This post is deals with some less known real world implication of developing and integrating WebRTC with telecom service providers network and bring the solution in action . The regulatory and legal constrains are bought to light after the product is in action and are mostly result of short sightedness . The following is a list of factors that must be kept in mind while webRTC solution is in development stages
WebRTC services from telecom provider depend on the access technology, which may differ if the user accessing the network through a third party Wi-Fi hotspot.
User/network type may also dictate if decryption of the media is possible/required.
For Peer-to-Peer paths, media could be extracted through the use of network probes or other methodology
Then there are Other Considerations such as specific services, for example if WebRTC is used to create softphones software permitting users to receive or originate calls to the PSTN, the current view is to treat this as a fully interconnected VoIP service subject to all the rules that apply to the PSTN – regardless of technologies employed.
CALEA
Communications Assistance for Law Enforcement Act (CALEA) , a United States wiretapping law passed in 1994, during the presidency of Bill Clinton.
CALEA requirement for an LTE user may be very different than the CALEA requirements for a user accessing the network through a third party Wi-Fi hotspot.
For media going through the SBC, CALEA may use a design similar to existing CALEA designs.
calea intercept infrastructure
Read more on WebRTC Security here which discusses SOP (single origin policy ) , CORs ( cross origin requests) , JSONP , ICE , location sharing , scerensharing , Long term access to camera and microphone , SRTP DTLS as well as best practises for secure communication
VoIP and WebRTC platform security largely depend on the underlying protocols such as SIP . SIP is an robuts and time tested VoIP proctol to facilitate VoIP calls . To learn more about SIP security against atacks like
We have already learned about Sip user agent and sip network server. SIP clients initiates a call and SIP server routes the call . Registrar is responsible for name resolution and user location. Sip proxy receives calls and send it to its destination or next hop.
Presence is user’s reachability and willingness to communicate its current status information . User subscribe to an event and receive notification . The components in presence are :
Presence user agent
Presence agent
Presence server
Watcher
Sip was initially introduced as a signaling protocol but there were Lack of method to emulate constant communication and update status between entity
Three more method was introduced namely – Publish , Subscribe and Notify
Subscribe request should be send by watchers to presence server
Presence agent should authenticate and send acknowledgement
State changes should be notified to subscriber
Agents should be able to allow or terminate subscription
Presence is a way to have sustained stateful communication. The SIP User agents can use presence service to know about others user’s online status . Presnece deployment must confirm to security standards .
I use the term legacy telecom system many a times , but have not really described what a legacy system actually is . In my conferences too I am asked to just exactly define a legacy system . Often my clients are surprised to hear what they have in current operation is actually fitted in our own version of definition of ” Legacy system “. This write up is an attempt to describe the legacy landscape . It also describes its characteristics, elements and transformation.
Source : Unknonw. Figure describes an IP based communication system catering to various endpoints and networks
1G , introduced in 1980s , used analog signals as compared to digital in 2G onward. In 1G voice was modulated to higher frequency and then converted to digital while communication with radio towers .
2.Legacy system have ATM / Frame Relay transmission .
This is basically Hardware Specific and results in High Expenses.
3. Legacy systems have POTS / PSTN / ISDN as their access layer technology .
Access layer is the first layer of telecom architecture which is responsible for interacting directly with the end use / subscriber . Legacy system technologies are again Hardware Specific , bear High Expenses and offer Low stability.
4. Legacy system use Traditional Switches / ISDN in their Core Layer
Core layer is the main control hub of the entire telecom architecture . Using old fashioned switches render high CAPEX ( capital Expenditure ) and OPEX ( Operational Expenses ) .
5. In the service delivery front legacy system employ Traditional IN switches
MAN (Metropolitan area networks) connected ~30 miles of LAN (local networks) with a BN (backbone network). WAN(Wide Area Network) connected these MANs for longer distances ~100 miles. The telco were carriers with these larger internetworks and connections such as At&T or BellSouth. This led to development of PSTN.
