Specifications

A.14 Fault Tolerance in Trees
A–34 FDDI Configuration Capabilities
A.14.2 Example of Tree Backplane Healing
As shown in Figure A–28, if Concentrator 1 is removed, Concentrator 2 and Switch
1 continue communications with each other and with all other FDDI stations in the
tree.
If Concentrator 2 fails, Concentrator 1 and Switch 1 can no longer communicate with
each other. Within seconds of when Concentrator 2 becomes unavailable, the Hub
Manager automatically reconnects Switch 1 to Concentrator 1 and the tree is reestab-
lished.
If, at a later time, a replacement concentrator of the same type is installed into the
same slot that held Concentrator 2, the replacement concentrator is reinserted into
the tree through the Auto Healing feature.
Figure A–28 Tree Configuration
M M M M M M M M M M M M
S MS M
S
Backplane Ports
LKG-10125-96F
Front Panel Ports
Concentrator 1 Concentrator 2 Switch 1