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Fibre Channel (SAN)

Occasional Contributor
Posts: 13
Registered: ‎06-08-2011

info on FC FC routing

Hi to all,


i have two SAN environment completely different about the FC-FC connection, both the environment have 2 site that are connected via FC-FC through DWDM, but while in the ENVIRONMENT-1 the two FCR (Brocade 7500) make a single backbone fabric that is separeted from the edge fabric, in the ENVIRONMENT-2 the two FCR (Brocade 7500) they are part of the edge fabric and does not exist any backbone fabric. Both environment are in production and work correctly.

I try to outline the environment



SITE-1                                                                                     SITE-2

----------------           ---------------------------------------------                        -----------------

FABRIC1   |          |              BB FABRIC               |                      |   FABRIC2 |

dcx-8510 |          | mpr7500-1 <>  mpr7500-2 |                      |dcx-8510  |

                |         |                     2DWDM            |                      |                 |

----------------           ---------------------------------------------                       ------------------



----------------                                                                               ------------------

FABRIC1  |                                                                               |FABRIC2    |

dcx8510 |                                                                               |dcx8510   |

dcx         |                                                                               |dcx           |

mpr7500|                              <>                                            |mpr7500   |

---------------                              2DWDM                                     -------------------


The question is: what is the better configuration and why ENVIRONMENT-1 and ENVIRONMENT-2 are different, there are 2 different architectural designe?


Thanks a lot to all


Best Regards

Broadcom Moderator
Posts: 467
Registered: ‎03-29-2011

Re: info on FC FC routing

Hi Alessandro,


the first environment, where 2 x 7500 is part of backbone fabric, provice isolation between two edge fabric.

For example, when xWDM (or FCIP) is unstable and goes down temporarily, the FCR does not send out RSCN

that the links is down directly. So, you have seperate error domain - one for each edge fabrics so issues is

isolated to the edge fabrics. And you can have different FOS code level, and settings if needed in the different

edge. Best practices is 80/20 traffic distribution - 20% of traffic at most should go over the LSAN zones.


The second environment, where the 7500 are part of the fabrics, you have a singel error domain and not isolation.

If a lot of traffic goes over the xWDM, this is preferred.  Best practice is same FOS level and settings should be the same.

Easier to manage, no requirement for LSAN zones and less complex.


Dependent on your requirements and traffic patters between the two sites, determine which solution is best.

Notice the FOS 6.x is not supported in same fabrics as FOS 8.x (connected via ISLs directly or indirectly) but

require a FCR to isolate from FOS 8.x

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Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers. All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider. If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution"

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