Contents

Basic IP forwarding commands· 1

display fib· 1

ip forwarding· 3

ip last-hop hold· 4

last-hop backup enable· 4

ipv6 forwarding· 6

Load sharing commands· 7

bandwidth-based-sharing· 7

ip load-sharing local-first enable· 7

ip load-sharing mode· 8

 

Basic IP forwarding commands

display fib

Use display fib to display FIB entries.

Syntax

display fib [ topology topology-name | vpn-instance vpn-instance-name ] [ ip-address [ mask | mask-length ] ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

topology topology-name: Specifies a topology by its name, a case-sensitive string of 1 to 31 characters. To specify a public topology, use base as the topology name. To display FIB entries for the public network, do not specify this option.

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 FIB entries for topology mt.

<Sysname> display fib topology mt

Route destination count: 8

Directly-connected host count: 0

 

Flag:

  U:Useable   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

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

127.255.255.255/32 127.0.0.1       UH       InLoop0                  Null

224.0.0.0/4        0.0.0.0         UB       NULL0                    Null

224.0.0.0/24       0.0.0.0         UB       NULL0                    Null

255.255.255.255/32 127.0.0.1       UH       InLoop0                  Null

# Display all FIB entries of the public network.

<Sysname> display fib

Route destination count: 5

Directly-connected host count: 0

 

Flag:

  U:Useable   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

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

Route destination count: 6

Directly-connected host count: 0

 

Flag:

  U:Useable   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

127.0.0.0/8        127.0.0.1       U        InLoop0                  Null

192.168.1.0/24     192.168.1.247   U        GE1/5/1/0                Null

192.168.1.0/32     192.168.1.247   UBH      GE1/5/1/0                Null

192.168.1.3/32     192.168.1.3     UH       GE1/5/1/0                Null

192.168.1.21/32    192.168.1.21    UH       GE1/5/1/0                Null

# Display the FIB entries matching the destination IP address 10.2.1.1.

<Sysname> display fib 10.2.1.1

Route destination count: 1

Directly-connected host count: 1

 

Flag:

  U:Useable   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

 

ip forwarding

Use ip forwarding to enable IPv4 packet forwarding on an interface that has no IPv4 address configured.

Use undo ip forwarding to disable IPv4 packet forwarding on an interface that has no IPv4 address configured.

Syntax

ip forwarding

undo ip forwarding

Default

If an interface has no IPv4 address configured, it cannot forward IPv4 packets.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

On a device that supports both IPv4 and IPv6, the next hop of an IPv4 packet might be an IPv4 address or an IPv6 address. If the output interface has no IPv4 address configured, the interface cannot forward the IPv4 packet. To resolve this issue, execute this command on the interface. This feature allows the interface to forward IPv4 packets even though the interface has no IPv4 address configured.

Examples

# Enable IPv4 packet forwarding on GigabitEthernet 2/0/1 that has no IPv4 address configured.

<Sysname> system-view

[Sysname] interface gigabitethernet 2/0/1

[Sysname-GigabitEthernet2/0/1] ip forwarding

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

Eth-channel interface view

Serial interface view

Predefined user roles

network-admin

mdc-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 fast forwarding 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.

<Sysname> system-view

[Sysname] interface gigabitethernet 2/0/1

[Sysname-GigabitEthernet2/0/1] ip last-hop hold

last-hop backup enable

Use last-hop backup enable to enable last hop backup.

Use undo last-hop backup enable to disable last hop backup.

Syntax

last-hop backup enable

undo last-hop backup enable

Default

Last hop backup is enabled.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

This feature enables the system to transmit the forward flow and return flow between the local device and a peer device over the same path.

In an IRF fabric enabled with this feature, the IRF master device performs the following operations when receiving the first IP packet of a forward flow on an interface enabled with last hop holding:

1.     Saves the last hop information of the packet.

2.     Synchronizes the last hop information to subordinate devices in the IRF fabric.

The last hop information can be used for guiding the return flow when the flow arrives at the master device or is forwarded through a subordinate device.

For this feature to takes effect, you must also enable last hop holding on the master device in the IRF fabric.

This command takes effect only when the session synchronization is enabled by using the session synchronization enable command. For more information about the session synchronization enable command, see Security Command Reference.

