Verilink 9000 Series (34-00271) Product Manual - Manual (Page 171)

9
U
NISYS
U
NISCOPE
Introduction This chapter provides specific information for the Unisys Uniscope protocol and
how it operates using TXPORT MultiPro platforms and NMCS software.
Poll/Select
Basics Unisys Uniscope is a poll/select type of protocol. The basic concept of poll/select
operation is simple. All information is stored at the central site for all branch sites
to use. The centralized mainframe where this information is stored is commonly
referred to as the host. All branch-site locations extract and send information
commonly from terminals, therefore these locations are referred to as terminals.
Two examples of non-terminal devices are ATM machines and printers. They
communicate with the network poll/select protocol being used. The host site polls
all terminal devices at the branch sites, querying whether there is data to receive
from them. Upon being polled, the terminal device transmits some indication to the
host as to whether there is information to be transmitted or received. The host,
having an indication of a terminal device needing service, selects that terminal
device, and the transaction is completed. Polling then resumes from the host site.
TXPORT MultiPro platforms support the Unisys Uniscope protocol. This protocol
follows the same concepts as other poll/select-type protocols. If a port is connected
to a host end on the TXPORT device, that port should be configured using that
particular protocol’s host port parameters. If the port selected is connected to a
terminal end on the TXPORT device, that port should be configured using that
particular protocol’s terminal parameters. All host TXPORT device ports must
have a list of which terminal addresses to service. Likewise, each terminal
TXPORT device port must have a unique host name where the terminal data
should be sent.
All host and terminal TXPORT device ports emulate a host or terminal
respectively, thereby only passing non-polling sequences through the transport
(WAN) connection. This protocol emulation is commonly referred to as spoofing.
Spoofing allows more efficient use of the WAN connection, freeing up bandwidth
as well as keeping bandwidth costs down, particularly in the frame relay
environment.
Figure 9-1 on page 150 shows a typical Unisys Uniscope network using frame
relay as the transport medium. This figure shows addressing information as address
table information for Port 4 on unit 002 and unit 003, Port 1 Frame Relay
Endpoint Lists for all units, and the Host name field on unit 001’s Port 4.