Carrying Address Families without MPLS / LDP in BGP Peers

[sourav goyal]

Hi,

Can we exchange / carry Multiple & VPN address families around BGP Peers with out forming any MPLS/LDP/LSP relation among them.

or MPLS is only method to achieve sharing Multiple & VPN Address families.

Regards

Sourav 

[Nagendra Kumar Nainar]

Hi Sourav,

You can use BGP peering to advertise different AF. FOr example, IPv4 session could be used to advetise both IPv4 and IPv6. As long as the nexthop advetised is reachable via respective AF, it should not be a problem. When you use IIPv4 session to advertise IPv6 prefixes, they still will be advertised with IPv6 nexthop. Your device should have reachability to this IPv6 nexthop.

MPLS comes into picture when your underlay is different address family. For example 6PE scenarios where you advertise IPv6 over IPv4 network. So you use a modified IPv6 nexthop (v4-mapped-v6) and use LSP to label switch Ipv6 packet over IPv4 underlay network.

If the network is dual stacked, MPLS is not required.

HTH,

Nagendra

[sourav goyal]

Dear Kumar,

have updated my query,,

seeking behaviour for VRF / VPN address families.

what you think about that.

thanks !

[Nagendra Kumar Nainar · Accepted solution]

Hi,

When an egress receives a packet from core, it needs a way to identify the VPN/VRF it belongs to. When core is MPLS enabled, the labels are used for this purpose. When core is IP (non-MPLS), it still is possible using mGRE.

Below is a sample configuration:

http://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/layer-3-vpns-l3vpn/116725-configure-mgre-00.html

Thanks,

Nagendra