Overview of TCP IP
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This document provides an overview of the TCP/IP protocol stack. It discusses the four layers of TCP/IP - network interface, internet, transport and application layer - and how they relate to the seven-layer OSI model. Key protocols of each TCP/IP layer like IP, TCP, UDP, HTTP, FTP, SMTP are explained along with their functions. Other topics covered include ports, port scanning, and Windows sockets API.
Overview of TCP IP
- 1. Overview of TCP/IP Lecture 2 Subject: Web Engineering Class: BSIT-5th Inam.bth@gmail.com, administrator@computingcage.com Recommended: TCP/IP White Paper by Microsoft
- 2. TCP/IP • A highly standardized protocol used widely on the Internet • The basic backbone protocol • 5th basic component of Data Communication (DC) = protocol • Definition: set of rules used in DC. • Standards area available in the form of RFC documents • Request For Comments (RFC) • Standards are overseen by the Internet Engineering Task Force (IETF) WebEngineering,TCP-IP Protocols,Universityof EducationOkara 2
- 3. ISO-OSI Seven Layer Model Layer 7 Application Layer 6 Presentation Layer 5 Session Layer 4 Transport Layer 3 Network Layer 2 Data Link Layer 1 Physical Source: http://starter.sdsu.edu/remote/demo/osi-tcp.html WebEngineering,TCP-IP Protocols,Universityof EducationOkara 3 Open Systems Interconnection International Organization for Standardization
- 4. Layers with Protocols Application Application FTP, Telnet, SMTP, HTTP..Presentation Session Transport Host-to-Host TCP, UDP Network Internet IP, ICMP, IGMP Data Link Network Access Ethernet, Token-Ring ... Physical Source: http://starter.sdsu.edu/remote/demo/osi-tcp.html WebEngineering,TCP-IP Protocols,Universityof EducationOkara 4
- 5. Source: TCP/IP White Paper by Microsoft WebEngineering,TCP-IP Protocols,Universityof EducationOkara 5
- 6. TCP/IP Layers • Network interface layer • Internet layer • Host-to-host transport layer • Application layer WebEngineering,TCP-IP Protocols,Universityof EducationOkara 6 • In the following slides, the following is described for each layer • Layer function • Core protocols • Relationship to ISO/OSI model Some Core Protocols • IEEE 802.3, IEEE 802.5 and IEEE 802.11 series of protocols
- 7. Network Interface Layer • Responsible for sending and receiving TCP/IP packets on the network medium (physical/Data Link) • Applicable LAN technologies • Ethernet, Token Ring, FDDI. • Applicable WAN technologies • X.25 (old), Frame Relay, ATM etc. • Note that some technologies such as ATM and FDDI may be used at both the WAN and the LAN levels WebEngineering,TCP-IP Protocols,Universityof EducationOkara 7Physical Layer Data Link Layer Network Interface Layer OSI Model TCP/IP Model
- 8. Core Internet Layer Protocols • IP • A connectionless unreliable protocol that is part of the TCP/IP protocol suite • ARP (Address Resolution Protocol) • Resolves IP addresses to MAC addresses • ICMP (Internet Control Message Protocol) • Diagnostics and error reporting • (IGMP) Internet Group Management Protocol • Management of group multicast WebEngineering,TCP-IP Protocols,Universityof EducationOkara 8 • Packaging • Addressing • Routing Internet Layer >>
- 9. More on (ARP) NIC ID AA.BB.CC.DD NIC ID AB.BD.CD.DE 130.182.190.90 130.182.190.50 Resolves, for example, IP addresses to the corresponding MAC level hardware address, for instance broadcasting. IP MAC WebEngineering,TCP-IP Protocols,Universityof EducationOkara 9
- 10. Transport Layer • Sequencing and transmission of packets • Acknowledgment of receipts • Recovery of packets • Flow control • In essence, it engages in host-to-host transportation of data packets and the delivery of them to the application layer • Core protocols: TCP & UDP WebEngineering,TCP-IP Protocols,Universityof EducationOkara 10
- 11. TCP & UDP • Transmission Control Protocol (TCP) • One-to-one and connection-oriented reliable protocol • Used in the accurate transmission of large amount of data • Slower compared to UDP because of additional error checking being performed WebEngineering,TCP-IP Protocols,Universityof EducationOkara 11 • User Datagram Protocol (UDP) • One-to-one or one-to-many, connectionless and unreliable protocol • Used for the transmission of small amount of data • Accuracy is not of prime concern • The overhead of establishing a TCP connection is not warranted • Used in video and audio casting • Multicasting • Broadcasting • Also used for multimedia transmission • Faster compared to TCP
