Thursday, August 6, 2009

Multi-layer switching

Started on MLS tonight. Actually had a couple of drinks while studying so I am feeling pretty well right now... CEF or cisco express forwarding is the predominately used method for layer 3 switches nowadays. CEF contains a fowarding information base (aka an FIB) for processing L3 information, and an adjacency table that is used for L2 information. CEF consists of 2 planes, which I actually need to do a bit more reading on:
Control Plane: builds the arp and ip routing tables
Data Plane: places data into the L3 switches memory, and encapuslates data before forwading.

Fastest switching to slowest...
  1. Distributed CEF (done by multiple processors)
  2. CEF
  3. Fast Switching
  4. Process Switching
**IPX, SNA, LAT, and AppleTalk are not supported by CEF**

Basic L3 commands:
(config) ip routing (enable ip routing on the damn switch! its not enabled by default)
(config-int) no switchport (enable an L3 switchport so you can configure an ip address on it)
(config)interface vlan [#] (create and SVI, or switched virtual interface)

Create a bridge group for non supported protocols
(config)bridge-group [#]
(config)int vlan [#]
(config-int)bridge-group [#]

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