White Papers

Version Description
9.10(0.1) Introduced on the S6010-ON and S4048T-ON.
9.10(0.0) Introduced on the S3148.
9.10(0.0) Introduced on the S6100-ON.
9.8(2.0) Introduced on the S3100 series.
9.8(1.0) Introduced on the Z9100–ON.
9.8(0.0P5) Introduced on the S4048-ON.
9.8(0.0P2) Introduced on the S3048-ON.
9.7(0.0) Added the ipv4 multicast and ipv6 unicast parameters.
9.4.(0.0) Added support for VRF.
9.2(1.0) Introduced on the Z9500.
9.0.2.0 Introduced on the S6000.
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.3.7.0 Introduced on the S4810.
7.8.1.0 Introduced on the S-Series.
7.7.1.0 Introduced on the C-Series.
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.
The following describes the show ip bgp summary command shown in the following example.
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, 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.
440 Border Gateway Protocol