abr-summary (OSPFv3 area view)

Function

The abr-summary command configures route summarization on an area border router (ABR).

The undo abr-summary command disables route summarization from an ABR.

By default, route summarization is not configured on ABRs.

Format

abr-summary ipv6-address prefix-length [ not-advertise | cost cost-value | hold-max-cost interval ] ^*

undo abr-summary ipv6-address prefix-length

Parameters

Parameter	Description	Value
ipv6-address	Specifies the IPv6 address of a summary route.	The value is a 32-digit hexadecimal number, in the format of X:X:X:X:X:X:X:X.
prefix-length	Specifies the prefix length of a summary route.	The value is an integer ranging from 1 to 128.
not-advertise	Prevents the summary route with the specified IPv6 prefix length from being advertised.	By default, the summary route with the specified IPv6 prefix length is advertised.
cost cost-value	Specifies the cost of a summary route.	The value is an integer ranging from 0 to 16777214. By default, the largest cost of the specific routes for summarization is used as the cost of the summary route.
hold-max-cost interval	Specifies the interval at which the maximum cost is advertised in the summary route.	The value is an integer ranging from 10 to 1800, in seconds.

Views

OSPFv3 area view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ospf	write

Usage Guidelines

Usage Scenario

Routes with the same IPv6 prefix can be summarized into one route. On a large-scale OSPFv3 network, route lookup may slow down because of the large size of the routing table. To reduce the routing table size and simplify management, configure route summarization. With route summarization, if a link connected to a device within an IPv6 address range that has been summarized alternates between Up and Down, the link status change is not advertised to the devices beyond the IPv6 address range. This prevents route flapping and improves network stability.

To configure route summarization on an ABR, run the abr-summary command. When an ABR transmits routing information to other areas, it generates Type 3 LSAs for each network segment. If contiguous segments exist in this area, run the abr-summary command to summarize these segments into one segment so that the ABR sends only one summarized LSA. The summarization reduces the routing table size and improves device performance.

Precautions

The abr-summary command applies only to ABRs. To configure route summarization on an AS boundary router (ASBR), run the asbr-summary command.

Example

# In OSPFv3 area 1, summarize routes 2001:db8:1:1::/64 and 2001:db8:1:2::/64 into route 2001:db8:1::/48 with cost 400, and advertise the summary route to other areas.

<HUAWEI> system-view
[~HUAWEI] ospfv3 1
[*HUAWEI-ospfv3-1] area 1
[*HUAWEI-ospfv3-1-area-0.0.0.1] abr-summary 2001:db8:1:: 48 cost 400