Dear Marko,
I flapped the route and now the route from the 200.254.254.2 is the older
but still the other route was chosen as seen below.
R8#sh ip bgp vpnv4 all 123.123.123.123
BGP routing table entry for 1000:2:123.123.123.123/32, version 5
Paths: (1 available, best #1, no table)
Not advertised to any peer
200 1000
200.254.254.2 (metric 1) from 100.254.254.9 (100.254.254.9)
Origin IGP, metric 0, localpref 100, valid, internal, best
Extended Community: RT:1000:1000,
mpls labels in/out nolabel/203
BGP routing table entry for 1000:3:123.123.123.123/32, version 10
Paths: (1 available, best #1, no table)
Not advertised to any peer
200 1000
200.254.254.3 (metric 1) from 100.254.254.9 (100.254.254.9)
Origin IGP, metric 0, localpref 100, valid, internal, best
Extended Community: RT:1000:1000,
mpls labels in/out nolabel/303
BGP routing table entry for 1000:8:123.123.123.123/32, version 11
Paths: (2 available, best #1, table sp1000)
Advertised to update-groups:
1
200 1000, imported path from 1000:3:123.123.123.123/32
200.254.254.3 (metric 1) from 100.254.254.9 (100.254.254.9)
Origin IGP, metric 0, localpref 100, valid, internal, best
Extended Community: RT:1000:1000,
mpls labels in/out 816/303
200 1000, imported path from 1000:2:123.123.123.123/32
200.254.254.2 (metric 1) from 100.254.254.9 (100.254.254.9)
Origin IGP, metric 0, localpref 100, valid, internal
Extended Community: RT:1000:1000,
mpls labels in/out 816/203
Below also are some debugs while i flapped the route.
00:03:55: BGP: Import walker start version 9, end version 10
00:03:55: BGP: ... start import cfg version = 0
00:03:55: VPN: BGP nettable start scan for VPN sp1000
00:03:55: vpn: Start import processing for: 1000:3:123.123.123.123
00:03:55: vpn: Import check for sp1000; flags mtch
00:03:55: vpn: Import for sp1000 permitted; import flags mtch
00:03:55: BGP: Prefix 1000:3:123.123.123.123/32 to be imported as 1000:8:
123.123.123.123/32 -- Permitted
nexthop 200.254.254.3, origin i, localpref 100, metric 0, path 200 1000,
extended community RT:1000:1000
00:03:55: Path added
00:03:55: vpn: 1000:3:123.123.123.123 (ver 10), imported as:
00:03:55: vpn: 1000:8:123.123.123.123 (ver 11)
R8#
00:03:55: VPN: Scanning for import check is done.
*00:03:56: RT(sp1000): Nexthop for 123.123.123.123/32 updated*
R8#
I looked in Cisco but couldn't find any thing that could explain this
behaviour. I did like Bryan mentioned changed the RD and see if it changed
anything but also this didn't produce any result.
Waiting your feedback.
On Sun, Oct 18, 2009 at 1:43 PM, Marko Milivojevic <[email protected]>wrote:
> I am sure the "older route wins" selection takes place here. We should
> probably dig deeper on Cisco's site to find specifics on route
> selection in this case, but evidence points to it.
>
> Take a look, I will make comments in-line. To test, try removing the
> route in 1000:3, wait few minutes and reactivate it. See if the same
> selection takes place. If not, this is indeed the case. If the same
> route is chosen, we need to look even deeper (debug).
>
> > BGP routing table entry for 1000:2:123.123.123.123/32, version 8 <---
> note version
> > Paths: (1 available, best #1, no table)
> > Not advertised to any peer
> > 200 1000
> > 200.254.254.2 (metric 1) from 100.254.254.9 (100.254.254.9)
> > Origin IGP, metric 0, localpref 100, valid, internal, best
> > Extended Community: RT:1000:1000,
> > mpls labels in/out nolabel/214
>
> > BGP routing table entry for 1000:3:123.123.123.123/32, version 5 <---
> note version
> > Paths: (1 available, best #1, no table)
> > Not advertised to any peer
> > 200 1000
> > 200.254.254.3 (metric 1) from 100.254.254.9 (100.254.254.9)
> > Origin IGP, metric 0, localpref 100, valid, internal, best
> > Extended Community: RT:1000:1000,
> > mpls labels in/out nolabel/306
>
> > BGP routing table entry for 1000:8:123.123.123.123/32, version 9
> > Paths: (2 available, best #1, table sp1000) <--- Older route is chosen
> > Advertised to update-groups:
> > 1
> > 200 1000, imported path from 1000:3:123.123.123.123/32
> > 200.254.254.3 (metric 1) from 100.254.254.9 (100.254.254.9)
> > Origin IGP, metric 0, localpref 100, valid, internal, best
> > Extended Community: RT:1000:1000,
> > mpls labels in/out 816/306
> > 200 1000, imported path from 1000:2:123.123.123.123/32
> > 200.254.254.2 (metric 1) from 100.254.254.9 (100.254.254.9)
> > Origin IGP, metric 0, localpref 100, valid, internal
> > Extended Community: RT:1000:1000,
> > mpls labels in/out 816/214
>
> --
> Marko
> CCIE #18427 (SP)
> My network blog: http://cisco.markom.info/
>
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