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Enabling and Disabling CoS OxID Hash Control for FCoE Traffic on Standalone Switches

 

The originator exchange identifier (OxID) field is one of several fields that the switch can use in its hash function computation for FCoE traffic load balancing over multiple outgoing links in an Ethernet link aggregation group (LAG) on ports that face an FCoE forwarder (FCF). You can configure whether or not the switch uses the OxID in the hash computation.

Including the OxID field in the load-balancing hash computation allows different exchanges between a pair of Fibre Channel (FC) endpoints (such as an FCoE host and an FC storage device) to take different paths across the network, thus improving the aggregate network throughput.

However, if the paths between different sets of FC endpoints have common links, congestion on one set of FC endpoints can affect the other set of endpoints. Such congestion can happen if the FCoE traffic on the two sets of endpoints uses the same priority (IEEE 802.1p code point). It is common for networks to use priority 3 (IEEE 802.1p code point 011) for FCoE traffic. However, you can assign different IEEE priorities to different lossless FCoE flows as described in Understanding CoS IEEE 802.1p Priorities for Lossless Traffic Flows to further separate the traffic flows.

OxID hash control is enabled by default.

  • To enable OxID hash control field for FCoE traffic load balancing:

    [edit forwarding-options hash-key]

    user@switch# set family fcoe oxid enable
  • To disable OxID hash control field for FCoE traffic load balancing:

    [edit forwarding-options hash-key]

    user@switch# set family fcoe oxid disable