Specifications

RADring
Installation & Operation Manual Functional Description
3/11/98 12:33 Elementary Bridge Modules Functional Description 2-39
2.9 Elementary Bridge Modules Functional Description
TRE Token Ring
Elementary
Bridge Module
The TRE-8D Token Ring Elementary Bridge Module connects a LAN
consisting of 80 remote workstations to the central Token Ring LAN.
Connection is made through a synchronous or asynchronous serial
communication link, operating at data rates of 1.2 to 512 Kbps, over
point-to-point or public networks. Link operation at data rates of 9.6 Kbps
or higher is recommended to reduce response time and link delay.
The TRE-8D operates like a MAC level remote bridge, performing filtering
and forwarding of only those packets addressed to the remote stations. The
TRE-8D uses a different algorithm than that used by full bridges, providing
optimum performance for applications requiring connection of small remote
LANs to a central LAN.
The TRE-8D includes status indicators for module power, management
control, LAN's data rate and activity.
TRE-8D Operation
The TRE-8D operates as follows:
The TRE-8D connected to the remote LAN is self-learning, recognizing the
addresses of all attached workstations. This information is transmitted to the
TRE-8D connected to the main LAN. The remote TRE-8D forwards all
packets whose destination address is not in the remote site and ignores the
other frames.
The TRE-8D connected to the main LAN forwards (to the remote LAN) only
those packets whose destination address belongs to the remote site and
ignores the other frames.
Broadcast and multicast frames are forwarded to both LANs, unless they are
masked out.
TRE-8D operation is automatic and includes serial link start-up and
recovery.
The serial link interface can be V.35, V.24/RS-232, X.21, V.36/RS-422 or
RS-530, via conversion cable to a 25-pin D-type connector. This allows
interfacing to a wide range of modems and public networks, including
connection over the ISDN network. In synchronous mode, the TRE-8D is
configured as a DTE, with clocking provided by the serial link. In
asynchronous mode, the bit rate and data format are programmed by the
user.
The TRE-8D module supports the physical and data link layers of the OSI
model, and is completely transparent to higher level protocols such as
TCP/IP, DECNET, XNS, ISO and to operating systems such as Netware,
3COM and VINES.