Brocade Web Tools Administrator's Guide - Supporting Fabric OS v7.0.0 (53-1002152-01, March 2012)

172 Web Tools Adminstrator’s Guide
53-1002152-01
Specifying frame order delivery
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When the exchange-based routing policy is in effect, the Loss Less DLS radio buttons display
on the Routing tab
4. Click Apply, and then click OK.
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, refer to the Fabric OS Administrator’s Guide.
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.
To specify frame order delivery, perform the following steps.
1. Open the Switch Administration window as described in “Opening the Switch Administration
window” on page 33.
2. Select the Routing tab.
3. Click On in the In-Order Delivery (IOD) area to force in-order frame delivery across topology
changes or click Off to restore out-of-order frame delivery across topology changes.
4. Click Apply.
Configuring the link cost for a port
This section describes how to set the cost of an interswitch link (ISL). The cost of a link is a
dimensionless positive number. The fabric shortest path first (FSPF) protocol compares the cost of
various paths between a source switch and a destination switch by adding the costs of all the ISLs
along each path. FSPF defines the path with minimum cost. If multiple paths exist with the same
minimum cost, FSPF employs load sharing over these paths.
Every ISL has a default cost that is inversely proportional to its bandwidth.
Use this procedure to set a non-default, “static” cost for any port.
1. Open the Switch Administration window as described in “Opening the Switch Administration
window” on page 33.
2. Select the Routing tab.