SPBM Edge Router L3 Next-Hop Selection Rule
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Solution Overview
Problem
Conventional mechanisms for L3 traffic recovery in SPBM networks experience significant delays due to the failure of L3 Egress Nodes, as the recovery time is dependent on the number of L3 routes, leading to inefficient traffic restoration.
Innovation Solution
Implementing a method where edge routers determine whether a second edge router advertises a single or multiple BMAC addresses, using the first BMAC address for routing when only one is advertised and selecting one of the multiple addresses for routing when more than one is available, allowing for quicker next-hop updates and independent convergence times from the number of L3 routes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional route selection mechanisms are used for L3 Egress Node failure, then traffic recovery is performed by reprogramming each route individually, but the recovery time increases significantly with the number of L3 routes
Solution Approach 1:
The patent extracts the L3 next-hop selection logic from the individual route configuration and consolidates it into a separate forwarding table that maps L3 next-hop addresses to L2 forwarding information. This separation allows the L3 next-hop to be changed independently of the individual L3 routes, enabling bulk updates without reprogramming each route separately.
Solution Approach 2:
The patent pre-establishes the mapping between L3 next-hop addresses and L2 forwarding information in a dedicated forwarding table before failures occur. This preliminary structure enables rapid redirection of traffic by simply updating the next-hop address in the forwarding table, rather than modifying each route individually when failures happen.
2Device complexity
If the L3 next-hop is selected as the edge router with single BMAC address, then routing is simplified, but traffic loss occurs and recovery is slow when the selected node fails
Solution Approach 1:
The patent merges multiple BMAC addresses associated with the same L3 next-hop into a single consolidated forwarding entry. The forwarding table stores the L3 next-hop address mapped to multiple L2 (BVLAN, BMAC) tuples, allowing the system to maintain simplified L3 routing while having multiple L2 paths available for redundancy.
Solution Approach 2:
The patent changes the parameter representation by storing multiple BMAC addresses per L3 next-hop in the forwarding table, rather than selecting a single BMAC. This parameter change enables the system to switch between multiple BMAC addresses when one fails, improving reliability without complicating the L3 routing structure.
3Reliability
If multiple BMAC addresses are advertised by an edge router, then redundancy is provided, but the route selection process becomes more complex
Solution Approach 1:
The patent segments the routing functionality into two distinct components: L3 route selection (which remains simple and unchanged) and L2 forwarding (which handles the multiple BMAC addresses). The forwarding table acts as an intermediary that translates the simple L3 next-hop selection into multiple L2 forwarding entries, isolating the complexity of multiple BMACs from the L3 routing logic.
Data Source
AI summary
A method, apparatus and computer program product for providing a best route selection rule is presented. A determination is made at a first edge router, whether a second edge router in a network advertises a first BMAC address and at least one other BMAC address When the second edge router advertises only a first BMAC address, then the first BMAC address is used in a routing table for a Layer 3 (L3) next hop for a route. When the second edge router advertises more than one BMAC address, at least one other BMAC address is used in the routing table for said L3 next hop for the route.