Table 12: General operating rules for port trunks
Media:
For proper trunk operation, all ports on both ends of a trunk group must have
the same media type and mode (speed and duplex). (For the switches, it is
recommended to leave the port mode setting at
Auto
or, in networks using
Cat 3 cabling,
Auto-10
.)
Port Configuration:
The default port configuration is
Auto
, which enables a port to sense speed
and negotiate duplex with an auto-enabled port on another device. It is
recommended 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.
Recommended port mode setting for LACP example
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 142.
Trunk configuration:
All ports in the same trunk group must be the same trunk type (LACP or trunk).
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 type LACP, Trunk) 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 149.For spanning-tree 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 spanning-
tree 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
traffic distribution across trunked links
Table Continued
Chapter 5 Port Trunking
133