The NP cache is used to cache a conversation between the network processor (NP) and the SPU on an IOC. A conversation could be a session, GTP-U tunnel traffic, IPsec VPN tunnel traffic, and so on. A conversation has two NP cache entries, one for incoming traffic and the other for reverse traffic.
The session cache table is extended to support the NP cache. Express Path (formerly known as services offloading) traffic and NP cache traffic share the same session cache table on IOCs. The NP cache on the IOC leverages the Express Path functionality.
To optimize system resources and conserve session entries on IOCs, certain priority mechanisms are applied to both flow and the IOCs to selectively install NP cache.
To enable NP cache on the IOC you need to run the set chassis fpc <fpc-slot> np-cache command.
