Extreme Networks delivers 4G mobile backhaul equipment

Extreme Networks today unveiled new Ethernet backhaul gear that it says is specifically designed to meet the needs of emerging 4G mobile operators that require the additional capabilities a packet-based backhaul platform can offer.

“We’re talking about 4G that requires packet backhaul,” Extreme Networks Senior Director of Service Provider Marketing and Business Development Mark Showalter told Connected Planet.

Although today’s 2G and 3G networks often use TDM-based backhaul, increasingly carriers are deploying Ethernet backhaul to support higher data rates and to prepare their networks to support 4G in the future. Ethernet can support TDM traffic using circuit emulation. But a couple of factors have prevented Ethernet from becoming a full replacement for the SONET infrastructure that traditionally had underpinned backhaul networks, Showalter said.

Traditionally Ethernet backhaul networks have lacked the synchronization provided by SONET and, if deployed using a tree architecture, Ethernet is not as resilient as SONET, said Showalter. “Ethernet has been trying to replace SONET for a long time, but without resiliency and synchronization it will never get there,” he said.

Extreme’s new equipment, scheduled for release before the end of 2011, aims to address both of these requirements.

The new Extreme Networks Ethernet backhaul equipment supports the International Telecommunications Union’s G.8032 standard for packet ring resiliency, as well as Ethernet automatic protection switching (EAPS), a ring resiliency technology developed by Extreme seven years ago. The G.8032 standard draws heavily on EAPS, Showalter said.

A ring network using G.8032 or EAPS for resiliency is easier to deploy than a solution such as MPLS-TP that is based on MPLS, said Showalter. “MPLS and Layer 3 VPNs are complex to operate as you push them into the metro network,” he said.

Showalter argued that the optimal resiliency solution for carriers will be to use a solution such as G.8032 for individual rings and to use MPLS-TP to provide service protection end to end across multiple rings.

For synchronization, which will be important to supporting real-time services such as voice using Ethernet backhaul, Extreme Networks plans to support both the ITU’s Synch-E standard as well as the IEEE’s 1588 standard.

“1588 is a packet-based software upgrade,” Showalter said. “Performance varies with traffic level.”

Synch-E, he said, looks a lot like the BITS timing used with SONET. “It uses a physical interconnection for timing,” said Showalter. “It doesn’t use the transport path for timing.”

Extreme’s new product line includes the E4G-201 cell site router and the E4G-401 cell site aggregation router.