A Presentation Report

On

“ “ NETWORK NETWORK PROTOCOLS ”PROTOCOLS ”

Electronics & Communication

Year 2012-13.

Submitted By:

Shah Nautami

NetworkNetwork :- :-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 other.

Overview :-Overview :-

NetworkLayer

Link Layer

IP

ARP NetworkAccess RARP

Media

ICMP IGMP

TransportLayer

TCP UDP

Reverse Address Resolution Protocol(RARP)

Internet protocolInternet protocol( IP )( IP )

IP :-IP :-

Unreliable & connectionless datagram protocol – best-effort delievery service.

Must be paired with a reliable protocol such as TCP.

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 & delievery.

Version

(4 bits)

HLEN

(4 bits)

Service type

(8 bits)

Total length

(16 bits)

Identification (16 bits) Flags

(3 bits)

Fragmentation offset

(13 bits)

Time to live

(8 bits)

Protocol

(8 bits)

Header checksum

(16 bits)

Source IP address

Destination IP address

Option

Header Data

Address Resolution protocol ( ARP )

ARP :-• ARP associates an IP address with its physical ARP associates an IP address with its physical address. On a typical physical network, such as a address. On a typical physical network, such as a LAN, each device on a link is identified by a LAN, each device on a link is identified by a physical or station address that is usually physical or station address that is usually imprinted on the NIC.imprinted on the NIC.

• ARP is used to find the physical address of the ARP is used to find the physical address of the node when its internet address is known.node when its internet address is known.

• Anytime a host , or a router , needs to find Anytime a host , or a router , needs to find the physical address of another host on its now , the physical address of another host on its now , it format an ARP query packet that includes the ip it format an ARP query packet that includes the ip address and broadcast it over the n/w .address and broadcast it over the n/w .

REQUEST

Fig . ARP Request

Fig . ARP Responce

Looking for any MAC add. :A46EF45983AB

•ARP and RARP :-

• Four cases using ARP :-

Reverse Address Resolution Protocol(RARP)

RARPRARP :-

• RARP finds the logical RARP finds the logical address for a machine that only address for a machine that only knows its physical address.knows its physical address.

• The host wishing to The host wishing to retrieve its IP address broadcasts retrieve its IP address broadcasts an RARP query packet that an RARP query packet that contains its physical address to contains its physical address to every host on its physical every host on its physical network. a server on the network network. a server on the network recognizes the RARP packet & recognizes the RARP packet & returns the host ‘ s IP address .returns the host ‘ s IP address .

WHY DO WE NEED RARP ?

A host to have its IP address store in its hard

disk . 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 .

RARP operation :-RARP operation :-

ARP and RARP :-

RARP works much like ARP. The Internet is based on IP

addresses . Protocols may have different

(MAC) addresses . The ARP and RARP protocols

perform the translation between IP addresses and MAC layer addresses .

Internet Group Message Internet Group Message protocol protocol ( IGMP )( 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.

Fig . : IGMP operation

IGMP OPERATION :-IGMP OPERATION :-

Host Operations– 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 .

Fig. : Query & Report message

Internet Control Message Internet Control Message ProtocolProtocol(ICMP)(ICMP)

ICMP :-ICMP :-

ICMP is used by host and routers to send notification of datagram problems back to the sender .

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 messages.

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 host.

Table :Table : ICMPICMP messagesmessages

Destination-unreachable messages with codes 3 can be created only by the

destination host .

Other destination-unreachable messages can be created only by

routers.

Note:Note:

Example of error-reporting message :-

target host is reachebal target host is reachebal or not ?or not ?

An echo-request message can be sent by a host or router. An echo-reply message is sent by the host or router which receives an echo-

request message.

Note:Note:

Example of query message :-