Information Technology Reference
In-Depth Information
A BGP session cannot be associated with both a peer group and peer templates. The peer
templates feature is expected to ultimately replace the peer group feature. However, they
will continue to coexist for quite some time.
Update Groups
The update replication aspect of traditional peer groups is where the dynamic aspect of
dynamic peer groups comes into play. Peer templates provide a highly flexible replacement
for peer group configuration. However, this is based on relaxing the requirements that make
update replication across a peer group possible.
The router builds update groups dynamically based on examining the outbound policy of
the configured BGP sessions. The router dynamically assigns BGP peers to update groups
that have the same outbound policy configuration. No configuration is required for this
feature.
When changes are made to the outbound policy of BGP peers, the router automatically
recalculates the update groups. If any changes are required, the router automatically trig-
gers a soft clear outbound for all affected BGP peers.
You can obtain information about BGP update groups with the
show ip bgp update-group
command, as shown in Example 3-8.
Command Output for
show ip bgp update-group
Example 3-8
Router#show ip bgp update-group
...
BGP version 4 update-group 4, external, Address Family: IPv4 Unicast
BGP Update version : 0, messages 9482/0
Update messages formatted 11134, replicated 1002060
Number of NLRIs in the update sent: max 0, min 0
Minimum time between advertisement runs is 30 seconds
Has 91 members (* indicates the members currently being sent updates):
10.0.101.1 *10.0.101.100 *10.0.101.11 *10.0.101.12
*10.0.101.13 *10.0.101.14 *10.0.101.15 *10.0.101.16
*10.0.101.17 *10.0.101.18 *10.0.101.19 *10.0.101.20
... <TRUNCATED>
The output from Example 3-8 shows the essential information about the update group. The
truncated information consists of the rest of the IP addresses for update group members. In
this example, the update group 4 consists of IPv4 unicast eBGP peers. The replication
statistics provided include the number of BGP Update messages formatted and replicated.
The number of peers in the update group is given, along with a listing of those peers. An
asterisk next to a peer's IP address indicates that updates are still being sent to that peer.
