1-5
z
When a Marker Response Protocol Data Unit (PDU) is received from the peer or the timer expires,
the device starts to redistribute service traffic on all the new link aggregation member ports in
selected state.
Currently, the 3Com Switch 4500G family support returning Marker Response PDUs only after dynamic
link aggregation member ports receive Marker PDUs.
Link aggregation modes
There are two link aggregation modes: dynamic and static. Dynamic link aggregation uses LACP while
static link aggregation does not. A link aggregation group operating in static mode is called a static link
aggregation group, while a link aggregation group operating in dynamic mode is called a dynamic link
aggregation group.
Table 1-4
compares the two aggregation modes.
Table 1-4
A comparison between static and dynamic aggregation modes
Aggregation
mode
LACP status
on member
ports
Pros
Cons
Static Disabled
Aggregation is stable. The
aggregation state of the member
ports is not affected by their
peers.
The member ports cannot
change their aggregation
state in consistent with their
peers. The administrator
needs to manually maintain
link aggregations.
Dynamic Enabled
The administrator does not need
to maintain link aggregations. The
peer systems maintain the
aggregation state of the member
ports automatically.
The aggregation state of
member ports is easily
affected by the network
environment, which makes
dynamic aggregation
instable.
In a dynamic link aggregation group:
z
A selected port can receive and send LACPDUs.
z
An unselected port can receive and send LACPDUs only if it is up and have the same class-two
configurations as the aggregate interface.
Aggregating Links in Static Mode
LACP is disabled on the member ports in a static aggregation group. The aggregation state of the
member ports must be maintained manually.
Static link aggregation comprises:
z
Selecting a reference port
z
Setting the aggregation state of each member port
