Supporting BGP based IP-VPN in a routed network
View Patent ↗A new type of Provider Edge (PE) device is used to support BGP-based IP-VPNs. Each VRF instance in a PE device is associated with a dedicated IP address (Service IP address). Each service IP address is dedicated to a VRF in a PE device. The service IP address is distributed by BGP for VPN route association. Customer/VRF IP packets can be sent to a VRF instance in the egress PE device using service IP header encapsulation (with IP Destination Address=Service IP address of egress PE's VRF & IP Source Address=Service IP address of ingress PE's VRF). This obviates the need for explicit tunnels in the core.
1. Apparatus for providing virtual private network service in a routed network, comprising:
a first edge router comprising:
a plurality of virtual route forwarders including at least one source virtual route forwarder, each virtual route forwarder having a service IP address comprising an IP address which uniquely identifies that virtual route forwarder in the routed network;
a protocol engine configured to exchange routes and service IP addresses with a second edge router which has a plurality of virtual route forwarders including at least one destination virtual route forwarder, each virtual route forwarder having a service IP address comprising an IP address which uniquely identifies that virtual route forwarder in the routed network, the exchanged service IP addresses including the service IP addresses associated with the source virtual route forwarder and the destination virtual route forwarder; and
a forwarding plane configured to encapsulate a received protocol data unit with a service header, the service header including the service IP address associated with the source virtual route forwarder and the service IP address associated with the destination virtual route forwarder, and to transmit the encapsulated protocol data unit to the destination virtual route forwarder of the second edge router, the routed network routing the encapsulated protocol data unit using the service IP addresses, and without using L2TP, MPLS or a GRE-IP tunnel.
2. The apparatus of claim 1 wherein the service IP address of the source virtual route forwarder is a loop-back IP address.
3. The apparatus of claim 1 wherein the service IP address of the source virtual route forwarder is an interface or regular IP address.
4. The apparatus of claim 1 wherein the protocol engine is configured to transmit an update message which includes the service IP address dedicated to the source virtual route forwarder as a next-hop address.
5. The apparatus of claim 4 wherein a next-hop field in MP-REACH-NLRI, MP-UNREACH-NLRI is used to advertise the service IP address.
6. The apparatus of claim 4 wherein an update message is transmitted for each virtual route forwarder by a global routing engine.
7. The apparatus of claim 4 wherein a first portion of the service IP address is stored in a next-hop field and a second portion is stored in a service label location of MP-REACH-NLRI, MP-UNREACH-NLRI.
8. The apparatus of claim 4 wherein an RD value of the source virtual route forwarder is created using the service IP address as the IP address in a route distinguisher field.
9. The apparatus of claim 4 wherein the protocol engine is configured to utilize a modified MP-REACH-NLRI.
10. The apparatus of claim 1 wherein the first edge router stores the service IP address of the destination virtual route forwarder, and associates a VPN route with the service header in memory for subsequent lookup.
11. A method for providing virtual private network service in a device of a routed network, comprising:
with a first edge router comprising a plurality of virtual route forwarders including at least one source virtual route forwarder, each virtual route forwarder having a service IP address comprising an IP address which uniquely identifies that virtual route forwarder in the routed network:
exchanging routes and service IP addresses with a second edge router which has a plurality of virtual route forwarders including at least one destination virtual route forwarder, each virtual route forwarder having a service IP address comprising an IP address which uniquely identifies that virtual route forwarder in the routed network, the exchanged service IP addresses including the service IP addresses associated with the source virtual route forwarder and the destination virtual route forwarder;
encapsulating a received protocol data unit with a service header, the service header including the service IP address associated with the source virtual route forwarder and the service IP address associated with the destination virtual route forwarder; and
transmitting the encapsulated protocol data unit from the source virtual route forwarder to the destination virtual route forwarder, the routed network routing the protocol data unit without using L2TP, MPLS or a GRE-IP tunnel.
12. The method of claim 11 wherein the service IP address of the source virtual route forwarder is a loop-back IP address.
13. The method of claim 11 wherein the service IP address of the source virtual route forwarder is an interface or regular IP address.
14. The method of claim 11 including the further step of transmitting an update message which includes the service IP address dedicated to the source virtual route forwarder as a next-hop address.
15. The method of claim 14 including the further step of using a next-hop field in MP-REACH-NLRI, MP-UNREACH-NLRI to advertise the service IP address.
16. The method of claim 14 including the further step of transmitting a separate update message for each virtual route forwarder.
17. The method of claim 14 including the further step of storing a first portion of the service IP address in a next-hop field and storing a second portion in a service label location of MP-REACH-NLRI, MP-UNREACH-NLRI.
18. The method of claim 14 including the further step of creating a route distinguisher value of the source virtual route forwarder using the service IP address as the IP address in a route distinguisher field.
19. The method of claim 14 including the further step of utilizing a modified MP-REACH-NLRI.
20. The method of claim 11 wherein the first edge router stores the service IP address of the destination virtual route forwarder, and associates a VPN route with the service header in memory for subsequent lookup.