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The BGP Dynamic Update Peer-Groups feature introduces a new algorithm that dynamically calculates and optimizes update-groups of neighbors that share the same outbound policies and can share the same update messages. In previous versions of Cisco IOS software, Border Gateway Protocol (BGP) update messages were grouped together based on peer-group configurations. This method of grouping updates limited outbound policies and specific-session configurations. The BGP Dynamic Update Peer-Group feature separates update-group replication from peer-group configuration, which improves convergence time and flexibility of neighbor configuration.
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To support this feature, you must understand the following concepts:
In previous versions of Cisco IOS software, BGP update messages were grouped together based on peer-group configurations. This method of grouping neighbors together for BGP update message generation reduced the amount of system processing resources needed to process the routing table. This method, however, had the following limitations:
These limitations existed to balance optimal update generation and replication against peer-group configuration. These limitations also caused the network operator to configure smaller peer-groups, which reduced the efficiency of update message generation.
The introduction of the BGP Dynamic Update Peer-Groups feature separates BGP update generation from peer-group configuration. The BGP Dynamic Update Peer-Groups feature introduces an algorithm that dynamically calculates BGP update-group membership based on outbound routing policies. This feature does not require any configuration by the network operator. Optimal BGP update message generation occurs automatically and independently. BGP neighbor configuration is no longer restricted by outbound routing policies, and update-groups can belong to different address families.
The BGP Dynamic Update Peer-Groups feature was introduced with the BGP Configuration Using Peer Templates feature. The BGP Dynamic Peer-Groups feature improves the performance of BGP update message generation. The BGP Configuration Using Peer Templates feature improves the flexibility of BGP neighbor configuration through the introduction of peer-policy and peer-session configuration templates. Peer-policy configuration templates are used to configure policy-related commands. Peer-session configuration templates are used for the configuration of general session commands. Peer configuration templates support inheritance and more robust and flexible configurations.
With the configuration of the BGP Configuration Using Templates feature and the support of the BGP Dynamic Update Peer-Groups features, the network operator no longer needs to configure peer-groups in BGP and can benefit from improved configuration flexibility and system performance. For more information about the BGP Configuration Using Templates feature, refer to the following document:
The BGP Dynamic Update Peer-Group feature requires no configuration and occurs automatically. When a change to outbound policy occurs, the router automatically recalculates update-group memberships and applies the changes by triggering an outbound soft reset after a 3 minute timer expires. This behavior is designed to provide the network operator with time to change the configuration if a mistake is made. You can manually enable an outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command. For the best optimization of BGP update-group generation, we recommend that the network operator keeps outbound routing policy the same for neighbors that have similar outbound policies. This feature introduces new commands for monitoring and maintaining BGP update-groups. For more information about the new commands, see the next section titled "Monitoring and Maintaining BGP Dynamic Update Peer-Groups."
The BGP Dynamic Update Peer-Groups feature introduces the following new commands:
This section contains the following procedures:
The clear ip bgp update-group command is used to clear BGP update-group member sessions. Use the following steps to complete this task:
2. clear ip bgp update-group [index-group | ip-address]
The debug ip bgp groups command is used to display information related to the processing of BGP update-groups. Use the following steps to complete this task:
2. debug ip bgp groups [index-group | ip-address]
The show ip bgp replication command is used to display BGP update-group statistics. Use the following steps to complete this task:
2. show ip bgp replication [index-group | ip-address]
The show ip bgp update-group command is used to display information related to the processing of BGP update-groups. Use the following steps to complete this task:
2. show ip bgp update-group [index-group | ip-address] [summary]
The following examples illustrate the configuration and verification of this feature:
The following example clears the membership of neighbor 10.0.0.1 from an update-group:
Router# clear ip bgp update-group 10.0.0.1
The following example output from the debug ip bgp groups command shows the recalculation of update-groups after the clear ip bgp groups command was issued:
The following sample output from the show ip bgp replication command shows update-group replication information for all for neighbors:
The following sample output from the show ip bgp update-group command shows update-group information for all neighbors:
For information about the BGP Configuration Using Peer Templates feature, refer to the following document:
For additional information related to BGP Dynamic Update Peer-Groups, refer to the following references:
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This section documents new commands. All other commands used with this feature are documented in the Cisco IOS command reference publications.
To clear Border Gateway Protocol (BGP) update-group member sessions, use the clear ip bgp update-group command in privileged EXEC mode.
