Brocade Fibre Channel Networking Community

Re: Why E-port does not have "downstream" status?

  • 1.  Re: Why E-port does not have "downstream" status?

    Posted 02-11-2014 04:52 PM

    Wim had it almost right. The thing is that according to FC specs during build-up of a fabric FSPF  will flood frames on ALL ISL's however it will only use the FIRST ISL that responds with an ACK. This way it builds a spanning-tree root on which it communicates the fabric topology. It is by no means a definition on how dataframes will flow.


    So in your case it looks that the ISL between switch H16 and B16 acknowledged the FSPF BF or RF ILS commands before the ISL B24 and H16. This way the "spanning-tree root" flows via B16 hence you seen the upstream/downstream comments on these ISL's and not between B24 and H16.


    It has nothing to do with firmware levels, cosmetic issues or anything else. It has been in the specs since FC-SW started.


    Hope this explains the situation.



    Erwin van Londen