Port Configuration Overview
8-4 Port Configuration
Auto-Negotiation and Advertised Ability
Auto-negotiation is an Ethernet feature that facilitates the selection of port speed, duplex, and
flow control between the two members of a link, by first sharing these capabilities and then
selecting the fastest transmission mode that both ends of the link support. Auto-negotiation is
enabled by default.
Use the set port negotiation command to disable or enable auto-negotiation. Use the show port
negotiation to display the current auto-negotiation status for one or more ports.
The advertised ability feature allows for the port to share its port capabilities with the other end of
the link. Advertised capabilities will be used during the auto-negotiation process to select the
fastest transmission mode that both ends of the link support. Actual port capabilities, advertised
port capability and remote end advertised port capabilities can be displayed using the show port
advertise command. The following port capabilities can be advertised:
During auto-negotiation, the port “tells” the device at the other end of the segment what its
capabilities and mode of operation are. If auto-negotiation is disabled, the port reverts to the
values specified by default speed, default duplex, and the port flow control commands.
In normal operation, with all capabilities enabled, advertised ability enables a port to “advertise”
that it has the ability to operate in any mode. You may choose to configure a port so that only a
portion of its capabilities are advertised and the others are disabled. Use the set port advertise
command to configure what a port will advertise for speed/duplex capabilities in auto-
negotiation. Use the clear port advertise command to configure a port to not advertise a specific
speed/duplex capability when auto-negotiating with another port.
For G-Series systems, refer to “Configuring SFP Ports for 100BASE-FX” on page 8-7 for
information on configuring settings for 100 Mb SFP ports.
Port Speed and Duplex Mode
When auto-negotiation is enabled, the port speed (10, 100, or 1000 Mbps) and duplex mode (full-
or half-duplex) are determined automatically based on the established link. Note that auto-
negotiation is enabled by default on all ports.
If auto-negotiation is disabled, you can set the default speed for a port with the set port speed
command and the duplex mode with the set port duplex command. Use the show port speed and
show port duplex commands to display current settings.
MDI / MDIX Cable Type
Switch ports can automatically detect and configure the required cable type, either straight
through (MDI) or cross-over (MDIX), or the ports can be configured to only allow one type of
cable type, either MDI or MDIX.
10t 10BASE-T half duplex mode.
10tfd 10BASE-T full duplex mode.
100tx 100BASE-TX half duplex mode.
100txfd 100BASE-TX full duplex mode.
1000t 1000BASE-T half duplex mode.
1000tfd 1000BASE-T full duplex mode.
pause PAUSE for full-duplex links.
To Next Page
Loading...
Need help?
General