Multi-hop Pseudowire Auto-routing via BGP Table Population
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Solution Overview
Problem
Conventional Pseudowires are limited to extending between only one PE device and another PE device across a packet-switched network, restricting their functionality.
Innovation Solution
Implementing auto-routing mechanisms for multi-hop Pseudowires by populating Border Gateway Protocol (BGP) routing tables with routing state information for layer 2 capable devices, allowing the extension of Pseudowires beyond PE devices through BGP advertising and using address families reserved for layer 2 endpoint reachability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional Pseudowires are used to extend between PE devices across a packet-switched network, then point-to-point connectivity is achieved, but the ability to extend beyond PE devices to include local network devices is limited
Solution Approach 1:
The Pseudowire mechanism is extended from traditional point-to-point PE-to-PE connectivity to multi-hop paths that can include local network devices (L2 switches, bridges) as intermediate nodes. This multi-functional capability allows the same Pseudowire infrastructure to support both traditional PE-to-PE services and new scenarios involving local network device integration, thereby improving adaptability without requiring separate mechanisms.
Solution Approach 2:
Local network devices are introduced as intermediary nodes between PE devices in the Pseudowire path. These intermediaries enable extended connectivity scenarios where traffic can flow through local switching infrastructure before reaching the destination PE, allowing Pseudowires to span beyond traditional PE-to-PE boundaries while maintaining encapsulation and forwarding semantics.
2Adaptability or versatility
If multi-hop Pseudowires are established to span multiple PE devices and local network devices, then routing flexibility is improved, but routing table complexity and memory requirements increase
Solution Approach 1:
The routing information for multi-hop Pseudowires is merged into the existing BGP routing infrastructure. By utilizing BGP's established path vector protocol and existing routing table structures, the patent combines multiple hop information, local device reachability, and Pseudowire endpoint information into unified BGP routes, avoiding the need for separate routing tables and reducing overall memory requirements.
Solution Approach 2:
The BGP routing protocol is leveraged to serve multiple functions: traditional IP routing, Pseudowire endpoint reachability, and multi-hop path establishment. This multi-functional use of BGP eliminates the need for dedicated routing mechanisms for each scenario, thereby reducing the total quantity of routing table entries and memory usage compared to implementing separate routing systems.
3Extent of automation
If BGP routing tables are populated with routing state for layer 2 capable devices, then auto-routing of multi-hop Pseudowires is enabled, but protocol complexity increases
Solution Approach 1:
The system enables self-service auto-routing by allowing BGP speakers to automatically populate routing tables with layer 2 device reachability information and autonomously establish multi-hop Pseudowire paths. The BGP protocol itself carries the necessary routing state and path information, eliminating the need for manual configuration or separate control plane mechanisms, thereby achieving automation while keeping protocol implementation manageable through standard BGP extensions.
Data Source
AI summary
A method and computer system for auto-routing of multi-hop pseudowires is presented. A first Provider Edge (PE) device receives an advertisement from a layer 2 (L2) capable network device, the advertisement including routing state for reaching the L2 device. A first Border Gateway Protocol (BGP) table is populated with the routing state for the L2 capable network device which is reachable by way of an address family reserved for L2 end point reachability information. The first PE device advertises the first BGP table information within a first Service Provider (SP) network such that a multi-hop Pseudowire is capable of being established which includes the L2 capable device.