backward (Static bidirectional co-routed transit view)

Function

The backward command configures a reverse CR-LSP on a transit node.

The undo backward command tears down a reverse CR-LSP.

By default, no reverse CR-LSP is configured.

Format

backward in-label in-label-value nexthop next-hop-address outgoing-interface { interface-name | { interface-type interface-number } } out-label out-label-value [ [ bandwidth ct0 bandwidth ] | [ pir pir ] ] ^*

backward in-label in-label-value outgoing-interface { interface-name | { interface-type interface-number } } nexthop next-hop-address out-label out-label-value [ [ bandwidth ct0 bandwidth ] | [ pir pir ] ] ^*

backward in-label in-label-value nexthop next-hop-address out-label out-label-value [ [ bandwidth ct0 bandwidth ] | [ pir pir ] ] ^*

backward in-label in-label-value outgoing-interface { interface-name | { interface-type interface-number } } out-label out-label-value [ [ bandwidth ct0 bandwidth ] | [ pir pir ] ] ^*

Parameters

Parameter	Description	Value
in-label in-label-value	Specifies the incoming label value of a reverse CR-LSP on a transit node.	An integer ranging from 16 to 32783.
nexthop next-hop-address	Specifies the next-hop IP address of a transit node on a reverse CR-LSP.	The value is in dotted decimal notation.
outgoing-interface	Specifies the type and number of an outbound interface on a transit node.	-
interface-type interface-number	Specifies the type and number of an outbound interface on a transit node.	interface-type: specifies the type of an outbound interface. The value is a string of case-insensitive characters, spaces not supported. interface-number: specifies the number of an outbound interface. The value is a string of case-insensitive characters, spaces not supported. An interface number is in the format of slot number/sub-card number/interface number.
out-label out-label-value	Specifies an outgoing label value on a transit node.	The value is an integer ranging from 16 to 1048575.
bandwidth	Indicates the bandwidth of a static bidirectional co-routed LSP.	The value is in dotted decimal notation.
ct0 bandwidth	Specifies the bandwidth for CT0.	The value is an integer ranging from 0 to 4000000000, in kbit/s.
pir pir	Specifies the peak information rate (PIR) of the reservable bandwidth. If ct0 bandwidth is not set to 0, the PIR parameter must be set.	The value is an integer ranging from 0 to 4000000000, in kbit/s. The value cannot be smaller than the value of bandwidth.

Views

Static bidirectional co-routed transit view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mpls-te	write

Usage Guidelines

Usage Scenario

A static bidirectional co-routed CR-LSP is manually established and consists of two CR-LSPs passing through the same nodes and links and transmitting traffic in opposite directions. You have to configure MPLS forwarding entries in both directions on each node of a path over which the bidirectional CR-LSP is to be established and bind the two CR-LSPs in opposite directions to each other on both the ingress and egress.

To configure a static bidirectional co-routed LSP, perform the following operations to configure MPLS forwarding entries for traffic in opposite directions:

On the ingress
Run the forward (bidirectional static-cr-lsp ingress) command in the static bidirectional ingress LSP view to configure a CR-LSP.
Run the backward (bidirectional static-cr-lsp ingress) command in the static bidirectional ingress LSP view to configure a reverse CR-LSP.
On a transit node
Run the forward (bidirectional static-cr-lsp transit) command in the static bidirectional transit LSP view to configure a CR-LSP.
Run the backward (bidirectional static-cr-lsp transit) command in the static bidirectional transit LSP view to configure a reverse CR-LSP.
On the egress
Run the forward (bidirectional static-cr-lsp egress) command in the static bidirectional egress LSP view to configure a CR-LSP.
Run the backward (bidirectional static-cr-lsp egress) command in the static bidirectional egress LSP view to configure a reverse CR-LSP.

Precautions

If the static bidirectional co-routed LSP has the same outgoing label value, outbound interface, or next-hop IP address as a common static CR-LSP has, and the configuration fails.

If a pair of an outbound interface name and an outgoing label or a pair of a next-hop IP address and an outgoing label is assigned to an existing static LSP, a different parameter pair must be specified for the reverse LSP of a static bidirectional LSP to be established. If the same parameter pair is configured, an outsegment entry conflict occurs, which results in a service diversion failure.

Example

# Set the incoming label value to 17, the next-hop IP address to 10.1.2.1, outgoing interface to GE0/1/0, the outgoing label value to 17, and CT0 bandwidth to 1000 kbit/s for a reverse CR-LSP on a transit node.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] mpls te
[*HUAWEI-mpls] quit
[*HUAWEI] bidirectional static-cr-lsp transit abc
[*HUAWEI-bi-static-transit-abc] backward in-label 17 nexthop 10.1.2.1 outgoing-interface GigabitEthernet 0/1/0 out-label 17 bandwidth ct0 1000 pir 2000