BGP Host Route Update for Accurate Forwarding After Host Migration
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Solution Overview
Problem
Convergence devices fail to timely perceive host migration in networks, leading to packets being forwarded to the wrong access device after host migration, causing incorrect data forwarding.
Innovation Solution
A method and apparatus for updating routes by using Border Gateway Protocol (BGP) sequence numbers and Address Resolution Protocol (ARP) entries to ensure correct data forwarding to the new access device post-migration, involving the use of ARP requests to verify host presence and updating IP forwarding tables with new host routes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the convergence device uses traditional route updating mechanisms, then the route update process is simple, but the convergence device cannot perceive host migration in time, causing packets to be forwarded to the wrong access device
Solution Approach 1:
The access device proactively deletes the ARP entry corresponding to the host after successfully establishing a new connection, before the convergence device receives the route update. This preliminary action ensures that the convergence device will not forward packets to the old access device, resolving the timing issue between host migration perception and packet forwarding correction.
Solution Approach 2:
The access device sends a route update message to the convergence device to notify about the host's new location. This feedback mechanism enables the convergence device to update its routing information and stop forwarding packets to the incorrect access device, improving data forwarding accuracy.
2Reliability
If the access device deletes the ARP entry immediately after host migration, then incorrect packet forwarding is prevented, but the verification process becomes more complex
Solution Approach 1:
The access device autonomously manages its own ARP entries by deleting the entry corresponding to the migrated host after establishing a new connection. This self-service approach simplifies the overall process by eliminating the need for complex coordination between multiple devices, while still ensuring correct packet forwarding.
Data Source
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AI summary
Provided are a method and apparatus for route update. In the present application, when an access device receives a first host route and a first sequence number that are sent by a BGP peer of the present device, regardless of the value of the first sequence number, the first host route can be preferably selected as a route used when the present device forwards data to a target host, and a recorded first ARP entry corresponding to the target host is deleted in order to trigger, according to the existing route withdrawing mechanism, the BGP peer of the present device, that is, an aggregation device, to withdraw the host route related to the first ARP entry, such that the aggregation device can be prevented from erroneously forwarding, after the target host is migrated, a message sent to the target host to the access device accessed by the target host before migration, thereby ensuring accurate forwarding of data.