Extranet connectivity in LISP networks

1. A Location/Identifier Separation Protocol (LISP) mapping server, comprising:

a network interface for communicating with a LISP-enabled network;

a mapping database;

an extranet policy table; and

a shared subnetwork mapping engine (SSME) implemented by a processor and configured to:

receive a map request from a first endpoint serviced by a first tunneling router (xTR), the first endpoint on a first subnetwork, the map request for a second endpoint;

determine that the second endpoint is not a member of the first subnetwork based on the mapping database;

query the extranet policy table to identify a second subnetwork that the first subnetwork subscribes to, and to determine that the second endpoint is a member of the second subnetwork; and

provide to the first subnetwork a routing locator (RLOC) of an xTR servicing the second endpoint.

2. The LISP mapping server of claim 1 , wherein the second subnetwork is an extranet.

3. The LISP mapping server of claim 1 , wherein the first subnetwork is a consumer segment, and the second subnetwork is a provider segment.

4. The LISP mapping server of claim 1 , wherein the SSME is configured to provide to the first subnetwork the RLOC of the xTR servicing the second endpoint by providing an instance identifier (IID).

5. The LISP mapping server of claim 1 , wherein the SSME is further configured to provide multicast semantics.

6. The LISP mapping server of claim 5 , wherein the multicast semantics comprises receiving from the first endpoint a registration of interest for a multicast event from the second subnetwork, receiving from a third endpoint a registration of interest for the multicast event from the second subnetwork, identifying the first endpoint and third endpoint as listeners for the multicast event via the extranet policy table, and providing to the second subnetwork RLOCs for the first endpoint and third endpoint.

7. The LISP mapping server of claim 1 , wherein the SSME is further configured to send a copy of the extranet policy table to the first xTR.

8. The LISP mapping server of claim 1 , wherein the SSME is further configured to receive an extranet subnetwork registration from the first xTR.

9. The LISP mapping server of claim 8 , wherein the SSME is further configured to receive a registration for a subscribing subnetwork from another xTR, and to add the subscribing subnetwork to the mapping database for an extranet subnetwork.

10. One or more non-transitory computer-readable mediums having stored thereon executable instructions to instruct a hardware platform to:

communicatively couple to a LISP-enabled network;

provision a mapping database;

provision an extranet policy table; and

provide a shared subnetwork mapping engine (SSME) to:

receive a map request from a first endpoint serviced by a first tunneling router (xTR), the first endpoint on a first subnetwork, the map request for a second endpoint;

determine that the second endpoint is not a member of the first subnetwork based on the mapping database;

query the extranet policy table to identify a second subnetwork that the first subnetwork subscribes to, and to determine that the second endpoint is a member of the second subnetwork; and

provide to the first subnetwork a routing locator (RLOC) of an xTR servicing the second endpoint.

11. The one or more non-transitory computer-readable mediums of claim 10 , wherein the second subnetwork is an extranet.

12. The one or more non-transitory computer-readable mediums of claim 10 , wherein the first subnetwork is a consumer segment, and the second subnetwork is a provider segment.

13. The one or more non-transitory computer-readable mediums of claim 10 , wherein the SSME is to provide to the first subnetwork the RLOC of the xTR servicing the second endpoint by providing an instance identifier (IID).

14. The one or more non-transitory computer-readable mediums of claim 10 , wherein the SSME is to provide multicast semantics comprises receiving from the first endpoint a registration of interest for a multicast event from the second subnetwork, receiving from a third endpoint a registration of interest for the multicast event from the second subnetwork, identifying the first endpoint and third endpoint as listeners for the multicast event via the extranet policy table, and providing to the second subnetwork RLOCs for the first endpoint and third endpoint.

15. The one or more non-transitory computer-readable mediums of claim 10 , wherein the SSME is further to send a copy of the extranet policy table to the first xTR.

16. The one or more non-transitory computer-readable mediums of claim 10 , wherein the SSME is further configured to receive an extranet subnetwork registration from the first xTR.

17. The one or more non-transitory computer-readable mediums of claim 16 , wherein the SSME is further configured to receive a registration for a subscribing subnetwork from another xTR, and to add the subscribing subnetwork to the mapping database for an extranet subnetwork.

18. A Location/Identifier Separation Protocol (LISP) tunneling router (xTR), comprising:

a processor; and

an xTR routing engine executed by the processor and configured to:

communicatively couple to a consumer subnetwork; and

register the consumer subnetwork to a mapping server with a consumer subnetwork flag.

19. The LISP xTR of claim 18 , wherein the xTR routing engine is further configured to:

communicatively couple to a provider subnetwork; and

register the provider subnetwork to the mapping server with a provider subnetwork flag.

20. The LISP xTR of claim 18 , wherein the xTR routing engine is further configured to:

receive from the mapping server a copy of an extranet policy table for mapping between the consumer subnetwork and a provider subnetwork.