L2 Switch Session Table Management for NF Device Scaling
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Solution Overview
Problem
Conventional L2 switch technologies experience session interruptions when there are changes in the number of network function (NF) devices, leading to inefficient load distribution and communication disruptions due to rehashing processes.
Innovation Solution
An L2 switch is designed with a reception unit, determination unit, storing unit, and update unit to identify and manage session information and destination addresses, ensuring that upstream and downstream communications are routed through the same NF device by updating destination information in the session table when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hash calculation is used to determine distribution destination in L2 switch, then load distribution among NF devices is achieved, but session interruption occurs when network configuration changes (increase or decrease in number of NF devices)
Solution Approach 1:
The L2 switch performs preliminary actions by storing session information and destination information in the session table when upstream communication is received. This preliminary storage ensures that when downstream communication arrives, the switch already has the necessary information to maintain the correct routing path, preventing session interruption during network configuration changes.
Solution Approach 2:
The system implements feedback mechanisms where the L2 switch continuously monitors and updates session information in the session table based on received packets. When destination information changes, the switch feedbacks by updating the session table entries, ensuring that subsequent packets are routed correctly without session disruption.
2Productivity
If rehashing is performed when number of NF devices changes, then load distribution is optimized, but communication disruption occurs in NF devices that perform state management
Solution Approach 1:
The L2 switch performs preliminary action by capturing and storing session information and destination information at the time of upstream communication reception. This preliminary action eliminates the need for rehashing operations during downstream communication, thereby preventing communication disruption while maintaining optimized load distribution.
Solution Approach 2:
The session table acts as an intermediary mechanism between the load distribution system and the communication flow. It mediates the conflict between rehashing for load optimization and maintaining stable communication by storing destination information that remains valid even when NF device configuration changes.
Data Source
AI summary
A level 2 (L2) switch receives a packet of upstream communication and a packet of downstream communication that are transmitted from a network device. Further, in a case where it is determined whether or not the received packet is a packet of upstream communication, and when it is determined that the packet is of session upstream communication and is a packet at a session start time, the L2 switch acquires session information and destination information included in the packet of the upstream communication, and stores in a session table. Further, when it is determined that the packet is of upstream communication and is not a packet at a session start time, and destination information of the packet is different from destination information stored in the session table, the L2 switch updates the destination information of the packet to the destination information stored in the session table.