From: Alejandro Cadarso (a.cadarso@xxxxxxxxxxxxxx)
Date: Fri Aug 25 2000 - 11:31:09 GMT-3
Hi All,
Let's say we have three sub-ASes 1031, 1034 and 1039 connected sequencially lik
e this:
(AS1031)---(AS1034)---(AS1099)
They are part of the BGP confederation 100.
I know that within the subAS, all the BGP routers need to be fully meshed. Cool
.
1.- It is required to fully mesh the sub-ASes, that is do I have configure EBGP
peers between AS1031 and AS1099
also ?
I think it is not required, but I wanted to confirm, in my lab everything seems
to go Ok:
3640-1031#sh ip bgp summ
BGP router identifier 190.19.15.209, local AS number 1031
BGP table version is 5, main routing table version 5
1 network entries and 1 paths using 133 bytes of memory
1 BGP path attribute entries using 52 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP activity 2/15 prefixes, 3/2 paths, scan interval 15 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRc
d
190.19.15.65 4 1034 281 280 5 0 0 00:19:09 1
3640-1031#sh ip bgp
BGP table version is 5, local router ID is 190.19.15.209
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
*> 190.1.0.0 192.19.18.1 0 100 0 (1034 1099) i
I'm a little bit confused because the only sample configuration I could find ab
out confeds
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ics/icsbgp4.htm#xtocid2765140
>!Router C
>router bgp 65050
>bgp confederation identifier 500
>bgp confederation peers 65060 65070
>neighbor 128.213.10.1 remote-as 65050
>neighbor 128.213.20.1 remote-as 65050
>neighbor 128.210.11.1 remote-as 65060
>neighbor 135.212.14.1 remote-as 65070
>neighbor 5.5.5.5 remote-as 100
It seems to indicate that you need peering between every Sub-AS, assuming this:
I wasn't able to establish a peering session without the command:
neighbor 135.212.14.1 ebgp-multihop
I think it's logical, because it's an eBGP session, but I can't understand how
this sample configuration from Cisco (the only one
you could find in its Documentation) misses it.
2.- If you have peering between every Sub-AS then you have redundant informatio
n for each route and I think it could cause some
problem because the best route is the one you have from your multihop peering.
3640-1031#sh ip bgp summ
BGP router identifier 190.19.15.209, local AS number 1031
BGP table version is 8, main routing table version 8
1 network entries and 2 paths using 169 bytes of memory
2 BGP path attribute entries using 104 bytes of memory
2 BGP AS-PATH entries using 48 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP activity 2/25 prefixes, 5/3 paths, scan interval 15 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRc
d
190.19.15.65 4 1034 315 316 8 0 0 00:53:29 1
190.19.15.66 4 1099 20 21 8 0 0 00:12:54 1
3640-1031#sh ip bgp
BGP table version is 8, local router ID is 190.19.15.209
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
*> 190.1.0.0 192.19.18.1 0 100 0 (1099) i
* 192.19.18.1 0 100 0 (1034 1099) i
3.- Finally, if a router is part of a confederation and has no other connection
s other to a member of it's own Sub-AS in the
conferedation, do you still need to configure the confederation identifier and
which are its confederation peers Sub-ASs??
Alejandro
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:24:30 GMT-3