Carrier Routing System

From Wikipedia, the free encyclopedia

Carrier Routing System is a new (as of 2004) large-scale router, developed by Cisco Systems, Inc.. It runs IOS XR which is a train of IOS built upon the QNX microkernel. A single chassis holds a maximum of 16 line cards, and can run an OC-768 SONET interface. The system has the capability for combining multiple line card chassis using separate dedicated fabric chassis, allowing one system to replace a cluster of Internet core routers in a single site. In this multi-chassis configuration, each line card chassis (LCC) is connected over multiple fabric switching planes with one or more fabric card chassis (FCC). The chassis interconnections are achieved with PAROLI (parallel optical link) fiber optic bundles.

In both single- and multi-chassis configurations, the CRS-1 switch fabrics are based on a three-stage Benes architecture. In a single-chassis system, the three switching stages--S1, S2, and S3--are all contained on one fabric card. In a multi-chassis system, the S2 stage is contained within the FCCs, with the S1 and S3 stages resident in the LCCs at the egress and ingress interfaces fabric plane interfaces, respectively.

While the device was in development, it was known by the code name of HFR, which stood for either "Huge Freaking Router" or "Huge Fast Router".