Monday 16 July 2012

Multi VRF

The configuration below shows how to configure the PE and CE routers to extend a VRF to a customer site. This allows a CE (customer) router to support two separate routing tables. This configuration was created on GNS3 with IOS version c2691-adventerprisek9-mz.124-25d.bin. Parts of the configuration below have been omitted for brevity:


! PE (Provider Edge) Router Configuration

!
hostname PE-Router
!
! Create two VRFs 
ip vrf VRF1
 rd 1:100
 route-target export 1:100
 route-target import 1:100
!
ip vrf VRF2
 rd 2:100
 route-target export 2:100
 route-target import 2:100
!
! Create a loopback interface to act as the BGP router ID, note it is not part of
! a vrf
interface Loopback0
 ip address 100.1.1.1 255.255.255.255
!
! Create two more loopback interfaces, one in each VRF. This was just done to 
! illustrate that you can use overlapping address space
interface Loopback1
 ip vrf forwarding VRF1
 ip address 1.1.1.1 255.255.255.255
!
interface Loopback2
 ip vrf forwarding VRF2
 ip address 1.1.1.1 255.255.255.255
!
interface FastEthernet0/0
 no ip address
 speed 100
 full-duplex
!
! Create two subinterface with a dot1q tag and assign to each vrf
interface FastEthernet0/0.1
 encapsulation dot1Q 1 native
 ip vrf forwarding VRF1
 ip address 192.168.1.1 255.255.255.0
!
interface FastEthernet0/0.2
 encapsulation dot1Q 2
 ip vrf forwarding VRF2
 ip address 192.168.2.1 255.255.255.0
!
! Configure the BGP section
router bgp 1
 no synchronization
 bgp router-id 100.1.1.1
 bgp log-neighbor-changes
 no auto-summary
 !
 address-family ipv4 vrf VRF2
  redistribute connected
  neighbor 192.168.2.254 remote-as 100
  neighbor 192.168.2.254 activate
  no synchronization
 exit-address-family
 !
 address-family ipv4 vrf VRF1
  redistribute connected
  neighbor 192.168.1.254 remote-as 100
  neighbor 192.168.1.254 activate
  no synchronization
 exit-address-family
!

===============================================================


! CE (Customer Edge) Router Configuration

!
hostname CE-Router
!
! On this router we just create one VRF - the other received routes are going
! to go into the global routing table
ip vrf VRF2
 rd 2:100
!
interface FastEthernet0/0
 no ip address
 speed 100
 full-duplex
!
! Create subinterfaces with dot1q tags - note that only Fa0/0.2 has
! a vrf forwarding statement
interface FastEthernet0/0.1
 encapsulation dot1Q 1 native
 ip address 192.168.1.254 255.255.255.0
!
interface FastEthernet0/0.2
 encapsulation dot1Q 2
 ip vrf forwarding VRF2
 ip address 192.168.2.254 255.255.255.0
!
interface FastEthernet0/1
 no ip address
 speed 100
 full-duplex
!
! BGP configuration - note how one neighbour statement is in the global
! section and one is in the "address-family ipv4" section
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 redistribute connected
 neighbor 192.168.1.1 remote-as 1
 no auto-summary
 !
 address-family ipv4 vrf VRF2
  redistribute connected
  neighbor 192.168.2.1 remote-as 1
  neighbor 192.168.2.1 activate
  no synchronization
 exit-address-family
!

===============================================================

On the PE router:

! Only the loopback0 interface is in the global routing table
PE-Router#sh ip ro
     100.0.0.0/32 is subnetted, 1 subnets
C       100.1.1.1 is directly connected, Loopback0

PE-Router#sh ip route vrf VRF1
     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback1
C    192.168.1.0/24 is directly connected, FastEthernet0/0.1

PE-Router#sh ip route vrf VRF2
     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback2
C    192.168.2.0/24 is directly connected, FastEthernet0/0.2

PE-Router#sh ip bgp vpnv4 all
BGP table version is 14, local router ID is 100.1.1.1
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: 1:100 (default for vrf VRF1)
*> 1.1.1.1/32       0.0.0.0                  0         32768 ?
*  192.168.1.0      192.168.1.254            0             0 100 ?
*>                  0.0.0.0                  0         32768 ?
Route Distinguisher: 2:100 (default for vrf VRF2)
*> 1.1.1.1/32       0.0.0.0                  0         32768 ?
*  192.168.2.0      192.168.2.254            0             0 100 ?
*>                  0.0.0.0                  0         32768 ?

On the CE router:

CE-Router#sh ip ro
     1.0.0.0/32 is subnetted, 1 subnets
B       1.1.1.1 [20/0] via 192.168.1.1, 00:44:36
C    192.168.1.0/24 is directly connected, FastEthernet0/0.1

CE-Router#sh ip route vrf VRF2
     1.0.0.0/32 is subnetted, 1 subnets
B       1.1.1.1 [20/0] via 192.168.2.1, 00:39:49
C    192.168.2.0/24 is directly connected, FastEthernet0/0.2

CE-Router#sh ip bgp summary
BGP router identifier 192.168.1.254, local AS number 100
BGP table version is 4, main routing table version 4
2 network entries using 234 bytes of memory
3 path entries using 156 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 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 using 786 total bytes of memory
BGP activity 5/1 prefixes, 7/1 paths, scan interval 60 secs

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
192.168.1.1     4     1      54      53        4    0    0 00:45:31        2

CE-Router#sh ip bgp vpnv4 all
BGP table version is 7, local router ID is 192.168.1.254
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: 2:100 (default for vrf VRF2)
*> 1.1.1.1/32       192.168.2.1              0             0 1 ?
*  192.168.2.0      192.168.2.1              0             0 1 ?
*>                  0.0.0.0                  0         32768 ?


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