Core Router Aggregate Prefix Advertising for Backbone Routing
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Solution Overview
Problem
The rapid growth of routing tables in Internet backbone networks leads to increased router costs and slower route convergence, as existing technologies struggle to efficiently manage the scalability of IP routing and VPN routing without renumbering, resulting in large routing tables.
Innovation Solution
A method and system that reduces the number of routing tables by implementing a tree routing structure within the Internet backbone network, where only a core router advertises aggregate address prefixes, and border routers register mapping relationships between more detailed address prefixes and their addresses at the core router, enabling efficient packet forwarding through tunneling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hierarchical routing with IP address hierarchy alignment is used, then routing table size is reduced, but adaptability to network changes (site multi-homing, ISP switching) deteriorates
Solution Approach 1:
The patent segments the routing system into two distinct components: (1) a hierarchical routing layer that maintains aggregated routing tables for scalability, and (2) a tunneling layer that provides flexible adaptability to network changes. Border routers maintain full routing information locally, while core routers use aggregated tables, allowing the system to simultaneously achieve small routing tables at core routers and high adaptability through border router intelligence.
Solution Approach 2:
The patent introduces tunneling as an intermediary mechanism between the hierarchical routing structure and the need for adaptability. Tunnel endpoints at border routers enable flexible routing decisions for specific destinations while maintaining the aggregated hierarchical structure in the core network, thus mediating between routing table size reduction and adaptability to network changes.
2Loss of information
If routing tables are upgraded to handle larger sizes, then routing information completeness is improved, but router cost and processing capability requirements increase
Solution Approach 1:
The patent applies local quality by differentiating routing table requirements between core routers and border routers. Core routers maintain only aggregated routing tables with minimal information for efficient high-speed forwarding, while border routers maintain complete detailed routing tables locally. This localized differentiation allows routing information completeness to be preserved at border routers without increasing the complexity and cost of core routers.
3Quantity of substance
If aggregate address prefixes are advertised in backbone network, then routing table size at core routers is reduced, but packet forwarding complexity increases
Solution Approach 1:
The patent uses tunneling as an intermediary mechanism that simplifies packet forwarding in the core network. Core routers only need to perform simple aggregate prefix matching and forward packets to tunnel endpoints, reducing their forwarding complexity despite using aggregate addresses. The tunneling mechanism handles the complexity of mapping aggregate addresses to specific destinations at border routers, not at core routers.
Data Source
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AI summary
The present invention discloses a method and device for advertising routing information and a method and system for implementing packet routing. The method for advertising routing information includes that a routing information advertising device obtains its address information; the routing information advertising device adds the address information to routing information to advertise; and the routing information advertising device advertises the routing information that carries the address information. With the technical solution of the present invention, the number of routing tables in a backbone network is greatly reduced. This prevents the rise of router costs and effectively avoids slower route convergence. In addition, with the method provided by the present invention for advertising routing information, a router in the backbone network can dynamically obtain address information of a core router that advertises an aggregate prefix, so that it is easier to implement registration, update and query of the mapping between a more detailed address prefix and a border router.