Link Length - Cabletron Systems 100BASE-FX Cabling Manual

Link Length

The operation of the Token Ring network places limitations on the amount of time
a signal may travel through the Token Ring. This limitation, in conjunction with
the amounts of loss that signals are susceptible to over different types of cabling,
results in specified maximum link lengths for all cabling in any Token Ring
network. The maximum link lengths given below assume that the cabling being
used to make the link is all of a homogenous type (all Type 1, all Type 6, etc.) and
that all cabling meets the other specified limits for Token Ring cabling.
The link length maximums are dependent upon the operating speed of the Token
Ring network and the circuitry type being used. Active circuitry connections
(those that provide regeneration and reclocking of the Token Ring signal at each
port) can support longer links than passive Token Ring networks.
STP Type 1,2
An active Token Ring network operating at 4 Mbps may incorporate Type 1 or
Type 2 STP links with lengths not exceeding 300 m (984 ft). If the Token Ring
network operates at 16 Mbps, this length is reduced to 150 m (492 ft).
If the Token Ring network does not incorporate active technology, the maximum
link length for a 4 Mbps Type 1 or 2 STP connection is 200 m (656 ft). When the
network speed is 16 Mbps, the maximum length is reduced to 100 m (328 ft).
STP Type 6
No matter what circuitry or speed is used in a Token Ring network, the length of
any Type 6 cable in that network may not exceed 30 m (98 ft). Type 6 cabling that
exceeds this 30 m length limit may not function properly in a Token Ring
network.
NOTE
STP Type 9
An active Token Ring network operating at 4 Mbps may incorporate Type 9 STP
links with lengths not exceeding 200 m (656 ft). If the Token Ring network
operates at 16 Mbps, this length is reduced to 100 m (328 ft).
If the Token Ring network does not incorporate active technology, the maximum
link length for a 4 Mbps Type 9 STP connection is 133 m (436 ft). When the
network speed is 16 Mbps, the maximum length is reduced to 66 m (216 ft).
IEEE 802.5 Shielded Twisted Pair
STP cables of Type 6 should only be used as jumper or patch
cables.
Token Ring Network Requirements
10-3