Unified Forwarding Adjacency for MPLS Router Bypass
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Solution Overview
Problem
Current methods for providing bypass connectivity between routers in MPLS networks require a separate Routing Adjacency for each pair of interconnected routers, leading to a large number of routing adjacencies and increased processor resource consumption, which limits scalability and operational complexity.
Innovation Solution
The method involves configuring stand-alone Forwarding Instances between IP/MPLS routers, allowing direct traffic forwarding without requiring a separate Routing Adjacency for each pair, and using protocol demultiplexing to map MPLS labeled traffic onto Ethernet engineered paths, reducing the need for routing adjacencies by establishing a one-to-one correspondence between Routing and Forwarding Adjacencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate Routing Adjacency is established for each pair of interconnected routers, then direct traffic forwarding between routers is enabled, but the number of routing adjacencies increases significantly, leading to increased processor resource consumption and reduced scalability
Solution Approach 1:
The patent merges the functions of routing adjacencies and forwarding adjacencies into a single unified adjacency structure. This allows the network to maintain direct traffic forwarding capability between routers while reducing the total number of adjacencies from N*(N-1)/2 to a much smaller number, thereby decreasing processor resource consumption and improving scalability.
Solution Approach 2:
The unified adjacency structure serves multiple functions simultaneously: it provides routing information exchange, establishes forwarding adjacencies, and enables direct traffic forwarding. This multi-functionality eliminates the need for separate routing and forwarding adjacencies, resolving the contradiction between reliability and device complexity.
2Device complexity
If stand-alone Forwarding Instances are configured between IP/MPLS routers, then bypass connectivity is enabled with reduced routing overhead, but network integrity verification becomes more challenging
Solution Approach 1:
The patent implements feedback mechanisms within the unified adjacency to verify network integrity. Neighbors exchange information about the adjacency state and forwarding instances, allowing each router to confirm that the bypass path is properly configured and operational. This feedback loop ensures network integrity without requiring separate verification procedures for each forwarding instance.
Solution Approach 2:
The unified adjacency structure performs self-verification by automatically establishing and validating forwarding adjacencies as part of the routing adjacency formation process. The system self-manages the integrity of bypass connectivity through built-in verification mechanisms, eliminating the need for external monitoring or separate integrity checking procedures.
Data Source
AI summary
Forwarding Adjacencies (FAs) can be set up between IP/MPLS routers without requiring a Routing Adjacency (RA) to be brought up for every FA. This enables increased bypass connectivity to be established between end-point routers in the IP/MPLS network without attendant additional processing associated with having dedicated RA for each FA. Where it is possible to modify the end-point routers, the physical ports may be configured to support stand-alone FAs. A configured FA at a physical port is then associated with an IP address of a remote end-point router and a connection within the bypass technology. OAM is used to verify connectivity and configuration across the FA. Alternatively, an emulated Ethernet LAN segment may be used for IP traffic to enable full mesh connectivity to be provided by the bypass technology while requiring only one or a small number of RAs to be implemented at each end-point router.