>Hello Group, > >I got a problem with BGP aggregate route being advertised out to another AS, >and then readvertised back to the original AS through another entry router. > >R5_________R6 > | > R7 > >Basically an ethernet segment R5, R6, R7 on the same subnet. R5 & R6 in >AS600, and R7 in AS500. R5 sends out an aggregate of 172.16.0.0/16 to R7, >and then somehow R6 learns this aggregate route also.
Several observations. I would advise against using no sync. As Peter van Oene has pointed out, it does't give a signficant performance benefit in modern AS topologies, and Juniper consciously doesn't even have a knob for it. Next, I'm still confused what is being relearned, and how this creates a problem. Are you saying your routing policy is such that only the aggregating router should know about the aggregate? You want something like a NO-ADVERTISE policy on iBGP but _not_ a NO-EXPORT policy on eBGP? Why, if so? Again, I'm not seeing what problem is being caused, but could a blackhole local route for the aggregate, on R6, solve it? > >Configs: > >R5# >router bgp 620 > no synchronization > bgp router-id 10.10.10.5 > bgp log-neighbor-changes > bgp confederation identifier 600 > aggregate-address 172.16.0.0 255.255.0.0 as-set suppress-map sup_map > neighbor 10.10.10.4 remote-as 620 > neighbor 10.10.10.4 update-source Loopback0 > neighbor 10.10.10.7 remote-as 500 > neighbor 10.10.10.7 ebgp-multihop 2 > neighbor 10.10.10.7 update-source Loopback0 > neighbor 10.10.10.7 route-map set_med out > no auto-summary >! > >BGP table version is 16, local router ID is 10.10.10.5 >Status codes: s suppressed, d damped, h history, * valid, > best, i - >internal >Origin codes: i - IGP, e - EGP, ? - incomplete > > Network Next Hop Metric LocPrf Weight Path >*> 172.16.0.0 0.0.0.0 100 32768 (610) i >s>i172.16.1.0/24 216.30.30.2 0 100 0 (610) i >s>i172.16.2.0/24 216.30.30.2 0 100 0 (610) i >s>i172.16.3.0/24 216.30.30.2 0 100 0 (610) i >*>i172.16.4.0/24 216.30.30.2 0 100 0 (610) i >*> 192.168.22.0 10.10.10.7 0 500 400 i >R5# > > >R6# >router bgp 620 > no synchronization > bgp router-id 10.10.10.6 > bgp log-neighbor-changes > bgp confederation identifier 600 > neighbor 10.10.10.4 remote-as 620 > neighbor 10.10.10.4 update-source Loopback0 > neighbor 10.10.10.7 remote-as 500 > neighbor 10.10.10.7 ebgp-multihop 2 > neighbor 10.10.10.7 update-source Loopback0 > neighbor 10.10.10.7 route-map set_med out > no auto-summary >! > >BGP table version is 24, local router ID is 10.10.10.6 >Status codes: s suppressed, d damped, h history, * valid, > best, i - >internal >Origin codes: i - IGP, e - EGP, ? - incomplete > > Network Next Hop Metric LocPrf Weight Path >*>i172.16.0.0 10.10.10.5 100 0 (610) i >*>i172.16.1.0/24 216.30.30.2 0 100 0 (610) i >*>i172.16.2.0/24 216.30.30.2 0 100 0 (610) i >*>i172.16.3.0/24 216.30.30.2 0 100 0 (610) i >*>i172.16.4.0/24 216.30.30.2 0 100 0 (610) i >* i192.168.22.0 10.10.10.7 100 0 500 400 i >*> 10.10.10.7 0 500 400 i >R6# > >R7# >router bgp 500 > bgp router-id 10.10.10.7 > bgp log-neighbor-changes > neighbor 10.10.10.5 remote-as 600 > neighbor 10.10.10.5 ebgp-multihop 2 > neighbor 10.10.10.5 update-source Loopback0 > neighbor 10.10.10.6 remote-as 600 > neighbor 10.10.10.6 ebgp-multihop 2 > neighbor 10.10.10.6 update-source Loopback0 > neighbor 10.10.10.6 route-map change_weight in > neighbor 10.10.10.8 remote-as 400 > neighbor 10.10.10.8 ebgp-multihop 2 > neighbor 10.10.10.8 update-source Loopback0 > maximum-paths 2 > no auto-summary >! > >BGP table version is 9, local router ID is 10.10.10.7 >Status codes: s suppressed, d damped, h history, * valid, > best, i - >internal >Origin codes: i - IGP, e - EGP, ? - incomplete > > Network Next Hop Metric LocPrf Weight Path >*> 172.16.0.0 10.10.10.5 0 600 i Sent out to R7 >* 10.10.10.5 0 600 i Some how learnt it twice >*> 172.16.1.0/24 10.10.10.6 150 600 i >*> 172.16.2.0/24 10.10.10.6 0 600 i >*> 172.16.3.0/24 10.10.10.6 0 600 i >*> 172.16.4.0/24 10.10.10.5 50 0 600 i >* 10.10.10.6 100 0 600 i >*> 192.168.22.0 10.10.10.8 0 0 400 i >R7# Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=27822&t=27822 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
