Encore ENRTR-104 User Manual page 36

2-4-1 Special Application
Some applications require multiple connections, such as Internet gaming,
video conferencing, Internet telephony and others. These applications
cannot work when Network Address Translation (NAT) is enabled. When
users send this type of request to your network via the Internet, the Router
will forward those requests to the appropriate PC. If you need to run
applications that require multiple connections, specify the port normally
associated with an application in the "Trigger Port" field, select the
protocol type as TCP or UDP, then enter the public ports associated with
the trigger port to open them for inbound traffic.
TCP (Transmission Control Protocol) - A method (protocol) used
along with the Internet Protocol (Internet Protocol) to send data in
the form of message units between computers over the Internet.
While IP takes care of handling the actual delivery of the data, TCP
takes care of keeping track of the individual units of data (called
packets) that a message is divided into for efficient routing through
the Internet.
UDP (User Datagram Protocol) - A communications method
(protocol) that offers a limited amount of service when messages
are exchanged between computers in a network that uses the
Internet Protocol (IP). UDP is an alternative to the TCP and,
together with IP, is sometimes referred to as UDP/IP. Like the
Transmission Control Protocol, UDP uses the Internet Protocol to
actually get a data unit (called a datagram) from one computer to
another. Unlike TCP, however, UDP does not provide the service of
dividing a message into packets (datagrams) and reassembling it at
the other end. Specifically, UDP doesn't provide sequencing of the
packets that the data arrives in. This means that the application
program that uses UDP must be able to make sure that the entire
message has arrived and is in the right order. Network applications
that want to save processing time because they have very small data
units to exchange (and therefore very little message reassembling to
do) may prefer UDP to TCP.
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