Cabletron Systems switches - Manual (Page 17)

Token Ring 2-5
Review of Networking
Fast Ethernet networks designed using Class II repeaters may not exceed the
following maximum network radii:
- 200 m for homogenous 100BASE-TX networks
- 320 m for homogenous 100BASE-FX networks
• Buffered Uplinks: If a buffered uplink is used to make a connection, the
allowable length of the buffered uplink itself does not change, but the
maximum network radius calculations will change. Assuming that the
buffered uplink is the longest link in the repeater radius, the maximum
allowable network radius will change to the values given below:
- 500 m for mixed 100BASE-TX and buffered 100BASE-FX uplink
- 800 m for homogenous 100BASE-FX networks
• Number of Stations per Network: IEEE standards specify that the maximum
allowable number of stations per single-segment network is 1,024, regardless
of media type.
• Maximum Signal Path: The maximum allowable signal path for a Fast
Ethernet network is one Class I repeater, two segments for all media types. The
use of bridges, switches, or routers can allow the creation of larger networks.
Token Ring
Token Ring network operation is based on the principle that the operation of the
entire network determines when a station may transmit and when it will receive.
Stations monitor one another, and one station acts as an overall ring monitor,
keeping track of important statistics. Token Ring stations are connected to one
another in a predetermined order, and network frames pass from one station to
the next, following that order. A specialized network frame, called a token, is
passed around the ring at regular intervals. The transmission of the token helps
establish some of the operational statistics for the network, and receiving it allows
a station to transmit.
The Token Ring technology is designed to operate at either of two speeds: 4 Mbps
or 16 Mbps. This speed selection is made when the network is installed, and the
speed must apply equally to all stations (you may not split a ring into groups of
16 Mbps and 4 Mbps stations).
NOTE
If it becomes necessary to extend the network beyond the IEEE
limit of 1,024 devices, a bridge or switch can be used to
connect another full specification Fast Ethernet network.