:20 UTC; 24s ago
  Process: 13751 ExecStopPost=/usr/sbin/ngcp-rtpengine-iptables-setup stop (code=exited, status=0/SUCCESS)
  Process: 13797 ExecStartPre=/usr/sbin/ngcp-rtpengine-iptables-setup start (code=exited, status=0/SUCCESS)
 Main PID: 13814 (rtpengine)
    Tasks: 19
   Memory: 10.5M
      CPU: 102ms
   CGroup: /system.slice/ngcp-rtpengine-daemon.service
           └─13814 /usr/sbin/rtpengine -f -E --no-log-timestamps --pidfile /run/ngcp-rtpengine-daemon.pid --config-file /etc/rtpengine/rtpengine.conf --table 0

To start recording service

/etc/init.d/ngcp-rtpengine-recording-daemon start

RTP engine receives command offer

Received command 'offer' from :53888
Dump for 'offer' from :53888: {  
    "sdp":"v=0 
 o=- 1554978148897419 1 IN IP4 pvt_ip 
 s=Bria 3 release 3.5.5 stamp 71243 
 c=IN IP4 192.168.1.23 
 t=0 0 
 m=audio 50754 RTP/AVP 0 98 101 
 a=rtpmap:98 ILBC/8000 
 a=rtpmap:101 telephone-event/8000 
 a=fmtp:101 0-15 
 a=sendrecv 
 ",
    "ICE":"remove",
    "record-call":"yes",
    "direction":[  
       "internal",
       "internal"
    ],
    "flags":[  
       "no-rtcp-attribute"
    ],
    "replace":[  
       "origin",
       "session-connection"
    ],
    "transport-protocol":"RTP/AVP",
    "call-id":"732597d6-6d96-485b-b6dc-7d93703c1405",
    "received-from":[  
       "IP4",
       ""
Creating new call
Turning on call recording.
Wrote metadata file to temporary path: /var/spool/rtpengine/tmp/
...

RTP engine receives command delete

Received command 'delete' from :57304
 Dump for 'delete' from :57304: { "call-id": "732597d6-6d96-485b-b6dc-7d93703c1405", "received-from": [ "IP4", "" ], "from-tag": "cb8a1e30", "command": "delete" }
Deleting call branch 'cb8a1e30' (via-branch '')
Call branch 'cb8a1e30' (via-branch '') deleted, no more branches remaining
  Deleting entire call
 INFO: [ID="732597d6-6d96-485b-b6dc-7d93703c1405"]: Final packet stats:
 --- Tag 'cb8a1e30', created 0:05 ago for branch '', in dialogue with ''
 ------ Media #1 (audio over RTP/AVP) using unknown codec
 --------- Port   :10044 <&gt;    :50754, SSRC 0, 0 p, 0 b, 0 e, 5 ts
 freeing send_timer
 --------- Port   :10045 <&gt;    :50755 (RTCP), SSRC 0, 0 p, 0 b, 0 e, 5 ts
 freeing send_timer
 --- Tag '', created 0:05 ago for branch '', in dialogue with 'cb8a1e30'
 ------ Media #1 (audio over RTP/AVP) using unknown codec
--------- Port   :10032 <&gt;          (null):0    , SSRC 0, 0 p, 0 b, 0 e, 5 ts
freeing send_timer
--------- Port   :10033 <&gt;          (null):0     (RTCP), SSRC 0, 0 p, 0 b, 0 e, 5 ts
freeing send_timer
 rtpengine: ci=732597d6-6d96-485b-b6dc-7d93703c1405, created_from=:53888, 
 last_signal=1554978149, 
 tos=0, 
 ml0_start_time=1554978149.645290, 
 ml0_end_time=1554978154.822680, 
 ml0_duration=5.177390, 
 ml0_termination=REGULAR, 
 ml0_local_tag=cb8a1e30, 
 ml0_local_tag_type=FROM_TAG, 
...

SIPp is an opensource (GNU GPL license) performance testing tool for the SIP protocol and is widely used for Quality assurabce of callflows in voip applications for UAC / UASs cenarios. It can emulate functioing of a sip phone such as REGISTER , establishes and releases multiple calls with
the INVITE and BYE methods , send other SIP requests and wait for reponsesbased on dafult of custom xml scenario files .

