User's Manual

AT-9000 Gigabit Ethernet Switch Installation Guide

Combo Ports

The AT-9000/28, AT-9000/28POE, and AT-9000/28SP switches have four

combo pairs of uplink ports, each consisting of one slot for an SFP

transceiver and a redundant 10/100/1000 Base-T twisted-pair port. These

combo ports are numbered 25 through 28 on the switches. The twisted-

pair ports in each of the combo pairs are identified with the letter “R” for

“Redundant” as part of their number on the front faceplate of the unit.

In each combo pair, only one port is active at a time. A link on an SFP

transceiver takes precedence over a link on the corresponding redundant

twisted-pair port. If an SFP transceiver is installed and has a link to an end

node, the twisted-pair port in the pair is inactive. If the SFP slot is empty,

or if an SFP module is inserted and does not have an active link, the 10/

100/1000Base-T twisted-pair port of the pair will be active.

Note

When the RJ-45 port is inactive, it may have a link to its end node.

However, the port will not pass traffic.

These guidelines apply when using these SFP slots and redundant

RJ-45 ports:

 Only one port in a pair can be active at a time — either the SFP

module or its corresponding twisted-pair port.

 The twisted-pair port is the active port when its SFP slot is empty,

or when an SFP module is installed but has not established a link

to an end node.

 A twisted-pair port automatically changes to the inactive mode

when an SFP module in the corresponding slot establishes a link

with an end node.

 A twisted-pair port automatically transitions back to the active

status when the link is down on the corresponding SFP module.

 In nearly all cases, a twisted-pair port and an SFP module share

the same configuration settings, such as port settings, VLAN

assignments, access control lists, and spanning tree.

An exception to the shared settings is port speed. If you disable

Autonegotiation on a twisted-pair port and set the speed and duplex mode

manually, the speed reverts to Autonegotiation when an SFP module

establishes a link with an end node.