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The Switching Time Fails to Meet the Specification Requirement When the TN11LOG Board Is Connected to a Third-Party Router

Publication Date:  2012-07-25 Views:  111 Downloads:  0

Issue Description

The client-side 1+1 protection is configured by using the TN11LOG board and the OLP board. The TN11LOG board and the OLP board are connected to the same third-party router for interconnection test. During the protection switching, it is found that the protection switching time reaches 200 ms or even several seconds. The switching time exceeds the specification value. 

Alarm Information


Handling Process

On the T2000, change the encapsulation mode of the TN11LOG board from GFP-F to GFP-T. The test switching time is 20 ms, which meets the requirements. Note that the TN11LOG board is reset after the encapsulation mode changes. 

Root Cause

The TN11LOG board supports two encapsulation formats, namely, GFP-F and GFP-T encapsulation. If the TN11LOG board adopts the GFP-F encapsulation format, it needs to negotiate again with the router after the switching is performed. However, the negotiation process performed by the PHY chip is slow. Thus, the service recovery process after the switching is long. If the TN11LOG board adopts the GFP-T encapsulation format, the services are transmitted transparently, and the negotiation process is ignored. By default, the TN11LOG board works in GFP-F mode. In this mode, it takes hundreds of milliseconds to perform the switching. If the TN11LOG board works in GFP-T mode, it takes about 20 milliseconds to perform the switching.