BFD Packet Length Switching via Pre-Switching Notification
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Solution Overview
Problem
The Bidirectional Forwarding Detection (BFD) protocol's size limitations in its standard mode can cause BFD sessions to be interrupted when large-size BFD packets are sent, as receiving ends may not support processing these packets, leading to disruptions in the network.
Innovation Solution
A method and apparatus for switching the length of BFD packets by sending a pre-switching packet to a second node in an asynchronous BFD session, allowing the length of the current BFD packet to be adjusted to a preset length, and performing the switch upon receiving an echo packet from the second node, thereby preventing session interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If large-size BFD packets are sent for MTU check, then the BFD protocol can perform path verification with larger packets, but the receiving end may discard the packets causing BFD session interruption
Solution Approach 1:
The patent applies preliminary action by sending a pre-switching packet before actually switching to large-size BFD packets. This pre-switching packet notifies the peer end of the intended packet length change, allowing the receiving end to prepare its processing capabilities in advance, thus preventing session interruption when large packets are subsequently sent
Solution Approach 2:
The patent implements feedback mechanism where the peer end responds to the pre-switching packet with an echo packet confirming its ability to process the specified packet length. This feedback loop ensures both ends are synchronized about the packet size capability before actual large-size packet transmission begins, maintaining session reliability
2Measurement precision
If the BFD packet length is increased for MTU detection, then more accurate path capability assessment is achieved, but peer nodes with smaller MTU support cannot process these packets
Solution Approach 1:
Before performing MTU detection with large BFD packets, the system sends a pre-switching packet to notify the peer end of the upcoming packet length change. This allows the peer node to verify its MTU capability in advance through the echo packet response, ensuring compatibility before the actual measurement packet is transmitted
Solution Approach 2:
The patent dynamically changes the BFD packet length parameter based on negotiation between two ends. The pre-switching packet carries information about the intended packet length, and upon receiving a positive echo response, the system adjusts the packet size parameter to match both ends' capabilities, achieving both measurement precision and node compatibility
Data Source
AI summary
Provided are a method and an apparatus for switching a length of a Bidirectional Forwarding Detection (BFD) packet, and a storage medium. The method includes: in a case where a length of a current BFD packet needs to be switched to a preset length, sending a pre-switching packet independent of the current BFD packet to a second node, wherein a BFD session running in an asynchronous mode is established between a first node and the second node, and the pre-switching packet is used for notifying the second node that the length of the current BFD packet needs to be switched to the preset length; and in a case where an echo packet fed back by the second node in response to the pre-switching packet is received, performing an operation of switching the length of the current BFD packet.