- Table of Contents
-
- 04-Layer 3—IP Services Command Reference
- 00-Preface
- 01-ARP commands
- 02-IP addressing commands
- 03-DHCP commands
- 04-DNS commands
- 05-mDNS relay commands
- 06-mDNS gateway commands
- 07-IP forwarding basics commands
- 08-Fast forwarding commands
- 09-Adjacency table commands
- 10-IRDP commands
- 11-IP performance optimization commands
- 12-UDP helper commands
- 13-IPv6 basics commands
- 14-DHCPv6 commands
- 15-IPv6 fast forwarding commands
- 16-Tunneling commands
- 17-GRE commands
- 18-HTTP redirect commands
- Related Documents
-
Title | Size | Download |
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07-IP forwarding basics commands | 64.80 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 vxlan-packet inner-protocol
Use forwarding vxlan-packet inner-protocol to enable hardware forwarding for specific packets received from VXLAN tunnels.
Use undo forwarding vxlan-packet inner-protocol to restore the default.
Syntax
forwarding vxlan-packet inner-protocol { ipv4 | ipv6 } *
undo forwarding vxlan-packet inner-protocol [ ipv4 | ipv6 ]
Default
Packets received from VXLAN tunnels are delivered to the CPU for processing.
Views
System view
Predefined user roles
network-admin
Parameters
ipv4: Specifies IPv4 packets.Only ARP packets are supported.
ipv6: Specifies IPv6 packets.Only MLD packets are supported.
Usage guidelines
By default, the device forwards ARP and MLD packets received from VXLAN tunnels to the CPU for processing when acting as a VTEP in a distributed EVPN gateway network. If a large number of such packets are received, packet loss might occur because of software rate limit, which might cause service exceptions on downlink devices.
To resolve this issue, you can enable the device to forward ARP and MLD packets received from VXLAN tunnels in hardware without delivering them to the CPU.
Traffic forwarding issues might occur if you use this command together with either of the following commands:
· flooding disable all all-direction
· flooding disable broadcast all-direction
To make sure the device can forward traffic correctly, perform the following steps before you enable this feature:
1. Check the configuration for the flooding disable all all-direction and flooding disable broadcast all-direction commands.
2. If either command exists, do the following:
a. Execute the undo flooding disable command to enable flooding on the device.
b. Execute the flooding disable all command to disable the device from flooding any types of traffic received from ACs to VXLAN tunnel interfaces of the VSI.
c. Configure port isolation for the ACs to confine their flooding traffic.
To ensure access to slient devices, such as dumb terminals, you must also execute the undo mac-address static source-check enable command to disable the static source check feature. If you cannot identify whether silient devices exist, disable static source check as a best practice.
Examples
# Enable hardware forwarding for IPv4 packets received from VXLAN tunnels.
<Sysname> system-view
[Sysname] forwarding vxlan-packet inner-protocol ipv4
ip forwarding-table save
Use ip forwarding-table save to save the IP forwarding entries to a file.
Syntax
ip forwarding-table save filename filename
Views
Any view
Predefined user roles
network-admin
Parameters
filename filename: Specifies the name of a file, a string of 1 to 255 characters. For information about the filename argument, see file system management in Fundamentals Configuration Guide.
Usage guidelines
The command automatically creates the file if you specify a nonexistent file. If the file already exists, this command overwrites the file content.
To automatically save the IP forwarding entries periodically, configure a schedule for the device to automatically run the ip forwarding-table save command. For information about scheduling a task, see Fundamentals Configuration Guide.
Examples
# Save the IP forwarding entries to the fib.txt file.
<Sysname> ip forwarding-table save filename fib.txt
Load sharing commands
ip load-sharing local-first enable
Use ip load-sharing local-first enable to enable local-first load sharing.
Use undo ip load-sharing local-first enable to disable local-first load sharing.
Syntax
ip load-sharing local-first enable
undo ip load-sharing local-first enable
Default
Local-first load sharing is enabled.
Views
System view
Predefined user roles
network-admin
Usage guidelines
Local-first load sharing takes effect only on an IRF fabric.
Examples
# Enable local-first load sharing.
<Sysname> system-view
[Sysname] ip load-sharing local-first enable
ip load-sharing mode
Use ip load-sharing mode to specify a shift value for the load sharing algorithm result.
Use undo ip load-sharing mode to restore the default.
Syntax
ip load-sharing mode per-flow [ algorithm algorithm-number [ seed seed-number ] [ shift shift-number ] | [ dest-ip | dest-port | ingress-port | ip-pro | src-ip | src-port ] * | tunnel { all | inner | outer } ] } { global | slot slot-number }
undo ip load-sharing mode { global | slot slot-number }
Default
The shift value is 0 for the load sharing algorithm result.
Views
System view
Predefined user roles
network-admin
Parameters
algorithm algorithm-number: Specifies an algorithm for per-flow load sharing. The value range for the algorithm-number argument is 0 to 8.
seed seed-number: Specifies the seed value for the algorithm. The value range is 0 to 1.
shift shift-number: Specifies the shift value for the hash algorithm result. The value range is 0 to 15, and the default value is 0.
per-flow: Implements per-flow load sharing.
global: Configures the load sharing mode globally.
slot slot-number: Specifies an IRF member device by its member ID. If you do not specify a member device, this command configures the load sharing mode for all member devices.
Usage guidelines
If traffic is not shared equally, you can use the shift shift-number option to adjust the algorithm result.
Examples
# Configure the device to use algorithm 0 for global per-flow load sharing and set the shift value to 1 for the algorithm result.
<Sysname> system-view
[Sysname] ip load-sharing mode per-flow algorithm 0 shift 1 global