Backup P2MP LSP Sub-Tree for MPLS Ingress Egress Protection

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Solution Overview

Problem

Current methods for protecting ingress and egress nodes in Multiprotocol Label Switching (MPLS) networks, such as those using backup P2MP LSP approaches, require additional network resources and may cause delays in traffic delivery, which is unacceptable for real-time services like VoIP and IPTV.

Innovation Solution

The system and method involve designating a backup ingress node and a backup egress node to detect failures and reroute traffic via a backup P2MP LSP sub-tree, merging it back into the primary P2MP LSP without establishing a separate backup P2MP LSP to all egress nodes, thus conserving resources and reducing delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate backup P2MP LSP is established to all egress nodes, then reliability is improved, but network resource consumption increases

Engineering Contradiction:

Improveingress and egress node protectionVSAvoidnetwork bandwidth

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The backup path is segmented into two parts: a shared backup P2MP LSP from backup ingress node to a merge point, and the existing primary P2MP LSP from ingress node to egress nodes. This segmentation allows the backup path to share resources with the primary path after the merge point, reducing overall bandwidth consumption while maintaining protection capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The backup P2MP LSP merges with the primary P2MP LSP at a designated merge point downstream. After merging, both primary and backup traffic flow through the same path to egress nodes, eliminating redundant bandwidth consumption on the shared downstream path while maintaining end-to-end protection.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If a separate backup P2MP LSP is established to all egress nodes, then reliability is improved, but traffic delivery delay increases

Engineering Contradiction:

Improvenode failure protectionVSAvoidtraffic delivery delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The backup P2MP LSP is pre-established from the backup ingress node to the merge point, with all routing and label switching information configured in advance. When failure occurs, traffic can immediately switch to the pre-configured backup path without computation or setup delay, minimizing traffic delivery delay while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If backup P2MP LSP sub-tree is used instead of separate backup P2MP LSP, then network resource consumption is reduced, but protection scope is limited

Engineering Contradiction:

Improvenetwork bandwidthVSAvoidprotection coverage

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The shared backup P2MP LSP sub-tree serves multiple functions: it provides backup capacity for the primary P2MP LSP, can be activated for any failure point along the path, and merges with the primary path to serve all downstream egress nodes. This multi-functionality achieves comprehensive protection coverage without requiring separate dedicated backup paths for each egress node.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8773978B2System and method for protecting ingress and egress of a point-to-multipoint label switched path

Publication Date: 2014.07.08 FUTUREWEI TECHNOLOGIES INC

AI summary

A network comprising a first edge node, a second edge node, a third edge node that backs up either the first edge node or the second edge node, and an internal node coupled to the first edge node, the second edge node, and the third edge node, wherein a point-to-multipoint (P2MP) label switched path (LSP) extends across the network from the first edge node, through the internal node, and to the second edge node, and wherein a LSP sub-tree extends between the third edge node and the internal node, but does not extend across the network.