P2MP TE Tunnel Fast Reroute via RSVP-TE Branch LSP Segmentation
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Solution Overview
Problem
Conventional mechanisms lack the ability to establish point to multipoint (P2MP) Traffic Engineering (TE) tunnels, which are essential for managing bandwidth and quality of service in computer networks, particularly in scenarios involving multiple destinations.
Innovation Solution
The techniques extend Resource Reservation Protocol with Traffic Engineering (RSVP-TE) to create point to multipoint (P2MP) TE tunnels by utilizing RSVP semantics, establishing branch LSPs between source and receiver provider edge routers and merging them to form a P2MP TE LSP, allowing for efficient packet replication and minimizing state and intelligence in the network core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional RSVP-TE mechanisms are used, then point to point (P2P) TE tunnels can be established, but point to multipoint (P2MP) TE tunnels cannot be established
Solution Approach 1:
The P2MP tunnel is segmented into multiple P2P branch LSPs that share common path segments. Each branch LSP is established independently using existing RSVP-TE P2P mechanisms, while the shared segments are identified and merged by the network. This segmentation allows P2MP functionality to be built from P2P components without requiring complete protocol redesign.
Solution Approach 2:
The invention makes the existing RSVP-TE protocol universal by enabling it to handle both P2P and P2MP tunneling through the same signaling mechanism. The protocol maintains its original P2P signaling while adding the capability to establish multiple branch LSPs that converge to form a P2MP tree, thus achieving multi-functionality without increasing device complexity.
2Reliability
If bypass tunnels are established for fast reroute, then traffic can be rerouted during link or node failures, but network state and intelligence requirements increase
Solution Approach 1:
Bypass tunnels are pre-established during normal operation before any failures occur. The fast reroute capability is prepared in advance by setting up backup paths and configuring the network state, so that when a failure occurs, traffic can be switched to the bypass tunnel immediately without requiring complex real-time computation or decision-making during the failure event.
Data Source
AI summary
Techniques are described for fast reroute of traffic associated with a point to multi-point (P2MP) tunnel. A system may, for example, include a source network device and a plurality of destination network devices. The system further includes a label switched path (LSP) tunnel from the source network device to the plurality of destination network devices. The LSP tunnel includes a plurality of branch LSPs and may include one or more bypass tunnel associated with one or more of the branch LSPs. In other configurations, the system may include a second LSP tunnel from the source network device to the plurality of destination network devices. The second LSP tunnel includes a plurality of detour branch LSPs, and each of the detour branch LSPs corresponds to a respective one of the branch LSPs for the first P2MP LSP tunnel.