Delivering new services via EoS - Ethernet over SONET

As service providers continue to search for better options to deliver new services over their existing infrastructures, they're finding solutions that employ EoS (Ethernet over SONET) via VC (virtual concatenation) to be viable and economical. The advantages EoS has over PoS (packet over SONET) and ATM are clear. Bandwidth allocation is far more efficient and products and their services are easier to deploy.

Carriers acknowledge that their customers' bandwidth-hungry applications will eventually force them to upgrade their core network infrastructures to accommodate Gigabit services. But what they're failing to recognize is that using lower-order VC in conjunction with their current business customer premises service delivery architecture allows them to deliver new data services today.

Regardless of the carriers' timelines to upgrade their core to higher OC-x rates or DWDM to support GigE services via higher-order (STS-1) VC, the objective is to deploy a single device at the CPE that can deliver traditional voice and new data services.

Whether a business customer's service demand warrants a T1 or a T3, if they have fiber going to their building, odds are their service provider will deliver at least an OC-3. Typically, 155 Mbps is overkill for their customer's needs, but service providers are willing to sacrifice the bandwidth to gain the advantages that optical SONET provides over DSL--reliability, redundancy, reach and visibility.

The emergence of next-gen SONET terminal multiplexers that support lower-order (VT1.5) VC allows service providers to efficiently use OC-3's extra bandwidth at their customers' premises to offer new services such as Transparent LAN while still delivering traditional T1/T3 service. They can do this without impacting their core equipment or provisioning methods. VC circuits are handled and mapped through the network core the same way T1 services are handled today.

Lower-order concatenation for Ethernet service delivery also allows carriers to segment data traffic in applications where multiple tenants are serviced from the same access multiplexer. They can offer Ethernet services on a tiered basis starting from as little as a single 1.5 Mbps pipe up to full rate 10BaseT in VT1.5 increments. When used in conjunction with LCAS (link capacity adjustment scheme), the customer's bandwidth can be increased or reduced without service interruption.

In a multi-tenant configuration, next-generation access multiplexers seamlessly deliver new Ethernet services to customers who want it, while still supporting traditional data services such as frame relay or private line.

A 10BaseT's direct connection via standard interfaces to a customer's data equipment eliminates the need for costly T1 or T3 WAN modules in their routers or switches, allowing carriers to more efficiently deliver voice and data services.

When carriers' customer's bandwidth needs grow to the point of justifying a GigE pipe, then carriers will need to make changes in the core. But, in the meantime, deploying lower-order VC devices solves last-mile bottleneck problems for new higher-speed data services. These devices give carriers a quick return on their existing network architecture investment and allow them to cut deployment costs by eliminating overlay networks to deliver mixed services.

David Boulos is vice president of product management for Telco Systems.

COPYRIGHT 2003 Horizon House Publications, Inc.
COPYRIGHT 2003 Gale Group