Plus factor is the dynamic display of statistics about running tests (call rate, round trip delay, and message statistics),
periodic CSV statistics dumps, TCP and UDP over multiple sockets or multiplexed with retransmission management,
regular expressions and variables in scenario files, and dynamically adjustable call rates.

sipp -sn uac -d 10000 -s 9876543210 127.0.0.1:5060  -l 10

It is widley used as aperformnace and load testing tool since it can test SIP equipements like SIP proxies, B2BUAs, SIP media servers, SIP/x gateways, and SIP PBXes and can also emulate thousands of user agents calling your SIP system.

Installation

Pre-requisites to compile SIPp are:
– C++ Compiler
– curses or ncurses library
– For TLS support: OpenSSL >= 0.9.8
– For pcap play support: libpcap and libnet
– For SCTP support: lksctp-tools
– For distributed pauses: Gnu Scientific Libraries

Download , extract and build with options like

tar -xvzf sipp-xxx.tar.gz

cd sipp

./configure --with-sctp --with-pcap --with-openssl

make

Verify installation
Run sipp with embedded server (uas) scenario:

sipp -sn uas

On the same host, run sipp with embedded client (uac) scenario:

sipp -sn uac 127.0.0.1 -trace_msg -trace_err

output for server 

 # sipp -sn uas

------------------------------ Scenario Screen -------- [1-9]: Change Screen --

  Port   Total-time  Total-calls  Transport

  5060      32.95 s           61  UDP

0 new calls during 0.874 s period      1 ms scheduler resolution

  19 calls                               Peak was 41 calls, after 28 s

  0 Running, 63 Paused, 12 Woken up

  0 dead call msg (discarded)          

  3 open sockets                        

                             Messages  Retrans   Timeout   Unexpected-Msg

----------> INVITE             61        0         0         0 
<---------- 180                61        0                               <---------- 200                61        0         0                     ----------> ACK         E-RTD1 61        0         0         0               

----------> BYE                61        0         0         0        
   <---------- 200                61        0                            
   [   4000ms] Pause              61                            0        
 ------------------------------ Test Terminated --------------------------------

----------------------------- Statistics Screen ------- [1-9]: Change Screen --

  Start Time             | 2019-02-04    13:04:32.108663 1549265672.108663         

  Last Reset Time        | 2019-02-04    13:05:04.189720 1549265704.189720         

  Current Time           | 2019-02-04    13:05:05.065119 1549265705.065119         

-------------------------+---------------------------+--------------------------

  Counter Name           | Periodic value            | Cumulative value

-------------------------+---------------------------+--------------------------

  Elapsed Time           | 00:00:00:875000           | 00:00:32:956000          

  Call Rate              |    0.000 cps              |    1.851 cps             

-------------------------+---------------------------+--------------------------

  Incoming call created  |        0                  |       61                 

  OutGoi

traceings

———————————————– 2019-02-04 13:08:13.939148
UDP message sent (530 bytes):

INVITE sip:service@127.0.0.1:5060 SIP/2.0
 Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-25-0
 From: sipp ;tag=52422SIPpTag0025
 To: service 
 Call-ID: 25-52422@192.x.x.x
 CSeq: 1 INVITE
 Contact: sip:sipp@192.x.x.x:5061
 Max-Forwards: 70
 Subject: Performance Test
 Content-Type: application/sdp
 Content-Length:   135

v=0

o=user1 53655765 2353687637 IN IP4 192.x.x.x

s=-

c=IN IP4 192.x.x.x

t=0 0

m=audio 6004 RTP/AVP 0

a=rtpmap:0 PCMU/8000

———————————————– 2019-02-04 13:08:13.939310
UDP message received [321] bytes :

SIP/2.0 180 Ringing

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-0

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 1 INVITE

Contact: 

Content-Length: 0

———————————————– 2019-02-04 13:08:13.939905
UDP message received [486] bytes :

SIP/2.0 200 OK

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-0

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 1 INVITE

Contact: 

Content-Type: application/sdp

Content-Length:   135

v=0

o=user1 53655765 2353687637 IN IP4 192.x.x.x

s=-

c=IN IP4 192.x.x.x

t=0 0

m=audio 6000 RTP/AVP 0

a=rtpmap:0 PCMU/8000

———————————————– 2019-02-04 13:08:13.940159
UDP message sent (371 bytes):

