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Highlighted
Beginner

Inter vrf - MPLS link

Hello

 

I'm trying to setup a poc where I want to interconnect vrf's.

2 Branches with different subnets connected with a mpls connection. 

 

I have following setup: 

PC1 ---- SW1 -----SW2----PC2

 

Config SW1:

 

ip vrf MGMNT
rd 65000:200
route-target export 65000:200
route-target import 65000:200

interface Loopback0
 ip address 1.1.1.1 255.255.255.255
!
interface GigabitEthernet0/1
 switchport access vlan 200
 switchport mode access
!
interface GigabitEthernet0/0
 no switchport
 ip address 10.10.10.1 255.255.255.252
 mpls ip
!
interface Vlan200
 ip vrf forwarding MGMNT
 ip address 10.100.10.1 255.255.255.0
!
router bgp 65000
 bgp log-neighbor-changes
 neighbor 2.2.2.2 remote-as 65000
 neighbor 2.2.2.2 update-source Loopback0
 !
 address-family vpnv4
  neighbor 2.2.2.2 activate
  neighbor 2.2.2.2 send-community both
  neighbor 2.2.2.2 next-hop-self
 exit-address-family
 !
 address-family ipv4 vrf MGMNT
  redistribute connected
 exit-address-family

!
ip route 2.2.2.2 255.255.255.255 10.10.10.2
!

 

Config SW2:

 

ip vrf MGMNT
 rd 65000:200
 route-target export 65000:200
 route-target import 65000:200
!

interface Loopback0
 ip address 2.2.2.2 255.255.255.255
!
interface GigabitEthernet0/1
 switchport access vlan 200
 switchport mode access
!
interface GigabitEthernet0/0
 no switchport
 ip address 10.10.10.2 255.255.255.252
 mpls ip
!
interface Vlan200
 ip vrf forwarding MGMNT
 ip address 10.200.10.1 255.255.255.0
!
router bgp 65000
 bgp log-neighbor-changes
 neighbor 1.1.1.1 remote-as 65000
 neighbor 1.1.1.1 update-source Loopback0
 !
 address-family vpnv4
  neighbor 1.1.1.1 activate
  neighbor 1.1.1.1 send-community both
  neighbor 1.1.1.1 next-hop-self
 exit-address-family
 !
 address-family ipv4 vrf MGMNT
  redistribute connected
 exit-address-family
!

ip route 1.1.1.1 255.255.255.255 10.10.10.1

!

 

PC1:

ip: 10.100.10.10/24

PC2: 

ip: 10.200.10.10/24

 

Both PC's can ping their gateway. If I want to ping from one side to the other however, pings don't return.

I'm not sure what's wrong here or is the virtual setup the cause here.

 

Any help appreciated.

Thanks a lot.

 

3 REPLIES 3
Highlighted
Beginner

Re: Inter vrf - MPLS link

Some show commands:

 

Is it normal behavior that there is no label for that one subnet, while SW2 (mirror config) does get a label for it's subnet.

 

SW1#show mpls forwarding-table
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
17         Pop Label  2.2.2.2/32       0             Gi0/0      10.10.10.2
18         No Label   10.100.10.0/24[V]   \
                                       0             aggregate/MGMNT

 

SW2#show mpls forwarding-table
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
16         Pop Label  1.1.1.1/32       0             Gi0/0      10.10.10.1
18         Pop Label  10.200.10.0/24[V]   \
                                       13514         aggregate/MGMNT

 

 

SW1#show ip route vrf MGMNT
Routing Table: MGMNT
Gateway of last resort is not set
      10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C        10.100.10.0/24 is directly connected, Vlan100
L        10.100.10.1/32 is directly connected, Vlan100
B        10.200.10.0/24 [200/0] via 2.2.2.2, 00:30:53
 
SW2#show ip route vrf MGMNT
Routing Table: MGMNT
Gateway of last resort is not set
      10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
B        10.100.10.0/24 [200/0] via 1.1.1.1, 00:30:46
C        10.200.10.0/24 is directly connected, Vlan200
L        10.200.10.1/32 is directly connected, Vlan200
 
 
Kind regards.

 

 

Highlighted
Collaborator

Re: Inter vrf - MPLS link

Hi,

 

    Control-plane works, as you see the routes; data-plane is the problem, due to the missing label on SW1; try rebooting it.

 

Regards,

Cristian Matei.

Highlighted
Hall of Fame Master

Re: Inter vrf - MPLS link

Hello Cristian,

thanks for having provided this useful suggestion!

At first sight SW1 looked like correct but compared to SW2 output the no label is like a ringing bell when troubleshooting MPLS issues.

 

control plane even when an IP only path exists.

the forwarding plane requires an MPLS end to end path working

 

L3 VPN use two labels the inner label is provided by MP BGP as an attribute of the MP NLRI.

 

SW1 failed to allocate a label to the locally attached route /FEC in VRF with real devices I would look to licensing problems in IOS XR or nexus NX OS but here the SW1 and SW2 are likely running IOS XE.

 

Best Regards

Giuseppe