Hello, If all the individual paths have the same AS_PATH, then the aggregate will have that same AS_PATH.
On Sat, Oct 31, 2009 at 9:31 AM, jmangawang <jmangaw...@gmail.com> wrote: > 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 > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > -- Bryan Bartik CCIE #23707 (R&S), CCNP Sr. Support Engineer - IPexpert, Inc. URL: http://www.IPexpert.com
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com