nexthop recursive-lookup (BGP-VPNv4 address family view) (route-policy)

Function

The nexthop recursive-lookup command configures route-policy/route-filter-based next hop recursion.

The undo nexthop recursive-lookup command disables route-policy/route-filter-based next hop recursion.

By default, route-policy-based next hop recursion is disabled.

Format

nexthop recursive-lookup route-policy route-policy-name

undo nexthop recursive-lookup route-policy

Parameters

Parameter	Description	Value
route-policy route-policy-name	Indicates the name of a route-policy.	The name is a string of 1 to 200 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string.

Parameter

Description

Value

route-policy route-policy-name

Indicates the name of a route-policy.

The name is a string of 1 to 200 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string.

Views

BGP-VPNv4 address family view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
bgp	write

Usage Guidelines

Usage Scenario

BGP needs route recursion in case of next hops. If route recursion is not limited, BGP routes may be incorrectly iterated, causing traffic loss. Therefore, next hops should perform recursion according to certain conditions.

To control route recursion based on a route-policy, run the nexthop recursive-lookup route-policy command. If a target recursive route is filtered out by the route-policy, the route is considered unreachable. In this manner, BGP route recursion will fail.

Prerequisites

The target recursive route has been determined, and a route-policy has been configured.

Note:

Before configuring a route-policy, ensure that all desired target recursive routes will not be filtered out by the route-policy.

Precautions

The command does not apply to the routes received from LinkLocal peers.

Example

# Configure BGP to filter routes based on a specified route-policy.

<HUAWEI> system-view
[~HUAWEI] route-policy nexthop permit node 0
[*HUAWEI-route-policy] if-match ip-prefix ip_nexthop
[*HUAWEI-route-policy] quit
[*HUAWEI] ip ip-prefix nexthop permit 0.0.0.0 32 greater-equal 32 less-equal 32
[*HUAWEI] bgp 100
[*HUAWEI-bgp] ipv4-family vpnv4
[*HUAWEI-bgp-af-vpnv4] nexthop recursive-lookup route-policy nexthop