WAN SWITCH: A Diamond at the Core

Two major trends in telecom networks are likely

to influence purchasing decisions regarding WAN switches. One, both the

incumbent operators and private telcos are in the process of introducing

broadband services. Two, the emergence of Multiprotocol Label Switching (MPLS).

Both BSNL and MTNL are about to launch DSL services across the country. Both

already have a managed leased line data network services in the metros and major

cities, which is being expanded to more than a hundred cities. Private operators

like Tatas and Reliance have also indicated that they will be launching a host

of data services, in addition to telephone services.

This is forcing the service providers to go in for a high-bandwidth capable

backbone. Incumbents are having to upgrade their Asynchronous Transfer Mode

(ATM) infrastructures. The existing ATM switches simply can’t cope with the

number of connections they’re now having to handle–bearing in mind that each

DSL user needs at least a couple of ATM connections. The rollout of 2.5G mobile

networks by GSM operators and data applications on CDMA networks is also likely

to have a similar impact.

Multiprotocol Label Switching (MPLS) has emerged as a mechanism for

aggregating customer data IP streams in carrier networks, to make them

manageable. It underpins the rollout of IP-based services such as virtual

private networks (VPNs) and LAN-interconnect–services that promise to help

carriers make a profit sooner or later.

Although the rollout of MPLS is still in its early days (BSNL is implementing

the country’s first MPLS-based VPN services), carriers can’t ignore it. They

need to make sure that whatever WAN equipment they install now will support MPLS

and native Internet Protocol (IP) when and if they need it–and not just

support it but also deliver outstanding performance so they’re not left behind

in the race to roll out next-generation IP services.

General Buying Tips

For strategic purchase of WAN switches, there is a



trade-off among the following general criteria:

• Functions and features

• Scale and expandability

• Performance

• — Throughput

• — Congestion tolerance/control

• — Latency

• Network management/operational considerations

• Vendor support resources/architecture/other vendor
  
  considerations

• Ability to accommodate new technologies

• Price

There are two options before operators today–multiservice

switches and Ethernet switches.

n Multiservice

Switch: This is a good option for the incumbent operators, who already have

TDM-based data services. Competition is making them also offer new data services

such as DSL and IP-based services such as VPN. ATM’s scalable bandwidth and

ability to serve as a common infrastructure for a multiplicity of packet, cell,

and circuit-based network services has made it an attractive choice for service

providers. Multiservice switch is both used at the core of the network as well

as the edge for last mile access. The edge multiservice WAN switch usually has

provisions for multiple access technologies such as ATM, Frame Relay, and

Ethernet.

Modularity: E1 lines (2 Mbps) are the norm in India today,

but this does not mean that users will not demand data links of higher capacity

tomorrow. Already several companies, especially tier-2 and tier-3 service

providers, are having multiple E1 lines in their main offices. Tomorrow, there

will be demand for nx2Mb links, even STM1 and STM4 links. So the equipment that

service providers purchase today should be modular with option of scaling up

rapidly and scope for adding large number of links.

Technology Versatility: In a highly competitive scenario with

multiple players, there will be need for operators to match the different kinds

of services that competitors might offer in future. Also, one is not sure which

access technologies will gain usage among users. Hence, it is better to go for

equipment that will support the maximum number of access technologies.

Differential Services Capability: In a highly heterogeneous

market as India, there are big multinational users who have the need for the

best-of-quality service at any cost and there are also such users who would want

to go in for the just-enough bandwidth and minimal service level guarantees.

Operators must keep in mind that they have to satisfy both ends of the spectrum.

Operational Flexibility: The equipment must have a network

management system that is highly user-friendly so that for the operator’s

engineers there is minimal fuss in provisioning and maintaining the services. It

is also highly recommended that the equipment has a mechanism where the

intelligence of the network is taken to the edge of the network, with such

operations as dynamic change of link capacities and choice of service levels

being in the hands of the users.

Intelligent Fault Resolution Mechanism: The equipment must

have the ability to monitor the network performance and pre-empt network faults.

It is a huge value-add if the operator is able to know that a link is going to

go down and the same is communicated to the customer. If a backup link is

provided while the primary link is down, the value-add is even greater.

n Ethernet

Switch: Ethernet has gained favor worldwide for its simplicity, performance

and low cost. Today, Longreach Ethernet has become a serious option for service

providers to provide last-mile high-bandwidth links for both data and voice

services. This gradual acceptance of Ethernet among service providers have

pushed several vendors to develop a slew of next-generation, high-performance 10

Gigabit Ethernet solutions.

Ethernet is especially being favored by greenfield operators

who do not have to go for traditional TDM-based transport technologies for the

bouquet of data services that they are planning to provide through their metro

optical rings. Since these operators have laid their optical fiber touching

various commercial hubs in the metropolises, what they are looking for is the

best last-mile access technologies. It is here that Ethernet switches figure in

their scheme of things, in addition to DSL and Co-ax.

Criteria for Selection: Line-rate, Non-blocking Performance:

The current generation of switches and routers were not built to handle the

increased speeds and scalability required to support this new high-performance

technology. In fact, most switches today have limited bandwidth capacity per

line card slot, preventing them from delivering full line-rate, non-blocking

multi-gigabit Ethernet. Since some of the Ethernet links have be at aggregation

points in the network, line-rate, non-blocking performance is an absolute

necessity.

n Carrier-class

Software: While the hardware are being developed to support high-speed

transport, the software that switches or routes the traffic have to be also

designed to suit WAN applications.

n SDH

Interoperability: SDH networks will be there, despite the popularity of DWDM.

They are an integral part of the WAN environment. Therefore, new solutions,

including 10 gigabit Ethernet, must offer a cost-effective way to interoperate

with existing infrastructures and support native packet over SDH and Ethernet

over SDH interfaces.

n Scalability:

New equipment must have scalable capacity to support at least three to five

years’ worth of network growth. Next-generation solutions must have the

backplane capacity, port density and overall system architecture to scale along

with the network

n Carrier-class

Availability: Regardless of the application, users share a common need for

high reliability and availability in their networking equipment. Redundant

switch fabrics, route processors, power and fans are a given in today’s

environment; other techniques are also required to improve network availability.

Market Information

The worldwide multiservice switches market is dominated by Lucent, Alcatel,

Nortel and Cisco, with their marketshares varying quarter to quarter between

20-30 percent each.

In India, however there are two major players in this segment–Alcatel

and Tellabs. The other two major dominant players seem to be not focusing on

this segment in India. India has been traditionally an incumbent operator market

as far as this segment is concerned. However, with private telcos also set to

implement data services, all four major vendors are likely to pursue the

opportunities.

The metro Ethernet market is a fairly new market worldwide,

with players like Force 10, Extreme and Fore Networks being strong contenders to

overall switch giants Cisco, Enterasys, 3Com and Nortel. In India, companies

from other non-US markets are also in the news for Ethernet products. Atree

Networks from Taiwan had sold some switches to BSES Telecom which is operating

an metro Ethernet service. And, Atricia an Israeli company was recently rumored

to be near striking a metro Ethernet deal with Reliance Infocomm.

EXPERTS PANEL Sanjay Badri, vice president, Finolex Cables Ltd Umrao Khivsara, CFO, Aksh Optifiber