Deployment Guide

Border Gateway Protocol IPv4 (BGPv4) | 407
Usage
Information
In BGP, route attributes are maintained at different locations. When attributes that correspond to
multiple routes change, then attribute counts that the show ip bgp summary command displays are
calculated as summations of attributes corresponding to all the associated routes. For example, if
cluster_id is an attribute associated with thousand routes that contain exactly the same set of attributes,
then the cluster_id count is 1. If these thousand routes are set with different attribute values with the
same cluster_id, then the cluster_id count is 1000, since the same value is stored for thousand different
attribute records.
The attribute next-hop is a part of the BGP attribute data structure.
If two peers send the same route that contains similar path attributes, then two entries are maintained in
the back-end, as both these entries have different next-hops. If this same route is sent to a different
peer, an entry for each peer is created, as the next-hop is different. As a result, the BGP attributes count
in the summary output will differ accordingly.
Example
Figure 12-27. Command Example: show ip bgp summary
Table 12-16. Command Example fields: show ip bgp summary
Field Description
BGP router identifier Displays the local router ID and the AS number.
BGP table version Displays the BGP table version and the main routing table version.
network entries Displays the number of network entries and route paths and the amount of
memory used to process those entries.
paths Displays the number of paths and the amount of memory used.
denied paths Displays the number of denied paths and the amount of memory used.
BGP path attribute entries Displays the number of BGP path attributes and the amount of memory
used to process them.
BGP AS-PATH entries Displays the number of BGP AS_PATH attributes processed and the
amount of memory used to process them.
BGP community entries Displays the number of BGP COMMUNITY attributes processed and the
amount of memory used to process them. The show ip bgp community
command provides more details on the COMMUNITY attributes.
Dampening enabled Displayed only when dampening is enabled. Displays the number of paths
designated as history, dampened, or penalized.
Neighbor Displays the BGP neighbor address.
AS Displays the AS number of the neighbor.
#show ip bgp summary
BGP router identifier 120.10.10.1, local AS number 100
BGP table version is 34, main routing table version 34
9 network entrie(s) using 1372 bytes of memory
5 paths using 380 bytes of memory
4 denied paths using 164 bytes of memory
BGP-RIB over all using 385 bytes of memory
2 BGP path attribute entrie(s) using 168 bytes of memory
1 BGP AS-PATH entrie(s) using 39 bytes of memory
1 BGP community entrie(s) using 43 bytes of memory
2 neighbor(s) using 7232 bytes of memory
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
100.10.10.2 200 46 41 34 0 0 00:14:33 5
120.10.10.2 300 40 47 34 0 0 00:37:10 0
#