ACK sip:service@127.0.0.1:5060 SIP/2.0

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-5

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 1 ACK

Contact: sip:sipp@192.x.x.x:5061

Max-Forwards: 70

Subject: Performance Test

Content-Length: 0

~ RTP

———————————————– 2019-02-04 13:08:13.941658
UDP message sent (371 bytes):

BYE sip:service@127.0.0.1:5060 SIP/2.0

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-7

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 2 BYE

Contact: sip:sipp@192.x.x.x:5061

Max-Forwards: 70

Subject: Performance Test

Content-Length: 0

———————————————– 2019-02-04 13:08:13.952888
UDP message received [313] bytes :

SIP/2.0 200 OK

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-7

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 2 BYE

Contact: 

Content-Length: 0

Time

---------------------------- Repartition Screen ------- [1-9]: Change Screen --

  Average Response Time Repartition 1                                           

           0 ms <= n <        10 ms :        293                                
          10 ms <= n <        20 ms :          9                                
          20 ms <= n <        30 ms :          0                                
          30 ms <= n <        40 ms :          0                                
          40 ms <= n <        50 ms :          0                                
          50 ms <= n <       100 ms :          0                                
         100 ms <= n <       150 ms :          0                                
         150 ms <= n <       200 ms :          0                                
                   n >=      200 ms :          0                                

  Average Call Length Repartition                                               

           0 ms <= n <        10 ms :          0                                
          10 ms <= n <        50 ms :          0                                
          50 ms <= n <       100 ms :          0                                
         100 ms <= n <       500 ms :          0                                
         500 ms <= n <      1000 ms :          0                                
        1000 ms <= n <      5000 ms :        262                                
        5000 ms <= n <     10000 ms :          0                                
                   n >=    10000 ms :          0                                

------------------------------ Sipp Server Mode -------------------------------

Output for client

uac.xml
 SIPp UAC Remote
 |(1) INVITE |
 |------------------>|
 |(2) 100 (optional) |
 |<------------------| 
 |(3) 180 (optional) | 
  |<------------------| 
|(4) 200             | 
|<------------------| 
|(5) ACK             | 
|------------------>|
 |                     |
 |(6) PAUSE             |
 |                     |
 |(7) BYE             |
 |------------------>|
 |(8) 200             |
 |<------------------|

sipp -sn uac 127.0.0.1 -trace_msg -trace_err
Resolving remote host ‘127.0.0.1’… Done.
—————————— Scenario Screen ——– [1-9]: Change Screen —
Call-rate(length) Port Total-time Total-calls Remote-host
10.0(0 ms)/1.000s 5061 17.32 s 98 127.0.0.1:5060(UDP)

3 new calls during 0.286 s period 1 ms scheduler resolution
0 calls (limit 30) Peak was 25 calls, after 10 s
0 Running, 101 Paused, 7 Woken up
0 dead call msg (discarded) 0 out-of-call msg (discarded)
3 open sockets

                             Messages  Retrans   Timeout   Unexpected-Msg
  INVITE ---------->         98        0         0                  
     100 <----------         0         0         0         0        
     180 <----------         98        0         0         0        
     183 <----------         0         0         0         0        
     200          98        0                            
   Pause [      0ms]         98                            0        
     BYE ---------->         98        0         0                  
     200 <----------         98        0         0         0        

—————————— Test Terminated ——————————–

----------------------------- Statistics Screen ------- [1-9]: Change Screen --

  Start Time             | 2019-02-04    13:08:03.908208 1549265883.908208         

  Last Reset Time        | 2019-02-04    13:08:20.954289 1549265900.954289         

  Current Time           | 2019-02-04    13:08:21.241152 1549265901.241152         

-------------------------+---------------------------+--------------------------

  Counter Name           | Periodic value            | Cumulative value

-------------------------+---------------------------+--------------------------

  Elapsed Time           | 00:00:00:286000           | 00:00:17:332000          

  Call Rate  

Tracings

———————————————– 2019-02-04 13:08:13.934840
UDP message received [527] bytes :

