At 10:06 PM +0000 9/10/02, Priscilla Oppenheimer wrote: >Mann, Chris wrote: >> >> Can someone please explain what is meant by a switch fabric? Or >> what is > >It's just a fancy term for switch architecture. It's a good term, though, >because it helps answer the incessant question about the difference between >a bridge and a switch. The older bridges had a simple bus and could only >forward one frame at a time across the bus. Switches have a much more >complicated switch fabric. Think of like a plaid or checkered fabric versus >a linear line. In technical terms, switches use architectures such as >crossbar, crosspoint, star-wired point-to-point, and so on. These >architectures allow many frames to be forwarded at one time. We had a good >discussion about this in the past. You may be able to find some good info in >the archives.
From the standpoint of a router/switch designer, I'd be more specific. Any such device that aims for significant performance separates the control and forwarding planes. The control plane usually has a general-purpose (albeit RISC) processor that handles routing protocols, command lines, SNMP, statistics, etc. The forwarding plane includes the input and output interfaces plus the fabric among them. Since there may be quite a bit of processing on the interfaces (especially the input), and the fabric may be intelligent enough to do multicast replication, failover, and the like, it's worth differentiating between interface and fabric logic. > > means to have blades in your Catalyst switch that are fabric >> enabled? > >Sounds like some marketing drones took the generic term and used it for >something specific. ;-) > >Priscilla Agreed -- although some fabrics are modular (e.g., the 7200 has three 200 Mbps busses bridged together). Fabric enabling _might_ relate to how much of the bandwidth to which interfaces connect. With pretty much off-the-shelf chipsets, you can get 2.4, 4.8, or 10 Gbps fabric paths, and greater throughput with parallelism. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=53056&t=52992 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
