Link Protection Device for Network Link Failures
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Solution Overview
Problem
In computer networks, when a link protection device switches from a primary to a backup link due to a failed network switch, other switches may not be informed, leading to network traffic being sent to a 'dead' port, causing communication disruptions until the backup switch learns the new network device's address, typically taking up to 5 minutes due to aging timers.
Innovation Solution
A link protection device that determines failed network switches and switches connections between primary and backup links, and transmits a specially constructed update data packet with the network address of the protected device as the source and the broadcast address as the destination to inform other switches of the link change, facilitating immediate re-learning and preventing communication disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the link protection device switches connection from first link to second link upon network switch failure, then network connectivity is maintained, but other network switches are not informed of the link change, causing traffic to be sent to dead ports
Solution Approach 1:
The link protection device acts as an intermediary that generates and transmits update data packets to inform other network switches of the link change. This mediator function resolves the information loss problem by actively communicating the topological change to the network, ensuring other switches update their forwarding tables correctly.
Solution Approach 2:
The link protection device transmits the update data packet immediately upon detecting the link failure and switching to the backup link. This preliminary action ensures that other network switches are notified before they attempt to forward traffic to the failed link, preventing traffic loss and maintaining network efficiency.
2Reliability
If the link protection device transmits update data packets to inform network switches of link changes, then communication disruptions are prevented, but additional network traffic is generated
Solution Approach 1:
The update data packet uses the broadcast address as the destination parameter, ensuring that all network switches receive the link change information simultaneously. This parameter change approach efficiently communicates the topological change without requiring individual unicast messages to each switch, minimizing overall traffic while ensuring complete notification.
3Measurement precision
If network switches use aging timers to prevent stale information in filtering database, then information freshness is maintained, but communication disruptions occur during the aging period after link failure
Solution Approach 1:
The link protection device transmits the update data packet immediately upon detecting link failure and switching to backup link, before the aging timer expires. This preliminary action prevents the information staleness problem by proactively notifying other switches of the topological change, eliminating the need to wait for the aging timer to expire and thus preventing communication disruptions.
Solution Approach 2:
The update data packet provides feedback to other network switches about the current network topology, informing them that the protected network device is now accessible through a different link. This feedback mechanism allows switches to update their filtering databases immediately rather than waiting for aging timers, maintaining information freshness and preventing communication disruptions.
Data Source
AI summary
An apparatus and method for updating a network as to the link used by a protected network device when a first switch for the protected network device fails or is determined to be once again operational. The link protection device builds and transmits an update data packet on a second link for the protected network device that emulates a data packet sent from the protected network device on the second link.