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Table Of Contents
BGP Dynamic Update Peer-Groups
Information About BGP Dynamic Update Peer-Groups
BGP Update Generation and Dynamic Update Peer-Groups
BGP Dynamic Update Peer-Groups and BGP Configuration Using Peer Templates
BGP Dynamic Update Peer-Group Configuration
How to Monitor and Maintain BGP Dynamic Update Peer-Groups
Using the clear ip bgp update-group command
Using the debug ip bgp groups command
Using the show ip bgp replication command
Using the show ip bgp update-group command
Configuration Examples for BGP Dynamic Update Peer-Groups
clear ip bgp update-group Example
show ip bgp replication Example
show ip bgp update-group Example
BGP Dynamic Update Peer-Groups
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.
Feature History for the BGP Dynamic Update Peer-Groups Feature
12.0(24)S
This feature was introduced.
12.2(18)S
This feature was integrated in Cisco IOS Release 12.2(18)S.
12.3(4)T
This feature was integrated in Cisco IOS Release 12.3(4)T.
Finding Support Information for Platforms and Cisco IOS Software Images
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Contents
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Information About BGP Dynamic Update Peer-Groups
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Information About BGP Dynamic Update Peer-Groups
To support this feature, you must understand the following concepts:
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BGP Update Generation and Dynamic Update Peer-Groups
In previous versions of Cisco IOS software, BGP update messages were grouped based on peer-group configurations. This method of grouping neighbors 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:
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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.
BGP Dynamic Update Peer-Groups and BGP Configuration Using Peer Templates
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 BGP Configuration Using Peer Templates document.
BGP Dynamic Update Peer-Group Configuration
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 section "How to Monitor and Maintain BGP Dynamic Update Peer-Groups."
How to Monitor and Maintain BGP Dynamic Update Peer-Groups
The BGP Dynamic Update Peer-Groups feature introduces the following new commands:
This section contains the following procedures:
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Using the clear ip bgp update-group command
The clear ip bgp update-group command is used to clear BGP update-group member sessions. Use the following steps to complete this task:
SUMMARY STEPS
1.
2.
DETAILED STEPS
Using the debug ip bgp groups command
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:
SUMMARY STEPS
1.
2.
DETAILED STEPS
Using the show ip bgp replication command
The show ip bgp replication command is used to display BGP update-group statistics. Use the following steps to complete this task:
SUMMARY STEPS
1.
2.
DETAILED STEPS
Using the show ip bgp update-group command
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:
SUMMARY STEPS
1.
2.
DETAILED STEPS
Configuration Examples for BGP Dynamic Update Peer-Groups
The following examples illustrate the configuration and verification of this feature:
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clear ip bgp update-group Example
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
debug ip bgp groups Example
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:
Router# debug ip bgp groups5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.5 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.5 flags 0x0 cap 0x0 and updgrp 2 fl05w4d: BGP-DYN(0): Update-group 2 flags 0x0 cap 0x0 policies same as 10.4.9.5 fl05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.8 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.8 flags 0x0 cap 0x0 and updgrp 2 fl05w4d: BGP-DYN(0): Update-group 2 flags 0x0 cap 0x0 policies same as 10.4.9.8 fl05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.21 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.21 flags 0x0 cap 0x0 and updgrp 1 f05w4d: BGP-DYN(0): Update-group 1 flags 0x0 cap 0x0 policies same as 10.4.9.21 f05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.5 Up5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.21 Up5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.8 Upshow ip bgp replication Example
The following sample output from the show ip bgp replication command shows update-group replication information for all for neighbors:
Router# show ip bgp replicationBGP Total Messages Formatted/Enqueued : 0/0Index Type Members Leader MsgFmt MsgRepl Csize Qsize1 internal 1 10.4.9.21 0 0 0 02 internal 2 10.4.9.5 0 0 0 0
show ip bgp update-group Example
The following sample output from the show ip bgp update-group command shows update-group information for all neighbors:
Router# show ip bgp update-groupBGP version 4 update-group 1, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Route map for outgoing advertisements is COST1Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 1 member:10.4.9.21BGP version 4 update-group 2, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 2 members:10.4.9.5 10.4.9.8
Where to Go Next
For information about the BGP Configuration Using Peer Templates feature, refer to the BGP Configuration Using Peer Templates document.
Additional References
The following sections provide references related to the BGP Dynamic Update Peer-Group feature:
Related Documents
BGP commands
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BGP configuration tasks
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BGP peer template configuration tasks
Standards
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, tools, and lots more. Registered Cisco.com users can log in from this page to access even more content.
TAC Home Page:
http://www.cisco.com/public/support/tac/home.shtml
BGP Support Page:
http://www.cisco.com/cgi-bin/Support/browse/psp_view.pl?p=Internetworking:BGP
Command Reference
This section documents new commands. All other commands used with this feature are documented in the Cisco IOS command reference publications.
