3Com Switch 7750 Configuration Guide Guide

182 CHAPTER 22: LINK AGGREGATION CONFIGURATION
Aggregation Group
Categories
Depending on whether or not load sharing is implemented, aggregation groups
can be load-sharing or non-load-sharing aggregation groups.
In general, the system only provides limited load-sharing aggregation resources
(currently up to 64 load-sharing aggregation groups can be created), so the system
needs to reasonably allocate the resources among different aggregation groups.
The system always allocates hardware aggregation resources to the aggregation
groups with higher priorities. When load-sharing aggregation resources are used
up by existing aggregation groups, newly-created aggregation groups will be
non-load-sharing ones.
The priorities of aggregation groups for allocating load-sharing aggregation
resources are as follows:
■ An aggregation group containing special ports (such as 10GE port) which
require hardware aggregation resources has higher priority than any
aggregation group containing no special port.
■ A manual or static aggregation group has higher priority than a dynamic
aggregation group (unless the latter contains special ports while the former
does not).
■ For two aggregation groups of the same kind, the one that might gain higher
speed if resources were allocated to it has higher priority than the other one.
■ If the two groups can gain the same speed after resources are allocated to
them, the one with smaller master port number has higher priority than the
other one.
When an aggregation group of higher priority appears, the aggregation groups of
lower priorities release their hardware resources. For single-port aggregation
groups, if they can transceive packets normally without occupying aggregation
resources, they will not occupy hardware aggregation resources.
c
CAUTION: A load-sharing aggregation group contains up to two selected ports,
however, a non-load-sharing aggregation group can only have one selected port
at most and others are standby ports.
Tabl e 114 Restriction of non-type-A I/O Modules on link aggregation
I/O Module
type
Cross-chip
aggregation
Aggregation
type
Maximum
number of
ports in an
aggregation
group
Maximum
number of
selected ports
in an
aggregation
group
Non-type-A I/O
Module
Supported
Manual
aggregation
8 8
Static/dynamic
aggregation
The number of
ports on the I/O
Module
8