HP StorageWorks Fabric OS 6.1.1 administrator guide (5697-0235, December 2009)

Fabric OS 6.1.x administrator guide 327
As an option, you can configure these parameters manually. To change the fabric parameters on a switch
in the edge fabric, execute the configure command. To change the fabric parameters of an EX_Port on
the 400 MP Router or 4/256 SAN Director or DC Director with an FR4-18i blade, use the
portCfgEXPort command. If you want to change the fabric parameters of a VEX_Port, use the
portCfgVEXPort command.
The backbone fabric PID mode and the edge fabric PID mode do not need to match, but the PID mode for
the EX_Port or VEX_Port and the edge fabric to which it is attached must match. You can statically set the
PID mode for the fabric by using the -p option with the portCfgEXPort command. (Use the -t option to
disable the negotiate fabric parameter feature). Otherwise, the PID mode is autonegotiated. The various
edge fabrics may have different PID modes.
Fabric parameter settings, namely, E_D_TOV (error-detect timeout value), R_A_TOV (resource-allocation
timeout value), and PID format, must be the same on EX_Ports or VEX_Ports and on the fabrics to which
they are connected. You can set the PID format on an EX_Port when you configure an interfabric link.
The default values for E_D_TOV and R_A_TOV for an EX_Port or VEX_Port must match those values on other
HP switches. Only if you have adjusted these parameters for the edge fabric do you need to adjust them for
an EX_Port or VEX_Port.
The default values for R_A_TOV and E_D_TOV are the recommended values for all but very large fabrics
(ones requiring four or more hops) or high-latency fabrics (such as ones using long-distance FCIP links).
Configuring EX_Port frame trunking (optional)
In Fabric OS 5.2.0 and later, you can configure EX_Ports to use frame based trunking just as you do
regular E_Ports. EX_Port frame trunking support is designed to provide the best utilization and balance of
frames transmitted on each link between the FCR and the edge fabric. You should trunk all ports connected
to the same edge fabrics.
The FC router front domain has a higher node WWN—derived from the FC router—than that of the edge
fabric. Therefore, the FCR front domain initiates the trunking protocol on the EX_Port.
After initiation, the first port from the trunk group that comes online is designated as the master port. The
other ports that come online on the trunk group are considered the slave ports. Adding or removing a slave
port does not cause frame drop.
The restrictions for EX_Port frame trunking are the same as for E_Ports—all the ports must be adjacent to
each other using the clearly marked groups on the front of the product.
EX_Port frame-based trunking has a master trunk link. If the master trunk link goes down, the entire
EX_Port-based trunk will reform and it will be taken offline for a short period of time. If there are no other
links to the edge fabric from the backbone, the master port going offline may cause a traffic disruption in
the backbone.
IMPORTANT: Fabric OS 5.2.0 introduces the EX_Port trunking feature. This feature should be enabled
only if the entire configuration is running Fabric OS 5.2.0 and later. Enabling the EX_Port trunking feature
on a switch running Fabric OS 5.2.0 or later in a configuration containing a Fabric OS 5.1.0 switch will
cause the Fabric OS 5.1.0 switch to panic.
If router port cost is used with EX_Port trunking, the master port and slave ports share the router port cost of
the master port.
For information about setting up E_Port trunking on an edge fabric, see ”Administering ISL trunking” on
page 367.