1. INTRODUCTION
1-11
EIGHT SEGMENT BRIDGE
The “Spanning Tree” Algorithm
The “Spanning Tree” algorithm avoids the generation of infinite loops by
dynamically defining one and only one direct logical path between any
two bridged LANs.
The spanning tree algorithm uses the fields:
root identifier
cost to root
transmitter
to dynamically identify one “root” bridge for each network and one
designated LAN bridge for each LAN on the network.
LAN #2
Destination #1
LAN #1
Source #1
1
4
Bridge #1
Bridge #2
Packet #1
Address Cache
source 1
source 1
source 1
source 1
LAN 1
LAN 2
LAN 1
LAN 2
Packet #1
Address Cache
source 1
source 1
source 1
source 1
LAN 1
LAN 2
LAN 1
LAN 2
9
2
7
1 2
5
3
2
6
1 1
1 0
8
1 3