SOFTSWITCH: Adolescence Blues

NewSouth Communications, a US-based broadband integrated communications

provider (ICP), recently consolidated its voice and data networks onto a single

distributed backbone network, by deploying media gateway controllers (MGCs) in a

packet tandem architecture. Earlier, it had a time division multiplexing (TDM)

network for voice services and an IP network for data services. The service

provider claims that the deployment of MGCs delivers investment payback in less

than ten months and has allowed NewSouth to increase network efficiency,

streamline capital expenditures, and benefit from ongoing operational savings.

By deploying a softswitch solution, the company claims, it has been able to

streamline and simplify its network architecture, and reduce the number of voice

trunks by as much as 80 percent. More than that, NewSouth can now deploy new

services independent of the underlying architecture. According to Robert J

Leithman, chief technology officer, NewSouth, the consolidation of voice and

data infrastructure, and the implementation of a distributed call model have

allowed NewSouth to realize ongoing cost savings. "We have been focused on

driving down operational costs and in future, will focus on creating new

services that allow us to increase market share, revenue, and profits," he

says.

Five years old in the business with just over 2 lakh installed lines,

NewSouth Communications’ softswitch deployment may not be the best case to

declare that finally softswitch has arrived and so TDM switches must now go into

hibernation. Also, it is not that some of the bigger operators like AT&T,

Worldcom, and China Telecom are either in the process of deploying softswitch

solutions or running trials. The day of softswitch is still years away. Yet, the

deployment of NewSouth softswitch and other such cases do point at the future–if

service providers have to consolidate networks, bring down opex, and quickly

create new innovative services, softswitch is the way. This is one point on

which both the vendors or the service providers are in agreement. Of course, how

and when remain the questions that will need plausible answers.

The Promise



The emergence of the softswitch not only appeared fundamentally challenging

more than a 100-year-old status quo in the telecom world but also came with the

promise of network efficiency, low opex, and faster service creation for service

providers. Compared to the TDM world where everything is proprietary, softswitch

is all about open standards. The proprietary nature of the TDM switch ensured

that service creation was impossible without vendor support. An independent

professional could not add any value to the TDM switches in terms of new

services. This is one of the reasons why new service creation is always a

long-drawn process in the TDM world. On the contrary, service creation in a

softswitch environment is purported to be easy and fast, with no support

required from the switch vendor. In fact, service providers deploying softswitch

solutions can even outsource new service creation to external agencies. The

possibilities of creating new services are endless. Service providers can create

services for specific segments, and segmentation can be based on tangible

offerings. Services for as little as 1,000 subscribers can be created. "The

most exciting thing today is price reduction. But there is a limit to that. So

it is better to go after service creation and get more avenues for subscribers

to spend," Himanshu Goel, national technical manager, (sales), Commworks,

specifies.

Another great benefit supposedly offered by softswitch is that it does not

matter where the customer is coming from, whether it is wireless, DSL, cable,

leased line or just plain copper. The entire thing is independent of access.

More than anything else, the same switch can be used for multiple services. The

opex would be low, as one set of infrastructure can be used for all kinds of

services. And as the entire network can be managed from a central place,

requirement for trained manpower would be less. It is a perfect solution for

Indian operators, as most of them offer both fixed and wireless services.

All this is attractive for any operator. After all, operators across the

world want low opex, want to create and deploy new services, and differentiate

their offerings. Besides, as Vijay Yadav and Himanshu Goel of Commworks put it,

operators also want to have an option to fail or get out. "Any failure in

business should not lead to bankruptcy. As softswitch allows an operator to

start services on a small scale, failures can be less painful," remarks

Goel. Moreover, Goel adds that by leveraging the flexibility inherent in the

IP-based networks, carriers can conduct market research and build services

around accurate return-on-investment figures. "Low-risk, high-profit will

be more than just lip service with networks built around the softswitch

framework," he claims.

