| 摘要 |
<p>RSVP-TE Enhancement for MPLS-FRR Bandwidth Optimization is a method of RSVP-TE protocol enhancement for optimizing network resources when FRR is protecting LSP traffic in a topology where the bypass LSP tunnel traverses the original previous hop(s) of the protected LSP. The basic idea is to enhance the RSVP-TE protocol such that the node providing FRR protection, the PLR, in such a topology where it will send traffic back towards the original path in the bypass tunnel, will use the enhanced message TLVs to report to the nodes all the way back to the HE node. The node(s) on the original path prior to the PLR node can check if there is a better alternative bypass tunnel to use to provide FRR from a network resource optimization perspective (such as using the bypass tunnel from the HE node in a ring topology to reduce the traffic in the ring). A first node of a ring serves as the HE node. Data packets that are being sent from the HE node to the TE node typically follow a predefined path, proceeding from hop to hop until reaching the ultimate destination at the TE node. However, when a link failure occurs during the transmission of the data packets, the point of local repair (PLR) node implements FRR protection via its bypass tunnel. The data packet will travel into the bypass tunnel and go back from hop to hop to the HE node and proceed from the opposite direction of the ring to the TE node. TLV messages prevent subsequent data packets from having to take the same path as the original data packets, promoting bandwidth efficiency. The TLV messages permit subsequent data packets being sent from the HE node to the TE node to use the HE node's bypass tunnel directly rather than traveling to the PLR node and then traversing back the same path they came before finally traveling to the TE node. The proposed enhanced RSVP-TE protocol will have several new TLVs in a PathErr (notification of local repair) message, a RESV (stop sending refresh) message and a ResvErr (dismissing detour) message. When the HE node of the protected LSP receives the PathErr TLV, it switches to use its local bypass tunnel to send traffic to the opposite direction of the ring. The HE node will from now on use its bypass tunnel to send the traffic of the protected LSP to the TE node. The HE node will also notify the original PLR by sending another new TLV in the ResvErr message indicating that a better bypass was found and the detour is dismissed, and the original PLR will stop refreshing the LSP through the tunnel and stop sending the PathErr message to the HE node.</p> |
