System information

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Cisco SN 5428-2 Storage Router Software Configuration Guide

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Chapter 12 Command Line Interface Reference

interface fc? ext-credit

To configure the specified interface for credit extension, use the interface fc? ext-credit command.

interface fc? ext-credit nn

Syntax Description

Defaults No extended credits are available. By default, each FC interface has 12 data buffer credits available.

Command Modes Administrator.

Command History

Usage Guidelines By default, each SN 5428-2 Storage Router Fibre Channel (FC) interface has a data buffer capacity of

12 maximum sized FC frames or “credits.” This enables full bandwidth class 2 service over a distance

of 20 kilometers at 1 Gbps, or 10 kilometers at 2 Gbps, for fibre optic cables. Longer distances can be

spanned at full bandwidth by extending the credits available to an interface. An interface configured for

credit extension draws on a pool of credits donated by designated donor interfaces. Each donor interface

contributes 11 credits to the pool from which the recipient interfaces can draw.

In order to receive donated credits, the interface must have a running port type of E_Port, F_Port or

G_Port. An interface with a running loop mode port type (FL_Port, GL_Port or translated loop) cannot

receive donated credits. In order to donate credits, the interface port type must be donor.

Each interface with a port type of donor donates 11 buffer credits; all 11 buffer credits must go to a single

recipient interface.

Use the show interface command to display the maximum data buffer credits available to an interface,

and to display the ports receiving donated credits.

To make the interface unavailable for donated data buffer credits, use this command with a maximum

number of additional buffer credits of 0 (zero).

fc? The name of the interface to receive the additional buffer credits. Valid

values are fc1 through fc8. When you type the interface fc? command, the

CLI lists the interfaces available. You cannot specify a nonexistent

interface.

nn The maximum number of additional buffer credits available to this

interface. Valid values are 0, 11, 22, 33, 44, 55, 66 or 77.

Release Modification

3.2.1 This command was introduced.