P2MP Ring LSP Signaling via Leaf Identification Object
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Solution Overview
Problem
In computer networks, establishing point-to-multipoint (P2MP) label switched paths (LSPs) in ring networks requires sending multiple resource reservation request messages, which is inefficient and consumes computing resources, especially when dealing with a large number of leaf network devices.
Innovation Solution
The technique involves signaling a P2MP ring LSP by sending a single resource reservation request message that includes a leaf identification object, allowing network devices to explicitly or implicitly identify themselves as leaf nodes, thereby reducing the need for multiple messages and eliminating the requirement for Explicit Route Objects (ERO) or Record Route Objects (RRO), thus conserving resources and improving scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple resource reservation request messages are sent to establish P2MP ring LSPs, then resource reservation can be achieved, but signaling overhead and computing resource consumption increase
Solution Approach 1:
The patent combines multiple resource reservation request messages into a single message by introducing a leaf identification object that lists multiple leaf nodes. Instead of sending separate RSVP_PATH messages to each leaf node, the ingress router sends one consolidated message containing identifiers for all leaf nodes, thereby reducing signaling overhead while maintaining complete resource reservation functionality
Solution Approach 2:
The leaf identification object serves multiple functions: it identifies all leaf nodes in the P2MP LSP, enables intermediate routers to determine whether they should branch to additional leaves, and provides a universal mechanism that works for any number of leaf nodes without requiring separate messaging protocols
2Reliability
If multiple resource reservation request messages are sent, then complete path establishment is achieved, but path state storage and computing resources are consumed
Solution Approach 1:
The patent merges multiple path states into a single consolidated path state by using the leaf identification object to represent all destination leaf nodes. Routers maintain one path state entry that includes the list of leaf identifiers, rather than maintaining separate path state entries for each individual leaf node, thereby reducing memory consumption while preserving complete path establishment information
3Reliability
If traditional RSVP-TE signaling is used for P2MP ring LSPs, then resource reservation is established, but scalability is limited due to multiple messages requirement
Solution Approach 1:
The leaf identification object creates a universal signaling mechanism that can accommodate any number of leaf nodes without requiring changes to the fundamental RSVP-TE protocol structure. The same single-message approach works whether there are 2 leaf nodes or 200 leaf nodes, enabling the system to scale efficiently while maintaining reliable resource reservation
Solution Approach 2:
The patent changes the parameter structure by introducing a list-based leaf identification object that can dynamically accommodate varying numbers of leaf nodes. This parameter change allows the signaling mechanism to adapt to different network sizes and configurations without requiring multiple different message types or protocols
Data Source
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AI summary
Techniques are described for signaling a resource reservation point-to-multipoint (P2MP) label switched path (LSP) in a ring network. For example, the techniques include sending a single resource reservation request message without the ingress needing to send multiple resource reservation request messages, one for each leaf network device of the P2MP ring LSP. The resource reservation request message includes a leaf identification object from which network devices of a P2MP ring LSP may explicitly or implicitly identify themselves as prospective leaf network devices of the P2MP ring LSP. A network device determined to be a leaf network device may send a resource reservation response message back to the ingress network device of the P2MP ring LSP and send a modified resource reservation request message (if explicit) and/or the same resource reservation request message (if implicit) to a next hop network device along the P2MP ring LSP.