Java Network Programming (3rd ed) [Electronic resources] نسخه متنی

Chapter 9. Sockets for Clients

Data is transmitted across the Internet in packets of finite size
called
datagrams.
Each datagram contains a
header
and a
payload.
The header contains the address and port to which the packet is
going, the address and port from which the packet came, and various
other housekeeping information used to ensure reliable transmission.
The payload contains the data itself. However, since datagrams have a
finite length, it's often necessary to split the
data across multiple packets and reassemble it at the destination.
It's also possible that one or more packets may be
lost or corrupted in transit and need to be retransmitted or that
packets arrive out of order and need to be reordered. Keeping track
of thissplitting the data into packets, generating headers,
parsing the headers of incoming packets, keeping track of what
packets have and haven't been received, and so
onis a lot of work and requires a lot of intricate code.

Fortunately, you don't have to do the work yourself.
Sockets allow the programmer to treat a
network connection as just another stream onto which bytes can be
written and from which bytes can be read. Sockets shield the
programmer from low-level details of the network, such as error
detection, packet sizes, packet retransmission, network addresses,
and more.