3Com SuperStack 4 Configuration Manual page 44

56 C 2: P O
HAPTER ORT PERATION
For the member ports in an aggregation group, their basic configurations must be
the same. That is, if one is a trunk port, the others must also be; when it turns into
access port, then others must change to access port.
The basic configuration includes STP setting, QoS setting, VLAN setting, and port
setting. The STP setting includes STP enabling/disabling, link attribute
(point-to-point or not), STP priority, path cost, max transmission speed, loop
protection, root protection, edge port or not. The QoS setting includes traffic
limiting, priority marking, default 802.1p priority, bandwidth assurance,
congestion avoidance, traffic redirection, traffic statistics. The VLAN setting
includes permitted VLAN types, and default VLAN ID. The port setting includes
port link type.
The Switch 5500G-EI can support up to 32 aggregation groups. Each group can
have eight Gigabit Ethernet ports or four 10G ports at most.
Brief Introduction to LACP
IEEE802.3ad-based Link Aggregation control protocol (LACP) implements dynamic
link aggregation and disaggregation and exchanges information with the peer
through LACP data unit (LACPADU). When LACP is enabled on it, the port notifies,
through sending LACPDU, the peer of its system priority, system MAC, port
priority, port number and operation key. On receiving this information, the peer
compares the received information with that stored at other ports to determine
which ports can be aggregated, so that the two parties can agree on
adding/deleting which port into/from a certain dynamic aggregation group.
The operation key is a configuration set generated by LACP based on port setting
(speed, duplex mode, basic configuration and management key). When LACP is
enabled, the management key of a dynamic aggregation port is 0 by default, but
the management key of a static aggregation port consists with the aggregation
group ID. For a dynamic aggregation group, all member ports must have the same
operation key, while for a manual or static aggregation group, only the active
member ports must have the same operation key.
Types of Link Aggregation
The types of link aggregation are described in the following sections:
Manual Aggregation and Static LACP Aggregation
■
Dynamic LACP Aggregation
■
Manual Aggregation and Static LACP Aggregation Both manual
aggregation and static LACP aggregation require manual configuration of
aggregation groups and prohibit automatic adding or deleting of member ports by
the system. You must delete the aggregation group, instead of the port, if the
group contains only one port. At a manual aggregation port, LACP is disabled and
you are not allowed to enable it. LACP is enabled at a static aggregation port.
When a static aggregation group is deleted, its member ports form one or several
dynamic LACP aggregation groups and LACP remains enabled on them. You are
not allowed to disable LACP protocol at a static aggregation group.
In a manual or static LACP aggregation group, its ports may be in active or inactive
state and only the active ports can transceive user service packets. The active port