Specifications

Functional Description
RADring
Installation & Operation Manual
2-2 Radring Functional Description - Token Ring 3/11/98 12:33
Physical Topology
Stations are connected to the ring by means of access units (wire
concentrators) or hubs, such that the physical topology is that of a star (see
Figure 2-2). This topology allows central connection and management of
the cabling. The access unit or hub will insert the station into the ring only
on request from the station, otherwise the station will be bypassed.
Under normal operation the signal circulates on the main path (one twisted
pair or fiber cable) only. The station is automatically bypassed unless it
requests entry into the ring.
The back-up path (second twisted pair or fiber cable) becomes operational
only when under trunk cable fault conditions.
Ring Physical
Limitations
The ring size is physically limited by the attenuation of the transmitted
signal as it passes through the ring. To overcome this limitation, repeaters
can be placed in the ring. The number of stations that can be attached to a
single ring is limited by the jitter accumulated by the signal as it is
transmitted around the ring. Without the use of jitter reduction circuits
(found in the RADring repeaters) the number of stations is limited to 260
over STP cabling, 72 over regular UTP cabling and 104 over enhanced UTP
cabling.
RI
RI RO
RO
ACCESS UNIT/HUB
TRUNK CABLE
TRUNK CABLE
M
A
I
N
B
A
C
K
U
P
BYPASSEDBYPASSED
INSERTED
Figure 2-2 RADring Physical Connection