PSTN were Circuit – Switching telephone network which were designed to carry analog data. Connnecting over PSTN required a modem convertor which converted analog to digital at 28/56 Kbps. During the set up portion of a telephone call, a special circuit is created, which is then torn down when the call is completed.
TDM was designed to provide continuous, compact and orderly data transfer for voice and video. It does so using a constant bandwidth over a secure connection.
ISDN can provide end-to-end digital communications for Fax, Data, audio, image and video transmission. It is a switched digital telecommunication line that can be delivered over regular copper wires. Speed for a single ISDN line is 128 Kbps. Multiple ISDN lines can be combined together to achieve higher communication speeds. It was mostly used to provide remote access to LANs.
Digital lines with ISDN
Basic Rate Interface or BRI are used for home or SOHO connection
2B + D channel
Primary Rate Interface or PRI is used for large businesses
23 B channels and 1 D channel
B channels are known as bearer channels and is used to carry information D channel is known as the Delta channel used for signalling purposes
An Intelligent Network (IN) service, which offers the functions of a private telephone network. The basic idea behind this service is that business customers are offered the benefits of a (physical) private network, but spared from owning and maintaining it
b) Access Screening(ASC)
An IN service, which gives the operators the possibility to screen (allow/barring) the incoming traffic and decide the call routing, especially when the subscribers choose an alternate route/carrier/access network (also called Equal Access) for long distance calls on a call by call basis or pre-selected.
c) Number Portability(NP)
An IN service allows subscribers to retain their subscriber number while changing their service provider, location, equipment or type of subscribed telephony service. Both geographic numbers and non-geographic numbers are supported by the NP service.
The telecommunications industry has been going through a significant transformation over the past few years. At the outset incumbent operators used to focus on mainly basic voice services and still remained profitable due to the limited number of players in the space and requirement of huge amounts as initial investment.
However, with the advent of competitive vendors, rise in consumer base, and introduction of cost effective IP based technologies a major revolution has come about. This has enabled operators to come out of their traditional business models to maintain and enhance subscriber base by providing better and cheaper voice, multimedia and data services in order to grab the biggest possible share in this multi- billion dollar industry.
The evolution in Telecom industry has been accelerating all the time. The Next-Generation Operators wants to keep pace with the rapidly changing technology by, adapting to market needs and looking at the system and business process from multiple perspectives concurrently. Communication Service Providers (CSPs) need to consider several factors in mind before proposing any solution. They need to deploy solutions which are highly automated, highly flexible, caters to customer needs coupled with ultra low operating costs.
The Softswitch is decomposed into two logical components of a subscriber-facing unit and a PSTN-facing unit.
Subscriber facing unit in Softswitch is upgraded to AGCF (Access Gateway Control Function)
PSTN facing unit is upgraded to MGCF (Media Gateway Controller Function) to interwork with IMS as shown.
By separating the Softswitch into these components, the network can be more easily scaled for better overall network efficiencies. More AGCFs can be added as required, allowing the network to scale with an increase in subscribers. Similarly, More PSTN trunks can be added as traffic increases. Once PSTN and subscriber control functions are separated, the IMS elements, CSCF and BGCF functions can be introduced. BGCF is the interface for interconnecting IMS with legacy PSTN networks.
New SIP-based services can now be rapidly rolled out by deploying new Application Servers (AS) and its integrations to other SBC for UCC( unified communication and colloboartion ) systems. IMS has 3GPP specified ISC interface, which is a SIP-based interface for interfacing-to-application servers. Using these constructs, multiple application servers from multiple vendors can be interconnected over the IMS ISC interface.
Telecom networks (2014) are made up of integrated service digital network (ISDN), the public switched telephone network (PSTN) ,the Public Land Mobility Network (PLMN) and many others. Intelligent networks (IN) ensures that call control is handed over to a control platform. The control platform determines how the establishment of this call shall continue. Applying IN to any of these networks has in common that call establishment is intercepted at a designated node in the network
By hosting new services on the new platform and combining new and old services CSP‟s aim to provide service bundles that would generate new revenue streams. This process is largely dependant on IMS ( IP Multimedia Subsystem ) architecture .
