BGP Backpressure Notifications for Router Stability
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Solution Overview
Problem
Existing techniques for managing Border Gateway Protocol (BGP) updates are inadequate, leading to situations where BGP sessions can overwhelm routers, causing network outages due to the inability to handle high rates of updates within the physical capabilities of the routers.
Innovation Solution
The implementation of backpressure notifications to BGP peers, which involves detecting triggers indicative of the need for backpressure, sending notification messages to apply or remove backpressure, and constraining these notifications to peers that support this functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If routers accept BGP updates from multiple peers at high rates, then routing information completeness is improved, but router overload and network outages occur
Solution Approach 1:
The patent implements a feedback mechanism where routers monitor their own resource utilization (CPU, memory, RIB fill rate) and send backpressure notification messages to peers when thresholds are exceeded. This closed-loop feedback allows the router to dynamically control the incoming BGP update rate based on its current capacity, preventing overload while maintaining routing information completeness when resources are available.
Solution Approach 2:
The system dynamically adjusts the BGP update acceptance rate based on real-time router conditions. The backpressure mechanism transitions the router from a static, fixed-capacity model to a dynamic model where the effective capacity fluctuates with available resources. This allows the router to adapt to changing load conditions, accepting more updates when resources are abundant and rejecting fewer when resources are constrained.
2Reliability
If filtering is applied to maintain RIB size, then router resource usage is controlled, but routing information completeness deteriorates
Solution Approach 1:
Instead of filtering BGP updates after they arrive at the router, the backpressure mechanism takes preliminary action by notifying peers in advance to reduce or pause update transmission. This prevents excessive updates from reaching the router in the first place, eliminating the need for aggressive filtering that would discard routing information. The action is taken upstream at the peer router rather than downstream at the overwhelmed router.
3Reliability
If BGP sessions are terminated to reduce load, then router overload is prevented, but network connectivity and routing information are lost
Solution Approach 1:
The backpressure mechanism applies partial action by selectively controlling BGP update flow rather than completely terminating sessions. Instead of the all-or-nothing approach of session termination, the system applies a controlled, partial reduction in update rate that is proportional to the overload condition. This allows the routing session to remain active and routing information to continue flowing, just at a reduced and manageable rate.
Data Source
AI summary
A router configured to implement Border Gateway Protocol (BGP) includes circuitry configured to receive BGP updates from one or more BGP peers connected to the router, detect a trigger related to BGP updates where the trigger is indicative of a need to apply backpressure by the one or more BGP peers, and send a backpressure notification message to the one or more BGP peers based on the trigger, such that the one or more BGP peers apply the backpressure. The circuitry can be further configured to monitor one or more criteria associated with operation of the router, for the trigger.