Soft Switches: Best of Both Worlds

VoicenData Bureau
New Update

The current downturn in the telecom industry is exasperating, and is the

cause of worry for most of the people in the tech industry. A question that is

on top of minds of some players is what will happen to IP telephony? It was

supposed to have changed the way we interact and work, which would have helped

in the development of some ‘cool’ applications. Though operators are

planning to deploy IP telephony, the interest levels for IP telephony are at an

all-time high.


In the era of the burst of telecom bubble, the equipment that a carrier buys

must pay for itself, and IP telephony equipment is no exception, even though

calculation of RoI for IP telephony equipment is usually limited to the cost per

port for an equivalent number of TDM ports. And the overall return should not

only be based on the cost per port but also on the overall total cost of

ownership with operational costs also being taken into account.


expectations from the VoIP equipment vendors are new enhanced voice services,

reduced operational and capital expenditure and integration of the Web with

voice services in new and innovative ways. They want new enhanced voice services

and other features to be able to integrate with the old-world networks, provide

carrier grade reliability (six nines) and offer very high density interfaces.

Softswitches happen to bridge the gap between the IP voice world and the

telecom voice world. They provide all the features that the carrier is looking

for and provide a platform on which to deploy the new services.


Softswitches have evolved from the early days of VoIP when they were deployed

as Internet offload solutions and least cost router solutions. Softswitches

provided an easy way out of diverting dial-up Internet traffic from the voice

switches (Internet offload). Today, softswitches are deployed in a more

centralized fashion and have taken the ‘replacement’ tag of the classic

tandem nomenclature. Much of the softswitch market is today defined as Class 5

replacement or Class 4 replacement.

Currently, vendors are primarily looking at replacing the features of a Class

4 or Class 5 switching of the telecom vendors. One question that must be

answered here is how many features that have been deployed in the telecom

environment are of use today? Another question is that since most of the

softswitches are integrated with media gateways of specific companies, how much

of it is interoperable? What is more prudent to look at is a vendor that only

has softswitches in its product portfolio, or a media gateway vendor who also

has a softswitch. Deployment of softswitches will also require the integration

of the SS7 signaling of the PSTN network. Another important feature of a

softswitch is that it can operate in almost all forms of an IP network, be it

cable, copper, fiber or wireless. This gives the flexibility that most customers

would want (one cable for everything) and would give operators the option of

acquiring customers irrespective of the access networks.

Some of the first applications would include VoIP VPN, where multiple offices

of a business can connect over an IP VPN, thus saving on potentially expensive

leased line costs. IP Centrex that can act as an IP PBX sitting in the operators’

premises, with the customer having only Ethernet phones hooked up on a

high-speed connection. Road warrior application is another application where the

highly mobile professional can connect to his corporate network and access all

his voice mails and his office PBX functionality.


One application, which is supposed to help operators in the new revenue

streams, would be the one that integrates mobile, voice, and Internet

applications. This would include interesting applications in ‘Presence

Management’ with the integration of instant messaging and the mobile networks.

Presence management in its various forms would enable the carrier to harvest

information on the availability of a subscriber on the network using IP, and

then use that for offering value-added services.

Coming back to the old question, how would IP telephony grow? The growth in

IP telephony in the carrier space shall evolve with the development of IP-based

infrastructure followed by the deployment of media gateways and softswitches. In

this phase, IP telephony shall co-exist with PSTN and shall have to inter-work

with PSTN-like features and functionalities. With the integration of higher

speeds in the access networks, customers would be offered newer value-added

services leading to more robust growth of IP telephony.

Avijeet Mukherjee, Senior Consultant (network service provider/telco practice

division) HP Services