Fabric OS Administrator's Guide v7.0.0 (53-1002148-02, June 2011)

72 Fabric OS Administrator’s Guide
53-1002148-02
Routing policies
4
Routing policies
By default, all routing protocols place their routes into a routing table. You can control the routes
that a protocol places into each table and the routes from that table that the protocol advertises by
defining one or more routing policies and then applying them to the specific routing protocol.
The routing policy is responsible for selecting a route based on one of two user-selected routing
policies:
• Port-based routing
• Exchange-based routing
On the Brocade 300, 5100, 5300, 5410, 5450, 5460, 5470, 5480, 6510, 7800, 8000, and
VA-40FC switches, Brocade DCX and DCX-4S, and the Brocade DCX 8510 enterprise-class
platforms (all 4 Gbps ASICs and later), routing is handled by the FSPF protocol and either the
port-based routing or exchange-based routing policy.
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.
The current policy is displayed, followed by the supported policies for the switch.
Example of the output from the aptPolicy command
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
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.