1.3(a) Networks and Topologies

1 mark each to max 3 • Slower transmission of data // less data can be transmitted at the same time // the transmission rate decreases // time to send/receive increases • (More devices mean) more data is being transmitted (at a time) • Bandwidth will be split between all the devices (sending data) // each device uses some of the bandwidth • …this means that there is less bandwidth for each device • Devices have to wait longer before they can transmit // increased latency • If the maximum bandwidth is used then devices cannot transmit • Central device/switch/router has to handle more requests and may run slower • More collisions (likely) // higher error rate … • …more data has to be retransmitted • Loss of more packets … • …more data has to be retransmitted

1 mark e.g. • Bandwidth • Interference // by example • Wired // wireless // transmission medium • Type/amount of data being transmitted • Central hardware performance // by example e.g. router/switch • Error rate • Distance between nodes • Topology // physical layout • Wireless repeaters

1 mark from: • Uses dedicated/own/internal hardware // no external/third party hardware/infrastructure // computers use MAC addresses to communicate within the LAN

1 mark each to max 4: e.g. • Allows more devices to connect … • …for example televisions, mobile phones • Easy to connect (devices) // Easier to setup (wireless connections) // By example e.g. easier for guests to connect their devices • Home is likely small area • … so short distance wireless is sufficient • Devices can move around // can use devices in different areas // can connect from anywhere in the house // can use where wires don't reach // can access from a larger area (than wired) • … by example e.g. student is using a laptop so does not need to be tied to one place // by example e.g. they don't have to disconnect before moving // e.g. they can stay connected whilst moving • Cheaper to purchase/install/setup for new devices // no cost for (new/replacement) wires/hardware • …because no additional/fewer wires are needed • Fewer trip hazards from trailing wires // reduce risk of damage to cables // fewer cables to damage • More compatible // some devices only have wireless connections

Easier to add new nodes // easier to setup BOD Central device can monitor/control transmissions Faster data transmission Fewer data collisions One connection/computer breaks the network still works Less cost of cables 1 mark for drawback e.g. Switch fails the network fails // reliant on a central device (working) // single point of failure Extra cost of central device/switch

Connects the devices together in the network // allows devices to communicate in the network Receives data from (all) devices in the star topology Record/register/store the address of devices connected to it … … in a table Uses MAC address of devices Direct data to destination … if address not recorded transmit to all devices