- Table of Contents
-
- 07-Layer 3—IP Services Command Reference
- 00-Preface
- 01-ARP commands
- 02-IP addressing commands
- 03-DHCP commands
- 04-DNS commands
- 05-HTTP commands
- 06-IP forwarding basics commands
- 07-Fast forwarding commands
- 08-Adjacency table commands
- 09-IRDP commands
- 10-IP performance optimization commands
- 11-UDP helper commands
- 12-IPv6 basics commands
- 13-IPv6 neighbor discovery commands
- 14-DHCPv6 commands
- 15-IPv6 fast forwarding commands
- 16-IPv6 transition technologies commands
- 17-WAAS commands
- 18-HTTP redirect commands
- 19-Web caching commands
- Related Documents
-
Title | Size | Download |
---|---|---|
06-IP forwarding basics commands | 50.11 KB |
Basic IP forwarding commands
display fib
Use display fib to display FIB entries.
Syntax
display fib [ vpn-instance vpn-instance-name ] [ ip-address [ mask | mask-length ] ]
Views
Any view
Predefined user roles
network-admin
network-operator
Parameters
vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. To display the FIB entries for the public network, do not specify any VPN instance.
ip-address: Displays the FIB entry that matches the specified destination IP address.
mask: Specifies the mask for the IP address.
mask-length: Specifies the mask length for the IP address. The value range is 0 to 32.
Usage guidelines
If you specify an IP address without a mask or mask length, this command displays the longest matching FIB entry.
If you specify an IP address and a mask or mask length, this command displays the exactly matching FIB entry.
Examples
# Display all FIB entries of the public network.
<Sysname> display fib
Destination count: 5 FIB entry count: 5
Flag:
U:Usable G:Gateway H:Host B:Blackhole D:Dynamic S:Static
R:Relay F:FRR
Destination/Mask Nexthop Flag OutInterface/Token Label
0.0.0.0/32 127.0.0.1 UH InLoop0 Null
1.1.1.0/24 192.168.126.1 USGF M-GE0/0/0 Null
127.0.0.0/8 127.0.0.1 U InLoop0 Null
127.0.0.0/32 127.0.0.1 UH InLoop0 Null
127.0.0.1/32 127.0.0.1 UH InLoop0 Null
# Display the FIB entries for VPN vpn1.
<Sysname> display fib vpn-instance vpn1
Destination count: 6 FIB entry count: 6
Flag:
U:Usable G:Gateway H:Host B:Blackhole D:Dynamic S:Static
R:Relay F:FRR
Destination/Mask Nexthop Flag OutInterface/Token Label
0.0.0.0/32 127.0.0.1 UH InLoop0 Null
20.20.20.0/24 20.20.20.25 U M-GE0/0/0 Null
20.20.20.0/32 20.20.20.25 UBH M-GE0/0/0 Null
20.20.20.25/32 127.0.0.1 UH InLoop0 Null
20.20.20.25/32 20.20.20.25 H M-GE0/0/0 Null
20.20.20.255/32 20.20.20.25 UBH M-GE0/0/0 Null
# Display the FIB entries matching the destination IP address 10.2.1.1.
<Sysname> display fib 10.2.1.1
Destination count: 1 FIB entry count: 1
Flag:
U:Usable G:Gateway H:Host B:Blackhole D:Dynamic S:Static
R:Relay F:FRR
Destination/Mask Nexthop Flag OutInterface/Token Label
10.2.1.1/32 127.0.0.1 UH InLoop0 Null
Table 1 Command output
Field |
Description |
Destination count |
Total number of destination addresses. |
FIB entry count |
Total number of FIB entries. |
Destination/Mask |
Destination address and the mask length. |
Nexthop |
Next hop address. |
Flag |
Flags of routes: · U—Usable route. · G—Gateway route. · H—Host route. · B—Blackhole route. · D—Dynamic route. · S—Static route. · R—Relay route. · F—Fast reroute. |
OutInterface/Token |
Output interface/LSP index number. |
Label |
Inner label. |
ip last-hop hold
Use ip last-hop hold to enable last hop holding.
Use undo ip last-hop hold to disable last hop holding.
Syntax
ip last-hop hold
undo ip last-hop hold
Default
Last hop holding is disabled.
Views
Layer 3 Ethernet interface view
Layer 3 Ethernet subinterface view
Dialer interface view
Predefined user roles
network-admin
Usage guidelines
Last hop holding implements symmetric routing.
When the interface enabled with this feature receives the first IP packet of a forward flow, this feature implements the following operations:
· Obtains the forward flow information and last hop information of the packet.
· Based on the obtained information, creates a fast forwarding entry for the return flow.
When packets of the return flow arrive at the device, the device forwards those packets according to the entry.
Last hop holding relies on fast forwarding entries. If the MAC address of a last hop changes on an Ethernet link, this feature can function correctly only after the fast forwarding entry is updated for the MAC address.
This command is not applicable to an MPLS network.
Examples
# Enable the last hop holding feature on GigabitEthernet 0/0/1.
<Sysname> system-view
[Sysname] interface gigabitethernet 0/0/1
[Sysname-GigabitEthernet0/0/1] ip last-hop hold
# Enable the last hop holding feature on Dialer0.
<Sysname> system-view
[Sysname] interface dialer 0
[Sysname-Dialer0] ip last-hop hold
This operation will degenerate performance badly. Continue? [Y/N]:y