Configuring Port Speed - Cisco MDS 9000 Series Configuration Manual

Chapter 3 Configuring Fibre Channel Interfaces
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Use the following guidelines to configure 4-port 10-Gbps switching modules when starting with the
default configuration:
1.
2.

Configuring Port Speed

The port speed on an interface, combined with the rate mode, determines the amount of shared resources
available to the ports in the port group on a 48-port, 24-port 4-Gbps, or any 8-Gbps Fibre Channel
switching module. Especially in the case of dedicated rate mode, the port group resources are reserved
even though the bandwidth is not used. For example, on Generation 2 modules, if an interface is
configured for autosensing (auto) and dedicated rate mode, then 4 Gbps of bandwidth is reserved even
though the maximum operating speed is 2 Gbps. For the same interface, if autosensing with a maximum
speed of 2 Gbps (auto max 2000) is configured, then only 2 Gbps of bandwidth is reserved and the
unused 2 Gbps is shared with the other interface in the port group.
Note •
•
•
Changing port speed and rate mode disrupts traffic on the port. Traffic on other ports in the port group
Caution
is not affected.
To configure the port speed on an interface on a 4-Gbps or 8-Gbps switching module, follow these steps:
Command
Step 1
switch# config t
switch(config)#
Step 2
switch(config)# interface fc 1/1
switch(config-if)#
OL-19445-02, Cisco MDS NX-OS Release 4.2(x)
Configure the port mode.
See the "About Interface Modes" section on page
Configure the BB_credits, performance buffers, and extended BB_credits, as necessary.
See the "BB_Credit Buffers for Switching Modules" section on page
Fabric Switches" section on page
The Generation 2, 4-port 10-Gbps switching module supports 10-Gbps traffic only.
On Generation 3, 8-Gbps modules, setting the port speed to auto enables autosensing, which
negotiates to a maximum speed of 8 Gbps.
On Generation 2, 4-Gbps modules, setting the port speed to auto enables autosensing, which
negotiates to a maximum speed of 4 Gbps.
Configuring Module Interface Shared Resources
2-3.
4-16, and the "About Extended BB_Credits" section on page
Purpose
Enters configuration mode.
Selects the interface and enters interface
configuration submode.
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
4-6, "BB_Credit Buffers for
4-17.
3-19