HP Brocade 4Gb SAN Switch for HP BladeSystem c-Class - Manual (Page 60)

60 Managing your fabrics, switches, and ports
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 HP StorageWorks Fabric OS 4.x procedures user guide.
When you enable or disable IOD for the Core Switch 2/64 and SAN Director 2/128 configured for two
logical switches, the configuration is on a logical-switch basis. This means that for each logical switch, you
enable or disable IOD individually.
To configure the IOD setting:
1. Launch the Switch Admin module as described on page 43 .
2. Click the Routing tab.
3. Select On in the In-Order Delivery area to force in-order frame delivery across topology changes or
select Off in the In-Order Delivery area to restore out-of-order frame delivery across topology changes.
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.
4. Click Apply.
Configuring link cost
When you configure link cost for the Core Switch 2/64 or SAN Director 2/128 configured for two logical
switches, the configuration is on a logical-switch basis. This means that for each logical switch, you
configure link cost individually.
For information regarding link cost, refer to the
linkCost
command in the HP StorageWorks Fabric OS
4.x command reference guide.
To configure the link cost for a port:
1. Launch the Switch Admin module as described on page 43 .
2. Click the Routing tab.
3. Perform of the following, depending on the type of switch:
• For Core Switch 2/64 and SAN Director 2/128, select the slot number of the logical switch under
Link Cost in the navigation tree.
• For HP StorageWorks SAN Switch 2/8V, SAN Switch 2/16V, SAN Switch 2/32, and SAN Switch
4/32, select Link Cost in the navigation tree.
4. Double-click in the row in the Cost column that corresponds to the appropriate port.
5. Type the link cost.
For a 1 Gbps ISL, the default cost is 1000. For a 2 Gbps or a 4 Gbps ISL, the default cost is 500.
Valid values for link cost range from 1 through 9999. Setting the value to
0
sets the link cost to the
default value for that port.
6. Click Apply.