User`s guide

AT-S45 User’s Guide
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Port Trunking Overview
Port trunking is an economical way for you to increase the bandwidth
between an AT-9410GB Gigabit Ethernet Switch and another network
device, such as a server, router, workstation, or another switch. A port
trunk is two or more data ports that have been grouped together to
increase the bandwidth between a switch and a network node by
functioning as one logical path. This increase in bandwidth can prove
useful in situations where a single connection between the switch and a
node is insufficient to handle the traffic load.
Port trunks are also useful in adding redundancy to the critical devices of
your network. If one link of a port trunk fails, the remaining links will
continue to provide a communications link to the end node.
Despite the software configuration and physical connections, there are
no data loops in a port trunk because of load balancing. The port trunk
always sends packets from a particular source to a particular destination
over the same link within the trunk. A single link is designated for
flooding broadcasts and packets of unknown destination.
Below are the guidelines to follow when planning a port trunk:
❑ The switch can support up to four port trunks at a time.
❑ A port trunk can have as many as four ports.
❑ A port can be a member of only one trunk at a time.
❑ The duplex mode, speed, and flow control settings must be the
same for all of the ports in a trunk.
❑ The ports of a port trunk must be members of the same VLAN. A
port trunk cannot consist of ports that are members of different
VLANs.
❑ 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-9410GB switches. On the first AT-9410GB switch you
had chosen ports 2, 3, 4, and 5 for the trunk. On the second
AT-9410GB switch you had chosen ports 1, 2, 3, and 4. To