What is Softswitch?

mick

What is Softswitch?
Mobile in a Minute?/font> from:
www.mobileIN.com
Simply put, Softswitch is the concept of separating the network hardware fro
m network software. In traditional circuit switched networks, hardware and s
oftware is not independent. Circuit switched networks rely on dedicated faci
lities for inter-connection and are designed primarily for voice communicati
ons. The more efficient packet based networks use the Internet Protocol (IP)
to efficiently route voice and data over diverse routes and shared faciliti
es.
As much an initiative as it is a concept, the International Softswitch Conso
rtium (ISC) is leading the charge to evolve traditional networks to more eff
icient and feature rich softswitch networks. To date, the industry has met s
ome success to the extent that the basic components of traditional networks
have been de-coupled. The transport portion of telecommunications networks i
s increasing evolving to utilize the IP. In addition to data transport, this
IP backbone is also increasingly the medium for Voice over IP (VoIP) servic
es. An example of the de-coupling initiative is exemplified by special gatew
ay and mediation equipment that is deployed to connect IP based networks to
circuit based networks for VoIP.
However, Softswitch is more than simply separating the basic components. In
this regard, Intelligent Networks (IN) have not yet been fully de-coupled. T
his current situation is disappointing to Softswitch proponents who claim th
at one of the primary benefits of separation of IN components would be to cr
eate an open environment for service creation. The notion is that IN would n
ot follow traditional call control models, which are voice oriented and cons
training. Instead, new control models would be session-based and support dat
a, voice, and multimedia services equally well.
In an independent but related effort, work is underway within the Internet E
ngineering Task Force (IETF) to define capabilities for hybrid IN + IP netwo
rks. One such hybrid is referred to by the IETF as PINT, which stands for PS
TN (Public Switched Telecommunications Network) and Internet Interworking. T
he motivation for PINT is to allow Internet subscribers to add traditional I
N related telephony functions. The idea is to have traditional network capab
ilities and services accessible and useable by Internet users.
Another hybrid is the converse of PINT. SPIRIT stands for Services in the PS
TN/IN Requesting Internet Services. The desire for SPIRIT is to augment IN s
ervices with IP capabilities. Therefore, the goal is to make Internet based
content and applications accessible and useable by traditional network users
.
The efforts of both the ISC and the IETF have the same goal in mind - establ
ish a more distributed telecommunications architecture in which the source o
f functional components is completely independent. These functional componen
ts include transport, switching, network control, and service logic.
For example, one goal is to establish a "Softswitch" that does not have the
hard constraints that traditional switches have, including the need for circ
uit based switching and transport, intelligent network triggers and mechanis
ms, and service logic. A completely Softswitch is one in which these functio
nal entities reside in various distributed physical components. As we mentio
ned earlier, the transport function has already begun to migrate to IP based
network components. However, the future benefit of Softswitch will be dicta
ted by the extent to which network control and service logic also migrate aw
ay from the switch.
This distribution of functionality will enable the benefits of improved feat
ure development and delivery as well as lower costs. Distributing functional
ity means that switches will be simpler, more efficient, and cheaper. Switch
es will be able to focus on switching, allowing other components to provide
network control and service logic. Distributed service logic means that appl
ication development will not be constrained to centralized creation, control
, and delivery of services. Instead, services can be created and deployed at
various places through an extended network.
While providing the potential for many benefits, creating and deploying this
model is not without its challenges. Having a vested interested in perpetua
ting traditional networks, some less-than-forward looking infrastructure pro
viders are hesitant to cooperate with the Softswitch initiative. Additionall
y, integration of Softswitch with traditional networks will be required as S
oftswitch deployment will not happen everywhere all at once. A final major c
oncern is that there will be special mediation needs between disparate netwo
rks. These needs go beyond mere protocol conversion requirements and include
such things as authentication and authorization of network elements and app
lications. In traditional networks, well-established processes and protocols
such as SS7 handle these mediation functions. These procedures will certain
ly be more complicated in the hybrid networks of the future.
Despite these challenges, telecommunications technology will continue to evo
lve for the overall benefit of society. The efforts discussed in this articl
e will play a large role in that development. For more information about the
se activities see visit the ISC and IETF at www.softswitch.org and www.ietf.
org respectively. Hybrid IN/IP networks and the evolution of mobile IN to be
come more data centric is also discussed in the book Wireless Intelligent