TDT RZ2, Manual

Page: 74 / 736

1-68 System 3
RZ-UDP Communications Interface
Manual
In manual mode the IP address is selected by the client (manually by the user or
any other means) and the DHCP protocol messages are used to inform the server
that the address has been allocated.
The UDP Protocol
UDP or “User Datagram Protocol” is a core protocol of the Internet Protocol suite or
more commonly known as the TCP/IP protocol suite. UDP allows programs and
networked computers to send datagrams or data organized in a specific structure
(commonly referred to as a packet).
Note: The UDP protocol is considered “connectionless” since devices send data to a
defined IP address and are not actively connected to the destination device or PC.
As such, the UDP Ethernet interface will send or receive data from the last IP
address it is configured to communicate with.
When information from a data protocol (UDP or TCP) is sent, the information may
get lost or delayed along the way. UDP protocol allows time critical data to be
transmitted with very low latency since UDP protocol does not implement data
tracking. Conversely, when TCP detects that information has been lost or received
out of order, it resends the suspect information. This is insufficient for time
dependent data found in most neuroscience applications.
Note: The UDP protocol does not account for data received out of order.
Process Layers
The UDP Ethernet interface operates on a structure of layers. These layers interact
with each other as segments to produce the end result; to send data from one
source and receive it intact on another source. Five layers of this structure are
shown below.
Each process begins with encoding in which the data is organized into packets before
it is sent through the data link to a network. Once the device is recognized on the
network (through an IP address) data transmission can occur. In order for the
destination to be selected and the device to be recognized, the NetBIOS protocol
translates any present NetBIOS names to IP addresses and the target source’s
application may receive the data packet for further processing. Once resolved, the
Layer - Name Entity or Protocol Segment Task
1 – Physical UDP Ethernet Interface Encodes the data into packets.
2 – Data Link Ethernet Provides a means to move data
packets.
3 – Network IP Provides a link between one or more
data sources.
4 – Transmission UDP Manages the transfer of data packets
to or from sources.
5 – Presentation Application Used to manipulate or analyze the
data packets.