How To Configure DCB on Dell Force 10 switch

 

DCB allows switches to prioritise different types of traffic via either a lossless queue or Priority Flow Control (PFC). This permits to the switch to pause non-priority traffic when congested. Traffic is paused according to the 802.1p priority. You can also divide available bandwidth between different traffic types by setting parameters known as Enhanced Transmission Selection (ETS).

 

This article gives an example of configuring DCB on a pair of Force10 MXL’s connected to an Equallogic SAN.

 

Configure Equallogic

From version 6 of the Equallogic firmware the array can automatically detect if there is an invalid DCB configuration on the switch. If there is you will see the below error.

To specify the DCB vlan go to the advanced tab as shown below. In my example I am using vlan 3000

Save your changes.

 

Configure MXL

In my example I am configuring DCB with Force10 MXL switches. You can find instructions for other switches here.

 

You will need to enter the below commands on BOTH MXL switches. The red commands may need to be changed based on your config.

  1. Disable flow control on all ports (note the port ranges may change depending on what interfaces are set to quad mode)

    Interface range te0/1-32, te0/41-56

    No flowcontrol rx on tx off

    Exit

    Interface range fo0/33, fo0/37

    No flowcontrol rx on tx off

    Exit

  2. Check DCB is enabled with the show dcb command. If not enabled you will need to enable and reload the switch (after saving the config of course).
  3. Create tagged VLAN for all iSCSI ports and port-channels. In my setup po100 is the VLT port channel.

        Interface vlan 3000

        No shutdown

        Tagged te0/1-15

        Tagged te0/41-56

        Tagged po100

        Exit

  4. Configure DCB policies

    dcb-map CP-DCB

    priority-group 0 bandwidth 50 pfc off

    priority-group 1 bandwidth 50 pfc on

    priority-pgid 0 0 0 0 1 0 0 0

    exit

  5. Apply policies to switch ports used for iSCSI

    Int range te0/1-15, te0/41-56

    Dcb-map CP-DCB

    Int range fo0/33,fo0/37

    Dcb-map CP-DCB

    Exit

    Exit

  6. Save the config!

     

Check DCB Settings on Equallogic

Right click on the iSCSI interface of the member and select DCB details. Please then check:-

  • In the traffic class group (Group 1 in this example) only iSCSI is present
  • ETS Bandwidth is set from 1-100% (50% in this example)
  • Recommended priority for iSCSI is 4
  • Lossless in on foe the iSCSI group

THE END

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