BGP Route Limiting in Satellite Networks

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Solution Overview

Problem

In networks utilizing the Border Gateway Protocol (BGP), routers face challenges with large routing tables that exceed available memory resources, particularly in satellite networks where physical resources are limited.

Innovation Solution

Implementing mechanisms to limit the number of routes learned by routers, such as designating a default route and using filters to restrict reflected routes, thereby reducing the size of routing tables and improving resource efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If routers maintain complete routing tables to track all paths between autonomous systems, then network reachability information is comprehensive, but memory resources are exceeded

Engineering Contradiction:

Improvenetwork reachability informationVSAvoidmemory resources

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential routing information needed for satellite networks by implementing route filtering mechanisms that selectively accept or reject BGP routes based on predefined criteria, thereby reducing the routing table size while maintaining necessary reachability information

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different route filtering policies to different satellite networks or autonomous systems based on their specific requirements, allowing each network to optimize its routing table size according to local needs rather than applying a uniform approach

Inventive Principle:

Principle #3Local quality

2Loss of information

If routers accept all BGP routes from autonomous systems, then routing information is complete, but device complexity increases

Engineering Contradiction:

Improverouting information completenessVSAvoidrouting table size

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent implements preliminary route filtering through BGP route maps and prefix lists that evaluate and filter routes before they are installed in the routing table, preventing unnecessary routes from being processed and stored, thus reducing device complexity while maintaining information completeness for essential routes

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If satellite networks use full BGP routing tables, then network connectivity is comprehensive, but scalability is limited due to resource constraints

Engineering Contradiction:

Improvenetwork connectivityVSAvoidnetwork scalability

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements partial routing information propagation by filtering routes to include only those necessary for satellite network operation, using mechanisms such as default routes and selective route advertisement to achieve sufficient connectivity without the overhead of complete routing tables, thereby enabling scalability

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8675543B2Route limiting in border gateway protocol over satellite networks

Publication Date: 2014.03.18 VERIZON PATENT & LICENSING INC

AI summary

Routes stored by routers in a network that uses the border gateway protocol may be limited to a default route. A device may set, a first route in a routing table, advertised using BGP by a first predetermined network, to be a default route for the device. The device may block forwarding of second routes, advertised using BGP, when the second routes do not correspond to the default route.