relationship between DCE/RPC and NT Named Pipes.

Joe Doran joed at
Thu Jan 10 07:58:08 GMT 2002

> On Thu, Jan 10, 2002 at 12:49:27AM +0000, Luke Kenneth Casson Leighton
> wrote:
>> unix supports TCP (guaranteed and ordered data delivery)
>> and it supports UDP (guaranteed message sizes) but it doesn't
>> support both.
>  [if anyone has a more technically accurate explanation,
>   i'd appreciate it if you could clarify this limited
>   and ambiguous assessement: you know what i mean, but
>   i can't find the words].
>   lkcl

TCP and UDP are the two transport protocols used in the IP architecture.

TCP is a connection oriented transport protocol designed to work in 
conjunction with IP. TCP provides its user (application layer) with the 
ability to transmit reliably a byte stream to a destination and allows for 
multiplexing multiple TCP connections within a transmitting or receiving 
host computer. 

Being connection oriented, TCP requires a connection establishment phase 
(like dialing a number to make a phone call) which is followed by the data 
transmission phase. A connection is terminated when it is no longer in use. 
TCP/IP is ideal for the transmission of bursty data. It works on the 
principle of retransmission of dropped packets which is one of the major 
contributors to delays in transmission. However, since voice and video data 
are time sensitive, packet technologies such as TCP/IP cannot guarantee the 
proper delivery of such data.

UDP, on the other hand, is a connectionless transport protocol designed to 
operate over IP. Its primary functions are error detection and 
multiplexing. UDP does not guarantee the delivery of packets (compare with 
the ordinary postal service) but guarantees that if a packet is ever 
delivered in error, such error will be detected (use of checksum). It also 
allows for communicating with multiple processes residing on the same host 

UDP packet format is simple. It is also fast compared to the use of TCP, 
since there is no connection establishment phase. Moreover, UDP is 
important since RTP (Real time Transport Protocol) is supported over UDP.

Definition found on


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