But Still Miles to go…



Unfortunately, most of these promises have remained just promises when it

comes to commercial deployment. There are still a number of crucial issues that

need to be addressed before softswitch solutions could become the darling of

service providers. They have a long way to go before they could be compared with

the maturity and reliability of TDM switches. Listing lack of uniform standards

and interoperability as the key issues, Gerard Chevalier, director (voice

networks division), Alcatel India, reminds that softswitch cannot work alone.

"It needs to work with the backbone and the gateways. We, at Alcatel, feel

that at the backbone level, ATM is the best choice but IP is the future, so one

day, backbone too will have to ride on IP. It is here that softswitch and

gateways would come. However, we strongly feel that a full-scale migration to

NGN is not possible today because that would mean undoing their investments in

class-4 and class-5 switches," he adds.

Chevalier says that the class-5 switch is the big issue because no operator

would take the risk of losing customers, as NGN is neither mature nor all TDM

services are available on softswitch. Also, interconnection between two

softswitch-based NGNs is a big issue and multi-vendor environment is not yet

proven. He further says, even though, technically, different vendors have

demonstrated interoperability, it still cannot be said with surety as to whether

that could work perfectly in commercial deployments. Agrees Sandeep Sharma,

manager, (VoIP and intelligent networking), Nortel Networks. "The

softswitch technology is still not mature enough to inspire confidence among

service providers. Even though some standards have been accepted across the

industry, basic interoperability among different vendors is still not

there," observes Sharma.

Lack of an industry-wide standard has definitely kept service providers away

from deploying softswitch solutions. Today, the softswitch market has a

multiplicity of standards like H.323, SIP, H248, and MGCP. MEGACO represents the

latest effort on the part of the vendors towards standardization. While a few

MEGACO-based products are out in the market, most key vendors are yet to adopt

it. Then there are issues related to call billing, as there is no standard

method for billing IP or packet calls. MGCP (for gateways) and SIP (for end

devices) is now expected to emerge as more widely accepted standards.

Even though field trials to test interoperability among products of different

vendors have been successful to a certain extent, vendors believe full

interoperability is still at least two years away. "There is always a huge

gap between what is achieved at field trials and what really works in commercial

deployments," points out Chevalier of Alcatel India. Alcatel did over a

dozen field trials (in Chile, Portugal and France), in cooperation with Lucent

and Ericsson, to test interoperability. Even though a lot of things worked out,

a few like capacity- and service-handling capabilities were not tested.

Compatibility with the existing TDM network and reliability are the other big

issues. No operator can wish away the investment made in the legacy networks and

compromise on reliability. Leave aside incumbents, even green-field operators

are not confident of the reliability of a softswitch solution and often worry

about how a softswitch-based network would talk to a PSTN network. All this has

meant that, as of today, softswitches are not ready to deliver their ultimate

promise–that of one switch, multiple services. To put it simply, except for a

few enthusiastic risk-takers, not many really trust softswitch solutions.

Apart from all this, the relatively high capex (when compared to a TDM

switch) involved in deploying a softswitch solution and the existing business

model of operators is also impeding deployments. Softswitch solutions are

finding it hard to compete with the price of TDM switches, which continue to

touch new lows. While almost all switch vendors have a softswitch product to

offer, none of them seem to have anticipated a crash in TDM prices. TDM switch

prices are a moving target today, making it difficult for the softswitch vendors

with their high R&D investments to compete with them.

Voice continues to be a strong revenue-generator despite its falling rates.

And it is a fact that TDM is doing a good job on the voice front. "This

negates the need for softswitch at this juncture," says Sharma of Nortel

Networks.

The Indian Market



Even though India is still to see any softswitch deployment, it is expected

that the year 2003 would see some action on this front. ISPs and large

enterprises could be the first users of softswitch in India. ISPs already have

an IP backbone and are familiar with standards like legacy VoIP standards like

H.323. As for the large enterprises, the first buyers of softswitch would be

those who are looking at deploying IP telephony.

Indian telecom operators cannot be expected to deploy a softswitch solution

very soon because of two reasons. One, they have just finished rolling out their

TDM networks and second there is not much demand for services. However, Ruchir

Godura, country manager and director (south Asia operations), UTStarcom,

believes that softswitches would be the key to roll out services, by private

operators in new locations where they do not have a backbone. "As

softswitch allows operators to start operations on a low scale, they can be very

cost-effective in locations with small number of subscribers," says Godura.