INVITE sip:service@127.0.0.1:5060 SIP/2.0

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-0

From: sipp ;tag=52422SIPpTag001

To: service 

Call-ID: 1-52422@192.x.x.x

CSeq: 1 INVITE

Contact: sip:sipp@192.x.x.x:5061

Max-Forwards: 70

Subject: Performance Test

Content-Type: application/sdp

Content-Length:   135

v=0

o=user1 53655765 2353687637 IN IP4 192.x.x.x

s=-

c=IN IP4 192.x.x.x

t=0 0

m=audio 6004 RTP/AVP 0

a=rtpmap:0 PCMU/8000

———————————————– 2019-02-04 13:08:13.936616
UDP message sent (321 bytes):

SIP/2.0 180 Ringing

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-0

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 1 INVITE

Contact: 

Content-Length: 0

———————————————– 2019-02-04 13:08:13.937003
UDP message sent (486 bytes):

SIP/2.0 200 OK

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-0

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 1 INVITE

Contact: 

Content-Type: application/sdp

Content-Length:   135

v=0

o=user1 53655765 2353687637 IN IP4 192.x.x.x

s=-

c=IN IP4 192.x.x.x

t=0 0

m=audio 6000 RTP/AVP 0

a=rtpmap:0 PCMU/8000

———————————————– 2019-02-04 13:08:13.948679
UDP message received [371] bytes :

ACK sip:service@127.0.0.1:5060 SIP/2.0

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-5

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 1 ACK

Contact: sip:sipp@192.x.x.x:5061

Max-Forwards: 70

Subject: Performance Test

Content-Length: 0

~ RTP

———————————————– 2019-02-04 13:08:13.949168
UDP message received [371] bytes :

BYE sip:service@127.0.0.1:5060 SIP/2.0

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-7

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 2 BYE

Contact: sip:sipp@192.x.x.x:5061

Max-Forwards: 70

Subject: Performance Test

Content-Length: 0

———————————————– 2019-02-04 13:08:13.949245
UDP message sent (313 bytes):

SIP/2.0 200 OK

Via: SIP/2.0/UDP 192.x.x.x:5061;branch=z9hG4bK-52422-1-7

From: sipp ;tag=52422SIPpTag001

To: service ;tag=52416SIPpTag011

Call-ID: 1-52422@192.x.x.x

CSeq: 2 BYE

Contact: 

Content-Length: 0

time

---------------------------- Repartition Screen ------- [1-9]: Change Screen --

  Average Response Time Repartition 1                                           

           0 ms <= n <        10 ms :        657                                
          10 ms <= n <        20 ms :         20                                
          20 ms <= n <        30 ms :          0                                
          30 ms <= n <        40 ms :          0                                
          40 ms <= n <        50 ms :          0                                
          50 ms <= n <       100 ms :          0                                
         100 ms <= n <       150 ms :          0                                
         150 ms <= n <       200 ms :          0                                
                   n >=      200 ms :          0                                

  Average Call Length Repartition                                               

           0 ms <= n <        10 ms :        649                                
          10 ms <= n <        50 ms :         28                                
          50 ms <= n <       100 ms :          0                                
         100 ms <= n <       500 ms :          0                                
         500 ms <= n <      1000 ms :          0                                
        1000 ms <= n <      5000 ms :          0                                
        5000 ms <= n <     10000 ms :          0                                
                   n >=    10000 ms :          0                                

------ [+|-|*|/]: Adjust rate ---- [q]: Soft exit ---- [p]: Pause traffic -----

Last Error: Overload warning: the major watchdog timer 3000ms has been t…

Controlling sipp

• [+|-|*|/]: Adjust rate
• p Pause traffic
• q Quit SIPp (after all calls complete, enter a second time to quit immediately)
• Q Quit SIPp immediately s Dump screens to the log file (if -trace_screen is passed)

References :
https://media.readthedocs.org/pdf/sipp-wip/latest/sipp-wip.pdf

Blockchain is essentially a decentralized algorithm for distributed storage and processing , using a non immutable data structures and securing them with signatures and keys . These sequential chain of records called blocks , can contains almost anything from timestamped transactions , metadata , contracts , files etc just as long as they are chained using hash pointers to previous blocks  .

what is a hash ?

function f (x) = y , takes an i/o and give a determined o/p . example heaxadecimeal output of my name , md5(altanai bisht) = 2b9e76d57842ebafaf19fd33bb3573a3.