Transformation towards IMS (Total IP)
Optimization in operator landscape evolve as result of synergistic technologies that come together to address the innovation and cost optimization needs of operator for better user experience. In following sections different technological evolutions that are affecting overall operator ecosystems have been discussed with focus towards Service Layer.
“Fixed Mobile Convergence is a transition point in the telecommunications industry that will finally remove the distinctions between fixed and mobile networks, providing a superior experience to customers by creating seamless services using a combination of fixed broadband and local access wireless technologies to meet their needs in homes, offices, other buildings and on the go.”
System can communicate over the cellular network, or act as a new endpoint on the IP network. Home Subscriber Server (HSS) manages subscriber data uniformly between the cellular and IP worlds. The Handoff Server runs on top of the ISC interface, and provides a seamless experience when subscribers move from the cellular network to a Wi-Fi network. The AGCF remains the functional centre of the network, but with the introduction of the HSS, has added the Cx and Sh interfaces defined by the IMS.
This section broadly covered the aspects of migration from legacy IN solution to new age JAINSLEE framework based one. Applies to Legacy IN hosting voice based services mostly such as VPN, Access Screening ,Number Portability, SIP-Trunking,Call Gapping.
Most operator environments have seen a rise in the number of service delivery platforms. Also complexity of telecom networks have increased manifold hence CSPs are facing multiple challenges. Increased efforts and costs are required for maintaining all the SDP platforms. These platforms are generally of different vendors and cater to different technologies thereby greatly increase chances of limiting the scalability and flexibility of the operator landscape. More effort required for sustaining the life cycle of the platform and challenges in integrating non compatible SDPs due to proprietary design have been stumbling blocks in the progress of CSPs across the world.
To overcome these challenges there is trend in the market to move towards SDP consolidation wherein instead of maintaining several SDPs with their proprietary design CSPs prefer maintaining a single or less number of SDPs having standardized interfaces.
As illustrated in the above figure there is a transition that is taking place in the industry towards consolidation of service delivery session control. This would provide a cost effective sustenance of existing applications and the rapid creation and deployment of new services leading to increased revenue recognition by CSPs.
Agile Development
Innovative services
open SOA based architectures
IN/NGN Platform and Services
Reuse of existing investments in legacy service platforms
low cost of new service development
faster time to market
Monetize investment in Network Infrastructure uplift – SIP trunking, VoLTE etc.
Services that should be covered in the Scope of Migration from fixed line to IP telephony are:
Virtual Private Network (VPN) : An Intelligent Network (IN) service, which offers the functions of a private telephone network. The basic idea behind this service is that business customers are offered the benefits of a (physical) private network, but spared from owning and maintaining it.
Access Screening(ASC): An IN service, which gives the operators the possibility to screen (allow/barring) the incoming traffic and decide the call routing, especially when the subscribers choose an alternate route/carrier/access network (also called Equal Access) for long distance calls on a call by call basis or pre-selected.
Number Portability(NP) : An IN service allows subscribers to retain their subscriber number while changing their service provider, location, equipment or type of subscribed telephony service. Both geographic numbers and non-geographic numbers are supported by the NP service.
Using WebRTC Solution for Delivering In Context Voice which provides new monetizing benefits to the Enterprise customers of Service Providers. This includes following components:
WebRTC Gateway for implementation for inter-connect with SIP Legacy
Enhancement of WebRTC Client with new features like Cloud Address Book, Conferencing & Social Networking hooks.
Since long I have been advocating the benefits of migration to IMS from a current fixed line / legacy/ proprietary VOIP / SS7 based system . However I decided to write this post on the challenges in migration to IMS system from a telecom provider’s view. Though I could think of many , I have jot down the major 4 . they are as follows :
Data Migration challenges
Establishing a common data model definition
Data migration seamlessly
Configuration management
Extracting data from multiple sources and vendors , that includes legacy systems
Extracting data due to its large scale and volume
Training
Creating an effective knowledge share and transfer for live operations
Training in fallback plans, standards and policies .
