VPLS Service Switching via Selective Forwarding Table Updates
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Solution Overview
Problem
Current VPLS service switching methods consume network bandwidth and affect unrelated services by requiring the emptying and re-learning of forwarding tables, and may fail to detect faults in the absence of data messages.
Innovation Solution
A method and system that rapidly switches a VPLS service to a secondary PW by transmitting a message containing faulty PE device information, allowing PE devices to replace forwarding path items without emptying their tables, using protocols like LDP, BGP, or L2TPv3, and employing a fault detection module to notify PE devices on the secondary PW for address replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the VPLS forwarding table is emptied and re-learned to switch services to secondary PW, then the VPLS service can be switched to backup path, but network bandwidth is consumed and processing payload increases
Solution Approach 1:
The patent segments the forwarding table update process by identifying and updating only the specific MAC address entries related to the faulty primary PW, rather than emptying and re-learning the entire forwarding table. This selective update approach maintains service reliability while avoiding unnecessary bandwidth consumption from broadcasting all VPLS service messages.
Solution Approach 2:
The patent applies partial action by performing only the necessary forwarding table updates for affected MAC addresses instead of the complete re-learning process. This partial update mechanism achieves the required reliability improvement without the excessive bandwidth consumption associated with full forwarding table re-learning.
2Reliability
If the VPLS forwarding table is emptied and re-learned to switch services to secondary PW, then the VPLS service can be switched to backup path, but other unrelated services are affected
Solution Approach 1:
The patent segments the forwarding table into specific MAC address entries and updates only those related to the faulty primary PW. This segmentation ensures that unrelated services with different MAC addresses remain unaffected, maintaining system adaptability while achieving the required reliability improvement.
Solution Approach 2:
The patent applies local quality by making the forwarding table update localized to specific MAC address entries rather than applying a global re-learning process. This localized update approach ensures that only the necessary portions of the system are modified, preserving the functionality of unrelated services.
3Reliability
If fault detection relies on receiving VPLS data messages, then fault can be detected, but fault detection fails when no data messages are present
Solution Approach 1:
The patent implements preliminary action by establishing a timer that proactively detects faults based on the absence of VPLS data messages within a predetermined time period. This preliminary detection mechanism ensures that faults are identified even when no data messages are being transmitted, maintaining reliable fault detection under all conditions.
Solution Approach 2:
The patent uses feedback through a timer mechanism that monitors whether VPLS data messages are received within an expected time frame. When no messages are received within the predetermined period, the timer triggers fault detection. This feedback loop ensures continuous monitoring and reliable fault detection regardless of data message presence.
Data Source
AI summary
A method and system for switching the serving services of virtual private LAN is provided. When a fault occurs on a normal service transmission path, a PE device on the secondary path transmits a message including an information of the failure device on the normal service transmission path to the other PE devices on the path to indicate the path switching; the other PE devices replace the faulty PE device corresponding to the transmission path item in VPLS transmission table as the PE device on the secondary path according to the received message for indicating the path switching. Using the present invention, when an access device detects a fault, the VPLS service can switch to the secondary path immediately without affecting other services; because the VPLS messages do not need to be broadcasted during path switching, the network bandwidth will not be wasted.