Protocol :is a set of
predefined rules used by devices in network for data transfer. It is a
communication standard followed by computers in a network to communicate with
each other.
Network Protocols:
NetBIOS/NetBEUI
TCP/IP
ARP/RARP
ICMP/IGMP
UDP
IPX/SPX
HDLC/SDLC
NetBIOS/NetBEUI
:-
Developed
by IBM and later adopted by Microsoft
Network
Basic Input/Output System (NetBIOS) used for communication within LAN
Operates
at Transport and Session layers of OSI model
NetBIOS
Extended User Interface (NetBEUI) adds capabilities to NetBIOS and an advanced
version of NetBIOS used in MS Windows OS
Widely
used in Ethernet, Token Ring and Windows NT networks.
NetBIOS
Services :-
Supports
three distinct services: Name service for name registration and resolution,
Session service for connection oriented communication and datagram service for connectionless
communication.
Name
Service :-
Implemented
in Microsoft Windows as Windows Internet Name Service (WINS).
Provides
means to application to register its NetBIOS name
NetBIOS
names are 16 bytes length
Service
uses UDP port 137
Name
Service functions include
·
Add Name
·
Add Group Name
·
Delete Name
·
Find Name
Session
Service :-
Establishes session for
data exchange between computers using TCP port 139
Datagram
Service :-
Uses
the UDP port 138 and provides a connectionless and broadcast-oriented data
communication between two devices.
Divides
data in datagrams before sending
Datagram
service functions include:
·
Send Datagram
·
Send Broadcast Datagram
·
Receive Datagram
·
Receive Broadcast Datagram
NetBIOS
Name Resolution :-
Used
to map NetBIOS names to IP addresses
Methods
used to resolve names:
·
NetBIOS Name Cache
·
NetBIOS
Name Server (NBNS)
·
Local Broadcast
NetBEUI
:-
Enhanced
version of NetBIOS
Used
by LAN manager, LAN server, Windows for workgroups, Windows 95 and Windows NT
Adapted
to other protocols such as IPX or TCP/IP as it does not support routing of
messages to other networks
TCP/IP
:-
Two
layer communication protocol used by Internet
TCP
provides connection-oriented reliable transport service
Divides
the message into smaller packets called segments
IP
is a connectionless and unreliable datagram protocol and provides no error
checking
IP
transfers data in the form of packets called datagrams
TCP/IP
Protocol Suite :-
Designed
before OSI model
Consists
of five layers
Provides
independent protocols at each layer
Description
of Each Layer :-
Ø Physical
and Data link layer – standard and proprietary protocols
are supported by these layers.
Ø Network
layer –
1. IP – It sends data in the form of packets called
datagrams.
2. ARP
– It is used to translate the IP
address to Ethernet MAC address.
3.
RARP – It is used to determine the
IP address of the host only when its IP address is known.
4.
ICMP – used to send query and error
reporting messages to the sender and
not to correct them.
5. IGMP – Uses class D IP address.
Ø Transport
layer –
1.
UDP – It adds port address and error control
information and error control information to the data and
delivers the data.
2.
TCP – divides data into segments
each having a sequence number.
3. Stream Control Transmission Protocol (SCTP) – multiple streams of
data can be transmitted simultaneously. Used over wireless network and
transmission of multimedia data. Supports voice over IP and combines the best
features of TCP and UDP
Ø Application
layer –
1. SMTP
– It is used to transfer e-mail message across the network.
2.
FTP – It is used to exchange files
from host to another connected over internet.
3.
DNS – It is used to store and
resolves the internet domain names of
host to IP address and vice versa.
4. SNMP –
Based on client-server model.
5. NFS
– Allows different Operating systems to share files and disk storage.
6. TFTP
– Uses UDP to upload or download files and does not provide security
features.
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