Configuring BGP Route Summarization
Pre-configuration Tasks
On IPv4 networks, BGP supports automatic route summarization and manual route summarization. Manual route summarization takes precedence over automatic route summarization.
Before configuring BGP route summarization, complete the following task:
Procedure
- Configure automatic route summarization.
- Run summary automatic
BGP summarizes subnet routes based on natural mask.
The command summarizes the routes imported by BGP. These routes can be direct routes, static routes, RIP routes, OSPF routes, or IS-IS routes. The command, however, is invalid for the routes imported using the network command.
- Run summary automatic
- Configure IPv4 manual route summarization.
- Perform any of the following operations to configure manual route summarization:
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To advertise the summarized routes and specific routes, run the aggregate ipv4-address { mask | mask-length } command.
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To advertise only the summarized routes, run the aggregate ipv4-address { mask | mask-length } detail-suppressed command.
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To advertise the summarized routes and specific routes that meet the specified route-policy, run the aggregate ipv4-address { mask | mask-length } suppress-policy route-policy-name command.
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To advertise the summarized routes of which the AS_Set attribute helps detect routing loops, run the aggregate ipv4-address { mask | mask-length } as-set command.
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To set attributes for the summarized routes, run the aggregate ipv4-address { mask | mask-length } attribute-policy route-policy-name command.
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To summarize the specific routes that meet the specified route-policy, run the aggregate ipv4-address { mask | mask-length } origin-policy route-policy-name command.
IPv4 manual route summarization is valid for the routes in the local BGP routing table. For example, if the local BGP routing table does not contain routes with mask longer than 16 bits, such as 10.1.1.1/24, BGP will not generate an aggregated route for it even if the aggregate 10.1.1.1 16 command is used.
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- Perform any of the following operations to configure manual route summarization:
- Configure IPv6 manual route summarization.
- Perform any of the following operations to configure manual route summarization:
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To advertise the summarized routes and specific routes, run the aggregate ipv6-address { mask | mask-length } command.
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To advertise only the summarized routes, run the aggregate ipv6-address { mask | mask-length } detail-suppressed command.
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To advertise the summarized routes and specific routes that meet the specified route-policy, run the aggregate ipv6-address { mask | mask-length } suppress-policy route-policy-name command.
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To advertise the summarized routes of which the AS_Set attribute helps detect routing loops, run the aggregate ipv6-address { mask | mask-length } as-set command.
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To set attributes for the summarized routes, run the aggregate ipv6-address { mask | mask-length } attribute-policy route-policy-name command.
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To summarize the specific routes that meet the specified route-policy, run the aggregate ipv6-address { mask | mask-length } origin-policy route-policy-name command.
IPv6 manual route summarization is valid for the routes in the local BGP routing table. For example, if the local BGP routing table does not contain routes with mask longer than 64 bits, such as fc00:1::1/128, BGP will not generate an aggregated route for it even if the aggregate fc00:1::1 64 command is used.
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- Perform any of the following operations to configure manual route summarization:
Verifying the Configuration
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Run the display bgp routing-table [ ipv4-address [ { mask | mask-length } [ longer-prefixes ] ] ] command to check information about summarized routes.
- Run the display bgp multicast routing-table [ ip-address [ mask-length [ longer-prefixes ] | mask [ longer-prefixes ] ] ] command to check the MBGP routing table.