[c-nsp] IP-VPN CE-PE local pref problem

Oliver Boehmer (oboehmer) oboehmer at cisco.com
Fri Oct 3 05:05:23 EDT 2008


That's strange... can you show "show ip bgp vpnv4 vrf ipvpn_00000001 <prefix>", this shows the resulting vrf BGP table (i.e. after import) which might or might not be identical to the "rd <rd>" output (wowever it looks like you're using the same RD on both PEs, so this might not make a difference here).
Can you disable soft-reconfiguration inbound from the PE-CE eBGP session and see if it helps?

	oli


Mark Tech <> wrote on Wednesday, October 01, 2008 11:15 AM:

> Hi, thanks for all the suggestions
> I have now changed the route-map are things are looking good.
> 5.14.93.0/24 is the route in question. In PE2, local pref can now be
> seen as 90  
> 
> PE1#show ip bgp vpnv4 rd 894:1
> BGP table version is 258, local router ID is 5.14.95.243
> 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
> Route Distinguisher: 894:1 (default for vrf ipvpn_00000001)
> *> 5.14.89.1/32   0.0.0.0                0         32768 ?
> *>i5.14.89.2/32   5.14.95.244            0    100      0 ?
> *> 5.14.93.0      5.14.93..222            0    100      0 65535 i
> 
> PE2#show ip bgp vpnv4 rd 894:1
> BGP table version is 285, local router ID is 5.14.95.244
> 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
> Route Distinguisher: 894:1 (default for vrf ipvpn_00000001)
> *>i5.14.89.1/32   5.14.95.243            0    100      0 ?
> *> 5.14.89.2/32   0..0.0.0                0         32768 ?
> *>i5.14.93.0      5.14.95.243            0    100      0 65535 i
> *                 5.14.93.226            0     90      0 65535 i
> <------------------------------------------------- 
> 
> ===========================================================
> 
> Going on from this, if I now check the routing installed in the vrf
> for 5.14.93.0/24, it seems to be installed in PE1 (with high local
> pref as expected)  
> 
> PE1#sh ip route vrf ipvpn_00000001
> Routing Table: ipvpn_00000001
>       5.14.89.0/32 is subnetted, 2 subnets
> B        5.14.89.1 is directly connected, 19:44:47, Loopback2
> B        5.14.89.2 [200/0] via 5.14.95.244, 19:43:47
>       5.14.93.0/24 is variably subnetted, 3 subnets, 3 masks
> B        5.14.93.0/24 [20/0] via 5.14.93.222, 00:02:42  
> <---------------------------------------- 
> C        5.14.93.220/30 is directly connected, GigabitEthernet3/48
> L        5.14.93.221/32 is directly connected, GigabitEthernet3/48
> 
> 
> However in PE2, there is no route to 5.14.93.0/24
> 
> PE2#sh ip route vrf ipvpn_00000001
> Routing Table: ipvpn_00000001
>       5.14.89.0/32 is subnetted, 2 subnets
> B        5.14.89.1 [200/0] via 5.14.95.243, 00:42:11
> B        5.14.89.2 is directly connected, 19:47:26, Loopback2
>       5.14.93.0/24 is variably subnetted, 2 subnets, 2 masks
> C        5..14.93.224/30 is directly connected, GigabitEthernet3/48
> L        5.14.93.225/32 is directly connected, GigabitEthernet3/48
> 
> If I change the local pref in PE2 from 90 to 110 for example, then
> PE2 becomes the primary route and the exact opposite happens, i.e.
> the 5.14.93.0/24 route is installed in PE2 and does not exist in PE1;
> is this normal behaviour?   
> 
> Regards
> 
> Mark
> 
> ----- Original Message ----
> From: Luan Nguyen <luan at netcraftsmen.net>
> To: Mark Tech <techconfig at yahoo.com>; David Freedman
> <david.freedman at uk.clara.net>; cisco-nsp at puck.nether.net 
> Sent: Tuesday, September 30, 2008 8:03:38 PM
> Subject: RE: [c-nsp] IP-VPN CE-PE local pref problem
> 
> 
> Try changing the route-map to:
> 
> route-map ipvpn_00000001 permit 10
> set extcommunity soo 894:1
> set local-preference 90
> 
> instead of:
> 
> route-map ipvpn_00000001 permit 10
> set extcommunity soo 894:1
> 