Syntax Description
Defaults
No default behavior or values.
Command Modes
Command History
Usage Guidelines
If no argument is specified, this command will recalculate all update-groups. Specific index numbers for update groups and information about update-group membership is displayed in the output of the show ip bgp update-group and debug ip bgp groups commands.
When a change to outbound policy occurs, the router automatically recalculates update-group memberships and applies the changes by triggering an outbound soft reset after a 3 minute timer expires. This behavior is designed to provide the network operator with time to change the configuration if a mistake is made. You can manually enable an outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command.
Examples
The following example clears the membership of neighbor 10.0.0.1 from an update-group:
The following example clears update-group information for all peers in the index 1 update-group:
Related Commands
To display information related to the processing of BGP update-groups, use the debug ip bgp update privileged EXEC command. To disable the display of BGP update information, use the no form of this command.
Syntax Description
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Defaults
This command has no default behavior.
Command Modes
Command History
Usage Guidelines
The output of this command displays information about update-group calculations and the addition and removal of update-group members. Information about, peer-groups, peer-policy, and peer-session templates will also be displayed in the output of this command as neighbor configurations change.
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Note The output of this command can be very verbose. This command should not be deployed in a production network unless your are troubleshooting a problem. |
When a change to outbound policy occurs, the router automatically recalculates update-group memberships and applies the changes by triggering an outbound soft reset after a 3 minute timer expires. This behavior is designed to provide the network operator with time to change the configuration if a mistake is made. You can manually enable an outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command.
Examples
The following example output from the debug ip bgp groups command shows that peering has been established with neighbor 10.4.9.8 and update-group calculations are occurring for this member:
The following example output from the debug ip bgp groups command shows the recalculation of update-groups after the clear ip bgp groups command was issued:
Related Commands
To display update replication statistics for Border Gateway Protocol (BGP) update-groups, use the show ip bgp replication command in EXEC mode.
Syntax Description
Command Modes
Command History
Usage Guidelines
The output of this command displays BGP update-group replication statistics.
When a change to outbound policy occurs, the router automatically recalculates update-group memberships and applies the changes by triggering an outbound soft reset after a 3 minute timer expires. This behavior is designed to provide the network operator with time to change the configuration if a mistake is made. You can manually enable an outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command.
Examples
The following sample output from the show ip bgp replication command shows update-group replication information for all for neighbors:
The following sample output from the show ip bgp replication command shows update-group statistics for the 10.4.9.5 neighbor:
Related Commands
To display information about BGP update-groups, use the show ip bgp update-group command in EXEC mode.
Syntax Description
Command Modes
Command History
Usage Guidelines
Displays information about BGP update-groups.
When a change to outbound policy occurs, the router automatically recalculates update-group memberships and applies the changes by triggering an outbound soft reset after a 3 minute timer expires. This behavior is designed to provide the network operator with time to change the configuration if a mistake is made. You can manually enable an outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command.
Examples
The following sample output from the show ip bgp update-group command shows update-group information for all for neighbors:
The following sample output from the show ip bgp update-group command shows a summary of update-group information for the 10.4.9.8 neighbor:
Related Commands
dynamic peer-group—Another name for an update-group.
peer-group—A group of neighbors, calculated at configuration time, that share the same outbound policies and can be replicated in the same updates.
peer-template—A peer template is a configuration pattern that can be applied to neighbors that share common policies. Peer templates are reusable and support inheritance, allowing the network operator to group and apply distinct neighbor configurations for BGP neighbors that share common policies, and define very complex configuration patterns through the ability of a peer template to inherit configurations from other peer templates. There are two types of peer templates "policy-templates" and "session-templates."
peer-policy template—Peer policy templates are used to used group and apply the configuration of commands that are applied within specific address-families and NLRI configuration mode.
peer-session template—Peer session templates are used to group and apply the configuration of general session commands that are common to all address-family and Network Layer Reachability Information (NLRI) configuration modes.
update-group—Like a peer-group, an update-group is a group of neighbors, calculated at configuration time, that share the same outbound policies and can be replicated in the same updates. However, update-groups are calculated dynamically and are not restricted by outbound policies.
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Note Refer to the Internetworking Terms and Acronyms for terms not included in this glossary. |
Posted: Thu Aug 21 13:54:55 PDT 2003
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