Connecting Networks Repeater: physical layer Bridge: data link layer Router: network layer Gateway: network layer and above. mazharjaved2001@yahoo.com
Bridge That connects two or more networks with different types of protocols Copies frames from one network to another A Bridge will connect two segments of a LAN, but it also acts as a repeater. A bridge will read the destination address of a packet of data being transmitted to determine whether to let it across the bridge to the other segment or to keep it within the original segment. It reads the address of sending and receiving computers This helps keep the traffic on the network lower by not having packets lost in the wrong segments. BRIDGE mazharjaved2001@yahoo.com
Segment A Segment B mazharjaved2001@yahoo.com
Segmentation A segment is a run of cable to which are attached a number of workstations Problem:a large number of computers and heavy traffic can slow down the network so This problem is solved by segmenting the network into manageable segments by inserting a bridge or router between each network segment. Traffic is then reduced on each segment, giving better network performance mazharjaved2001@yahoo.com
Routers A Router can do the job of a repeater and a bridge but it also has special software that reads the destination address. That connects multiple networks using similar or different protocols. Router is suitable for big Wide Area Network. It can connect networks of different countries It send data in less time. The device then makes a decision as to the best path the data packet must take to get closer to its destination. A router table database is used to help choose the correct path, but heavy transmission or a fault on a line would be detected by the router and an alternative path would be given. mazharjaved2001@yahoo.com
Gateway Operates as a router. It can convert data according to the protocol. Can be used to connect a personal computer network to mainframe computer network Data conversions above the network layer. A Gateway is an enhanced router, usually used to connect a series of LAN’s to a WAN. The specialised software on the gateway is used to read different protocols from different operating systems and different hardware an be able to connect them all together. Conversions: encapsulation - use an intermediate network translation - connect different application protocols encryption - could be done by a gateway mazharjaved2001@yahoo.com
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Switch A multiport Bridge, functioning at the Data Link Layer Each port of the bridge decides whether to forward data packets to the attached network Keeps track of the Mac addresses of all attached devices (just like a bridge) Similarly priced to Hubs – making them popular Acts like a Hub, but filters like a Bridge Each port on a Switch is a collision domain mazharjaved2001@yahoo.com
Advantages and Disadvantages of Repeater Can connect different types of media can extend a network in terms of distance does not increase network traffic Disadvantages – Extends the collision domain can not filter data can not connect different network architectures limited number only can be used in network mazharjaved2001@yahoo.com
Advantages and Disadvantages of Hub Advantages – Cheap can connect different media types Disadvantages – Extends the collision domain can not filter information passes packets to all connected segments mazharjaved2001@yahoo.com
Advantages and Disadvantages of Bridge Advantages – Limits the collision domain can extend network distances, uses MAC address to filter traffic eases congestion can connect different types of media some can connect differing architectures Disadvantages – Broadcast packets can not be filtered more expensive than a repeater slower than a repeater – due to additional processing of packets mazharjaved2001@yahoo.com
Advantages and Disadvantages of switch Limits the collision domain can provide bridging can be configured to limit broadcast domain Disadvantages – More expensive than a hub or bridge configuration of additional functions can be very complex mazharjaved2001@yahoo.com
Advantages and Disadvantages of Router Advantages – Limits the collision domain can function in LAN or WAN connects differing media and architectures can determine best path/route, can filter broadcasts Disadvantages – Expensive must use routable protocols can be difficult to configure (static routing) slower than a bridge mazharjaved2001@yahoo.com
Modem To do this the computer must be equipped with a modem (Modulator – Demodulator). The modem converts digital signals into analogue signals that can be sent along telephone lines. It can also convert analogue signals it receives back into digital signals the computer can use. mazharjaved2001@yahoo.com
Dial up Connection Telephone line Digital signal One Tone ‘1’ represents Binary ‘1’ ‘1’ MODEM A different Tone represents Binary ‘0’ ‘0’ Disadvantages Dial up ties up your telephone line and so it cannot be used for anything else. It takes a while for the computer to set up a connection i.e many seconds. Internet Service Providers may charge you by the minute and so a slow link means you pay more. mazharjaved2001@yahoo.com