Users Guide

126 Fabric OS Administrator’s Guide
53-1002920-02
Frame order delivery
4
• An EX_Port goes offline
• A device goes offline
Setting DLS
Use the following procedure to set DLS.
1. Connect to the switch and log in using an account with admin permissions.
2. Enter the dlsShow command to view the current DLS setting.
One of the following messages appears:
• “DLS is set” indicates that DLS is turned on.
• “DLS is not set” indicates that DLS is turned off.
• ”DLS is set with Lossless enabled.” DLS is enabled with the Lossless feature. Load sharing
is recomputed with every change in the fabric, and existing routes can be moved to
maintain optimal balance. In Lossless mode, no frames are lost during this operation.
• “DLS is set by default with current routing policy. DLS is set with Lossless enabled.” The
current routing policy (exchange-based) requires DLS to be enabled by default. In addition,
the Lossless option is enabled. Frame loss is prevented during a load sharing
recomputation. If you get this message, you cannot perform step 3, so you are done with
this procedure.
3. Enter the dlsSet command to enable DLS or enter the dlsReset command to disable it.
Example of setting and resetting DLS
switch:admin> dlsshow
DLS is not set
switch:admin> dlsset
switch:admin> dlsshow
DLS is set
switch:admin> dlsreset
switch:admin> dlsshow
DLS is not set
Frame order delivery
The order in which frames are delivered is maintained within a switch and determined by the
routing policy in effect. The frame delivery behaviors for each routing policy are:
• Port-based routing
All frames received on an incoming port destined for a destination domain are guaranteed to
exit the switch in the same order in which they were received.
• Exchange-based routing
All frames received on an incoming port for a given exchange are guaranteed to exit the switch
in the same order in which they were received. Because different paths are chosen for
different exchanges, this policy does not maintain the order of frames across exchanges.
• Device-based routing
All frames received on an incoming port for a given pair of devices are guaranteed to exit the
switch in the same order in which they were received.