level: Lecture 3
Questions and Answers List
Wired Transmission.
level questions: Lecture 3
| Question | Answer |
|---|---|
| Three main type of network cables: | Coaxial. Twisted pair. (un-shielded and shielded). Fibre optics. |
| Bandwidth. | Maximum data rate transfer possible. |
| Throughput. | The actual data transfer rate; less than or equal to bandwidth. |
| Electromagnetic Interference (EMI): | Caused by the presence of electrical and/or magnetic signals. |
| Radio Frequency Interference (RFI): | Caused by the presence of radio signals. |
| Attenuation: | Signal loss caused by degradation of signal over distance. |
| Characteristics of Copper Wire. | Soft, malleable, ductile metal. Very high thermal and electric conductivity. Conductor of heat and electricity. Data transmitted as ANALOG. |
| Two types of copper wire: | Coaxial. Twisted Pair. |
| What is/Characteristics of a coaxial cable? | Thick copper wire surrounded by three layers. |
| Three layers surrounding the copper wire of a coaxial cable? | - Plastic Jacket. - Braided shield. - Plastic (PVC or Teflon). |
| The layers of a coaxial cable help to reduce: | Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI). |
| Characteristic of Thin Ethernet "Thinnet". | 10 base 2. 10 mbps. Baseband. 185m. 5mm or 2/10" diameter, Radio-Grade 58(RG58). 30 nodes per segment. |
| Characteristics of a Thick Ethernet "Thicknet" | 10 base 5. 10 mbps. Baseband. 500m. 1/2" diameter, Radio-Grade 8(RG8). 1024 nodes per segment. |
| Two types of Coaxial Connectors: | F-Type Connector (75 OHM). BNC Connector (50 OHM). |
| These describe how data is transmitted between two nodes. | Baseband. Broadband. |
| Baseband | Baseband Technology transmits a singles data signal/stream/channel at a time. |
| Broadband | Broadband Technology transmits multiple data signals/streams/channels simultaneously at the same time. |
| Two types of Twisted Pair Cables: | Un-shielded twisted pair.(UTP) Shielded twisted pair.(STP) |
| The current Twisted Pair Categories: | Cat 5: 100MHz/2 pairs; 100 mbps (100 base TX). Cat 5e: 100MHz/4 pairs; 1,000 mbps (1000 base T). Cat 6: 250MHz/2pairs; 1,000 mbps (1000 base TX). Cat 6a: 500MHz/4 pairs; 10,000 mbps (10G base T). |
| Carrier sense multiple access with collision detect. | - Nodes listens to wire. - Node transmits data. - If another transmission data, there is collision. - Nodes send a jam signal and wait using the back-off algorithm. |
| Two types of fibre-optic cables: | Multi-mode fibre (MMF). Single-mode fibre (SMF). |
| Fibre Optic Cables. | Flexible, transparent, strand of glass (silica) or plastic slightly thicker than a human hair. It allows longer distances and higher bandwidths than copper cables. Data is transmitted as DIGITAL. |
| Fibre-Optic Characteristics. | Glass or plastic core (distance vs cost) surrounded by glass or plastic cladding, plastic, amour coating, (usually Kevlar) and PVC or Teflon. |
| Fibre Optic Connectors egs: | Straight Tip (ST), Local Connector (LC), Square Connector(SC). |
| Total distance of a twisted pair cable: | 100m |
| Total distance of a Thinnet cable: | 185m |
| Total distance of a Thicknet cable? | 500m |
| Total distance of a multi-mode fibre cable: | 1000m/1km |
| Total distance of a single-mode fibre cable: | 50km |