Riverstone aims to make IP routers more SONET-like

Riverstone Networks Inc. this month unveiled software for its metropolitan Ethernet routers designed to give service providers SONET-like reliability in IP routing equipment.

Riverstone’s Hitless Protection System (HPS) software can be installed on an existing Riverstone box to let a router with dual-control modules failover more quickly than a similarly configured device with one active control module and one “warm standby” card. Riverstone said the software can cut router downtime caused by component failure or equipment maintenance from 10 minutes to eight seconds.

HPS establishes a “heartbeat” communication link between redundant control modules, letting a primary control blade update its backup every second with information on what the router is doing. If the primary module goes down or is taken offline, the back-up control module can take over all routing functions within eight seconds, the company said.

Previously, Riverstone routers configured with dual-control modules – as well as similarly configured competing products – could take up to 10 minutes to recover, Riverstone said.

HPS also lets service providers implement a single redundant router as an alternative to having two separate routers that use Virtual Router Redundancy Protocol (VRRP) for failover, Riverstone said. While VRRP can improve router failover to one minute of downtime, the company said, HPS is still faster and does not require the deployment of two chassis, which can be expensive in terms of equipment and collocation space costs.

The HPS software upgrade is available in Version 8.0 of Riverstone’s router software, which is available as a free upgrade for all Riverstone router models.

In addition to HPS, Riverstone during the next few months will introduce several other software and hardware features for its metropolitan Ethernet routers intended to boost reliability of router hardware and software-based functions.

Next month, Riverstone is expected to release its own version of Resilient Packet Ring (RPR) technology with its Rapid Ring Spanning Tree (RRST) software. RPR is an emerging standard that takes advantage of the dual fibre-optic ring topology of SONET networks – if the primary ring fails, the back-up ring kicks in and moves traffic in the opposite direction.

RPR would use both rings to transmit traffic and implement quality-of-service prioritization to traffic flows in the event of a line break, giving higher-priority flows, such as IP voice, more bandwidth on the backup ring over lower priority traffic, such as e-mail or music downloads.

According to Riverstone, its RRST software, which is based on the IEEE 802.1w Rapid Spanning Tree algorithm, could be used to introduce basic SONET-like link recovery functions for Ethernet switches deployed in a ring topology where traffic flows in one direction. In case of a link or node failure on a metropolitan Ethernet ring, RRST software would identify the outage and redirect traffic in the opposite direction, the company said.

“This is the poor man’s version of RPR for pure Ethernet over dark fibre networks,” said Steve Garrison, Riverstone’s director of corporate marketing.

Riverstone is also expected to release new line cards for its high-end metropolitan routers, which include the RS 8000, 16000 and 38000 models. The line cards will interoperate with Cisco’s proprietary version or RPR, called Dynamic Packet Transport.

Riverstone said the line cards will be aimed at letting service providers work its gear into Cisco-based metropolitan-area networks. Costs haven’t been set, and a release date wasn’t disclosed.

Riverstone is expected to release software upgrades in January for its Multi-protocol Label Switching line cards that provide MPLS tunnel failover for traffic flows. The software would set aside a bandwidth “reservoir” that could pick up traffic from a failed MPLS tunnel.