Category: SIP servers

Why Lua is a good choice for Scripting call configurations in SIP servers like Kamailio and Freeswitch

Programing in SIP servers enables the IP telephony provider to add complex control that is difficult to realise with simple dialplan XML and IVR menus. These are best handled by using a program that is compiled with the telecom application server and invoked by SIP requests or responses in the session. This may include using … Continue reading Why Lua is a good choice for Scripting call configurations in SIP servers like Kamailio and Freeswitch

Kamailio DNS and NAT

DNS sub-system in Kamailio DNS failoverDNS load balancingNAT ( Network Address Translation)NAT ( Network Address Translation)Why is NAT is important in SIP?Types of NAT solutionsNAT behavioursRTP NATFixing NATNAT Traversal ModuleWhy use keepalive when Registrations are already there for NATing ?How keepalives work for NATing ?function nat_keepalive()ParamsFunctionsclient_nat_test()fix_contact()nat_keepalive()Pseudo VariablesStatisticsNATHelper ModuleNAT pinging typesUDP packetSIP requestparamsfunctionsPseudo VariablesRPC Commands In … Continue reading Kamailio DNS and NAT

Asterisk – installation and dial plans for WebRTC supported PJSIP clients

Asterisk is a framework or toolkit designed for VOIP systems . It can support Enterprise communication systems like PBXs, call distributors, VoIP gateways , conference bridges etc . It is open source and free to use . It is developed in C and runs in linux . Technically , Asterisk has protocol support for many … Continue reading Asterisk – installation and dial plans for WebRTC supported PJSIP clients

Kamailio WebRTC SIP Server

Why Kamailio?Kamailio SIP Signaling ProxySystem ArchitectureTLS module Configuration GuideStep 1: Create Certificate Directory StructureStep 2: Generate Certificate Authority (CA)Step 3: Generate Server CertificateStep 4: Install CertificatesStep 5: Create CA Certificate ListStep 6: Configure TLS in kamailio.cfgTesting TLS ConfigurationWebsocket moduleConfigurationNAT Detection and HandlingRTPengineInstallationRunning RTP EngineKamailio RTP Engine IntegrationTesting RTP EngineJSSIPJSSIP WebRTC client for KamailioSIP over WEBSOCKET … Continue reading Kamailio WebRTC SIP Server

Opensips Modules

If you are new are opensips you cab read Over view of Opensisp SIP server here https://telecom.altanai.com/2018/06/06/opensips/ This article talks about modules and subparts of Opensips and their role in defining the purpose and application of Opensips which can be as an lighweight proxy to loadbalancer or even as AAA server. Dispatcher Module This modules … Continue reading Opensips Modules

Opensips

Due to its very flexible and customisable routing engine it can be used in number of scenarios such as an SIP proxy or a router and due to its high throughput it is widely recommended as an enterprise grade inbound/outbound proxy server.

Lua Scripts for kamailio Routing

Kamailio uses a native scripting laguage for its configuration file kamailio.cfg . This components of this file are : global parameters loading modules module parameters routing blocks like request_route {…}, reply_route {…}, branch_route {…} etc These parameters including initialization event routes , are interpeted and loaded at kamailio startup. We know that restart of sip … Continue reading Lua Scripts for kamailio Routing

RTPengine on kamailio SIP server

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.

Opensips as SIP gateway

Load BalancerHealth Monitoring OpenSIPS config fileSubscriber and Location OpenSIP provided dispatcher modules which computes hashes over parts of the request and selects an address from a destination set which is then as outbound proxy. Combination of opensips working scenarios scripts with code is at https://github.com/altanai/opensipsexamples. In the config of opensips load the file dispatcher.list with … Continue reading Opensips as SIP gateway

Kamailio as Inbound/Outbound proxy or Session Border Controller (SBC)

role of an SBC is to shield the core network from external entities such as user agent's , carrier network while also providing security , auth and accounting services . In many cases SBC also provides NAT traversal and policy control features ( such as rate limiting , ACL etc ) . In advanced cases transcoding, topology concealment and load balancing is also achievable via a SBC such as Kamailio .

Freeswitch PBX system

IP PBXFreeSWITCHClass 4 switchClass 5 switchfreeswitch-setup-as-hosted-ip-pbxFreeswitch as B2BUA This article talks about setting up an in-house hosted Enterprise PBX system for sure and private communication within enterprise communication. IP PBX A PBX acts as the central switching system for phone calls within a business. Cloud Hosted IP PBX SystemsOn-premise IP PBX An IP PBX is … Continue reading Freeswitch PBX system

Oracle Communication Application Server ( OCAS)

Back in 2010 , there was a very resilient SIP server called BEA weblogic , essentially used to write B2BUA ( back to back user agent application ) using SIP servlets for SIP based call flows . It was later acquired by Oracle and termed as Oracle Weblogic , then OCAS - Oracle Communication application … Continue reading Oracle Communication Application Server ( OCAS)