Query Protocol; Transport Protocol; Tcp Connection Setup And Teardown - Omron V740-BA50C22A-US Operation Manual

2. Query Protocol

Reference Guide
This chapter lays the groundwork for the
communication protocol between client software
running on a remote computer and the V740 reader.
The client software may be a database system,
enterprise software, or user software.
In this chapter, we discuss the underlying transport
protocol used and present the initial communication
protocol RQL. This protocol is loosely based on the
SQL language with extensions for a better notion of
time. This protocol was designed for rapid prototyping
of applications, where a full query to the reader can be
encapsulated in a single line of ASCII text. A simple
polling mechanism exists for automatically receiving
tag event.
V740 RFID READER/WRITER, ANTENNA
OPERATION MANUAL

2.1 Transport Protocol

In the current implementation, TCP/IP is used as the
transport protocol. TCP is a connection-oriented
protocol that provides a reliable, in-order data
transport layer with end-to-end checksums and flow
control.
2.1.1 TCP Connection Setup and
Teardown
A session between client software and the reader
consists of connection setup, data transactions, and
connection teardown.
At present, all connections are initiated only by the
client software. If, for example, the reader is
configured to automatically forward events and/or data
to the client software but the client software has not
established a connection, then no attempt is made by
the reader to contact the client software to establish a
connection. Furthermore, if an extant connection
terminates unexpectedly, the reader will not attempt to
contact the client software to re-establish a connection.
All responsibility for opening, maintaining, and closing
the connection during a session rests with client
software.
The client software sets up a TCP socket connection
on reader port 8080. After connecting successfully,
communication between the client software and the
reader can proceed as described below. Once the
client software has determined that communication
has concluded, the connection must be terminated at
the TCP level. In order to prevent synchronization
issues, each reader will support only one TCP
connection.
Other transport protocols may be used to
communicate between the client software and its
subjugate readers. The application-level protocol
discussed below is neutral with respect to the
transport layer.
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