User's Manual
Stack Installation Guide for 8100S Series Switches
105
 The 10/100/1000Base-T ports must be set to Auto-Negotiation, the 
default setting, to operate at 1000Mbps.
 The default duplex mode setting for the ports is Auto-Negotiation. 
This setting is appropriate for ports connected to network devices 
that also support Auto-Negotiation for duplex modes.
 The default duplex mode setting of Auto-Negotiation is not 
appropriate for ports connected to network devices that do not 
support Auto-Negotiation and have a fixed duplex mode. You 
should disable Auto-Negotiation on those ports and set their duplex 
modes manually to avoid the possibility of duplex mode 
mismatches. A switch port using Auto-Negotiation defaults to half-
duplex if it detects that the end node is not using Auto-Negotiation, 
which can result in a mismatch if the end node is operating at a 
fixed duplex mode of full-duplex.
Fiber Optic Ports Here are the guidelines to cabling the 100Base-FX fiber optic ports on the 
AT-8100S/16F8-SC and AT-8100S/16F8-LC Switches:
 The cable specifications for the 100Base-FX fiber optic ports are 
listed in Table 3 on page 25.
 Do not remove the dust covers from the fiber optic ports until you 
are ready to connect the fiber optic cables. Dust contamination can 
adversely affect the operations of the ports.
 The connectors on the cables should fit snugly into the ports, and 
the tabs should lock the connectors into place.
General
Guidelines
These guidelines apply to both the twisted pair and fiber optic ports:
 You should not connect the cables to ports of static or LACP port 
trunks until after you have created the trunks using the switch’s 
management software. Connecting the cables before creating the 
trunks will result in network loops, which can adversely affect 
network performance.
 If your network topology contains a loop where two or more 
network devices can communicate with each other over more than 
one network path, do not connect the network cables that form the 
loop until after you activate one of the spanning tree protocols on 
the stack. Data loops can adversely affect network performance. 
For background information on the spanning tree protocols, refer to 
the AT-8100 Series AlliedWare Plus Command Line Interface 
User’s Guide.










