Cisco’s CRS-X Router Packs 12.8 Tbps

When it comes to big, fast routers, Cisco’s CRS family has helped to pioneer the space.

Cisco announced the first CRS-1 router in 2004, followed it up with the CRS-3 in March of 2010, and is now expanding the line with the new CRS-X.

The CRS family of routers focus on extreme scale, and the CRS-X is no exception. One standard 7 ft rack chassis CRS-X deployment can deliver up to 12.8 terabits per second. The system can be clustered together in a massive configuration of up to 72 chassis, which would deliver up to 922 Tbps of throughput. The original CRS-1 in a similar clustered configuration could only scale up to 92 Tbps.

The CRS-X delivers such massive scale thanks in part to an enhanced fabric backplane that can enable a new generation of line cards. The CRS-X can now handle up to 400 Gbps per slot, up from only 40 Gbps on the CRS-1 and 140 Gbps on the current

There is now also a 4x 100GbE line card that can be plugged into each of the CRS-X router’s 16 slots, delivering a total of 64 x 100 GbE ports.

Stephen Liu, director of service provider marketing at Cisco, told Enterprise Networking Planet that the new 100 GbE port density on the CRS-X chassis originated in technology that Cisco gained from the acquisition of optical networking vendor Lightwave in February of 2012.

The Lightwave CPAC is a CMOS-based photonic technology that enables Cisco to reduce the power consumption of the optical transceivers on the CRS-X by up to 70 percent over prior generations. The reduced power consumption in turn allows for the development of denser line cards, with more ports per card.

“There is only a limited amount of physical space on a line card,” Liu said.

Liu sees Cisco CRS-X port density as a key point of competitive differentiation.

Cisco’s CRS family has competed with Juniper’s T-series for years. The most recent big router in the Juniper T-series, the T-4000, debuted around the same time as the CRS-3 back in 2010.


Cisco stresses the upgradability of the CRS family platform. Liu noted that the CRS-3 line cards will plug into the new CRS-X, enabling one degree of investment protection.

Existing CRS users also have the option to upgrade the fabric backplane to convert their chassis to a CRS-X.

Sean Michael Kerner is a senior editor at Enterprise Networking Planet and Follow him on Twitter @TechJournalist.

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