4 Replies Latest reply: Oct 20, 2009 12:55 PM by Conwyn RSS

    VRF on L3 switch

    Shaikh  Nizamuddin

      Hi Guys,

       

      I have some questions abt vrf.

      what is vrf?

      how it is used in layer 3 switch like 6509?

       

      till date i have seen vrf being mostly used in MPLS VPN but how one can use it on a core switch to support different customers which are using different type of wan connectivity?

       

       

      Nizam

        • 1. Re: VRF on L3 switch
          Scott Morris - CCDE/4xCCIE/2xJNCIE

          A VRF is a Virtual Routing/Forwarding instance.  In other words, a "mini routing table" that's isolated from all the others.

           

          While it comes from MPLS VPNs, you can use it without MPLS entirely.  This is called VRF-Lite.  And basically what it does is disables the requirement for an MBGP back-end to exist.  So you'll just have some interfaces with Cust-A, some with Cust-B, etc.  And each operates in their own little world without regard/care for anyone else.  

           

          HTH,

           

          Scott

          • 2. Re: VRF on L3 switch
            Conwyn

            Hi Shaikh

             

            ip vrf NetworkA
            rd 81:81
            !
            ip vrf NetworkB
            rd 82:82

            !

            interface FastEthernet0/0
            ip vrf forwarding NetworkA
            ip address 10.0.0.1 255.255.255.0
            duplex auto
            speed auto
            !
            interface FastEthernet0/1
            ip vrf forwarding NetworkB
            ip address 10.0.0.1 255.255.255.0
            duplex auto
            speed auto

             

            Router#show ip int brief
            Interface                  IP-Address      OK? Method Status                Protocol
            FastEthernet0/0            10.0.0.1        YES manual up                    up

            FastEthernet0/1            10.0.0.1        YES manual up                    up

             

            Regards Conwyn

            • 3. Re: VRF on L3 switch
              Scott Morris - CCDE/4xCCIE/2xJNCIE

              Just a quick point there Conwyn.

               

              The better show commands would be "show ip route" and "show ip route vrf NetworkA" and "show ip route vrf NetworkB"

               

              Scott

              • 4. Re: VRF on L3 switch
                Conwyn

                Hi Scott

                 

                Oh No - you spotted my little joke of duplicate IPs on the router.  I really do use VRF lite.

                 

                Regards Conwyn