Enabling And Disabling Dynamic Load Sharing; Specifying Frame Order Delivery - Brocade Communications Systems A7990A - StorageWorks SAN Director 4/16 Blade Switch Administrator's Manual

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 SilkWorm 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. Launch the Switch Admin module as described on
2. Click the Routing tab.
3. Click On in the Dynamic Load Sharing 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 SilkWorm 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.
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