i am trying to configure as-et with bgp aggregation but sounds somthing missing
in the attached topology
R0 AS 1
R1 AS 10
R2 as 20
i have advertised route from R1 then aggregate it
normally apear in all peers
als i did advertised a route in R2 THEN i aggregated this route in R1
this way R2 recive this aggregate as well
with as set i put it as 20 in the aggregate this way i blocked the summary from being seen by AS 20 only nice
the problem is
if i am tring to block the summary route advertised and aggregated in R1 useing as-et i get the whole summary route droped from R1 routing table and from others as well !! why?
in R1 i have the summary 184.108.40.206/16
now i blocked this summry from being sent to R2 but R0 now leaking the summry to R2
what i am trying to do is to add as 20 to the summary route this way even if R0 will leak it R2 will drop becuase it will see its AS in the as path of the summry route logical good
i did the following and the route get droped from the source R1 where i did the config and the summary and advertisment !!
i as-path access-list 1 permit ^20$
match as-path 1
Router bgp 10
aggregate-address 220.127.116.11 255.255.0.0 summary-only as-set advertise-map map1
then after this the route /16 disapear ???
note: i just need it like this is for study perpuses not a practical case
I was working on one of Narbik's advanced workbook tonight and it's similar to what you are asking. See the attachment
FYI, the question is truncated....
1. r2 should aggregate all the networks in 18.104.22.168 address space...........
2. Aggregation should be configured such that R1 in AS 100 is the only AS that receives the aggregate route, R3 and future peer neighbors should NOT receive the aggregate route.
Hi thanks for this information
but i did somthing like this and worked with me
if i want to apply my case to the yours
the oute is in R2 in your case and aggregated into bgp
and there is requirement to send only specific route to R1 and no aggregate but becuase R1 has link to R3 r3 sending this aggregate
with AS-set i want to pretend that AS of R1 is in the path by adding it through the advertise map
note: this description based on your case not my topology
Can you try removing the aggregate-address command and reapplying it.
actually i did alot of times
i just wanna know why when i do it like this the aggregate route disapear from R1 the one which dose the aggregation and then of course will disapear from others?
i think smothing worng but i cant find !!
This should work. I just tried a quick test as follow.
router bgp 2
aggregate-address 22.214.171.124 255.0.0.0 as-set summary-only advertise-map map1
neighbor 192.168.12.1 remote-as 1
ip as-path access-list 1 permit ^1$
route-map map1 permit 10
match as-path 1
Here are the results:
R2#sh ip bgp
BGP table version is 4, local router ID is 126.96.36.199
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 188.8.131.52 0.0.0.0 32768 1 i
s> 184.108.40.206/32 192.168.12.1 0 0 1 i
As you can see, the summary does get generated.
Can you post your full config for the R1.
Thanks for the additional information. I was a bit confused as I thought that the more specific routes to create 220.127.116.11/16 were advertised by AS 20.
The reason why it doesn't work is that your route-map map1 matches on AS 20 but this ASN doesn't exist in any of the more specific routes as they are originated in AS 10.
The purpose of the advertise-map is to select from the more specific routes, which ones will be selected to create the aggregate. In your case, none of the more specific routes qualify, hence the aggregate not being created.
i think i realized that but i wanted a confirmation
thanks for that,
i asked becuase i was reading a ccie lab case
and in the bgp
there was the following whihc i did not agree but they did it like this ( it is internetworkexpert)
there is a BB router in AS 54 ( 2 of them )
and lets say R1 in AS200 and R2 in AS 100
forst they asked to let AS 54 see R1 as in AS 100
now R1 is summrizing route not from R2 but it should be denied from going to R2
becuase R1 and R2 connected to BB AS 54 now AS 54 is leaking the summary to R2
the solusion for this is to make as i asked add R2 AS number to the summary route that R1 make it which is AS 100
but the contradiction here first we made R1 AS 200 to apear to AS54 as AS 100 (above) thats mean we will not need this step becuase AS 54 will see it as from AS 100
AM i right in this ?
also if want to make it with advertise map will not work becuase it is as the answer you have given to me !!
I can't really comment on the requirements directly as I haven't seen them but from what you are telling me the scenario seems a bit confused.
it is confusing you are CCIE and you know CCIE asks only complex things :)
anyway you confirmed to me what i have seen i mean the more specific prefixes need to be on the router that doing the aggregation from at least one AS not the local to use as set with a route map
in other words if i have the routes advertised by R1 and aggregated by R1 i cant add other any other AS in the as-set
in the above what is meant exactly
lets say you have tow routers R1 and R2
R1 AS 10 and R2 as 20
both of them connected to a router lets say R4 and R5
R4 and R5 are in one AS lets say AS 50
now in the case R1 havs route and has been aggregated this is fine
in the begining one of the requrement asked R1 should apear to AS 50 as it is in AS 20 !
done with local-as command
now AS 50 see any routes from R1 as its coming from AS 20 not the original one which is 10
other requremnt asked to filter out the aggrgate from being sent from R1 AS 10 to R2 AS 20 filter fine
but the issue here as they asked later that AS 50 is leaking the aggregate as both connected to it they solved it with as-set by adding as 20 to the aggrgate
there to problems first one is as you mentioned above the route need to be coming fron AS 20 at least one spicific route to make the as-set
why we doing this as in the begning we made R1 apear as in AS 20 this way AS 50 will send the aggregate to R2 as from AS 20 and thus will be droped because R2 in AS 20
sorry about that but i would like to share it with you :)
if you agree with me let me