HP ProCurve 6120G/XG Configuration Manual page 291

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.
N o t e
Link Connections. The switch does not support port trunking through an
intermediate, non-trunking device such as a hub, or using more than one media
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.
C a u t i o n
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.
Port Trunking
Overview
11-3