Q (1) Difference
between TCP and UDP?
Acronym for
|
Transmission Control Protocol
|
User Datagram Protocol or Universal
Datagram Protocol
|
Connection
|
TCP is a connection-oriented protocol.
|
UDP is a connectionless protocol.
|
Function
|
As a message makes its way across the
internet from one computer to another. This is connection based.
|
UDP is also a protocol used in message
transport or transfer. This is not connection based which means
that one program can send a load of packets to another and that
would be the end of the relationship.
|
Usage
|
TCP is suited for applications that
require high reliability, and transmission time is relatively less
critical.
|
UDP is suitable for applications that
need fast, efficient transmission, such as games. UDP's stateless
nature is also useful for servers that answer small queries from
huge numbers of clients.
|
Use by other protocols
|
HTTP, HTTPs, FTP, SMTP, Telnet
|
DNS, DHCP, TFTP, SNMP, RIP, VOIP.
|
Ordering of data packets
|
TCP rearranges data packets in the
order specified.
|
UDP has no inherent order as all
packets are independent of each other. If ordering is required, it
has to be managed by the application layer.
|
Speed of transfer
|
The speed for TCP is slower than UDP.
|
UDP is faster because there is no
error-checking for packets.
|
Reliability
|
There is absolute guarantee that the
data transferred remains intact and arrives in the same order in
which it was sent
|
There is no guarantee that the messages
or packets sent would reach at all.
|
Header Size
|
TCP header size is 20 bytes
|
UDP Header size is 8 bytes.
|
Common Header Fields
|
Source port, Destination port, Check
Sum
|
Source port, Destination port, Check
Sum
|
Weight
|
TCP is heavy-weight. TCP requires three
packets to set up a socket connection, before any user data can be
sent. TCP handles reliability and congestion control.
|
UDP is lightweight. There is no
ordering of messages, no tracking connections, etc. It is a small
transport layer designed on top of IP.
|
Data Flow Control
|
TCP does Flow Control. TCP requires
three packets to set up a socket connection, before any user data
can be sent. TCP handles reliability and congestion control.
|
UDP does not have an option for flow
control
|
Error Checking
|
TCP does error checking
|
UDP does error checking, but no
recovery options.
|
Fields
|
1. Sequence Number, 2. AcK number, 3.
Data offset, 4. Reserved, 5. Control bit, 6. Window, 7. Urgent
Pointer 8. Options, 9. Padding, 10. Check Sum, 11. Source port,
12. Destination port
|
1. Length, 2. Source port, 3.
Destination port, 4. Check Sum
|
Acknowledgement
|
Acknowledgement segments
|
No Acknowledgment
|
Handshake
|
SYN, SYN-ACK, ACK
|
No handshake (connectionless protocol)
|
Checksum
|
checksum
|
to detect errors
|