> route-map ipvpn_00000001 permit 20
> set local-preference 90
> 
> Luan
> 
> 
> ----------------------------------------------------------------------------
> -------------------------------------------------------------------------
> Luan Nguyen
> Senior Network Engineer
> Chesapeake NetCraftsmen, LLC.
> www.NetCraftsmen.net
> ----------------------------------------------------------------------------
> -------------------------------------------------------------------------
> 
> 
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Mark Tech
> Sent: Tuesday, September 30, 2008 2:55 PM
> To: David Freedman; cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] IP-VPN CE-PE local pref problem
> 
> Here you go
> 
> PE1#sh ip bgp vpnv4 rd 894:1 5.14.93.0
> BGP routing table entry for 894:1:5.14.93.0/24, version 222
> Paths: (3 available, best #2, table ipvpn_00000001)
>   Advertised to update-groups:
>      1
>   65535
>     5.14.95.244 (metric 11) from 5.14.95.244 (5.14.95.244)
>       Origin IGP, metric 0, localpref 100, valid, internal
>       Extended Community: SoO:894:1 RT:894:2
>       mpls labels in/out 26/23
>   65535
>     5.14.93.222 from 5.14.93.222 (5.14.93.253)
>       Origin IGP, metric 0, localpref 100, valid, external, best
>       Extended Community: SoO:894:1 RT:894:2
>       mpls labels in/out 26/nolabel
>   65535, (received-only)
>     5.14.93.222 from 5.14.93.222 (5.14.93.253)
>       Origin IGP, metric 0, localpref 100, valid, external
>       mpls labels in/out 26/nolabel
> 
> 
> PE2#sh ip bgp vpnv4 rd 894:1 5.14.93.0
> BGP routing table entry for 894:1:5.14.93.0/24, version 237
> Paths: (3 available, best #1, table ipvpn_00000001)
>   Advertised to update-groups:
>      1
>   65535
>     5.14.93.226 from 5.14.93.226 (5..14.93.254)
>       Origin IGP, metric 0, localpref 100, valid, external, best
>       Extended Community: SoO:894:1 RT:894:2
>       mpls labels in/out 23/nolabel
>   65535, (received-only)
>     5.14.93.226 from 5.14.93.226 (5.14.93.254)
>       Origin IGP, metric 0, localpref 100, valid, external
>       mpls labels in/out 23/nolabel
>   65535
>     5.14.95.243 (metric 11) from 5.14.95.243 (5.14.95.243)
>       Origin IGP, metric 0, localpref 100, valid, internal
>       Extended Community: SoO:894:1 RT:894:2
>       mpls labels in/out 23/26
> 
> inbound route-map from CE2 to PE2
> route-map ipvpn_00000001 permit 10
>  set extcommunity soo 894:1
> 
> route-map ipvpn_00000001 permit 20
>  set local-preference 90
> !
> 
> 
> 
> ----- Original Message ----
> From: David Freedman <david.freedman at uk.clara.net>
> To: cisco-nsp at puck.nether.net
> Sent: Tuesday, September 30, 2008 5:51:55 PM
> Subject: Re: [c-nsp] IP-VPN CE-PE local pref problem
> 
> can you post "show ip bgp vpnv4 rd <rd> x.x.x.x/y" from both PEs ? for
> the prefix in question?
> 
> Dave
> 
> Mark Tech wrote:
>> Hi
>> I have set up a dual homed IP-VPN network between 2 PE's and 2 CE's
>> using SoO - thas all working fine. 
> 
> I have added an inbound route-map to the 'backup' PE and CE to reduce
> the local preference in order to make the other PE and CE the
> preferred 
> gateways.
>> 
>> CE1--------PE1 primary
>>>                   |
>> CE2--------PE2 backup
>> 
>> The CE local pref works fine, however on the PE side, local pref
>> doesn't seem to have any affect, 
> 
> i.e. I have reduced the local pref to 90 on the backup link, however
> if 
> I check the routing in the backup PE, nothing seems to have changed.
> Can 
> I just check that local pref actually works across an MP-BGP
> environment? 
>> 
>> If so I must be doing something wrong
>> 
>> Regards
>> 
>> Mark
>> 
>> 
>> 
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> 
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