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Address Aging 189
Address Aging
This section explains how address aging works and identifies the slight
differences in options and operation between Layer 2 Switching Modules
and Multilayer Switching Modules.
Address aging only applies to dynamic addresses. (Static addresses are
never aged from the address table and cannot be learned on other ports
until they have been manually removed.)
Address Table
Dependencies
The amount of time that dynamic addresses remain in a module’s address
table depends on these factors:
■
The aging interval value that you configure (
bridge agingTime
)
■
The option that you select for the bridge STP state:
■
For Multilayer Switching Modules, choose
enabled
or
disabled
■
For Layer 2 Switching Modules, choose
enabled
,
disabled
, or
agingOnly
■
These options are explained later in this section.
■
The module's detection of link state changes on ports; shorter aging
intervals may be applied for a certain period of time, depending on
the STP state that you have selected.
■
The value that you configure for STP forward delay on the module or
that is assigned to the module by the STP root bridge. The value used
depends on the STP state that you have selected.
■
Other non-aging factors, such as STP topology changes and power
cycles. See “Important Considerations” in the previous section “MAC
Address Table Design” for more information.
On Layer 2 Switching Modules, if you do not want to enable STP but you
do want accelerated aging to occur when ports go down, select the
agingOnly
option from the
bridge spanningTree stpState
command.
You may also want to modify the two STP parameters that the
agingOnly
function uses. None of these actions will enable STP itself.