These are irreversible ie one cant find the i/p from o/p . For this u need to try every combination using brute force. Hence these are generally used for cross verification without revealing the information itself .

Who are miners ?

-tbd –

Application of block chain :

Market analysts and industry specialist have said that block-chain is a revolutionizing technology which will create a decentralized network for not just currency exchange but also many other aspects such as double spent problem , universal identities  , document management etc . Example : Bitcoin protocol , which contains a full record of every transaction ever executed with the currency at any time in past. It is also a solution to problem like black – money , double spending , tax evasions etc. Other areas include:

• Decentralizing document keeping such as government records , digital assets , equity information , medical and health records etc . The system also provide data ownership and Intellectual property protection .
• Fintech as AML( Anti money laundering) , eKYC ( Know Your customer )  , epay , loans, stock trading .
• Smart contracts such as in ethereum . Allows to keep program code that would execute on an event.
• Shared economy for a p2p payment system .
• Crowdfunding , works on paradigm of  token owner’s voting and cooperation in decisions for crowd-sourced venture capital funds .
• Micro payments / fractional concurrency for small amounts suits power selling and buying  such as on solar renewable power micro grid

Since a block chain is a ledger of facts shared across many peer nodes , all communication and inter node transaction uses the power of crypto to authenticate  each other and validate each others requests from the genesis block .

what is a genesis block ?

First block of blockchain which needs to be hard-coded into software . It is the only block which does not reference a previous block .

As any peer wants to add a fact to the ledger , a consensus needs to be obtained from the network. This way of network agreement ensures that fraudulent behavior is prevented .

Example : bitcoin’s genesis block

01000000 - version
0000000000000000000000000000000000000000000000000000000000000000 - prev block
3BA3EDFD7A7B12B27AC72C3E67768F617FC81BC3888A51323A9FB8AA4B1E5E4A - merkle root
29AB5F49 - timestamp
FFFF001D - bits
1DAC2B7C - nonce
01 - number of transactions
01000000 - version
01 - input
0000000000000000000000000000000000000000000000000000000000000000FFFFFFFF - prev output
4D - script length
04FFFF001D0104455468652054696D65732030332F4A616E2F32303039204368616E63656C6C6F72206F6E206272696E6B206F66207365636F6E64206261696C6F757420666F722062616E6B73 - scriptsig
FFFFFFFF - sequence
01 - outputs
00F2052A01000000 - 50 BTC
43 - pk_script length
4104678AFDB0FE5548271967F1A67130B7105CD6A828E03909A67962E0EA1F61DEB649F6BC3F4CEF38C4F35504E51EC112DE5C384DF7BA0B8D578A4C702B6BF11D5FAC - pk_script
00000000 - lock time

Forks 

There is only one path from top block on chain to genesis root , however  there can many forks upwards from genesis block . It is so because blocks may be created within a short span of time or be  under processing . One of the two block will be added to main chain and other will be orphaned or added to pool of queued transactions or even be lost.

Steps to Programming a simple block-chain application :

Lets assume we are creating a block chain for call records.

Structure of a block which is an object which typically looks like

block = {
"index" :1,
"timestamp " :20-02-2017/10:00
"callstatus " : [ { caller : sip:john@domain.com" ,
callee : "alice@domain.com ",
active call time : 3:00
]},
"proof" : 23897897
"previous hash ":"9868768"
}

Blocks have an index , timestamp , transactions ( in our case call status such as outgoing or incoming calls ) and the hash link of previous block , which enables the chain formation ,

Create a class , blockchain , for member function and variables. Create functions as :

1. init() : create a new chain and transaction object

1. createNewTranscation( ) : this creates the information which needs to be fed into the next mined block  and returns the index of the new block which the transaction will be added to .

function createNewTranscation(_caller , _callee , _calltime ){

current_transaction.append({
caller : _caller ,
callee : _callee,
activeCallTime : _calltime
})

return lastBlock['index'] +1;

}

1. createNewBlock() : at first we need to create a genesis block

2. fetchLastBlock() ,

3. boolean isBlockValid ( newBlock , oldBlock) – checks if the oldblocks index is sequentially aligned with new block and whether old blocks hash is equal to new blocks previous hash . Also calculates whether hash of new block is actually same as the supplied hash value in new block ( give  below) .

