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04-IP forwarding basics commands | 49.49 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. |
forwarding split-horizon
Use forwarding split-horizon to enable split horizon forwarding.
Use undo forwarding split-horizon to disable split horizon forwarding.
Syntax
forwarding split-horizon
undo forwarding split-horizon
Default
Split horizon forwarding is disabled.
Views
System view
Layer 2 Ethernet interface view
Layer 3 Ethernet interface view
Predefined user roles
network-admin
Usage guidelines
This feature prevents IPv4 and IPv6 packets from being forwarded out of the physical interface on which they were received, avoiding network loops.
You can configure split horizon forwarding in system view or interface view. The configuration in system view takes effect globally and the configuration in interface view takes effect only on the interface. To disable split horizon forwarding, you must disable it in both system view and interface view.
This feature is available only on physical interfaces. Logical interfaces, including virtual interfaces and aggregate interfaces, do not support this feature.
Examples
# Enable split horizon forwarding globally.
<Sysname> system-view
[Sysname] forwarding split-horizon