Page 16 - Telecom Reseller AprilMay 2015

16 Telecom Reseller
April/May 2015

ASHISH
continued from page 15

In this column my intent is not to give yet there are three aspects to consider: Security,
another opinion but put some facts together to Interworking, and session control. he
help you understand the relationship between all WebRTC standards don’t really deine a session
these fancy terms and make the right decision.
control protocol and relies on client based
Bridging
Javascript APIs without mandating any speciic
Let’s look at the traits of WebRTC and this implementation; whereas the telecom networks
newly coined term “WebRTC Gateway”. he do and are converging to using SIP for VoIP
most basic explanation of WebRTC is that it
session control.
is a set of protocol and API (JavaScript APIs
here are many ways to implement session
to be more precise) that enables real time control in WebRTC – using HTTP/ REST, JSON
communication capabilities on browser to support peer to peer voice calling and video over web sockets, XMPP over web sockets, SIP over web sockets, or anything proprietary. Each
without requiring any special applications, has its merits and demerits. For instance SIP
downloads, or plugins. So basically you don’t over web sockets is a good approach if the intent
need any phone device or a sotware application is to simply extend a SIP based telecom solution
(aka sotphone) to communicate. You can to the web – like a browser based sotphone; but
directly communicate within a WebRTC- the downside is that SIP based implementation
compliant browser as long as you have data it is not very web developer friendly and limits
connectivity.
the innovative uses to what SIP can ofer.
In any IP based real time communication
Fewer developers means higher costs and fewer
innovations.
Whereas HTTP/ REST appeals to a large
community web and mobile developer –
allowing them to embed communication in
browsers and mobile applications without
requiring to learn SIP. his could extend the
innovation beyond the traditional boundaries of
SOLUTIONS
telecom infrastructure. A great example of that
is improving a user experience of retail online
shopping by automatically passing a user’s
browsing context to the call agent when a user chooses to calls for help.
I love to use an analogy that unlike other
cars, Tesla was designed by keeping sotware
developers in mind and not car mechanics.
Likewise you can say that HTTP/ REST based
implementation of WebRTC is more oriented
for web developers whereas SIP over Web
sockets is more of an approach for traditional
telecom VoIP developers.
Let’s now talk about the role of a gateway in
the web world.
As long as the communication stays within
the web world (i.e. browser to browser),
“ideally” you should not need any gateway
function, but I say that with full skepticism.
We all once believed SIP would standardize IP
communications protocol and we all know the
reality of that statement!
WebRTC is an evolving “standard” and
there certainly are non-conformers who are
considering coming up with their own variation
of WebRTC implementation (likes of Microsot
and Apple). So there is a role of gateway
to provide interworking between diferent
implementations of WebRTC – session control,
choice of media codec, browser compatibility,
etc. For instance, there is a long standing
argument whether to standardize on VP8 vs
H.264 for video codec. he gateway function
solves that by brokering between these two
media codecs – or even others not part of the
speciication.
he more obvious role of a gateway, which
is what the WebRTC Gateway buzz is all
about, is to bridge the Web and telecom world
and provide interworking (or in other words
translate) Javascript API calls to SIP messages
to interact with the telecom network. Looks straight forward and sound simple, right? But
this is where an additional layer of complexity
comes. As mentioned earlier, SIP in the telecom
world is not standardized, so the gateway
function has to deal with adapting to multiple
variations of SIP to seamlessly connect to to any
telecom service, which by no means is an easy
task. his is where the decade’s worth of SBC
experience comes in handy.
I have been in the VoIP industry for well
over 14 years and have seen many evolution
of what is called an SBC – Session Border
Controller. One thing that SBC does best
is solve interworking between diferent IP
communication islands, which is a real value
prop of an SBC and mandates its role in any
IP communication network. It has well over

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