Introduction of Web programming Ins. Elaf Alhazmi LECTURE 2

Data Packets Packets is piece of data Sender divide large files into packets & transmit Receiver assemble packets. 2 Ins.Elaf Alhazmi

Fundamental parts of internet Routers Routers are special purpose computers that direct traffic in the form of data packets to their intended recipient. When one route is busy or blocked, router chooses another path using routing table and intelligent algorithms. Hubs or Switches connecting nodes(devices) without any routing or data translation abilities Bridges Link different local area networks (LAN) Cabling backbone The fiber optic networks called backbones carry much of the internet traffic under our city streets or across the oceans and the satellites all contribute to transmission of internet traffic 3 Ins.Elaf Alhazmi

Routers 4 Ins.Elaf Alhazmi

Hubs Switches 5 Ins.Elaf Alhazmi

The difference between Hubs, Bridges, Switches and routers Hubs, Switches and routers are all used to connect computers together on network but each of them has different capabilities Hubs,Each computer plugs into the hub with an Ethernet cable, and information sent from one computer to another passes through the hub. A hub can't identify the source or intended destination of the information it receives, so it sends the information to all of the computers connected to it, including the one that sent it. A hub can send or receive information, but it can't do both at the same time. This makes hubs slower than switches. Hubs are the least complex and the least expensive of these devices. 6 Ins.Elaf Alhazmi

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A bridge connects a local area network (LAN) to another local area network that uses the same protocol. Having a single incoming and outgoing port. bridge is more complex than hub. Bridge looks at the destination of the packet before forwarding unlike a hub. It restricts transmission on other LAN segment if destination is not found. The difference between Hubs, Bridges, Switches and routers 8 Ins.Elaf Alhazmi

Switches work the same way as hubs, but they can identify the intended destination of the information that they receive, so they send that information to only the computers that are supposed to receive it. Switches can send and receive information at the same time, so they can send information faster than hubs can. If your home network has four or more computers or you want to use your network for activities that require passing a lot of information between computers (such as playing network games or sharing music), you should probably use a switch instead of a hub. Switches cost a little more than hubs The difference between Hubs, Bridges, Switches and routers 9 Ins.Elaf Alhazmi

Routers enable computers to communicate and they can pass information between two networks—such as between your home network and the Internet. Routers can be wired (using Ethernet cables) or wireless. If you just want to connect your computers, hubs and switches work well; however, if you want to give all of your computers access to the Internet,use a router or a modem. Routers are more expensive than hubs and switches. The difference between Hubs, Bridges, Switches and routers 10 Ins.Elaf Alhazmi

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