Configuring Ip Forwarding Basics; Fib Table; Displaying And Maintaining The Fib Table - HP 10500 Series Configuration Manual

Configuring IP forwarding basics

Upon receiving a packet, the device uses the destination IP address of the packet to find a match from the
forwarding information base (FIB) table, and uses the matching entry to forward the packet.

FIB table

A device selects optimal routes from the routing table, and puts them into the FIB table. Each FIB entry
specifies the next-hop IP address and output interface for packets destined for a specific subnet or host.
For more information about the routing table, see Layer 3—IP Routing Configuration Guide.
You can use the display fib command to view FIB table entries. The following example displays the entire
FIB table.
<Sysname> display fib
Destination count: 6
Flag:
U:Useable
R:Relay
Destination/Mask
192.168.1.0/24
192.168.1.40/32
...
A FIB entry includes the following items:
• Destination—Destination IP address.
Mask—Network mask. The mask and the destination address identify the destination network. A
•
logical AND operation between the destination address and the network mask yields the address
of the destination network. For example, if the destination address is 192.168.1.40 and the mask
255.255.255.0, the address of the destination network is 192.168.1.0. A network mask is made up
of a certain number of consecutive 1s, and can be expressed in dotted decimal format or by the
number of the 1s.
NextHop—IP address of the next hop.
•
• Flag—Route flag.
OutInterface—Output interface.
•
InnerLabel—Inner label.
•
Token—Label switched path (LSP) index number.
•

Displaying and maintaining the FIB table

FIB entry count: 6
G:Gateway H:Host
Nexthop
0.0.0.0
127.0.0.1
B:Blackhole D:Dynamic
Flag OutInterface
U Vlan999
UH InLoop0
92
S:Static
InnerLabel Token
Null Invalid
Null Invalid