Intel SBCEFCSW manual I/O stream guard, Extending port credits, Click Port / Port Properties

Table 32. Port modes (continued)

State	Description
TL_Port	Translated loop port - Supports a loop of up to 124 private target devices or 125
	private initiator devices capable of communicating with up to 63 off-loop initiator
	devices or 64 off-loop target devices.
G_Port	Generic port - Self-discovers as an F_Port or an E_Port.
GL_Port	Generic loop port - Self-discovers as an F_Port, FL_Port, or an E_Port.
Donor	Donor port - Allows buffer credits to be used by another port.

Configuring translated loop (TL) modes (external ports only)

You can configure an external (0,15) TL_Port to support a loop of private target devices or a loop of private initiator devices.

•For a loop of up to 124 private target devices, click TL Target. This enables up to 63 initiator devices anywhere in the fabric to automatically connect with the private devices on the TL_Port. Group the TL_Port and up to 63 initiators in the same soft or ACL zone using the worldwide name or domain ID and port ID membership, to limit the number of possible initiators to 63.

•For a loop of up to 125 private initiator devices, click TL Initiator. This enables the private initiators on the TL_Port to automatically connect to up to 64 target and initiator devices in the same soft or ACL zone. You must group the TL_Port and the target devices in the same soft or ACL zone using the worldwide name or domain ID and port ID membership. If there are more than 65 members in the zone, the TL_Port is unable to communicate with the fabric.

Changing buffer-to-buffer credits (external ports only)

Each switch module external port (0,15) has a receive buffer capacity of 12 Fibre Channel frames or credits, which is equal to approximately 24 KB. Port buffer credits can be changed on ports to accommodate connections to other switch modules that have different port buffer capacities. Complete the following steps to change external port buffer credits:

1.Select one or more ports in the Faceplate window.

2.Click Port / Port Properties.

3.In the E_Port BB Credits field, type the new number.

4.Click OK to write the new buffer-to-buffer setting to the switch module.

I/O stream guard

The I/O Stream Guard feature suppresses registered state control notification (RSCN) messages on external ports (0,15).

Extending port credits

Each external port (0,15) is supported by a data buffer with a 12-credit capacity; that is, 12 maximum sized frames. For fiber-optic cables, this enables full bandwidth class 2 service over a distance of 20 km (12.4 mi) at 1 Gbps (0.6 credits per km), or 10 km (6.2 mi) at 2 Gbps (1.2 credits per km). Longer distances can be spanned at full bandwidth by borrowing credits from designated donor ports; therefore, pooling the buffer capacities. This is called credit extension. Each donor port contributes 11 credits to the pool from which the recipient ports can draw. Only external ports (0,15) can be donor or recipient ports. For example, one donor port contributes 11 credits to the pool from which a recipient draws for a total of 23 credits (11+12). This provides approximately 38 Km (23.6 mi) at 1 Gbps (23÷0.6) or 19 km (11.8 mi) at 2 Gbps (23÷1.2).

118Intel Blade Server Switch Module SBCEFCSW Management and User’s Guide