Redback rails against Cisco edge router

Redback Networks is taking shots at Cisco’s 7600 edge router, just when the 6-year-old product is ready to become a more direct competitor to Redback's offerings.

Cisco this week is announcing broadband remote access server (B-RAS) capabilities for the 7600 that will ship on the platform in the first quarter of 2007. B-RAS is being added to aggregate video traffic and is one feature intended to make the 7600 into a more converged, multi-application edge router for voice, video and data.

Yet Redback, a leading provider of edge routers for broadband services and subscriber management, says Cisco’s plan is a tall order.

“To deliver triple-play services, Cisco still uses three operating systems and three different network routers to deliver broadband, phone and TV services,” Doug Wills, Redback director of corporate communications, charged in an e-mail to Network World. “Single-service broadband routers are a little out-of-date in today’s multi-service, multi-access world. It’s a little like buying three computers today, then dedicating each PC to a single application such as word, power point and excel. Put another way, if Cisco were Starbucks, the San Jose company would figure out a way to sell you three different coffee machines to make you a single latte.”

Specifically, Redback claims the many iterations of the 7600 over the past six to 10 years have rendered the router a kluge for carrier-class triple play applications. The router’s switch fabric employs centralized forwarding susceptible to head-of-line blocking; and its distributed forwarding option is expensive to deploy, Redback charges.

The 7600’s multiple generations and versions of line cards and IOS software releases force service providers into mixing and matching the appropriate line cards, supervisor engines and IOS feature sets to attain the desired function and performance – such as B-RAS and Ethernet switching and multicast switching -- Redback charges.

And the router’s new B-RAS capabilities – housed in a portless module called the Multiprocessor WAN Application Module (MWAM), which Cisco now calls the Intelligent Services Gateway (ISG) – are inherited from Cisco’s decommissioned 6400 series Broadband Aggregators, Redback claims. MWAM supports only 3Gbps and 16,000 sessions per blade, meaning three will have to occupy a 7600 chassis in order to achieve the 64,000 session maximum Cisco touts for the router. That means there are three less slots for external ports, according to Redback.

Moreover, the MWAM saps the performance of the 7600’s Supervisor 720 route engine, and Gigabit Ethernet and 10G Ethernet modules because it forces the Supervisor 720 to default to a previous generation throughput of 16Gbps per slot instead of the 40Gbps per slot it is designed to offer, Redback claims.

Lastly, “the MWAM card on the 7600 uses a separate IOS than the rest of the 7600,” says Ravi Medikonda, Redback's director of product marketing.

"Our new BRAS capabilities are not based on MWAM, don't affect capacity in any way, don't use a separate IOS image, and have nothing at all to do with the 6400," a Cisco spokesman counters. "We have not at all rebranded MWAM as ISG -- the ISG is our strategic cross-platform BRAS software solution."