computer network fundamental note

computer network fundamental note

• 1.
  Computer Network by Mr.Arvind Pandey
• 14.
  Network Edge End System →End system are also referred to as host because the host (ie, run) application program such as a web browser program, a web server program, an email reader program. → Host are further divided into two categories: • Clients • Servers → Informally, clients can be desktop and mobile pc’s and so on, whereas servers can be more powerful machine that stores and distribute web pages, stream video so on. Clients and Servers → A client program running on one end system that requests and receive a service from a server running on other end system. → Not all internet applications are client-server model; they are also peer- to-peer model like Bit Torrent and eMute.
• 16.
  Network Core →It meansthe approach to moving data through a network of links and switches. →There are two types: • Circuit Switching • Packet Switching In circuit switching, each data unit know the entire path address which is provided by the source
• 20.
  There are twoapproaches in packet switched network  Any network that forwards the packets according to the destination address is called a datagram network.  The routers in the internet forwards packets according to the destination address. Hence, internet is datagram network. Virtual Circuit Network  Any network that forwards the packets according to virtual circuit identifier (fixed route) is called a virtual circuit network.  Preplanned route established before packets sent.  Examples are X25, Frame relay, ATM technologies. Datagram Network
• 21.
  Network Access Dial UPConnection : A dial-up connection is established when two or more communication devices use a public switched telephone network (PSTN) to connect to an Internet service provider (ISP). Many remote areas depend on Internet dial-up connections because broadband and cable are rare in remote areas with low population numbers Two major drawbacks: • Extremely slow, maximum 56 kbps. • Cannot use phone line while accessing internet.
• 22.
  DSL (Digital SubscriberLine) DSL internet is accessed from the same company that provides it wired local phone access. Advantages: High data rate (download 1-2 mbps, upload 128 kbps-1mbps) Users can simultaneously talk on the phone and access internet.