HP StorageWorks 2/16V Brocade Web Tools Administrator's Guide - Supporting Fab - Page 221

Enabling and disabling dynamic load sharing 16 Enabling and disabling dynamic load sharing The exchange-based routing policy depends on the Fabric OS dynamic load sharing feature (DLS) for dynamic routing path selection. When this policy is in force, DLS is always enabled and cannot be disabled. When the port-based policy is in force, you can enable DLS to optimize routing. When DLS is enabled, it shares traffic among multiple equivalent paths between switches. DLS recomputes load sharing either when a switch boots up or each time an E_Port or Fx_Port goes online or offline. Enabling this feature allows a path to be discovered automatically by the FSPF path-selection protocol. For more information regarding DLS, see the dlsset command in the Fabric OS Command Reference. When you enable or disable dynamic load sharing for a Brocade 24000 or 48000 configured for two logical switches, it is on a logical-switch basis. This means that for each logical switch, you must enable or disable dynamic load sharing individually. To configure the DLS setting 1. Open the Switch Administration window as described on page 31. 2. Click the Routing tab. 3. Click On in the Dynamic Load Sharing (DLS) area to enable dynamic load sharing or click Off to disable dynamic load sharing. When the exchange-based routing policy is in effect, the DLS radio buttons do not display in the Routing tab 4. Click Apply. Specifying frame order delivery In a stable fabric, frames are always delivered in order, even when the traffic between switches is shared among multiple paths. However, when topology changes occur in the fabric (for example, if a link goes down), traffic is rerouted around the failure, and some frames could be delivered out of order. By default, frame delivery is out-of-order across topology changes. However, if the fabric contains destination devices that do not support out-of-order delivery, you can force in-order frame delivery across topology changes. Enabling in-order delivery (IOD) guarantees that frames are either delivered in order or dropped. For more information regarding IOD, see the Fabric OS Administrator's Guide. When you enable or disable IOD for a Brocade 24000 that is configured for two logical switches, it is on a logical-switch basis. This means that for each logical switch, you enable or disable IOD individually. NOTE Enabling in-order delivery can cause a delay in the establishment of a new path when a topology change occurs, and therefore should be used with care. Web Tools Administrator's Guide 199 Publication Number: 53-1000435-01