DES-3326S Layer 3 Fast Ethernet Switch User’s Guide
66
Switch Management and Operating Concepts
transmissions of BPDU packets sent by the Root
Bridge to tell all other Switches that it is indeed the
Root Bridge. If you set a Hello Time for your Switch,
and it is not the Root Bridge, the set Hello Time will
be used if and when your Switch becomes the Root
Bridge.
Note:
The Hello Time cannot be longer than the Max. Age.
Otherwise, a configuration error will occur.
•
Max. Age
The Max. Age can be from 6 to 40 seconds.
At the end of the Max. Age, if a BPDU has still not
been received from the Root Bridge, your Switch will
start sending its own BPDU to all other Switches for
permission to become the Root Bridge. If it turns out
that your Switch has the lowest Bridge Identifier, it
will become the Root Bridge.
•
Forward Delay Timer
The Forward Delay can be
from 4 to 30 seconds. This is the time any port on
the Switch spends in the listening state while moving
from the blocking state to the forwarding state.
Note:
Observe the following formulas when setting the above
parameters:
Max. Age
≤
2 x (Forward Delay - 1 second)
Max. Age
≥
2 x (Hello Time + 1 second)
•
Port Priority
A Port Priority can be from 0 to 255.
The lower the number, the greater the probability the
port will be chosen as the Root Port.
•
Port Cost
A Port Cost can be set from 1 to 65535.
The lower the number, the greater the probability the
port will be chosen to forward packets.
