Dell 8 Web Tools Administrator’s Guide - Page 232

Specifying frame order delivery, Configuring the link cost for a port

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DRAFT: BROCADE CONFIDENTIAL 16 Specifying frame order delivery 3. Select On in the Loss Less (DLS) area to enable the mode, or select Off to disable dynamic load sharing. When the exchange-based routing policy is in effect, the Loss Less DLS radio buttons display on the Routing tab 4. Click Apply. 5. 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. Perform the following procedure to specify frame order delivery. 1. Open the Switch Administration window as described in "Opening the Switch Administration window" on page 35. 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. For a 1-Gbps ISL, the default cost is 1000. For a 2-Gbps ISL, the default cost is 500. 204 Web Tools Administrator's Guide 53-1001772-01

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204
Web Tools Administrator’s Guide
53-1001772-01
Specifying frame order delivery
16
DRAFT: BROCADE CONFIDENTIAL
3.
Select
On
in the
Loss Less (DLS)
area to enable the mode, or select
Off
to disable dynamic load
sharing.
When the exchange-based routing policy is in effect, the Loss Less DLS radio buttons display
on the
Routing
tab
4.
Click
Apply
.
5.
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.
Perform the following procedure to specify frame order delivery.
1.
Open the
Switch Administration
window as described in
“Opening the Switch Administration
window”
on page 35.
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. For a 1-Gbps ISL, the
default cost is 1000. For a 2-Gbps ISL, the default cost is 500.