Displaying The Current Routing Policy; Exchange-Based Routing; Port-Based Routing - Brocade Communications Systems 1606 Administrator's Manual

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Routing policies
Each switch can have its own routing policy and different policies can exist in the same fabric.
ATTENTION
For most configurations, the default routing policy is optimal and provides the best performance. You
should change the routing policy only if there is a performance issue that is of concern, or if a
particular fabric configuration or application requires it.

Displaying the current routing policy

1. Connect to the switch and log in as admin.
2. Enter the aptPolicy command with no parameters.
Example of the output from the aptPolicy command.

Exchange-based routing

The choice of routing path is based on the Source ID (SID), Destination ID (DID), and Fibre Channel
originator exchange ID (OXID), optimizing path utilization for the best performance. Thus, every
exchange can take a different path through the fabric. Exchange-based routing requires the use of
the Dynamic Load Sharing (DLS) feature; when this policy is in effect, you cannot disable the DLS
feature.
Exchange-based routing is also known as Dynamic Path Selection (DPS). DPS is where exchanges
or communication between end-devices in a fabric are assigned to egress ports in ratios
proportional to the potential bandwidth of the ISL or trunk group. When there are multiple paths to
a destination, the input traffic will be distributed across the different paths in proportion to the
bandwidth available on each of the paths. This improves utilization of the available paths, thus
reducing possible congestion on the paths. Every time there is a change in the network (which
changes the available paths), the input traffic can be redistributed across the available paths. This
is a very easy and non-disruptive process when the exchange-based routing policy is engaged.

Port-based routing

The choice of routing path is based only on the incoming port and the destination domain. To
optimize port-based routing, DLS can be enabled to balance the load across the available output
ports within a domain.
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The current policy is displayed, followed by the supported policies for the switch.
In the following example, the current policy is exchange-based routing (3) with the additional
AP dedicated link policy.
switch:admin> aptpolicy
Current Policy: 3 1(ap)
3 0(ap): Default Policy
1: Port Based Routing Policy
3: Exchange Based Routing Policy
0: AP Shared Link Policy
1: AP Dedicated Link Policy
Fabric OS Administrator's Guide
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