on engine 2 LCs (also known as Performance line cards)?
A. Yes, as of Cisco IOS software release 12.0(10)S. However, there are some restrictions due to the architecture of the Engine 2 line cards. The PSA is the Packet Switching ASIC used in Engine 2 line cards for IP and Multiprotocol Label Switching (MPLS) packets forwarding. It uses an mtrie-based lookup engine, microsequencers, and other special hardware to assist in the packet forwarding process. The PSA is a pipeline operation ASIC. Therefore, the performance of the Engine 2 line cards depends on the cycles of each of the six stages. Extra cycles required to support additional features or processing result in a performance degradation of the PSA. That’s why the Engine 2-based line cards cannot support simultaneously all the Cisco IOS software features. To assist customers in enabling certain features on the Engine 2 line card, several PSA microcode bundles are customized. For instance, ACLs cannot co-exist with per interface rate control (PIRC). Q.
