PROTOCOL ARCHITECTURE,TCP/IP,AND INTERNET-BASED APPLICATIONSAyyaz Yaqoob (Lecturer)Department of Computer ScienceUOS Mandi Bahauddin Campus

Key Points• A protocol architecture is the layered structure of hardware

and software• that supports the exchange of data between systems and

supports distributed applications, such as electronic mail and file transfer

• At each layer of a protocol architecture, one or more common protocols are implemented

Key Points• Each protocol provides a set of rules for the exchange of data

between systems• The most widely used protocol architecture is the TCP/IP

protocol and seven-layer OSI model

THE NEED FOR A PROTOCOL ARCHITECTURE

• When computers, terminals, and/or other data processing devices exchange data, the procedures involved can be quite complex

• There must be a data path between the two computers• The source system must either activate the direct data

communication path or inform the communication network of the identity of the desired destination system

• The source system must ascertain that the destination system is prepared to receive data

• If the file formats used on the two systems are different, one or the other system must perform a format translation function

THE NEED FOR A PROTOCOL ARCHITECTURE

• Communication is achieved by having the corresponding, layers in two systems

• The peer layers communicate by means of formatted blocks of data that obey a set of rules or conventions known as a protocol.

• The key features of a protocol are as follows:• Syntax: Concerns the format of the data blocks• Semantics: Includes control information for coordination and

error handling• Timing: Includes speed matching and sequencing

THE TCP/IP PROTOCOL ARCHITECTURE

• The Transmission Control Protocol (TCP/IP) protocol architecture is a result of protocol research and development conducted on the experimental packet-switched network

• In general terms, communications can be said to involve three agents: applications, computers and networks

• In TCP/IP five relatively independent layers• Physical layer• Network access layer• Internet layer• Host-to-host, or transport layer• Application layer

Physical layer of TCP/IP• The physical layer covers the physical interface between a data

transmission device (e.g., workstation, computer) and a transmission medium or network

• This layer is concerned with specifying the characteristics• of the transmission medium• the nature of the signals• the data rate• and related matters

Network access layer

• The network access layer is concerned with the exchange of data between an end system (server, workstation, etc.) and the network to which it is attached

• The sending computer must provide the network with the address of the destination computer

• The network access layer is concerned with access to and routing data across a network for two end systems attached to the same network

Network access layer

• The Network Interface layer (also called the Network Access layer) is responsible for

• placing TCP/IP packets on the network medium and receiving TCP/IP packets off the network medium

• TCP/IP was designed to be independent of the network access method, frame format, and medium

Internet layer• The Internet layer is responsible for addressing, packaging,

and routing functions• The core protocols of the Internet layer are IP, ARP, ICMP, and

IGMP.• The internet layer perform its functionality. where two devices

are attached to different networks, procedures are needed to allow data to traverse multiple interconnected networks

Internet layer• The Internet Protocol (IP) is used at this layer to provide the

routing function across multiple networks • Internet Protocol (IP) is implemented not only in the end

systems but also in routers• A router is a processor that connects two networks and whose

primary function is to relay data from one network to the other on its route from the source to the destination end system

Internet layer• The Internet Protocol (IP) is a routable protocol responsible for

IP addressing, routing, and the fragmentation and reassembly of packets.

• The Address Resolution Protocol (ARP) is responsible for the resolution of the Internet layer address to the Network Interface layer address such as a hardware address.

• The Internet Control Message Protocol (ICMP) is responsible for providing diagnostic functions and reporting errors due to the unsuccessful delivery of IP packets.

• The Internet Group Management Protocol (IGMP) is responsible for the management of IP multicast groups.

Host-to-host, or transport layer• The Transport layer (also known as the Host-to-Host Transport

layer) is responsible for providing the Application layer with session and datagram communication services

• The core protocols of the Transport layer are Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP)

• TCP provides a one-to-one, connection-oriented, reliable communications service. TCP is responsible for the establishment of a TCP connection, the sequencing and acknowledgment of packets sent, and the recovery of packets lost during transmission.

Host-to-host, or transport layer• UDP provides a one-to-one or one-to-many, connectionless,

unreliable communications service. UDP is used when the amount of data to be transferred is small (such as the data that would fit into a single packet), when the overhead of establishing a TCP connection is not desired or when the applications or upper layer protocols provide reliable delivery

Application layer• The Application layer provides applications the ability to

access the services of the other layers and defines the protocols that applications use to exchange data. There are many Application layer protocols and new protocols are always being developed.