Customer impact
Minimized customer outage
Enhance customer experience by delivering quality services on schedule
Ensuring security of customer’s confidential data
Transfer of customer services without any impact.
Testing in replicated environment
Physical pre-transfer test
Reducing cycle time
Verification and validation at every change in data environment
Detect production issues early in the test -lifecycle
Fallback plans
Pilot program and real network simulation for ensuring preparedness
From ARPANET(Advanced Reseracha nd Prjects Agency Network) in 1973 by US dept of defence , invention of HTTP in 19196 and finally evoluation of SIP in 2000 and availiability of broadband ethernet services, the telecom landscape has evolved. As far as infrastructure, services, and contents are concerned, the VoIP industry is witnessing a migration from POTS / PSTN/ Legacy integrations to NGN (Next Generation Network).
NGN was implemented globally as a means to change the cost base, agility and service capabilities of telecoms providers. The evolved architecture for the transition is one that provides flexibility to service providers by enabling them to deploy new services on IP based technologies, while leveraging existing services and infrastructure as long as it makes sense. This post describes the evolution of voice communication in access , transport and session layers respectively.
1G
2G
3G
4G
5G
Year of dev
1970-1984
1980-1999
1990-2002
2002-2010
2010-2015
Launch year
1987 by Telstra Australia
1991 in Finland by Elisa
1998 pre-commercial launched by NTT DoCoMo in Japan , branded as FOMA.
2009 in Stockholm (Ericsson and Nokia Siemens Networks systems)
We see that the speed enhances considerably with every generation- 1G offerd 2.4 kbps, 2G offered 64 Kbps based on GSM, 3G offered 144 kbps – 2 mbps whereas 4G offers 100 Mbps – 1 Gbps with LTE technology.
It is to be noted that one of requirements set by IMT-2000 was that speed should be at least 200Kbps to call it as 3G service and 384kbps ( wth stationary speeds of 2Mbps) for a “true” 3G.
IP transformation in access layer
Note that voice calls in GSM, UMTS and CDMA2000 were circuit switched but with newer technology voice calls became packet switched too and a lot of rereginerring was required.
LTE (Long Term Evolution) is a series of upgrades to existing UMTS technology involving OFDM and MIMO and newer upgrade were called LTE advanced also. Upcoming 5G offers speeds upto 35.46 Gbps.
While 2G introduced services like SMS , MMS , internal roaming , conference calls, call hold and billing based on services e.g. charges based on long distance calls and real time billing which were unheard of in 1G , there were challenges in terms of page load speed for interactive websites .
As 3G came into picture, usecases also enhanced with multimedia features siuch as fast web browsing, maps navigation, email, video downloading, picture sharing and other Smartphone technology
IMS at work from visiting to home locationAccess network agnostic
It is noteworthy that SKYPE provided VoIP services ( since 2003) much before mobile phone had 2G/3G ( 2010). In current times with many fantastic options to choose from( whatapp , FB messenger , insta cht , Viber , Hangouts ..) given the high bandwidth with 4G/5G and mych advanced media / signal processing tech , the glocal voip scene is touching 400 mililion subscribers and looks very attractive with 1.5$ billion market.
The GSM Association (GSMA) of mobile operators and related companies are devoted to supporting the standardising, deployment and promotion of the GSM mobile telephone system. The GSM Association was formed in 1995. It organises GSMA Mobile World Congress, in addition to smaller, targeted events GSMA Mobile Asia Expo and the GSMA NFC & Mobile Money Summit. Spanning more than 220 countries, the GSMA unites nearly 800 of the world’s mobile operators, as well as more than 200 companies in the broader mobile ecosystem, including handset makers, software companies, equipment providers, Internet companies, and media and entertainment organisations.
