Routing Preference; Route Backup; Displaying And Maintaining A Routing Table - HP 3100-8 v2 SI Configuration Manual

A route entry includes the following key items:
• Destination—IP address of the destination host or network.
Mask—Mask length of the IP address.
•
Pre—Preference of the route. Among routes to the same destination, the one with the highest
•
preference is optimal.
• Cost—If multiple routes to a destination have the same preference, the one with the smallest cost is
the optimal route.
NextHop—Next hop.
•
Interface—Output interface.
•

Routing preference

Different routing protocols can find different routes to the same destination. However, not all of those
routes are optimal. For route selection, direct routes and static routes are assigned different preferences.
The route with the highest preference is preferred.
The preference of a direct route is always 0 and cannot be changed. You can manually configure
preferences for any other route type. Each static route can be configured with a different preference. The
following table lists the types of routes and the default preferences. The smaller the preference value, the
higher the preference.
Table 2 Route types and their default route preferences
Routing approach
Direct route
Static route

Route backup

Route backup can improve network availability. Among multiple routes to the same destination, the route
with the highest preference is the main route and all others are backup routes.
The router forwards matching packets through the main route. When the main route fails, the route with
the highest preference among the backup routes is selected to forward packets. When the main route
recovers, the router uses it to forward packets.

Displaying and maintaining a routing table

Task
Display information about the
routing table.
Preference
0
60
Command
display ip routing-table [ verbose ] [ |
{ begin | exclude | include }
regular-expression ]
2
Remarks
Available in any view