The PE router stores both local and remote routes and includes a label entry for each route. For distributed platforms, the multiplicity of per-prefix labels consume memory. When there are many VRFs and routes, the amount of memory that the per-prefix labels consume can cause performance degradation on some platform devices. To avoid this issue, the MPLS VPN 6VPE per VRF Label feature allows the advertisement of a single VPN label for local routes throughout the entire VRF. The router uses a new VPN label for the VRF decoding and IP-based lookup to learn where to forward packets for the PE or customer edge (CE) interfaces.

The following conditions apply when you configure the MPLS VPN 6VPE per VRF Label feature:

• The VRF uses one label for all local routes.
• When you enable the MPLS VPN 6VPE per VRF Label feature, any existing per VRF aggregate label is used. If no per VRF aggregate label is present, the software creates a new 6VPE per VRF label.
• When you enable the MPLS VPN 6VPE per VRF Label feature, the CE router's learned local routes will experience some data loss.

The CE does not lose data when you disable the MPLS VPN 6VPE per VRF Label feature because the configuration reverts to the default labeling configuration of the Cisco 7600 platform, which uses the Per VRF Aggregate label from the local nonCE-sourced routes.

• When you disable the MPLS VPN 6VPE per VRF Label feature, the configuration reverts to the default configuration of the Cisco 7600 routers.
• A 6VPE Per VRF Label forwarding entry is deleted only if the VRF, the IPv6 VRF address family, or the BGP configuration is removed.

See the Implementing IPv6 VPN over MPLS (6VPE) configuration guide for detailed information about IPv6 VPN services and 6VPE.

1.    enable

2.    configure terminal

3.    mpls label mode {vrf vrf-name | all-vrfs} protocol {bgp-vpnv6 | all-afs} {per-prefix | per-vrf}

4.    end

5.    show vrf detail vrf-name

• Examples
  
• Troubleshooting Tips
  

The following example shows the 6VPE default label mode configuration (no label mode) for the Cisco 7600 router.

In this example output, the bold text indicates the default label mode for VPN1.

Router# show vrf detail vpn1
VRF vpn1 (VRF Id = 1); default RD 1:1; default VPNID <not set>
  Interfaces:
    GE4/1                    Lo1                     
Address family ipv4 (Table ID = 1 (0x1)):
  Connected addresses are not in global routing table
  Export VPN route-target communities
    RT:1:1                  
  Import VPN route-target communities
    RT:1:1                   RT:2:2                  
  No import route-map
  No export route-map
  VRF label distribution protocol: not configured
  VRF label allocation mode: per-prefix
    vrf-conn-aggr for connected and BGP aggregates (Label 17)
Address family ipv6 (Table ID = 503316481 (0x1E000001)):
  Connected addresses are not in global routing table
  Export VPN route-target communities
    RT:1:1                  
  Import VPN route-target communities
    RT:1:1                  
  No import route-map
  No export route-map
  VRF label distribution protocol: not configured
  VRF label allocation mode: per-prefix
    vrf-conn-aggr for connected and BGP aggregates (Label 18)

Router# show bgp vpnv6 unicast vrf vpn1 label
   Network          Next Hop      In label/Out label
Route Distinguisher: 1:1 (vpn1)
   2001:DB8:1:2::/96
                    2001:DB8:1:2::1 IPv6 VRF Aggr:18/nolabel
                    ::              IPv6 VRF Aggr:18/nolabel(vpn1)
   2001:DB8:4:5::/96
                    ::FFFF:127.0.0.4
                                    nolabel/17
   2001:DB8:2::1/128
                    ::              IPv6 VRF Aggr:18/nolabel(vpn1)
   2001:DB8:4::1/128
                    ::FFFF:127.0.0.4
                                    nolabel/18
   2001:DB8:CE2::1/128
                    ::FFFF:127.0.0.4
                                    nolabel/19
   2001:DB8:CE1::1/128
                    2001:DB8:1:2::1 19/nolabel
Router# show mpls forwarding
Local  Outgoing      Prefix            Bytes Label   Outgoing   Next Hop    
Label  Label or VC   or Tunnel Id      Switched      interface              
16     Pop Label     127.0.0.4/32      0             AT3/0/0.1  point2point 
17     Pop Label     IPv4 VRF[V]       0             aggregate/vpn1             
18     Pop Label     IPv6 VRF[V]       0             aggregate/vpn1             
19     No Label      2001:DB8:CE1::1/128[V]
                                       0             GE4/1      FE80::20C:CFFF:FEAD:A00A