The 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations, known as the Organizational Partners. The initial scope of 3GPP was to make a globally applicable third-generation (3G) mobile phone system specification based on evolved Global System for Mobile Communications (GSM) specifications within the scope of the International Mobile Telecommunications-2000 project of the International Telecommunication Union (ITU). The scope was later enlarged to include the development and maintenance of the Global System for Mobile Communications (GSM) including GSM evolved radio access technologies (e.g. General Packet Radio Service (GPRS) and Enhanced Data Rates for GSM Evolution (EDGE)) an evolved third Generation and beyond Mobile System based on the evolved 3GPP core networks, and the radio access technologies supported by the Partners (i.e., UTRA both FDD and TDD modes). It is an evolved IP Multimedia Subsystem (IMS) developed in an access independent manner
3GPP standardization encompasses Radio, Core Network and Service architecture. The project was established in December 1998 and should not be confused with 3rd Generation Partnership Project 2 (3GPP2), which specifies standards for another 3G technology based on IS-95 (CDMA), commonly known as CDMA2000. The 3GPP support team (also known as the “Mobile Competence Centre”) is located at the European Telecommunications Standards Institute (ETSI) headquarters in Sophia-Antipolis (France).
The Open Mobile Alliance (OMA) is a standards body which develops open standards for the mobile phone industry. Network-agnostic : The OMA only standardizes applicative protocols; meant to work with any cellular network technologies being used to provide networking and data transport. These networking technology are specified by outside parties. In particular, OMA specifications for a given function are the same with either GSM, UMTS or CDMA2000 networks. Legal status :The OMA is a British limited company.
Standard specifications The OMA maintains a number of specifications, including
Browsing specifications, now called “Browser and Content”, previously called WAP browsing. In their current version, these specifications rely essentially on XHTML Mobile Profile.
MMS specifications for multimedia messaging
OMA DRM specifications for Digital Rights Management
OMA Instant Messaging and Presence Service (OMA IMPS) specification, which is a system for instant messaging on mobile phones (formerly known as Wireless Village).
OMA SIMPLE IM Instant messaging based on SIP-SIMPLE
OMA CAB Converged Address Book, a social address book service standard.
OMA CPM Converged IP Messaging
OMA Client Provisioning (OMA CP) specification for Client Provisioning.
OMA Data Synchronization (OMA DS) specification for Data Synchronization using SyncML.
OMA Device Management (OMA DM) specification for Device Management using SyncML.
OMA BCAST specification for Mobile Broadcast Services.
OME RME specification for Rich Media Environment.
OMA PoC specification for Push to talk Over Cellular (called “PoC”).
OMA Presence SIMPLE specification for Presence based on SIP-SIMPLE.
OMA Service Environment
FUMO Firmware update
SUPL, an IP-based service for assisted GPS on handsets
MLP, an IP-based protocol for obtaining the position/location of mobile handset
WAP1, Wireless Application Protocol 1, 5-layer stack of protocols
The IP Multimedia Subsystem (IMS) Profile for Voice and SMS, documented in this Permanent Reference Document (PRD), defines a profile that identifies a minimum mandatory set of features which are defined in 3GPP specifications that a wireless device (the User Equipment (UE)) and network are required to implement in order to guarantee an interoperable, high quality IMS-based telephony service over Long Term Evolution (LTE) radio access. The scope includes the following aspects:
· IMS basic capabilities and supplementary services for telephony. · Real-time media negotiation, transport, and codecs. · LTE radio and evolved packet core capabilities. · Functionality that is relevant across the protocol stack and subsystems.
This document defines a voice over IMS profile by listing a number of Evolved Universal Terrestrial Radio Access Network (E-UTRAN), Evolved Packet Core, IMS core, and UE features which are considered essential to launch interoperable IMS based voice. The defined profile is compliant with 3GPP specifications.
On premise private branch exchanges ( PBX ) were the first kind of business telephone systems to which the analog PSTN systems of the company were conneced. These analog circuits were then replaced by digital PBX which provided enhanced features liek screening , voicemails , shared lines.
