Load Sharing In A Link Aggregation Group; Service Loop Group - 3Com Switch 4800G 24-Port Configuration Manual

Load Sharing in a Link
Aggregation Group

Service Loop Group

You need to maintain the basic configurations of these ports manually to ensure
consistency. As one configuration change may involve multiple ports, this can
become troublesome if you need to do that port by port. As a solution, you may
add the ports into an aggregation port group where you can make configuration
for all member ports.
When the configuration of some port in a static aggregation group changes, the
system does not remove the aggregation; instead, it re-sets the
selected/unselected state of the member ports and re-selects a master port.
Link aggregation groups fall into load sharing aggregation groups and non-load
sharing aggregation groups depending on their support to load sharing.
A load sharing aggregation group can contain at least one selected port but a
non-load sharing aggregation group can contain only one.
Link aggregation groups perform load sharing depending on availability of
hardware resources. When hardware resources are available, link aggregation
groups created containing at least two selected ports perform load sharing, while
link aggregation groups created with only one selected port does not perform load
sharing. After hardware resources become depleted, link aggregation groups
created work in non-load sharing mode.
Load sharing is implemented through the selected ports in an aggregation group.
However, the way of selecting forwarding ports varies by packet type:
For a Layer-2 unicast packet with a known destination MAC address, if the
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packet carries an IP datagram, the switch selects the forwarding port according
to the source IP address and destination IP address; otherwise, the switch
selects the forwarding port according to the source MAC address and
destination MAC address.
For a unicast IP packet with a known destination IP address, the switch selects
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the forwarding port according to the source IP address and the destination IP
address of the packet.
For a Layer-2 multicast packet with a known destination MAC address, the
■
switch selects the forwarding port according to the source MAC address, the
destination MAC address, and the receiving port of the packet.
For a Layer-3 multicast packet with a known IP address, the switch selects the
■
forwarding port according to the source IP address, the destination IP address,
and the receiving port of the packet.
For an unknown unicast/multicast/broadcast packet, the switch selects the
■
forwarding port according to the source MAC address, the destination MAC
address, and the receiving port of the packet.
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When only one selected port remains in a load sharing aggregation group, the
group keeps working in the load sharing mode.
You can create a service loop group by creating a manual aggregation group of
service-loop ports first and then specifying which services can be redirected for the

Load Sharing in a Link Aggregation Group

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