CS6250 Computer Networks Exam 1| Questions and 100% correct answers| Latest Update 2026/2027

CS6250 Computer Networks Exam 1| Questions and 100% correct answers| Latest Update 2026/2027 What are advantages and disadvantages of a layered architecture? Each protocol layer offers different services. Some advantages are scalability, flexibility, and ease of adding / removing components making it easier for cost-effective implementations. Disadvantages include: some layers functionality depends on the information from the other layer and violates the goal of layer separation; one layer may duplicate lower layer functionalities; overhead both in computation and in message headers caused by abstraction barriers between layers. What are the differences and similarities of the OSI model and five-layered Internet model? The OSI model and the 5-layered Internet Model have many of the same layers, with the difference being three of the layers are combined in the 5-layered model. Specifically the five-layer model combines the application, presentation, and session layers from the OSI model into a single application layer. What are sockets? A network socket is a software structure within a network node of a computer network that serves as an endpoint for sending and receiving data across the network. The structure and properties of a socket are defined by an application programming interface (API) for the networking architecture. Sockets are created only during the lifetime of a process of an application running in the :// Describe each layer of the OSI model. Application layer: Service, Interface, Protocol. Ex: Turn on your smartphone and look at the list of apps. (HTTP, SMTP, FTP, DNS) Presentation layer: Plays intermediate role of formatting the information received from the layer below and delivering it to the application layer. Ex: converting big endian to little endian. Session layer: Responsible for the mechanism that manages the different transport streams that belong to the same session between end-user and application process. Ex: teleconference app, it is responsible for tying together audio and video streaming. Transport layer: Responsible for the end-to-end communication between end hosts. 2 transport protocols, TCP and UDP. TCP includes a connection-oriented service to the applications that are running on the layer above, guaranteed delivery of the application-layer messages, flow control, and congestion control mechanism. UDP provides a connectionless, best-effort service to the applications that are running in the layer above without reliability, flow, or congestion control. In this layer the packet is called a segment. Network layer: This layer is responsible for moving the packet of information, called a datagram, from one host to another. The network layer is responsible for delivering the datagram to the Transport layer on the destination host. In this layer there are the IP Protocol and the routing tables. Data Link layer: Packets are referred to as frames. Examples include: ethernet, ppp, wifi. Responsible for moving the frames from one node (host or router) to the next node. Services offered by the data link layer protocol include reliable delivery (transmission of the data from one transmitting node, across one link, to the receiving node. Physical layer: This layer is the actual hardware responsible to transfer bits within a frame between two nodes connected through a physical link. Ex: Ethernet (twisted-pair copper, coax, fiber-optics). Provide examples of popular protocols at each layer of the five-layered Internet model.