Networking, Iris Scenarios: Speed and Duplex Settings
CAUTION: Changing speed and/or duplex settings can cause temporary disruption of service. Make sure you understand the issues of disabling auto-negotiation.
Selecting a group of ports to edit
From a Port Status Overview page, the first column contains an empty checkbox. After checking the boxes for the group of ports you wish to edit, click on the Change Settings tab.
All of the selected ports will be listed in the Edit Port Information page.
Pitfalls of disabling auto-negotiation
Many people think that if they set a switch port to a specific mode
(say 100Mb/full-duplex), and then plug in a workstation which uses
auto-negotiation, it should automatically sync up with the switch port
and configure itself to 100Mb/full-duplex. In fact, auto-negotiation is
an active procedure which requires both sides of the Ethernet link to
transmit information about their capabilities; if the switch port fails
to participate (because auto-negotiation is disabled), the workstation
will fall back to 100Mb/half-duplex, creating a duplex mismatch which will severely degrade the performance of the link.
If for some reason you really need to disable auto-negotiation, you
should be very careful to hand-configure the same speed and duplex
settings on both ends of the Ethernet link (i.e. the switch port and the workstation).