In the current landscape , the digital PBX of the company is connected to the external telco privider via a SBC or SIP trunking service .
An ompremise LAN based voIP system can be accessed from outside via a VPN on SSL/ IPsec. Although it incures greater CAPEX but ensufe maximum control and ownership of the data . Many time the local laws mandate the server to be hosted with a partuclat geographical area too where an on premise setup and data centre is used.
Enterprise communication shifts from on-premise to SaaS (cloud)
As for remote worksforce and employees working from home (such as during lockdown , pandemics ) it is even more crticial for enterprises to maange inter communication between teams and keep the communication private ie not using piblic messaging platforms , hence the role of cloud based PBX integrated with secure and end to end encrypted telco providers is of prime importance .
To read how a SME can setup their own flexible and scable enterprise comunication system read –
With the advent of other disruptive technologies such as free and opensource codecs in browser with WebRTC and well defined framework and standards, voIP definetly looks detsined to expand by leaps and bounds.
We know that a Service broker is a service abstraction layer between the network and application layer in a telecom environment. SB( Service Broker ) can enable us to make use of existing applications and services from Intelligent Network’s SCP ( Service Control Point ), IMS’s Application Server as well as other sources in a harmonized manner.
Service brokers allow operators to selectively trigger and run multiple services on a single network. SB’s can manage the signalling interactions between the services in a centralised middleware layer, which sits between the network and the services layer. Example: The OpenCloud Service Interaction SLEE (SIS) provides service brokeringand service interaction functionality for SS7 and IMS networks.
The service provider can combine the services from various sources written in various languages in numerous permutations and combinations. This saves the time, energy and reworks required to launch new services. I have written a couple of posts before on Service Broker. Description of What is Service Broker, its definitions and application can be found below. This also defines service orchestration and harmonization.
Another post on Service Borker’s role and functions which mentions the service brokering role in network environment. But ofcourse it was a mere introduction. The following post clarifies the concept in greater light.
I believe and it truly is a wonderful thing to make use of Service Broker while network migration from IN to IMS.The following architecture model depict the placement of Service Broker component in IN and IMS integrated environment .
The figure above portrays how a service provider acts as a central Node for Services invocation and services composition. SB is responsible for Services Orchestration / Interaction , service development, third party integration and acts like a protocol gateway .
Let us discuss service broker in a full fleshed network’s structure . It includes the access network components and detailed core network components with the name of interfaces between all nodes.
The Applications as described by the above figure could be majorly of 4 types :
1. applications developed on a SIP application Server and invoked via SIP/ ISC
2. Applications developed over SIP servlets or JAINSLEE platform such as mobicents , Opencloud Rhino etc
3. Application developed on a SCP ( Service Control Point ) of a IN ( Intelligent Network ) . This is invoked via INAP CS1/CS1+ or CAP
4. Application developed on a J2EE server Invocated via http REST API like GSMA OneAPI such as
Service Broker interfaces the core NGN ( next-generation networks ) and Core IMs ( IP multimedia subsystems ) via IN and SIP respectively. It is responsible to provide unform services to both endpoints such as- subscription options change/removal/ query options data subscription / modification / removal / Interrogation
Provisioning via fixed/mobile brands & « service profile» in Service Broker
Market trends are not in favour of Telecom Service /providers with increasing use of OTT ( Over The Top ) applications like WhatsApp, Facebook messenger, Google hangouts, skype, Viber, etc. OTT applications are often blamed to take a stake in voice traffic revenue by using IP calls where the telco could’ve charged based on its…
Develop a SCE ( Service Creation Environment ) to addresses all aspects of lifecycle of a Service, right from creation/development, orchestration, execution/delivery, Assurance and Migration/Upgrade of services.
A communication system can be made up of many components which are individually undergoing evolution such as access layer generations, and core layer upgrades. Harmonized and uniform open standard-based service delivery platforms over legacy Proprietary codebase is the preferred choice for most service providers to save the investment in their infrastructure and programming while keeping…
Telecom R & D 
