5 | DART Supported Protocols |
UDP
User Datagram Protocol (UDP) is the most basic transmission protocol provided by the Data Access Radio Transceiver (DART) 200. It is a thin protocol, adding only a port specification to the underlying Internet Protocol (IP). It has the same features as IP, that is a best effort, connectionless delivery service with the chief benefit being minimum overhead.
UDP is not considered reliable because packet delivery is not guaranteed. Packets can be lost, duplicated, delayed, or delivered out of sequence. These conditions are not detected, and the sender or receiver is not informed.
UDP is connectionless because sender and receiver are never logically connected. If the intended receiver is not active the message is lost. It is a best effort delivery, because the IP software makes an earnest attempt to deliver the packets, failing only if system resources are overloaded or the underlying networks fail.
Application programs using UDP must accept full responsibility for handling the problems of reliability, including message loss, duplication, delay,
These problems are often treated casually be programmers. Testing done when using highly reliable, low delay local networks may not expose potential failures. This explains why many applications that use UDP work well in a local environment but often fail in dramatic ways on a more global network.
Despite these warnings, UDP is still the most efficient and widely used protocol. Take care in analyzing the application being implemented, the network being used, and the Mobile Application Subsystem (MAS) device involved to determine if an application implementation using UDP is feasible.
∙How likely is it that the network being used can cause these problems?
Small,
∙How much compute power and programming capability does the MAS device have?
Lack of available memory or programming capability can preclude adding the needed reliability features into the application.
