Fibre Channel (SAN)

New Contributor
Posts: 3
Registered: ‎02-01-2010
Accepted Solution

Time TX Credit Zero value on a Trunk



When I look for Credit Zero on ports part of a trunk, all ports give same value.


Does it mean that only the Master Port record TX Credit Zero and slave Ports shows same value as the Master Port?


We use trunk with two ports and even traffics is almost well balanced between ports, value reported for each ports of Trunk are not equal except for TX Credit Zero.


I try to understand this and can't find a correct answer.


Thanks for help,



Brocade Moderator
Posts: 189
Registered: ‎03-29-2011

Re: Time TX Credit Zero value on a Trunk

Hi Bernard,


the master tracks the buffer credit to zero for the trunk (logical ISL) for the Condor based switches. 

Notice if the buffer credits are zero (for a Virtual Channel) for the first member sending out data,

the master select the next member with buffers avalable.   Value is presented in portstatsshow.

The underlaying HW measure buffer credit to zero on the under physical links. In the end, onlybuffer credits to zero on the whole trunk or logical link matters.



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