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

Wed Oct 1 05:15:04 EDT 2008

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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