Chapter 3 - Application Layer Functionalityand Protocols CCNA Exploration 4.0 CCNA Exploration 4.0 Overview • Describe how the functions of the three upper OSI model layers provide network services to end user applications. • Describe how the TCP/IP Application Layer protocols provide the services specified by the upper layers of the OSI model. • Define how people use the Application Layer to communicate across the information network. • Describe the function of well - known TCP/IP applications, such as the Học viện mạng Bách khoa - Website: www.bkacad.com • Describe the function of well - known TCP/IP applications, such as the World Wide Web and email, and their related services (HTTP, DNS, SMB, DHCP, STMP/POP, and Telnet). • Describe file-sharing processes that use peer-to-peer applications and the Gnutella protocol. • Explain how protocols ensure services running on one kind of device can send to and receive data from many different network devices. • Use network analysis tools to examine and explain how common user applications work. Introduction • Explain that applications provide the means for generating and receiving data that can be transported on the network. Học viện mạng Bách khoa - Website: www.bkacad.com OSI model • To address the problem of network incompatibility, the International Học viện mạng Bách khoa - Website: www.bkacad.com • To address the problem of network incompatibility, the International Organization for Standardization (ISO) researched networking models like Digital Equipment Corporation net (DECnet), Systems Network Architecture (SNA), and TCP/IP in order to find a generally applicable set of rules for all networks. • Using this research, the ISO created a network model that helps vendors create networks that are compatible with other networks. • The Open System Interconnection (OSI) reference model released in 1984 was the descriptive network model that the ISO created. • It provided vendors with a set of standards that ensured greater compatibility and interoperability among various network technologies produced by companies around the world. The OSI Model • Initially the OSI model was designed by the International Organization for Standardization (ISO) to provide a framework on which to build a suite of open systems protocols. Học viện mạng Bách khoa - Website: www.bkacad.com The OSI Model Học viện mạng Bách khoa - Website: www.bkacad.com OSI model • Explain the role of applications, services and protocols in converting communication to data that can be transferred across the data network. • Application layer: It is the layer that provides the interface between the applications we use to communicate and the underlying network over which our messages are transmitted. Học viện mạng Bách khoa - Website: www.bkacad.com OSI model Học viện mạng Bách khoa - Website: www.bkacad.com OSI model Học viện mạng Bách khoa - Website: www.bkacad.com OSI and TCP/IP Model • Functionality of the TCP/IP application layer protocols fit roughly into the framework of the top three layers of the OSI model: Application, Presentation and Session layers. Học viện mạng Bách khoa - Website: www.bkacad.com [...]... Bách khoa - Website: www.bkacad.com DNS - Example H c vi n m ng Bách khoa - Website: www.bkacad.com DNS - Example H c vi n m ng Bách khoa - Website: www.bkacad.com DNS - Example H c vi n m ng Bách khoa - Website: www.bkacad.com DNS - Example H c vi n m ng Bách khoa - Website: www.bkacad.com DNS - Example H c vi n m ng Bách khoa - Website: www.bkacad.com DNS - Example H c vi n m ng Bách khoa - Website:... distinct forms: peer-to-peer network design and peer-to-peer applications (P2P) Both forms have similar features but in practice work very differently Peer-to-Peer Networks • In a peer-to-peer network, two or more computers are connected via a network and can share resources (such as printers and files) without having a dedicated server H c vi n m ng Bách khoa - Website: www.bkacad.com Peer-to-Peer Networking... Applications (p2p) Peer-to-Peer Applications • A peer-to-peer application (P2P), unlike a peer-to-peer network, allows a device to act as both a client and a server within the same communication • In this model, every client is a server and every server a client Both can initiate a communication and are considered equal in the communication process • Peer-to-peer applications can be used on peer-to-peer networks,... ng Bách khoa - Website: www.bkacad.com Application Layer Services and Protocols • A single application may employ many different supporting Application • layer services Additionally, servers typically have multiple clients requesting information at the same time H c vi n m ng Bách khoa - Website: www.bkacad.com Peer-to-Peer Networking and Applications (p2p) The Peer-to-Peer Model • Peer-to-peer networking... Port 53 – Hypertext Transfer Protocol (HTTP) - TCP Port 80 – Simple Mail Transfer Protocol (SMTP) - TCP Port 25 – Post Office Protocol (POP) - UDP Port 110 – Telnet - TCP Port 23 – Dynamic Host Configuration Protocol - UDP Port 67 – File Transfer Protocol (FTP) - TCP Ports 20 and 21 H c vi n m ng Bách khoa - Website: www.bkacad.com DNS Services and Protocol • A domain naming system was developed in order... Bách khoa - Website: www.bkacad.com Application Layer Protocols and Services Examples • Now that we have a better understanding of how applications provide • an interface for the user and provide access to the network, we will take a look at some specific commonly used protocols Some of these services are: – Domain Name System (DNS) - TCP/UDP Port 53 – Hypertext Transfer Protocol (HTTP) - TCP Port... user H c vi n m ng Bách khoa - Website: www.bkacad.com WWW Service and HTTP • Browsers can interpret and present many data types, such as plain text or Hypertext Markup Language (HTML, the language in which web pages are constructed) Other types of data, however, may require another service or program, typically referred to as plug-ins or add-ons H c vi n m ng Bách khoa - Website: www.bkacad.com WWW... provide the rules and formats that govern how data is treated H c vi n m ng Bách khoa - Website: www.bkacad.com Application Layer Protocol Functions • Application layer protocols are used by both the source and destination devices during a communication session H c vi n m ng Bách khoa - Website: www.bkacad.com The Client-Server Model • In the client/server model, the device requesting the information is... the data in a manner that can be decompressed by the destination device 3 Encryption of the data for transmission and the decryption of data upon receipt by the destination Example: QuickTime, Motion Picture Experts Group (MPEG), Graphics Interchange Format (GIF), Joint Photographic Experts Group (JPEG)… H c vi n m ng Bách khoa - Website: www.bkacad.com OSI and TCP/IP Model The Session Layer • Functions... n m ng Bách khoa - Website: www.bkacad.com WWW Service and HTTP • • When a web address (or URL) is typed into a web browser, the web browser establishes a connection to the web service running on the server using the HTTP protocol URLs (or Uniform Resource Locator) and URIs (Uniform Resource Identifier) are the names most people associate with web addresses H c vi n m ng Bách khoa - Website: www.bkacad.com . khoa - Website: www.bkacad.com Peer-to-Peer Networking and Applications (p2p) The Peer-to-Peer Model • Peer-to-peer networking involves two distinct forms: peer-to-peer network design and peer-to-peer. peer-to-peer network design and peer-to-peer applications (P2P). Both forms have similar features but in practice work very differently. Peer-to-Peer Networks • In a peer-to-peer network, two or more computers. Chapter 3 - Application Layer Functionalityand Protocols CCNA Exploration 4.0 CCNA Exploration 4.0 Overview • Describe how the functions of