• The most widely-known Application layer protocols are those used for the exchange of user information:

• The Hypertext Transfer Protocol (HTTP) is used to transfer files that make up the Web pages of the World Wide Web.

• The File Transfer Protocol (FTP) is used for interactive file transfer.

• The Simple Mail Transfer Protocol (SMTP) is used for the transfer of mail messages and attachments.

Application layer• Telnet, a terminal emulation protocol, is used for logging on

remotely to network hosts.• Additionally, the following Application layer protocols help

facilitate the use and management of TCP/IP networks:• The Domain Name System (DNS) is used to resolve a host

name to an IP address.• The Routing Information Protocol (RIP) is a routing protocol

that routers use to exchange routing information on an IP internetwork.

• The Simple Network Management Protocol (SNMP) is used between a network management console and network devices (routers, bridges, intelligent hubs) to collect and exchange network management information.

Operation of TCP and IP

TCP and UDPTCP UDP

TCP is a connection-oriented protocol UDP is a connectionless protocolThere is absolute guarantee that the data transferred remains intact and arrives in the same order in which it was sent

There is no guarantee that the messages or packets sent would reach at all

TCP is suited for applications that require high reliability, and transmission time is relatively less critical

UDP is suitable for applications that need fast, efficient transmission, such as games. UDP's stateless nature is also useful for servers that answer small queries from huge numbers of clients

HTTP, HTTPs, FTP, SMTP, Telnet DNS, DHCP, TFTP, SNMP, RIP, VOIP

TCP and UDP

TCP header size is 20 bytes UDP Header size is 8 bytes.

TCP is heavy-weight. TCP requires three packets to set up a socket connection, before any user data can be sent. TCP handles reliability and congestion control

UDP is lightweight. There is no ordering of messages, no tracking connections, etc. It is a small transport layer designed on top of IP

TCP does error checking UDP does error checking, but no recovery options.

1. Sequence Number, 2. AcK number, 3. Data offset, 4. Reserved, 5. Control bit, 6. Window, 7. Urgent Pointer 8. Options, 9. Padding, 10. Check Sum, 11. Source port, 12. Destination port

1. Length, 2. Source port, 3. Destination port, 4. Check Sum

Acknowledgement segments No Acknowledgment

TCP and UDP

What is Internet Protocol (IP)?

• IP (short for Internet Protocol) specifies the technical format of packets and the addressing scheme for computers to communicate over a network. Most networks combine IP with a higher-level protocol called Transmission Control Protocol (TCP), which establishes a virtual connection between a destination and a source

• IP by itself can be compared to something like the postal system. It allows you to address a package and drop it in the system, but there's no direct link between you and the recipient

• TCP/IP, on the other hand, establishes a connection between two hosts so that they can send messages back and forth for a period of time

What is IPv4

• IPv4 (Internet Protocol Version 4) is the fourth revision of the Internet Protocol (IP) used to to identify devices on a network through an addressing system. The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks

• Pv4 is the most widely deployed Internet protocol used to connect devices to the Internet. IPv4 uses a 32-bitaddress scheme allowing for a total of 2^32 addresses (just over 4 billion addresses)

What is IPv6

• Pv6 (Internet Protocol Version 6) is also called IPng (Internet Protocol next generation) and it is the newest version of the Internet Protocol (IP) reviewed in the IETF standards committees to replace the current version of IPv4 (Internet Protocol Version 4).

• IPv6 is the successor to Internet Protocol Version 4 (IPv4)• IPv6 is designed to allow the Internet to grow steadily, both in

terms of the number of hosts connected and the total amount of data traffic transmitted

The Difference Between IPv6 and IPv4 IP Addresses

• An IP address is binary numbers but can be stored as text for human readers. For example, a 32-bit numeric address (IPv4) is written in decimal as four numbers separated by periods

• Each number can be zero to 255• For example, 1.160.10.240 could be an IP address• IPv6 addresses are 128-bit IP address written in hexadecimal

and separated by colons• An example IPv6 address could be written like

this: 3ffe:1900:4545:3:200:f8ff:fe21:67cf

IP and IPv6

IPv6