This feature is also applicable to multi-module devices enabled with service backup. If this feature is enabled on such a device, a device module performs the following operations when receiving the first IP packet of a forward flow on an interface enabled with last hop holding:

1.     Saves the last hop information of the packet.

2.     Synchronizes the last hop information to other modules in the device.

The last hop information can be used for guiding the backward flow when the flow arrives at one of these modules.

For this feature to take effect on a multi-module device, you must also enable session flow redirection by using the session flow-redirect enable command. For more information about the session flow-redirect enable command, see Security Command Reference.

Examples

# Disable last hop backup.

<Sysname> system-view

[Sysname] undo ip last-hop backup enable

Related commands

ip last-hop hold

session synchronization enable (Security Command Reference)

session flow-redirect enable (Security Command Reference)

ipv6 forwarding

Use ipv6 forwarding to enable IPv6 packet forwarding on an interface that has no IPv6 address configured.

Use undo ipv6 forwarding to disable IPv6 packet forwarding on an interface that has no IPv6 address configured.

Syntax

ipv6 forwarding

undo ipv6 forwarding

Default

If an interface has no IPv6 address configured, it cannot forward IPv6 packets.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

On a device that supports both IPv4 and IPv6, the next hop of an IPv6 packet might be an IPv4 address or an IPv6 address. If the output interface has no IPv6 address configured, the interface cannot forward the IPv6 packet. To solve this problem, execute this command on the interface. This feature allows the interface to forward IPv6 packets even though the interface has no IPv6 address configured.

Examples

# Enable IPv6 packet forwarding on GigabitEthernet 2/0/1 that has no IPv6 address configured.

<Sysname> system-view

[Sysname] interface gigabitethernet 2/0/1

[Sysname-GigabitEthernet2/0/1] ipv6 forwarding

 

Load sharing commands

bandwidth-based-sharing

Use bandwidth-based-sharing to enable IPv4 load sharing based on bandwidth.

Use undo bandwidth-based-sharing to disable IPv4 load sharing based on bandwidth.

Syntax

bandwidth-based-sharing

undo bandwidth-based-sharing

Default

The IPv4 load sharing based on bandwidth is disabled.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

This feature load shares flow traffic among multiple output interfaces based on their load percentages. The device calculates the load percentage for each output interface in terms of their expected bandwidths.

Devices that run load sharing protocols, such as Locator/ID Separation Protocol (LISP), implement load sharing based on the ratios defined by these protocols.

Examples

# Enable IPv4 load sharing based on bandwidth.

<Sysname> system-view

[Sysname] bandwidth-based-sharing

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 disabled.

Views

System view

Predefined user roles

network-admin

mdc-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 configure the load sharing mode.

Use undo ip load-sharing mode to restore the default.

Syntax

In standalone mode:

ip load-sharing mode { per-flow [ dest-ip | dest-port | ip-pro | src-ip | src-port ] * | per-packet } { global | slot slot-number }

undo ip load-sharing mode { global | slot slot-number }

In IRF mode:

ip load-sharing mode { per-flow [ dest-ip | dest-port | ip-pro | src-ip | src-port ] * | per-packet } { chassis chassis-number slot slot-number | global }

undo ip load-sharing mode { chassis chassis-number slot slot-number | global }

Default

The device performs per-flow load sharing.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

per-flow: Implements per-flow load sharing.

dest-ip: Identifies flows by destination IP address.

dest-port: Identifies flows by destination port.

ip-pro: Identifies flows by protocol number.

src-ip: Identifies flows by source IP address.

src-port: Identifies flows by source port.

global: Configures the load sharing mode globally.

per-packet: Implements per-packet load sharing.

slot slot-number: Specifies a card by its slot number. If you do not specify a card, this command configures the load sharing mode for all cards. (In standalone mode.)

chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument represents the member ID of the IRF member device. The slot-number argument represents the slot number of the card. If you do not specify a card, this command configures the load sharing mode for all cards. (In IRF mode.)

Usage guidelines

The per-packet load sharing mode does not take effect in fast forwarding.

Examples

# (In standalone mode.) Configure per-flow load sharing for slot 1.

<Sysname> system-view

[Sysname] ip load-sharing mode per-flow slot 1