LACP Session Timeout Extension for ISSU Traffic Continuity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Link Aggregation Control Protocol (LACP) limits permitted session downtime to 90 seconds, which can be exceeded during In-Service Software Upgrades (ISSU) of T0 devices, potentially leading to data traffic drop due to hardware limitations and increased feature sets, posing a risk of network disruption.
Innovation Solution
Modify LACPDU messages to increase the number of consecutively-missed packets tolerated before terminating the LACP session from 3 to 5, allowing a 150-second downtime, and implement a userspace application to send LACPDUs more frequently during ISSU to maintain LAG activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If LACP session timeout is increased to allow longer ISSU duration, then software upgrade flexibility is improved, but network reliability deteriorates due to higher risk of traffic drop
Solution Approach 1:
The system performs preliminary actions by sending a first modified LACPDU message before the ISSU process begins, notifying the peer device to extend its timeout threshold. This preliminary notification ensures the peer device is prepared to tolerate the extended downtime without triggering a session termination, thus maintaining network reliability while allowing longer upgrade durations.
Solution Approach 2:
The system implements feedback by continuously monitoring the ISSU progress and sending a second modified LACPDU message upon completion. This feedback mechanism informs the peer device that the extended timeout period is no longer needed, allowing the system to return to normal timeout behavior and maintain ongoing network reliability.
2Productivity
If LACP timeout threshold is extended beyond standard limits, then ISSU completion probability is improved, but data traffic loss risk increases
Solution Approach 1:
Before initiating the ISSU process, the system sends a modified LACPDU message with extended timeout parameters to the peer device. This preliminary action ensures the peer device adjusts its expectations and does not terminate the LACP session during the extended upgrade period, thereby preventing data traffic loss while enabling successful ISSU completion.
Solution Approach 2:
The system dynamically adjusts the LACP timeout threshold during the ISSU process by modifying LACPDU messages. The timeout parameter is temporarily extended only during the upgrade window and automatically returns to standard values after completion, creating a dynamic adaptation that prevents traffic loss only when necessary.
3Stability of the object's composition
If LACP session tolerance for missed packets is increased, then session continuity during ISSU is improved, but network security deteriorates due to potential unauthorized disconnections
Solution Approach 1:
The system sends a preliminary modified LACPDU message before ISSU to explicitly notify the peer device of the upcoming extended downtime. This preliminary notification distinguishes authorized extended disconnections from unauthorized ones, maintaining session continuity during legitimate upgrades while preserving security by requiring explicit authorization for timeout extensions.
Solution Approach 2:
The modified LACPDU message acts as an intermediary mechanism that mediates between the need for extended timeout during ISSU and the need to prevent unauthorized disconnections. By using a standardized protocol message with extended parameters, the system creates a controlled channel for timeout extension requests that maintains security through protocol-based authorization.
Data Source
AI summary
A method, computer program product, and computing system for reducing communication session downtime includes transmitting first signals at a predetermined time interval of X seconds; upon initiation of a reboot operation of a first device associated with the processor, decreasing the predetermined time interval from X seconds to Y seconds; transmitting the first signals at the time interval of Y seconds; and once the reboot of the driver is complete, increasing the predetermined time interval from Y seconds to X seconds.