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Segregate traffic on 6000B

  • 1.  Segregate traffic on 6000B

    Posted 11-11-2019 10:10 AM
    Hi everybody,

    Just looking into the option and see whether its possible to segregate live traffic from backup traffic on separate FC ISL links. We basically have a couple of data centres in a mesh topology connected with 16GB long haul connections. We've just upgraded these links and saw the opportunity of re-using the older 8Gb SFPs to bring up more ISLs that will be used solely for backup traffic.

    The need for this is that our storages are placed across 2-sites and we tend to keep the backup of the respective site in the other location hence we see approx 3Gb of backup traffic on our links. Getting connectivity across sites is easy however i'd like to see if there are ways to achieve this and have backup traffic (incoming from specific ports) to pass solely on the slower links (8Gb link).  Remember that we have just a couple of 6000B SWs so no directors or any other fancy stuff.


  • 2.  RE: Segregate traffic on 6000B

    Posted 11-12-2019 10:44 AM
    "solely on the slower links" raises a red flag. Fibre channel standards requires use a Fastest Shortest Path First algorithm. That means there is no way to have any traffic pass on a slower link in the same fabric when a higher speed link is available.

    If virtual fabrics is enabled, create a separate logical fabric on the same H/W and move all the ports for DR to that logical switch. This action is disruptive to the ports being moved. It will completely isolate the fabrics so there is no way to share the links in the different fabrics.

    If this doesn't work for you, you will need to have all ISLs running at the same speed. You can then use traffic isolation zoning to guide traffic down certain ports or use quality of service to give your production traffic priority while sharing the same ISLs.

    Field Applications Engineer

  • 3.  RE: Segregate traffic on 6000B

    Posted 12-02-2019 12:30 PM
    Hi Jack,

    Thank you for the information really useful. Have two questions on both options that you mentioned :

    Virtual Fabric options looks that it would provide what we need, however my only worry is that it would affect current config. All the setup are running on the default FID i.e 128. Also i understood that to enable the virtual fabric we need to reboot the switches. So, basically here i can reboot just the two switches where the 8GB ISL will be connected right ? No need to enable virtual fabric on the other switches. Also, when creating the virtual fabric it shouldn't affect the existing fabric correct ?

    Traffic isolation seems also a good option, however i understood that here irrespective of traffic type, all ISLs need to be of same speed even if you are directing traffic through specific ISL correct ?

    Thank you!

  • 4.  RE: Segregate traffic on 6000B

    Posted 12-02-2019 03:13 PM

    Traffic Isolation can't be used to get around the Fibre Channel FSPF algorithm (this is an IEEE spec). If you have multiple links at different speeds, you're only option is complete fabric isolation using virtual fabrics. Since you are running on FID 128, that implies that virtual fabrics is already enabled. To be sure, you use this command:

    lscfg --show

    If VF isn't enabled you'll get a message back to that effect. If it is, you'll get a response with the number of logical switches defined followed by a display of which FID each port is in. Creating another logical switch is non-disruptive. Any port you move to the new logical switch will have to be disabled so traffic on the ports moving to the new logical switch will be disrupted.

    Field Applications Engineer