IP Routing Features
Overview of IP Routing
The IP route table contains the best path to a destination.
■ When the software receives paths from more than one of the sources listed
above, the software compares the administrative distance of each path
and selects the path with the lowest administrative distance. The admin-
istrative distance is a protocol-independent value from 1 – 255.
The IP route table is displayed by entering the CLI command show ip route
from any context level in the console CLI. Here is an example of an entry in
the IP route table:
Destination Network Mask Gateway Type Sub-Type Metric
1.1.0.0 255.255.0.0 99.1.1.2 connected 1
Each IP route table entry contains the destination’s IP address and sub-net
mask and the IP address of the next-hop router interface to the destination.
Each entry also indicates route type, and for OSPF routes, the sub type, and
the route’s IP metric (cost). The type indicates how the IP route table received
the route.
To configure a static IP route, see “Configuring a Static IP Route” on page 11-19
IP Forwarding Cache
The IP forwarding cache provides a fast-path mechanism for forwarding IP
packets. The cache contains entries for IP destinations. When an HP ProCurve
routing switch has completed processing and addressing for a packet and is
ready to forward the packet, the device checks the IP forwarding cache for an
entry to the packet’s destination.
■ If the cache contains an entry with the destination IP address, the device
uses the information in the entry to forward the packet out the ports listed
in the entry. The destination IP address is the address of the packet’s final
destination. The port numbers are the ports through which the destination
can be reached.
■ If the cache does not contain an entry, the software can create an entry in
the forwarding cache.
Each entry in the IP forwarding cache has an age timer. If the entry remains
unused for five minutes, the software removes the entry. The age timer is not
configurable.
Note You cannot add static entries to the IP forwarding cache.
11-6
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