New Commands
clear ip bgp update-group
To clear Border Gateway Protocol (BGP) update-group member sessions, use the clear ip bgp update-group command in privileged EXEC mode.
clear ip bgp update-group [index-group | ip-address]
Syntax Description
Defaults
No default behavior or values
Command Modes
Privileged EXEC
Command History
12.0(24)S
This command was introduced.
12.2(18)S
This command was integrated in Cisco IOS Release 12.2(18)S.
12.3(4)T
This command was integrated in Cisco IOS Release 12.3(4)T.
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:
Router# clear ip bgp update-group 10.0.0.1The following example clears update-group information for all peers in the index 1 update-group:
Router# clear ip bgp update-group 1Related Commands
debug ip bgp groups
To display information related to the processing of BGP update-groups, use the debug ip bgp update privileged EXEC mode. To disable the display of BGP update information, use the no form of this command.
debug ip bgp groups [index-group | ip-address]
no debug ip bgp groups
Syntax Description
Defaults
No default behavior or values
Command Modes
Privileged EXEC
Command History
12.0(24)S
This command was introduced.
12.2(18)S
This command was integrated in Cisco IOS Release 12.2(18)S.
12.3(4)T
This command was integrated in Cisco IOS Release 12.3(4)T.
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.
Note
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:
Router# debug ip bgp groups5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.8 flags 0x0 cap 0x0 and updgrp 1 fl05w4d: BGP-DYN(0): Created update-group(0) flags 0x0 cap 0x0 from neighbor 10.4.05w4d: BGP-DYN(0): Adding neighbor 10.4.9.8 flags 0x0 cap 0x0, to update-group 05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.8 UpThe 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:
Router# debug ip bgp groups5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.5 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.5 flags 0x0 cap 0x0 and updgrp 2 fl05w4d: BGP-DYN(0): Update-group 2 flags 0x0 cap 0x0 policies same as 10.4.9.5 fl05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.8 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.8 flags 0x0 cap 0x0 and updgrp 2 fl05w4d: BGP-DYN(0): Update-group 2 flags 0x0 cap 0x0 policies same as 10.4.9.8 fl05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.21 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.21 flags 0x0 cap 0x0 and updgrp 1 f05w4d: BGP-DYN(0): Update-group 1 flags 0x0 cap 0x0 policies same as 10.4.9.21 f05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.5 Up5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.21 Up5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.8 UpTable 1 describes the significant fields shown in the display.
Related Commands
Resets a BGP connection or session.
Clears BGP update-group member sessions.
Displays BGP update-group replication statistics.
Displays information about BGP update-groups.
show ip bgp replication
To display update replication statistics for Border Gateway Protocol (BGP) update-groups, use the show ip bgp replication command in EXEC mode.
show ip bgp replication [index-group | ip-address]
Syntax Description
Command Modes
EXEC
Command History
12.0(24)S
This command was introduced.
12.2(18)S
This command was integrated in Cisco IOS Release 12.2(18)S.
12.3(4)T
This command was integrated in Cisco IOS Release 12.3(4)T.
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:
Router# show ip bgp replicationBGP Total Messages Formatted/Enqueued : 0/0Index Type Members Leader MsgFmt MsgRepl Csize Qsize1 internal 1 10.4.9.21 0 0 0 02 internal 2 10.4.9.5 0 0 0 0The following sample output from the show ip bgp replication command shows update-group statistics for the 10.4.9.5 neighbor:
Router# show ip bgp replication 10.4.9.5Index Type Members Leader MsgFmt MsgRepl Csize Qsize2 internal 2 10.4.9.5 0 0 0 0Table 2 describes the significant fields shown in the display.
Related Commands
show ip bgp update-group
To display information about BGP update-groups, use the show ip bgp update-group command in EXEC mode.
show ip bgp update-group [index-group | ip-address] [summary]
Syntax Description
Command Modes
EXEC
Command History
12.0(24)S
This command was introduced.
12.2(18)S
This command was integrated in Cisco IOS Release 12.2(18)S.
12.3(4)T
This command was integrated in Cisco IOS Release 12.3(4)T.
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:
Router# show ip bgp update-groupBGP version 4 update-group 1, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Route map for outgoing advertisements is COST1Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 1 member:10.4.9.21BGP version 4 update-group 2, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 2 members:10.4.9.5 10.4.9.8Table 3 describes the significant fields shown in the display.
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:
Router# show ip bgp update-group 10.4.9.8 summarySummary for Update-group 2 :------------------------------BGP router identifier 10.4.9.4, local AS number 101BGP table version is 1, main routing table version 1Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd10.4.9.5 4 101 35 35 1 0 0 00:26:22 010.4.9.8 4 101 39 39 1 0 0 00:26:21 0Table 4 describes the significant fields shown in the display.
Related Commands
Glossary
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 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.
Note
Copyright © 2003 Cisco Systems, Inc. All rights reserved.
