Allied Telesis AT-S62 - Manual (Page 122)

Chapter 8: Port Trunking
Section I: Basic Operations 122
say that an Allied Telesyn layer 2 managed switch cannot form a static
trunk with a device from another manufacturer; but there is the
possibility that the implementations of static trunking on the two
devices might not be compatible.
It should also be noted that this type of trunk does not provide for
redundancy or link backup. If a port in a static trunk loses its link, the
trunk’s total bandwidth is reduced. Though the traffic carried by the lost
link is shifted to one of the remaining ports in the trunk, the bandwidth
remains reduced until the lost link is reestablished or you reconfigure
the trunk by adding another port to it.
Static Port Trunk Guidelines
Here are the guidelines to creating a static trunk:
❑ Allied Telesyn recommends using static port trunks between
Allied Telesyn networking devices to ensure compatibility. While
an Allied Telesyn device might be able to form a static trunk with
a device from another equipment vendor, there is the possibility
that the implementation of this feature on the two devices might
not be compatible, resulting in undesired switch behavior.
❑ A static trunk can contain up to eight ports.
❑ The ports of a static trunk must be of the same medium type. They
can be all twisted pair ports or all fiber optic ports.
❑ The ports of a trunk can be either consecutive (for example Ports
5-9) or nonconsecutive (for example, Ports 4, 8, 11, 20).
❑ Before creating a port trunk, examine the speed, duplex mode,
flow control, and back pressure settings of the lowest number
port that will be in the trunk. Verify that its settings are correct for
the device to which the trunk will be connected. When you create
a static port trunk, the management software copies the current
settings of the lowest numbered port in the trunk to the other
ports, because all ports in a static trunk must have the same
settings. For example, if you create a port trunk consisting of ports
5 to 8, the parameter settings for port 5 are copied to ports 6, 7,
and 8 so that all the ports of the trunk have the same settings.
❑ Once you have created a port trunk, do not change the speed,
duplex mode, flow control or back pressure of any port in the
trunk without making the same change to the other ports.
❑ A port can belong to only one static trunk at a time.
❑ A port cannot be a member of a static trunk and a LACP trunk at
the same time.