Automation fallback to P2P LSPs for mLDP built multipoint-trees

An apparatus comprising:

• a first circuit configured to send a multicast label distribution protocol (LDP) label mapping message to a non-multicast LDP enabled core router;
• a second circuit configured to receive a first message from the non-multicast LDP enabled core router in response to the first circuit sending the multicast LDP label mapping message to the non-multicast LDP enabled core router;
• and
• a third circuit configured to send the multicast LDP label mapping message to a first edge router via a directed LDP session in response to the second circuit detecting that a multicast LDP session cannot be established with the edge router, wherein the detecting is based in part on the received first message.

A system comprising:

• first and second multicast label distribution protocol (LDP) enabled edge routers coupled to each other via a multicast LDP enabled core router and a non-multicast LDP enabled core router;
• wherein the first multicast LDP enabled edge router is configured to receive a protocol independent multicast (PIM) Join message;
• wherein the multicast LDP enabled core router is configured to receive a message from the non-multicast LDP enabled core router in response to the multicast LDP enabled core router sending a label mapping message to the non-multicast LDP enabled core router;
• wherein the multicast LDP enabled core router is configured to create a directed LDP session with the second multicast LDP enabled edge router in response to detecting that a multicast LDP session cannot be established with the second multicast LDP enabled edge router, wherein
• the detecting is based in part on the received message;
• and
• wherein the multicast LDP enabled core router is configured to send the label mapping message to the second multicast LDP enabled edge router via the directed LDP session.