More Related Content
Similar to Week 1-Foundations of Computer Networks.pptx
Similar to Week 1-Foundations of Computer Networks.pptx (20)
Recently uploaded
Recently uploaded (20)
Week 1-Foundations of Computer Networks.pptx
- 2. Today’s agenda: Foundational principles of networking 1 2 Design of a toy LAN technology 3 About this course
- 3. Course Learning Outcomes (CLOs) and Objectives: 1. Developing a sound conceptual grounding to computer networks and its design principles. 2. Going through the thought-process that went into designing the Internet which is the best example of a computer network that has adapted and scaled to changing environment. 3. Introduction to advanced topics in computer networks including communication technologies, network protocols, performance measurement and resource allocation
- 4. Attendance (75 % attendance is mandatory) 2.5% Workshop / Assignments/Case study 2.5% Surprise Test/Sudden Test, Quizzes 5% Semester Project 15% Mid Term Paper 25% Final Term paper 50% Total 100%
- 5. 1. “Computer Networks-A System Approach”, Peterson and Davis 4th Edition 2. “Data and Computer Communication” by William Stalling, Prentice Hall, 9th Edition 3. “Computer Networks -A Top-Down Approach Featuring the Internet” by Kurose and Ross
- 7. 1. Visible Light Communication (VLC)
- 8. 1. Unmanned Arial Vehicle (UAV) Communication z
- 9. 1. Software Defined Networking (SDN) z
- 10. 1. Biological organism assisted medium range molecular communication, architecture and multihop communication schemes 2. Resource allocation schemes for terrestrial communication for time critical and high data rate applications 3. SDN facilitating IoT 4. Providing HD data services at low cost to rural areas (Low cost rural HD services-communication technologies) 5. Swarm intelligence for next generation networks (security and resource allocation) 6. Caching strategies for UAV based HD services to rural areas 7. Green cashing in UAVs 8. Visible light communication for UAVs, resource allocation for NOMA and massive MIMO physical layer 9. IoT Protocols and Standards (IPv6, 6LoWPAN, RPL, 6TiSCH, RAW ) z
- 12. … … A protocol defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event.
- 13. Layers built on concept of abstraction and decomposition … … Applications Modularization based on abstractions is the way to build large systems …built on… …built on… Reliable (or unreliable) transport Best-effort global packet delivery Best-effort local packet delivery …built on… …built on… Physical transfer of bits
- 14. UDP TCP Data Link Physical Applications The Hourglass Model Narrow Waist FTP HTTP TFTP DNS TCP UDP IP NET1 NET2 NETn … … …
- 15. … … Statistical multiplexing: no fixed slot but allocation according to need Fixed multiplexing schemes: schemes like TDMA and FDMA are better suited to circuit switched approaches
- 16. … … The main benefits are in reduced avg. queueing delay and more efficient resource management of resources with bursty traffic.
- 17. … … This influential principle implies loose coupling with end-applications (which could change easily) and network (which was simple and generalized)
- 18. Chapter 2: Direct Link Networks [P&D] Chapter 1: Computer Networks and the Internet [K&R] All the chapter in general Section 1.4 (may be skipped/ skimmed for now)
- 19. [ End of lecture ]
Editor's Notes
- A layered architecture allows us to discuss a well-defined, specific part of a large and complex system. This simplification itself is of considerable value by providing modularity, making it much easier to change the implementation of the service provided by the layer. As long as the layer provides the same service to the layer above it, and uses the same services from the layer below it, the remainder of the system remains unchanged when a layer’s implementation is changed . A protocol layer can be implemented in software, in hardware, or in a combination of the two. Application-layer protocols—such as HTTP and SMTP—are almost always implemented in software in the end systems; so are transport-layer protocols. Because the physical layer and data link layers are responsible for handling communication over a specific link, they are typically implemented in a network interface card (for example, Ethernet or WiFi interface cards) associated with a given link. The network layer is often a mixed implementation of hardware and software hat it is very easy to create and deploy our own new application-layer protocols.
- Internet Architecture: The internet architecture, also called TCP/ IP architecture based on its two most famous protocols is shown above. The architecture evolved from experience in implementing ARPANET. While the 7 layer OSI model can be applied to the Internet (with some imagination), a four layer model is used instead. At the lowest layer is a variety of network protocols (also called data link layer or subnetwork layer). In practice, these protocols are implemented using a combination of hardware (network adapters) and software (network device driver). For example, you might find Ethernet card or Fiber Distributed Data Interface (FDDI) protocols at this layer. The second layer consists of a single protocol called Internet Protocol (IP). This is the protocol that supports the interconnection of multiple networking technologies into a single logical internetwork. The third layer consists of two main protocols---the Transmission Control Protocol and the User Datagram Protocol (UDP). TCP and UDP provide alternative logical channels to application programs. TCP provides a bye steam channel and UDP provides an unreliable datagram service. TCP and UDP are sometimes called end to end protocol. Running above the transport layer are a range of application protocol such as FTP, TFTP, HTTP, SMTP, Telnet, etc. Difference between application programs and application layer protocol. All the WWW browsers (Safari, Firefox, IE, Opera, Lynx, etc.) There is a similarly large numbers of webservers. The reason all of them can interwork is that they all conform to the HTTP application layer protocol. Internet architecture does not imply strict layering. The application is free to bypass the defined transport layer protocols and to directly use IP or any of the underlying networks. In fact, programmers are free to define new channel abstractions. Hour glass shape: Wide at the top and bottom but narrow at the waist: IP serves as the focal point of the architecture. IP is a common method of exchanging packets among a wide collection of networks. Image source: Jennifer Ruxford An application-layer protocol is distributed over multiple end systems, with the application in one end system using the protocol to exchange packets of information with the application in another end system. We’ll refer to this packet of information at the application layer as a message. Transport Layer The Internet’s transport layer transports application-layer messages between application endpoints. In the Internet, there are two transport protocols, TCP and UDP, either of which can transport application-layer messages. messages to the destination and flow control (that is, sender/receiver speed matching). TCP also breaks long messages into shorter segments and provides a congestion-control mechanism, so that a source throttles its transmission rate when the network is congested. Network Layer The Internet’s network layer is responsible for moving network-layer packets known as datagrams from one host to another. The Internet transport-layer protocol (TCP or UDP) in a source host passes a transport-layer segment and a destination address to the network layer, just as you would give the postal service a letter with a destination address. The network layer then provides the service of delivering the segment to the transport layer in the destination host Network Layer The Internet’s network layer includes the celebrated IP protocol, which defines the fields in the datagram as well as how the end systems and routers act on these fields. There is only one IP protocol, and all Internet components that have a network layer must run the IP protocol. Link Layer The Internet’s network layer routes a datagram through a series of routers between the source and destination. To move a packet from one node (host or router) to the next node in the route, the network layer relies on the services of the link layer. In particular, at each node, the network layer passes the datagram down to the link layer, which delivers the datagram to the next node along the route. At this next node, the link layer passes the datagram up to the network layer. The services provided by the link layer depend on the specific link-layer protocol that is employed over the link. For example, some link-layer protocols provide reliable delivery, from transmitting node, over one link, to receiving node. Note that this reliable delivery service is different from the reliable delivery service of TCP, which provides reliable delivery from one end system to another. Examples of link-layer protocols include Ethernet, WiFi, and the cable access network’s DOCSIS protocol. As datagrams typically need to traverse several links to travel from source to destination, a datagram may be handled by different link-layer protocols at different links along its route. For example, a datagram may be handled by Ethernet on one link and by PPP on