KB.15.15

Figure 57 Conceptual example of port trunking

With full-duplex operation in a eight-port trunk group, trunking enables the following bandwidth

capabilities:

Port connections and configuration

All port trunk links must be point-to-point connections between a switch and another switch, router,

server, or workstation configured for port trunking. No intervening, non-trunking devices are

allowed. It is important to note that ports on both ends of a port trunk group must have the same

mode (speed and duplex) and flow control settings.

CAUTION: To avoid broadcast storms or loops in your network while configuring a trunk, first

disable or disconnect all ports you want to add to or remove from the trunk. After you finish

configuring the trunk, enable or re-connect the ports.

NOTE:

Link connections The switch does not support port trunking through an

intermediate, non-trunking device such as a hub, or using

more than onemedia type in a port trunk group. Similarly,

for proper trunk operation, all links in the same trunk group

must have the same speed, duplex, and flow control.

Port security restriction Port security does not operate on a trunk group. If you

configure port security on one or more ports that are later

added to a trunk group, the switch resets the port security

parameters for those ports to the factory-default

configuration.

Port trunk operation

The switches covered in this guide offer these options for port trunking:

• LACP: IEEE 802.3ad—

• Trunk: Non-Protocol—

Up to 144 trunk groups are supported on the switches. The actual maximum depends on the number

of ports available on the switch and the number of links in each trunk. (Using the link aggregation

control protocol—LACP—option, you can include standby trunked ports in addition to the maximum

144 Port Trunking