HP ProCurve 6120G/XG Configuration Manual page 313

Spanning Tree and IGMP. If Spanning Tree and/or IGMP is enabled in the
switch, a dynamic LACP trunk operates only with the default settings for these
features and does not appear in the port listings for these features.
Half-Duplex and/or Different Port Speeds Not Allowed in LACP
Trunks. The ports on both sides of an LACP trunk must be configured for
the same speed and for full-duplex (FDx). The 802.3ad LACP standard speci­
fies a full-duplex (FDx) requirement for LACP trunking. (10-gigabit ports
operate only at FDx.)
A port configured as LACP passive and not assigned to a port trunk can be
configured to half-duplex (HDx). However, in any of the following cases, a
port cannot be reconfigured to an HDx setting:
■ If the port is a 10-gigabit port.
If a port is set to LACP Active, you cannot configure it to HDx.
■
■ If a port is already a member of a static or dynamic LACP trunk, you cannot
configure it to HDx.
■ If a port is already set to HDx, the switch does not allow you to configure
it for a static or dynamic LACP trunk.
Dynamic/Static LACP Interoperation: A port configured for dynamic
LACP can properly interoperate with a port configured for static (TrkX) LACP,
but any ports configured as standby LACP links will be ignored.
Port Trunking
Trunk Group Operation Using LACP
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