Cisco Catalyst 6500 Supervisor 2T Architecture - Ipland

White PaperPFC4 and DFC4The PFC4 provides hardware accelerated forwarding for packets traversing the switch. This includes forwarding forIPv4 unicast/multicast, IPv6 unicast/multicast, Multi-Protocol Label Switching (MPLS), and Layer 2 packets. Alongwith forwarding, the PFC4 is also responsible for processing a number of services that are handled during theforwarding lookup process. This includes, but is not limited to, the processing of security Access Control Lists(ACLs), applying rate limiting policies, quality of service classification and marking, NetFlow flow collection and flowstatistics creation, EtherChannel load balancing, packet rewrite lookup, and packet rewrite statistics collection.The DFC4 is a daughter card that is located on selected linecards. The DFC4 contains the same ASIC functionalblocks that are found on the PFC4. The main purpose of the DFC4 is to provide local forwarding services for thelinecard, offloading this function from the PFC4. Using DFC4s helps scale performance of the overall chassis.Without any DFC4s present in the chassis, the maximum performance of a chassis with Supervisor 2T is 60 Mpps(for IPv4 forwarding). Each DFC4 adds an additional 60 Mpps of forwarding performance to the aggregate forwardingcapacity of the chassis. All of the information written about the PFC4 below equally applies (function, scalability, andperformance) to the DFC4.The PFC4 is located on the right-hand side of the Supervisor 2T baseboard, as shown in the diagram below.Figure 7.Policy Feature Card 4 on the Supervisor 2TThe location of the DFC4 on a linecard is shown in the following diagram. In the photo below, the DFC4 is locatedunderneath a protective cover that protects the daughter card from getting damaged when the linecard is inserted orremoved from a chassis.© 2011-2012 Cisco and/or its affiliates. All rights reserved. This document is Cisco Partner Confidential Information. Page 16 of 46