- 12. Application Layer • Provides applications with the ability to access the services of the other layers • New protocols and services are always being developed in this category WebEngineering,TCP-IP Protocols,Universityof EducationOkara 12 HTTP FTP Telnet SMTP POP3 IMAP SNMP Some Core Protocols Some LAN Management/Operation Related Application Layer Protocols DNS RIP SNMP
- 13. HTTP & FTP • Protocol relating to web applications • Current version of HTTP 1.1 has additional features • Upload information to the server • Etc. • Default port number is 80 WebEngineering,TCP-IP Protocols,Universityof EducationOkara 13 • File Transfer Protocol • Used for downloading from most MP3 sites, for example • Designed for faster file transfer over the Internet compared to using the HTTP protocol • FTP sites can be configured alongside a web site to support FTP file transfer • FTP default ports are 20 and 21
- 14. HTTP and FTP • File transfer under FTP is faster than file transfer under HTTP • Choose an FTP site if there is one for downloading files etc. WebEngineering,TCP-IP Protocols,Universityof EducationOkara 14 Simple Mail Transfer Protocol (SMTP) • Governs the transmission of mail messages and attachments • SMTP is used in the case of outgoing messages • More powerful protocols such as POP3 and IMAP4 are needed and available to manage incoming messages
- 15. POP3/IMAP4 • Used for incoming mail • POP3 is the older protocol • IMAP4 is the more advanced protocol WebEngineering,TCP-IP Protocols,Universityof EducationOkara 15 • Supports terminal emulation or host sessions • For example, Telnet can be used for accessing a Unix machine and emulating a terminal attached to the Unix computer Telnet
- 16. Domain Name System (DNS) Resolves domain names to IP addresses and vice versa DNS Server 130.182.125.66www.refer.com WebEngineering,TCP-IP Protocols,Universityof EducationOkara 16
- 17. Routing Information Protocol (RIP) Router Network 1 Network 2 Used by Routers to route data packets on an IP Internet. Network 1 WebEngineering,TCP-IP Protocols,Universityof EducationOkara 17
- 18. Simple Network Management Protocol (SNMP) Router Router Remote Management Console Switch Bridge Facilitates the management of SNMP compliant routers, bridges, switches etc. by enabling the collection and exchange of network management information. WebEngineering,TCP-IP Protocols,Universityof EducationOkara 18
- 19. Ports • TCP requires port numbers on the host and destination for communication • Different port numbers are assigned to different protocols by default • HTTP 80, Telnet 23, FTP 20/21, RPC 135, NetBIOS 139 etc. • Standard port numbers have been assigned by the Internet Assigned Number Authority (IANA) WebEngineering,TCP-IP Protocols,Universityof EducationOkara 19 Using Port Numbers on Addresses • Standard access for web browsing • Ganesan.calstatela.edu • Default port of 80 is used in this case • Non-standard access • http://ganesan.calstatela.edu:5002 • The port number 5002 is used in this case to host the above web server
- 20. Sample TCP Port Numbers 20 FTP Data Channel 21 FTP Control Channel 23 Telnet 80 HTTP on WWW 135 RPC 139 NetBIOS Session Services Note: There are port numbers applicable to UDP as well. WebEngineering,TCP-IP Protocols,Universityof EducationOkara 20
- 22. Port Scanning • To test the security of a computer, its ports can be scanned and the port status can be displayed • Access Shieldup in www.grc.com to scan your computers port • Ports • Open is insecure • Closed is somewhat secure • Stealth is most secure WebEngineering,TCP-IP Protocols,Universityof EducationOkara 22
- 23. TCP/IP Application Interface • Applications require an Application Programming Interface (API) to use the services of TCP/IP • API is a standardized interface between the applications and the TCP/IP services • Windows Sockets interface and NetBIOS interface are two of the prominent examples of Windows API WebEngineering,TCP-IP Protocols,Universityof EducationOkara 23
- 25. Post Answers on ComputingForum 1. How many layers are there in the TCP/IP model? 2. How do they relate to the ISO-OSI model? 3. What are some of the TCP/IP related protocols? 4. Explain the purpose and function of the above protocols? 5. What are ports? Explain the implication of keeping the ports open. 6. How can the ports be protected from hacker attacks? 7. Where would one use the UDP protocol in place of the TCP protocol? The End WebEngineering,TCP-IP Protocols,Universityof EducationOkara 25