16-4 Smart Switch 1800 4. 0 User Guide , Rev 0 1
Bridge Node Default Parameters
1To assure correct operation of the spanning tree algorithm, follow these rules:
a. Bridg e Ma x Ag e must be less than or equal to twice the value of {Bridge Forward
Delay minus 1 second}.
b.Bri dge M ax Age must be greater than or equal to twice the value of {Bridg e Hello
Time plus 1 second}.
2This parameter is irrelevant on a a Token Ring SmartSwitch 1800.
Bridge Enabled
enables bridging in the node, implementing the spanning tree algorithm.
If Bridging is disabled, all Brid ge ports on the node will go in to Forwarding
stat e ( des crib ed unde r "B ridge Port Status" on page 20-2 2). No BP D Us (see
Bridge He llo Time below) will flow. No data will be bridged except termi-
nated LLC2 traffic.
Bridge Hello Time
is the frequency with which all bridges on the network will send "Hello" messages
(also called BPDUs, or Bridge Pro tocol Data Units) to ad jacent bridg es (the next o nes
in all bridge paths) when the local bridge is "Root." Note that a root bridge is the one
with the lowest ID (which contains its Bridge Priority and MAC address) on the
network.
Bridge Max Age
determines how long Hello messages will remain valid when the local bridge is root
(described under "Bridge He llo Time").
Bridge Forward Delay
is the time the bridge will wait after entering Listening state before entering Learning
state, or after entering Learning state before entering Forwa rding s ta te This delay is
intended to assure that the tree topology is stable before it is put into use.
The states are described under "Bridge Port Status" on page 20- 22.
Table 16-1 Bridge Node Default Parameters
Param eter Val id Val ues Default V a lue
Virtual LAN ID n/a – accept the default
Bridge Enable d Y/N Y
Bridge Hello Time 1–1 0 (seconds) 12
Bridge Max Ag e 6–40 (seconds) 120
Bridge Fo rward Delay 4–30 (seconds) 115
Bridge Aging Timer 10–1000 0000 (seconds) 300
Bridge Priority 0–65535 327 68
Max Size Bridge Forwarding Table 128–655 35 32768
IP Bridging Enabled Y/N N
IPX Bridging Enabled Y/N N
SRB ID 0–f (h ex) 0
Default Ethernet Frame Type 2Type II, 802.3 Type II