Extended IPv4 Host Cache
The extended IPv4 host cache feature provides additional, configurable storage space on L3-capable switches to store additional IPv4 hosts in the hardware routing tables. This feature is supported on all switches.
All switches support slow-path routing (using software routing tables), so adding more entries in the hardware routing table is a performance feature, which allows more hosts to benefit from fast-path routing. To use the extended IPv4 host cache feature effectively, it helps to understand how the hardware tables operate on the switches that support this feature. The hardware forwarding tables controlled by this feature store entries for the following:
- IPv4 local and remote hosts
- IPv4 routes
- IPv6 local hosts
- IPv6 routes
- IPv4 and IPv6 multicast groups
The extended IPv4 host cache feature works by customizing the forwarding table space allotted to these components.