Upstream Label Assignment for RSVP-TE P2MP LSPs

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Solution Overview

Problem

In computer networks, especially with increasing size and complexity, traffic congestion occurs due to approaching maximum bandwidth capacity on links, leading to inefficiencies in routing and traffic replication, particularly in Multi-Protocol Label Switching (MPLS) networks when handling multicast packets.

Innovation Solution

The implementation of upstream label assignment extensions to the Resource Reservation Protocol with Traffic Engineering (RSVP-TE) allows for the distribution of upstream labels across multiple downstream routers, enabling a single packet transmission and avoiding traffic replication on Local Area Networks (LANs) for Point to Multi-Point (P2MP) Label Switched Paths (LSPs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional RSVP-TE is used for P2MP LSPs, then multicast packets can be delivered to multiple destinations, but traffic replication occurs on LANs causing bandwidth inefficiency and congestion

Engineering Contradiction:

Improvebandwidth utilization efficiencyVSAvoidnetwork bandwidth consumption

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent inverts the traditional label assignment approach by having the upstream router assign labels to downstream routers instead of downstream routers assigning labels upstream. This inversion enables the upstream router to control label distribution and avoid traffic replication on LANs, thereby improving bandwidth utilization efficiency and reducing network bandwidth consumption.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces upstream label assignment as an intermediary mechanism that mediates between the source router and multiple downstream routers. The upstream router acts as an intermediary that receives single packets and distributes them to multiple downstream routers using assigned labels, eliminating the need for downstream routers to replicate traffic on LANs.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If downstream routers perform traffic replication on LANs, then all destinations receive multicast packets, but this increases device complexity and processing overhead

Engineering Contradiction:

Improvemulticast delivery reliabilityVSAvoidbranch router replication complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the traffic replication function from downstream branch routers and relocates it to the upstream router. By removing the replication responsibility from downstream routers, the patent reduces device complexity and processing overhead at branch routers while maintaining reliable multicast delivery through upstream-controlled label switching.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The upstream router performs self-service by assigning labels to itself for downstream routers, eliminating the need for downstream routers to perform complex replication operations. This self-service approach simplifies the overall system by centralizing the replication function at the upstream router that has better visibility of the network topology.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If multiple labels are assigned downstream for each P2MP LSP, then traffic can be routed to multiple destinations, but this increases the number of labels required and complicates label management

Engineering Contradiction:

Improvemulticast path flexibilityVSAvoidlabel management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the upstream router multi-functional by enabling it to perform both label assignment and label distribution functions. The upstream router assigns labels to itself for multiple downstream routers, providing universal label management that supports flexible multicast paths while reducing label management complexity through centralized control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8462635B1Resource reservation protocol with traffic engineering point to multi-point label switched path hierarchy

Publication Date: 2013.06.11 HEWLETT PACKARD ENTERPRISE DEV LP

AI summary

The invention is directed toward techniques for Multi-Protocol Label Switching (MPLS) upstream label assignment for the Resource Reservation Protocol with Traffic Engineering (RSVP-TE). The techniques include extensions to the RSVP-TE that enable distribution of upstream assigned labels in Path messages from an upstream router to two or more downstream routers of tunnel established over a network. The tunnel may comprise a RSVP-TE P2MP Label Switched Path (LSP) or an Internet Protocol (IP) multicast tunnel. The techniques also include extensions to the RSVP-TE that enable a router to advertise upstream label assignment capability to neighboring routers in the network. The MPLS upstream label assignment using RSVP-TE described herein enables a branch router to avoid traffic replication on a Local Area Network (LAN) for RSVP-TE P2MP LSPs.