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Protocols and Network Software

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ProtocolsProtocols are rules for communication.

Tasks: • Define how to interpret signals• Identify individual computers• Initiate and end networked communication• Manage information exchange across network

medium• Determine the type of error checking to be use

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Protocols -cont• A combination of protocols is called a protocol

stack or protocol suite. • Types of protocols:

– A connectionless protocol

treats each packet independently ,the packets may or may not travel to the same destination.

– A connection-oriented protocol

the source first makes a connection with the destination before sending packets ,when the connection is established , a sequence of packets can be sent .

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Introduction to TCP/IP

TCP and IP were developed by a Department of Defense (DOD) research project to connect a number different networks designed by different vendors into a network of networks (the "Internet"). It was initially successful because it delivered a few basic services that everyone needs (file transfer, electronic mail, remote logon) across a very large number of client and server systems.

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TCP/IP • Transmission Control Protocol /Internet Protocol

(TCP/IP)• It is the most common protocol suite used today for

LANs as well as the Internet. • It is composed of several different protocols.

TCPTCP

IPIP

ICMPICMP

IGMPIGMPARPARP

RARPRARP NTPNTP

NNTPNNTPFTPFTP

SMTPSMTPTFTPTFTP

BOOTPBOOTP

UDPUDP

DNSDNS

TCP/IP protocol suiteTCP/IP protocol suite

TelnetTelnet

fingerfinger

whoiswhoisRIPRIP

OSPFOSPFSNMPSNMP

and many more...and many more...

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TCP/IP

Transport Protocols

Application Protocols

Internet Protocols

Network Interface Protocols

XX

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1- Application Protocols

• Protocols :– Telnet

– FTP : (File Transfer Protocol)-an internet file transfer protocol.

– TFTP

– SMTP : (Simple Mail Transfer Protocol )-an internet protocol for transferring e-mail.

– LPD

– NFS

– SNMP: (Simple Network Management Protocol)-an internet protocol for monitoring networks and its components

– X WINDOWS

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2-Transport Protocols

• Protocols:• TCP• UDP• DNS

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2-Transport Protocols

1.Transmission Control Protocol (TCP)

• TCP is a connection-oriented transport protocol that sends data as an unstructured stream of bytes.

• TCP is responsible for the reliable transmission of data from one host to another (acknowledgment).

• When data has been lost in transit from source to destination, TCP can retransmit the data until either a timeout condition is reached or until successful delivery has been achieved.

• TCP can also recognize duplicate messages and will discard them appropriately.

• If the sending computer is transmitting too fast for the receiving computer, TCP can employ flow control mechanisms to slow data transfer.

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2-Transport Protocols

2. User Datagram Protocol (UDP)

• It is connectionless and it is very simple protocol

• Provides fast delivery of data but does not guarantee data reliability .

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3- Internet Protocols (network layer )

Responsible for addressing , packaging and routing the

data to be transmitted , it contains the following protocols:• Internet Protocol (IP)Responsible for addressing the data to be transmitted and getting it toits destination.

• Address Resolution Protocol ( ARP)Responsible for identifying the media access control address (MAC) ofthe next hop .

• Internet Control Message Protocol (ICMP)Responsible for providing diagnostic functions and reporting errors due to

unsuccessful delivery of data.

• Internet Group Management Protocol (IGMP)Responsible for the management of multicasting with TCP/IP

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4- Network Interface protocol

• Responsible for placing data on the network medium and receiving data off the network medium.

• Contains :• Network Cables• Network Adapters: has (MAC)

• It does not contain any software-based protocol, but it contains protocols that defines how data is transmitted on the networks.

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IP Addressing• The hosts on a TCP/IP network use a logical

address.• This logical address, called the IP address and it

assigned to each host. • IP is responsible for the addressing of packets.

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IP Addressing• Is responsible for moving packet of data from node to

node. • IP forwards each packet based on a four byte destination

address (the IP number). • The Internet authorities assign ranges of numbers to

different organizations. The organizations assign groups of their numbers to departments. IP operates on gateway machines that move data from department to organization to region and then around the world.

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Internet Protocol (IP)• It’s Job: get some data

– from source IP address

– to destination IP address

source: 140.117.34.7

destination: 196.57.3.201

Data

Data= hosts/routers on a network

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IP Addressing • An IP address is four bytes (octets). Each

contains eight bits (total of 32 bits in length).

• Each octet is a number from 1 to 254.• IP addresses are usually given as dotted

decimal notation EX: 196.57.3.201

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IP Addressing