UTStarcom is planning to launch its softswitch solution in India in the Q3 of

2003. Observing that IP networks in India are still not reliable, Nityananda S,

technology consultant, (India Development Centre), ipGen, says that late 2003

could expect softswitch trials.

Low capex for operators was one of the most-valued promises of the NGNs. But

that remained just a promise. Now softswitch vendors are focusing their effort

on helping operators achieve low opex. However, whether that would be possible

or not, still needs to be seen. It is being expected that in a couple of years

from now, vendors may finally overcome hurdles related to QoS, reliability,

interoperability, and standardization. But ultimately, at what cost would the

solution come to the operators would be the key to the acceptance of softswitch

among the operators. For the moment, doing right things at the right price

appears to be the biggest challenge for softswitch vendors.

Ravi Shekhar Pandey

Softswitch Basics

Softswitch is at the core of the next-generation network (NGN). It is a

combination of open-standard software and generic hardware that functions like a

traditional circuit switch, and provides its functionality over a distributed

control network. The softswitch controls the physical media access and media

gateway (MG) devices, as well as various other types of gateway devices, while

simultaneously interfacing with legacy signaling control networks, such as SS7.

It provides voice signaling, call control, number and routing analysis, service

and charging interface, using standard interfaces. The International Engineering

Consortium defines softswitch as a new approach to telephony switching that has

the potential to address all the shortcomings of the traditional local-exchange

switches. The softswitch is where all the service intelligence resides for the

delivery of local telephone services.

With the participation of service providers and equipment manufacturers, the

International Softswitch Consortium (www.softswitch.org)

has outlined the four baseline components of a softswitch. These components are

session agents, signaling gateways, application servers, and backend management.

Session agents provide distinct functionality and perform call-control, session

management, and device-control functions, for gateways and clients. These

components mediate session initiation protocol (SIP), H.323, media gateway

control (MEGACO), H.248, and media gateway control protocols (MGCPs), which

allow traffic from disparate networks to reach its destination. The signaling

gateways serve as the mechanism for integrating with the existing PSTN.

"Application and feature servers add versatility to the softswitch by

introducing new IP-based services to the network, such as unified messaging,

instant conferencing, and IP centrex. These servers interconnect with softswitch’s

call-control elements, using SIP or other open protocols. Network-centric

backend servers deliver critical functions, such as accounting, authentication

and rating, billing support, director mapping, and provisioning," explains

Himanshu Goel of Commworks. Key capabilities include call detail record (CDR),

support for upstream service provider and clearinghouse billing systems, and

management of IP telephony applications through a Web browser. They also

re-route calls to the PSTN in case of transient IP network conditions, more

commonly known as ‘crank bank’. These components work in tandem as a

call-control switching structure that is based on running software on open

systems instead of the proprietary circuit-switched based products, a distinct

change from the PSTN. Carriers can adopt the softswitch framework by

incorporating different components based on network needs and design. This

built-in flexibility further facilitates a smooth transition to the

next-generation networks.

These NGNs are based on a three-tier architecture that logically separates

the transport, call control, and service layers, within the network. This

enables service providers to address customer’s needs individually, by

designing solutions independently at each tier. Tier-one is the media-processing

layer, which consists of media gateways that accommodate traffic from a variety

of access media, including wired, wireless, narrowband and broadband. Tier-two

bridges different signaling and call-control protocols, enabling service

providers to integrate the PSTN and IP networks, and also integrate traffic from

networks using disparate protocols. Tier-three focuses on service creation. It

provides an open environment for interconnection of application servers that

enable rapid service customization and deployment. The softswitch sits at layers

2 and 3, directing voice and data traffic back and forth between the PSTN and

IP-based networks and to their end destinations. "The softswitch framework

de-couples services from the access and transport infrastructure, which is a

crucial element in allowing carriers to bring Internet-style creativity to

telephony services," says Goel.