3Com Switch 8800 Configuration Guide
Chapter 7 Link Aggregation Configuration
7-4
protocol types in determining if to use IP or MAC addresses. The packet with 0800
ETYPE Ethernet field is IP packet. In general, the system only provides limited
resources. The system will always allocate hardware aggregation resources to the load
balancing aggregation groups with higher priority levels. When the load sharing
aggregation resources are used up for existing aggregation groups, newly-created
aggregation groups will be non-load sharing ones. The priority levels (in descending
order) for allocating load sharing aggregation resources are as follows:
z
Aggregation groups of special ports with hardware aggregation resources
included
z
Aggregation groups including special ports which require hardware aggregation
resources
z
Aggregation groups that probably reach the maximum rate after the resources are
allocated to them
z
Aggregation groups with the minimum master port numbers if they reach the equal
rate with other groups after the resources are allocated to them
When aggregation groups of higher priority levels appear, the aggregation groups of
lower priority levels release their hardware resources. For single-port aggregation
groups, if they can transceive packets normally without occupying hardware resources,
they shall not occupy the resources.
II. Port state
In a aggregation group, its ports may be in active or inactive state and only the active
ports can transceive user service packets, but not inactive ports. The active port with
the minimum port number serves as the master port, while others as slave ports.
In a aggregation group, the system sets the ports to active or inactive state based on
these rules:
z
Based on the descending order of priority levels from full duplex/high speed, to full
duplex/low-speed, to half duplex/high speed and till half duplex/low speed, the
system sets the port with the highest priority to active state, and others to inactive
state.
z
The system sets to inactive state the ports which cannot aggregate with the
master port, due to hardware limit.
z
The system sets to inactive state the ports with basic configurations different from
the master port.
Since only a defined number of ports can be supported in an aggregation group, then if
the active ports in an aggregation group exceed the port quantity threshold for that
group, the system shall set some ports with smaller port numbers (in ascending order)
as active ports and others as inactive ports. The active ports can transceive user
service packets, but not inactive ports.
A load sharing aggregation group may contain several active ports, but a non-load
sharing aggregation group can only have one active port, while others as inactive ports.
