Specifications

A.15 Token Ordering of Trees or Dual Rings
FDDI Configuration Capabilities A–37
A.15.3 Example 2 — Token Flow Through Treed Network Modules
Figure A–30 shows the same hub that is now configured into a tree configuration
with FDDI network modules in slots 1, 2, 3, 4, 6, and 8.
Figure A–30 Token Flow through Treed DEChub 900 Modules
Note that the front panel S port is shown on the module in slot 4, therefore the token
enters and exits the hub at slot 4.
A ringmap, showing the order of token flow, is based on the ordering of the MACs in
the ring. FDDI rules require that a station’s MAC be located immediately prior to the
port where the token exits the station. The token enters the S port of slot 4 and flows,
in order, through the MACs in slots 1, 2, 3, 6, 8 and finally slot 4. To do this, the S
port of slot 8 must connect to the M port of slot 4.
In this example a ring map records the token order as: 1>2>3>6>8>4.
To Ring
Slot 1 2 3 4 5 6 7 8
Token order on ring map = 1>2>3>6>8>4
= Location of MAC
From Ring
S
M
S
MSM S
LKG-10073-96F
M S M S