Allied Telesis AT-S39 - Manual (Page 84)

84
❑ When cabling a trunk, the order of the connections should be
maintained on both nodes. The lowest numbered port in a trunk
on the switch should be connected to the lowest numbered port
of the trunk on the other device, the next lowest numbered port
on the switch should be connected to the next lowest numbered
port on the other device, and so on.
For example, assume that you are connecting a trunk between
two AT-8024 switches. On the first AT-8024 switch you had
chosen ports 12, 13, 14, 15 for the trunk. On the second AT-
8024 switch you had chosen ports 21, 22, 23, and 24. To
maintain the order of the port connections, you would
connect port 12 on the first AT-8024 switch to port 21 on the
second AT-8024, port 13 to port 22, and so on.
❑ You can create a port trunk of optional GBIC modules installed in
Port 25 and Port 26 of an AT-8024GB switch.
❑ You can create a port trunk of the fiber optic ports in an
AT-8026FC switch.
❑ You can create a port trunk of the ports in two expansion modules
in an AT-8016F switch, providing that the ports are of the same
medium type and have the same operating specifications.
Port Operating
Specifications
The speed, duplex mode, and flow control settings must be the same for
all the ports of a port trunk. When you create a port trunk, the
management software copies the current settings of the lowest
numbered port in the trunk to the other ports. For example, if you create
a port trunk consisting of ports 5 to 8, the speed, duplex mode, and flow
control settings for port 5 are copied to ports 6, 7, and 8 so that all the
ports of the trunk have the same settings. For this reason it is
recommended that before creating a port trunk you first examine the
settings of the lowest number port that will be in the trunk and verify
that it has the correct settings.
Once you have created a port trunk, do not change the speed, duplex
mode or flow control of any port in the trunk without making the same
change to the other ports.
Load
Distribution
Methods
There are two steps to creating a port trunk. The first is to identify the
ports on the switch that are to function as the port trunk. The second is
to select a load distribution method. This second step is important
because unless you select the correct distribution method for your
configuration, the switch might not evenly distribute the load across all
the links of a trunk. Naturally, this could greatly diminish the value and
purpose of the port trunk.