Allied Telesis AT-S111 User Manual
AT-GS950/48PS Switch Web Interface User’s Guide
65
Bridge Priority
and the Root
Bridge
The first task that bridges perform when a spanning tree protocol is
activated on a network is the selection of a root bridge. A root bridge
distributes network topology information to the other network bridges and
is used by the other bridges to determine if there are redundant paths in
the network.
activated on a network is the selection of a root bridge. A root bridge
distributes network topology information to the other network bridges and
is used by the other bridges to determine if there are redundant paths in
the network.
A root bridge is selected by the bridge priority number, also referred to as
the bridge identifier, and sometimes the bridge’s MAC address. The bridge
with the lowest bridge priority number in the network is selected as the root
bridge. If two or more bridges have the same lowest bridge priority
number, the one with the lowest MAC address is designated as the root
bridge.
the bridge identifier, and sometimes the bridge’s MAC address. The bridge
with the lowest bridge priority number in the network is selected as the root
bridge. If two or more bridges have the same lowest bridge priority
number, the one with the lowest MAC address is designated as the root
bridge.
You can change the bridge priority number in the AT-S111 Management
software. You can designate which switch on your network as the root
bridge by giving it the lowest bridge priority number. You may also
consider which bridge should function as the backup root bridge in the
event you need to take the primary root bridge off line and assign that
bridge the second lowest bridge identifier number.
software. You can designate which switch on your network as the root
bridge by giving it the lowest bridge priority number. You may also
consider which bridge should function as the backup root bridge in the
event you need to take the primary root bridge off line and assign that
bridge the second lowest bridge identifier number.
The bridge priority has a range 0 to 61440 in increments of 4096. To make
this easier for you, the AT-S111 Management software divides the range
into increments. You specify the increment that represents the desired
bridge priority value. The range is divided into sixteen increments, as
shown in Table 1.
this easier for you, the AT-S111 Management software divides the range
into increments. You specify the increment that represents the desired
bridge priority value. The range is divided into sixteen increments, as
shown in Table 1.
Table 1 Bridge Priority Value Increments
Increment
Bridge
Priority
Increment
Bridge
Priority
0x0000
0
0x8000
32768
0x1000
4096
0x9000
36864
0x2000
8192
0xA000
40960
0x3000
12288
0xB000
45056
0x4000
16384
0xC000
49152
0x5000
20480
0xD000
53248
0x6000
24576
0xE000
57344
0x7000
28672
0xF000
61440