4. hashBlock( block ) –  to create the hashes we need to add in block. Basically a SHA 256 hash of concatenated arguments as index, timestamp, message , previous hash and a nonce . example pseudo code :

Consensus Algorithms

All block-chains a\re deterministic state machines and transactions act upon them . Consensus filters out the invalid ones and reaches on agreement with valid ones.

DPOS (Delegated Proof of Stake)

A consensus algorithm used for electing producers and scheduling them in a fair and democratic way . It works on the simple principle that longest chain wins therefore incases of multiple forks or network disruption also , if an honest peer finds out a  valid strictly longer chain  , it will switch from its current fork to the longer chain. We assume that in all conditions ,  no other chain forked can be longer if 2/3 of producers are honest as 2/3 + 1 confirmations are required .

In crypto we trust !

Block chain is primarily 3 things : p2p network, public key cryptography and distributed consensus .

The security and accountability of such a system is managed via mass surveillance of transactions and cryptographic evidence. Ensures that blocks are always in chronological order  since meddling with the blocks will change the hash for preceding blocks

Verification of block uses ECDSA ( Elliptic Curve Digital Signature Algorithm ) to ensure that tokens are spend by their rightful owners only.

An ellipsis is a derived from the second degree equation like ax^2 + bcy + cy^2 + dx + ey +f =0 . Depending on attributes this could be hyperbola , parabola or even a circle . However elliptic curve cryptography uses a third degree equation  from either a pseudo -random curve  ( such as over prime  fields y^2=x^3+ax+b or binary fields y^2 + xy = x^3 + ax^2 + b ) or a special curve .

what is ECDSA ?

There are 2 types of auth schemes : Symmetric , relying on shared secret key and Asymmetric relying on private public keys . ECDSA is a asymmetric authentication scheme where in addition to sender and receiver , even 3rd party systems can be authenticated .  In this the sender uses his private key to sign the message and receiver uses the senders public key to verify the message’s signature .

Difficulty 

While publishing a block with pending facts  to be appended to a chain , the owner sends it to other nodes for confirmation on its validity. Once its approved , other nodes called miners add it to their copy of chains. However the new block has to be published after fixed time interval for fraud prevention ( example :  bitcoin blocks are published every 10 mins on avg ) .  This duration is dynamically recalculated as the network miners grow or shrink . A difficulty is a number metric that represents how difficult is it to find a hash for given target.

• To force increase time for calculating the matching hash  , difficulty is increased for miners work harder and take longer to earn the block reward .
• While  in case of  less miner participation , the block difficulty level is made lower

Ref :

• https://www.quora.com/What-is-a-block-chain-algorithm
• https://learncryptography.com/hash-functions/what-are-hash-functions
• https://en.bitcoin.it/wiki/Genesis_block
• https://www.maximintegrated.com/en/app-notes/index.mvp/id/5767
• https://cryptovoices.com/block-difficulty/

SIP is the most popular signalling protocol in VOIP ecosystem. It is most suited to a caller-callee scenario , yet however supporting scalable conferences on VOIP is a market demand. It is desired that SIP must for multimedia stream but also provide conference control for building communication and collaboration apps for new and customisable solutions.

Role of SIP in conference involves

• initiating confs
• inviting participants
• enabling them to join conf
• leave conf
• terminate conf
• expel participants
• configure media flow
• control activities in conf

Centralised vs Mesh signalling for Multi participant conf

In a Centralised signalling model , all communication flows via a centralised control point

In a decentralised or mesh signalling structure , participants can communicate p2p

Unicast vs Multicast Media Distribution

Decentralised Media , Multi unicast streaming

Decentralised media , Multicast

Centralised Media / MCU

Conference types

1. Bridge

Centralised entity to book conf , start conf , leave conf . Therefore single point of failure potentially .

To create conf : conf created on a bridge URL , bridge registers on SIP Server, participants join the conf on the bridge using INVITES

To stop conf : either participant can Leave with BYE or conf can terminate by sending BYE to all

2. Endpoints as Mixer

Endpoints handle stream , decentralised media , therefore adhoc suited

mixer UAs cannot leave untill conf finishes

3. Mesh

coplex and more processing power on each UA required

no single point of failure but endpoints have to handle NATIng