A Presentation Report
PROTOCOLS ”PROTOCOLS ”
Electronics & Communication
A network is a set of devices (often referred to as
nodes) connected by communication links. A
node can be a computer, printer, or any other
device capable of sending and/or receiving data
generated by other nodes on the network.
What is network protocol ?What is network protocol ?
The network protocol is a set of
very detailed rules, sequences, message
formats, and procedures that
computer systems use and understand
when exchanging data with each
Internet protocolInternet protocol
( IP )( IP )
IP :-IP :-
Unreliable & connectionless datagram protocol –
best-effort delievery service.
Must be paired with a reliable protocol such as
Ex. Post office service.
It transports data in packets called datagram. It
consisting of two parts : (1) Header & (2) Data.
Header contains information essential to routing
Identification (16 bits) Flags
Time to live
Source IP address
Destination IP address
• ARP associates an IP address with its physical address. On aARP associates an IP address with its physical address. On a
typical physical network, such as a LAN, each device on atypical physical network, such as a LAN, each device on a
link is identified by a physical or station address that islink is identified by a physical or station address that is
usually imprinted on the NIC.usually imprinted on the NIC.
• ARP is used to find the physical address of the node whenARP is used to find the physical address of the node when
its internet address is known.its internet address is known.
• Anytime a host , or a router , needs to find the physicalAnytime a host , or a router , needs to find the physical
address of another host on its now , it format an ARP queryaddress of another host on its now , it format an ARP query
packet that includes the ip address and broadcast it over thepacket that includes the ip address and broadcast it over the
n/w .n/w .
• RARP finds the logical address for aRARP finds the logical address for a
machine that only knows its physicalmachine that only knows its physical
• The host wishing to retrieve its IPThe host wishing to retrieve its IP
address broadcasts an RARP queryaddress broadcasts an RARP query
packet that contains its physical addresspacket that contains its physical address
to every host on its physical network. ato every host on its physical network. a
server on the network recognizes theserver on the network recognizes the
RARP packet & returns the host ‘ s IPRARP packet & returns the host ‘ s IP
address .address .
WHY DO WE NEED RARP ?
A host to have its IP address store in its hard
Now what if the host is a dioskless computer .
OR what if computer is being connect to the n/w
for a first time .
OR what if you get new computer but you
decide to keep old NIC .
ARP and RARP :-
RARP works much like ARP.
The Internet is based on IP addresses .
Protocols may have different (MAC)
The ARP and RARP protocols perform
the translation between IP addresses
and MAC layer addresses .
Internet Group MessageInternet Group Message
( IGMP )( IGMP )
Internet Group Management Protocol (IGMP) is a
communications protocol used by hosts and
adjacent routers on IP networks to establish
multicast group membership .
IGMP is an integral part of the IP multicast
specification. IGMP can be used for online
streaming video and gaming, and allows more
efficient use of resources when supporting these
types of applications .
IGMP is used on IPv4 networks.
IGMP OPERATION :-IGMP OPERATION :-
– To receive multicast datagram , a host
must join a group . To join a group , the
host sends an IGMP membership report
packet through an attached interface .
IGMP OPERATION :-
Multicast Router Operations
– Multicast routers listen to all multicast
addresses to detect
membership reports .
• 1. receiver (host) signals to join a group ,
• 2. creates an entry in the local group database .
• 3. To verify group membership , multicast routers
regularly send an IGMP
Query message .
Internet Control MessageInternet Control Message
ICMP :-ICMP :-
ICMP is used by host and routers to send
notification of datagram problems back to the
ICMP used for just error detection it will not correct
that error .
If a datagram travels from router to router untill
it reaches it one that can deliever it to its final
destination . If a router is unable to deliever the
datagram because of unsual conditions , ICMP
allows it to inform original source .
ICMP messages :-
ICMP messages are divided into
error-reporting messages and query
The error-reporting messages report
problems that a router or a host
(destination) may encounter.
The query messages get specific
information from a router or another