I was going thru new Workbook 3 ver 11 Volume 1 lab and was trying some
stuff out with BGP. One task was to configure an aggregate address for
network from AS 4 in BGP. FYI, ASes are lined up as AS4---AS256---AS9.
Easy enough. I did this in AS 256 with the no-summary command and as-set
options. But, when I do a "show ip bgp" on the AS 9 router, I expected the
AS path to show the path as "256 {4}". It didn't. It showed it as "256 4".
When I remove the as-set option, it properly shows the AS path as only
"256". I'm using proctor labs, pod 120, and the IOS is 12.4(24)T1. I
googled some examples and they all show aggregated addresses with their
as-set in curly braces. Anybody know why this might be? Here are some
outputs:
R5 is in AS 256 and aggregating networks received from R4 in AS4.
R5(config-router)#do sh ip bgp
--cut out--
Network Next Hop Metric LocPrf Weight Path
*> 204.40.0.0/14 0.0.0.0 100 32768 4 i
s> 204.40.4.4/32 141.141.45.4 0 0 4 i
s> 204.41.4.4/32 141.141.45.4 0 0 4 i
s> 204.42.4.4/32 141.141.45.4 0 0 4 i
s> 204.43.4.4/32 141.141.45.4 0 0 4 i
R9 is in AS 9. Per requirements of task, R9 is using local-as 99 and
talking with R6 that is using local-as 66 (which is why you see AS99 and 66
also in the path).
R9(config-router)#do sh ip bgp
--cut out--
Network Next Hop Metric LocPrf Weight Path
*> 204.40.0.0/14 6.6.6.6 0 99 66 256 4 i
Only indication any aggregation has been done is the blurb that says that
(aggregated by 256 5.5.5.5).
R9(config-router)#do sh ip bgp 204.40.0.0/14
BGP routing table entry for 204.40.0.0/14, version 17
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Advertised to update-groups:
2
99 66 256 4, (aggregated by 256 5.5.5.5)
6.6.6.6 (metric 2297856) from 6.6.6.6 (6.6.6.6)
Origin IGP, localpref 100, valid, external, best
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