peer default-route-advertise (BGP view) (group)

Function

The peer default-route-advertise command configures a BGP device to advertise a default route to its peer group.

The undo peer default-route-advertise command cancels the configuration.

By default, a BGP device does not advertise any default route to its peer group.

Format

peer group-name default-route-advertise [ route-policy route-policy-name ]

peer group-name default-route-advertise route-filter route-filter-name

peer group-name default-route-advertise [ route-policy route-policy-name ] { conditional-route-match-all | conditional-route-match-any } { ipv4-address { mask-length | mask } } &<1-4>

peer group-name default-route-advertise route-filter route-filter-name { conditional-route-match-all | conditional-route-match-any } { ipv4-address { mask-length | mask } } &<1-4>

undo peer group-name default-route-advertise

Parameters

Parameter	Description	Value
group-name	Specifies the name of a peer group.	The name is a string of 1 to 47 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string.
route-policy route-policy-name	Specifies 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.
route-filter route-filter-name	Specifies the name of a route-filter.	The value is a string of 1 to 200 case-sensitive characters, spaces not supported. If parameters are included in the referenced route-filter, specify values for them in the format of (var1, var2, ...var8) behind the route-filter name. A maximum of eight parameters can be specified, and each value ranges from 1 to 200 characters.
conditional-route-match-all	The default routes are sent to the peer group only when all the conditional routes are matched.	-
conditional-route-match-any	The default routes are sent to the peer group if any conditional route is matched.	-
ipv4-address	Specifies the IPv4 address of a peer.	It is in dotted decimal notation.
mask-length	Specifies the mask length of the conditional routes.	It is an integer ranging from 0 to 32.
mask	Specifies the mask of the conditional routes.	It is in dotted decimal notation.

Views

BGP-IPv4 unicast address family view, BGP view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
bgp	write

Usage Guidelines

Usage Scenario

Default routes are usually used in a network with the following characteristics:

Each device has multiple EBGP peers and receives full Internet routes from each EBGP peer.
There are multiple RRs, and each RR receives full Internet routes.
If load balancing is not performed on the network, a BGP peer receives at most one copy of active full Internet routes. If load balancing is performed on the network, the number of active routes received by a BGP peer is doubled, which causes the number of routes on the network to sharply increase. On such a network, you can configure a BGP device to advertise only default routes to its BGP peer and use default routes for traffic load balancing, which can greatly reduce the number of routes on the network.

Configuration Impact

When this command is run, the default route with the next hop as the local device is unconditionally sent to its peer group regardless of whether default routes exist in the routing table.

Example

# Configure a BGP device to advertise default routes to its peer group.

<HUAWEI> system-view
[~HUAWEI] bgp 100
[*HUAWEI-bgp] group test external
[*HUAWEI-bgp] peer test as-number 200
[*HUAWEI-bgp] peer test default-route-advertise