Cisco Catalyst 6500 Supervisor 2T Architecture - Ipland

White PaperPFC4 (and PFC4XL) Functional ElementsThe Layer 3 forwarding engine contains a number of functional elements, all of which work together to provide Layer3 processing for packets. The main functional elements are executed in the order shown and can be seen in thefollowing diagram.Figure 12.Layer 3 Forwarding Engine Functional ElementsEach of these functional elements is detailed in the following sections.Interface Processing and LIF Map TableA LIF is a new concept introduced with the PFC4. The LIF helps enable per-port-per-VLAN interface processing,which separates Layer 2 characteristics from Layer 3 characteristics. The LIF map table (which is separate from, butis mapped to, the LIF table located on the Layer 2 forwarding engine) contains 128 K entries, and helps scale thenumber of Layer 3 interfaces and sub-interfaces that can be supported by the PFC4. There are two LIF map tablesused by the Layer 3 forwarding engine: one for ingress LIFs and one for egress LIFs.© 2011-2012 Cisco and/or its affiliates. All rights reserved. This document is Cisco Partner Confidential Information. Page 34 of 46