3Com DUA1860-0AAA01 Network Hardware User Manual


 
3-4 C
HAPTER
3: A
DVANCED
B
RIDGING
DUA1860-0AAA01
ID:
Display Field. The identification number for the bridge. The ID
number uniquely identifies each bridge. The number is a
combination of the lowest Ethernet device address on the bridge
and a hexadecimal representation of the PRIORITY field. The
Ethernet device address is hard-coded in the Ethernet chip and
cannot be changed.
Priority:
Text Field. Enter the priority of the bridge. The priority
determines which bridge to use when two or more bridges are on
the same network. The highest priority bridge is the one set with
the lowest number. If two bridges have the same path cost to the
root bridge, the priority is used to determine which bridge to use.
The IEEE 802.1 spanning tree priority is a value between 0 and
65535. The default is 32768.
Changes to this field are saved and take effect immediately.
Maximum Age:
Text Field. Enter the amount of time a bridge
retains spanning tree configuration information before discarding
it.
All bridges in a spanning tree network need to receive
information about the configuration of the network. This
information is made available in the form of Configuration Bridge
Protocol Data Units (C-BPDUs) sent by the root bridge. If a bridge
does not receive valid C-BPDUs from a root bridge during the time
interval set by the MAXIMUM AGE field, it will assume that the
root bridge has failed and will establish a new network
configuration using itself as the new root bridge. This process
ensures that a root bridge always exists.
The maximum age must be between 6 and 40 seconds and
cannot be greater than the maximum age of the current root
bridge, shown on the right hand side of the screen. The default is
20
seconds, as recommended by the IEEE 802.1d specification.
The maximum age must be larger than the hello time of every
bridge in the network.
Changes to this field are saved and take effect immediately.