Modifying port mode, Auto negotiation speed limit – Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) User Manual
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Multi-Service IronWare Switching Configuration Guide
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Modifying port mode
1
NOTE
An auto negotiation port must be connected to another auto negotiation port. If you connect an auto
negotiation port to a fixed speed or duplex port, the behavior is undefined.
Also, ports must be disabled before changing speed.
Modifying port mode
You can configure a port to accept either full-duplex (bi-directional) or half-duplex (uni-directional)
traffic. Port duplex mode and port speed are modified by the same command.
To change the port speed of interface 1/8 from the default of 10/100 auto-sense to 10 Mbps
operating at full-duplex, enter the following command.
Brocade(config)# interface e 1/8
Brocade(config-if-e10000-1/8)# speed-duplex 10-full
Syntax: speed-duplex value
The value can be one of the following:
•
10-full
•
10-half
•
100-full
•
100-half
•
1000-full
•
1000-half
•
auto
The default is auto.
Auto Negotiation Speed Limit
Auto-negotiation is an active method of determining the link mode. Each interface is expected to
transmit specific information in a specific format. If an interface that is expecting to use
auto-negotiation does not receive this information from the other side, it assumes the other side
cannot detect or change its mode.
One of the most common causes of performance issues on 10/100/1000 Mb Ethernet links
occurs when one port on the link operates at half-duplex while the other port operates at
full-duplex. This occurs when one or both ports on a link are reset and the auto-negotiation process
does not result in both link partners having the same configuration. It also can occur when users
reconfigure one side of a link and forgets to reconfigure the other side. Both sides of a link should
have auto-negotiation on, or both sides should have it off.
The auto negotiation speed limit feature allows the user to reduce or limit the port speed when
auto- negotiation is configured. You can set the port to automatically reduce the speed from
1000Mb to 100Mb or 10Mb. The down-shift option will reduce the port speed to 100Mb from
1000Mb automatically once a 2-wire cable is detected.
The auto negotiation speed limit feature is supported only on FIXED (non SFP) copper ports when
auto-neg is ON.