Methods and routers for connectivity setup between provider edge routers

A method carried out by a router, wherein

• the router is at least one of an autonomous system border router, an area border router, and a route reflector,
• the router is also a Border Gateway Protocol (BGP) speaker;
• and
• the router stores filtering information to limit the propagation of network layer reachability information (NLRI);
• the method comprising:
• determining that a BGP update message comprising
• NLRI specific to a virtual private network (VPN-NLRI), and path information comprising an address of a next hop for said VPN-NLRI is due to be sent by the router to another BGP speaker (BGP peer);
• determining that the filtering information does not allow propagation, to the BGP peer, of NLRI comprising the address of the next-hop;
• modifying the filtering information to permit propagation, to the BGP peer, of NLRI comprising the address of the next hop;
• and
• sending the BGP update message to the BGP peer.

A network node for hosting a router function, wherein

• the network node is at least one of an autonomous system border router, an area border router, and a route reflector,
• the network node is also a Border Gateway Protocol (BGP) speaker;
• and
• the network node stores filtering information to limit the propagation of network layer reachability information (NLRI);
• the network node comprising:
• a receiving unit configured to receive, from another BGP speaker, a BGP update message comprising
• NLRI specific to a virtual private network (VPN-NLRI), and
• path information comprising an address of a next hop for said VPN-NLRI;
• a determining unit configured to determine that there is no route to the next hop;
• a modifying unit configured to modify the filtering information to permit propagation of NLRI comprising the address of the next hop;
• and
• a sending unit configured to send the modified filtering information to BGP neighbours of the network node.

A network node for hosting a router function, wherein

• the network node is at least one of an autonomous system border router, an area border router, and a route reflector,
• the network node is also a Border Gateway Protocol (BGP) speaker;
• and
• the network node stores filtering information to limit the propagation of network layer reachability information (NLRI);
• the network node comprising:
• a first determining unit configured to determine that a BGP update message comprising NLRI specific to a virtual private network (VPN-NLRI), and path information comprising an address of a next hop for said VPN-NLRI is due to be sent by the router to another BGP speaker (BGP peer);
• a second determining unit configured to determine that the filtering information does not allow propagation, to the BGP peer, of NLRI comprising the address of the next-hop;
• a modifying unit configured to modify the filtering information to permit propagation, to the BGP peer, of NLRI comprising the address of the next hop;
• and
• a sending unit configured to send the BGP update message to the BGP peer.