How to see vpnV4 label ?

[ganpatspatil]

HI,

PE7#sh ip cef vrf cust1 22.22.22.22

22.0.0.0/8, version 16, epoch 0, cached adjacency 40.40.40.1

0 packets, 0 bytes

tag information set

local tag: VPN-route-head

fast tag rewrite with Fa0/0.40, 40.40.40.1, tags imposed: {17 28}

via 4.4.4.4, 0 dependencies, recursive

next hop 40.40.40.1, FastEthernet0/0.40 via 4.4.4.4/32

valid cached adjacency

tag rewrite with Fa0/0.40, 40.40.40.1, tags imposed: {17 28}

what this tag imposed {17 28 } signifies ?

[attrgautam]

17 will be the IGP label for the PE router from where the update was learnt. 28 will be the VPN label by the remote PE for the VPN prefix. You can check that using sh ip bgp vpnv4 vrf labels

[ganpatspatil]

Thank you very much..........attrgautam .

[malikusman301998]

Hi ganpatspatil,

To late to answer but a guidance for the others. 17 is the IGP label/tag that will specify the next hop using which you can reach other side of the MPLS VPN. For instance Router A will send a Traffic to Router B with label/tag 17 and the router will look up in the LFIB and perform the PHP functions and send the packet to the other router assuming that it is the router to which the destination is directly connected with.

Then the second label in the stack that is 28 will be used to identify the VRF to which the destination belongs to. This label is known as VPN label. In Cisco IOS XRv you can see the vrf to which the label/tag is belongs to using the command,

"show bgp label table"