Routers/Switches /

Cisco software to enhance IP reliability

By Stephen Lawson and Network World staff
Network World, 05/20/02

Kicking off an initiative to provide for networks that just keep on going, Cisco last week outlined software features it will add to its Internet Operating System software this year to make network failures or updates invisible to end users.

The set of features, collectively called Cisco Globally Resilient Internet Protocol (GRIP), are designed to let Cisco routers and the links between them continue operating in case of failures or planned upgrades to hardware or software. Cisco's IOS software runs on Cisco routers and switches, providing a common feature and user interface across a network. The idea behind the new IOS features is to provide carrier-grade reliability for enterprise-class IP networks.

Rival Juniper Networks says it has had zero-packet-loss features on its boxes since they began shipping in 1998. Alcatel also says its carrier-grade ACEIS router will support similar features in the next few months.

Initially, Cisco's GRIP IOS features will be available on its 12000, 10000 and 7500 series Internet Routers, aimed at service provider networks. Later this year, Cisco will have releases of GRIP features for IOS that run on Catalyst 6500 series switches and Cisco 7600 series routers for enterprise-class customers.

As IP networks increasingly are used for time-critical applications such as Web services, data storage, voice calls and video streams, corporations and other users need to be able to rely on them at all times, Cisco CEO John Chambers said in a keynote address at NetWorld+Interop 2002 Las Vegas earlier this month.

The GRIP features, which Cisco says will be available next month, include:

Nonstop forwarding, which is designed to maintain route state information between two processors in a router so the standby processor can take over without disrupting the network or causing loss of packets.

Stateful switchover, which maintains link-layer state information on ATM, Ethernet, frame relay and other network links so packet forwarding can continue if a route processor fails.

IP event dampening, in which software in a router can detect a "flap" (in which a link in the network repeatedly fails and recovers) and keep the router from using that link until it is stable again.

Multi-protocol Label Switching fast-reroute node protection, which lets an MPLS tunnel be rerouted around a failed node in milliseconds.

Multicast Sub-Second Convergence, in which a multicast, such as a video or audio stream to many clients in a company, can be rerouted in less than 1 second in case of a failure.

Border Gateway Protocol-convergence optimization, which can reduce significantly the time it takes a router to recalculate the routes on a network. In tests, it let a router converge a routing table of about 200,000 routes 40% faster than before, according to Charles Goldberg, a product line manager in Cisco's IOS group.

Two additional GRIP features will be available in the second half of the year:

Stateful IP security and stateful network address translation, which help a router at the edge of a network rebuild encrypted tunnels and private IP addresses quickly if one router fails and turns over its work to a standby platform.

Gateway Load Balancing Protocol, which lets companies use a standby connection even when the primary link is working. This effectively could let some corporations double their WAN bandwidth.

Cisco's new software features come as part of a wave of new capabilities from various vendors to make IP data networks more like the public switched telephone network, according to Hilary Mine, an analyst at Probe Research. More resilient routers mean service providers don't just have a reliable service but they don't have to buy one backup for every router on the network.

Although Cisco uses some proprietary technologies in GRIP, the company has a track record of introducing technologies to standards bodies and driving them to standardization, Mine says.

The success of Web services and of outsourced offerings, such as Internet-based data storage, will depend on reliable networks, Mine says, using as an example a small business that adopts Internet-based data storage.

Lawson is a correspondent with the IDG News Service's San Francisco bureau.