IronPort Systems 4108GL - Manual (Page 212)

11-14
Optimizing Port Usage Through Traffic Control and Port Trunking
Port Trunking
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Table 11-5. General Operating Rules for Port Trunks
Media: All ports on both ends of a trunk group must have the same media type and mode (speed and duplex). The switch
blocks any trunked links that do not conform to this rule. (For the Switch 4108GL, HP recommends leaving the port Mode
setting at
Auto or, in networks using Cat 3 cabling, Auto-10 .)
Port Configuration: The default port configuration on the Switch 4108GL is Auto, which enables a port to sense speed
and negotiate duplex with an Auto-enabled port on another device. HP recommends that you use the Auto setting for all
ports you plan to use for trunking. Otherwise, you must manually ensure that the mode setting for each port in a trunk is
compatible with the other ports in the trunk.
All of the following operate on a per-port basis, regardless of trunk membership:
• Enable/Disable
• Flow control (Flow Ctrl)
LACP is a full-duplex protocol. See “Trunk Group Operation Using LACP” on page 11-25.
Trunk Configuration: All ports in the same trunk group must be the same trunk type (LACP, Trunk, or FEC). All LACP ports
in the same trunk group must be either all static LACP or all dynamic LACP.
A trunk appears as a single port labeled
Dyn1 (for an LACP dynamic trunk) or Trk1 (for a static trunk of any type:
LACP, Trunk, or FEC) on various menu and CLI screens. For a listing of which screens show which trunk types, see “How
the Switch Lists Trunk Data” on page 11-29.
For STP or VLAN operation, configuration for all ports in a trunk is done at the trunk level. (You cannot separately configure
individual ports within a trunk for STP or VLAN operation.)
Traffic Distribution: All of the switch trunk protocols use the SA/DA (Source Address/Destination Address) method of
distributing traffic across the trunked links. See “Outbound Traffic Distribution Across Trunked Links” on page 11-30.
Recommended Port Mode Setting for LACP