Network+ (N10-008) Cram Notes

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3. Network Media and Topologies

3.6 Given a scenario, troubleshoot common physical connectivity problems.

  • DB loss : Difference between signal at source and signal at destination is calculated using DB loss algorithm. Getting DB loss as 0 is impossible as there will be some DB loss in network. This number should be tried to keep minimum.

  • TXRX reversed: A TX that is Transmitter should be connected to RX that is Receiver. If crossover cables are used to connect similar devices then TX to TX and RX to RX connection can cause problems.

  • Cable placement: Right cable should be used in right location. If incorrect cable is used like a cable is used that is outside wiring standards can cause problems like interference, and attenuation. Ethernet cables should not be placed in close proximity with high voltage cables .

  • EMI/Interference: If cables run too close to devices which created electromagnetic waves like monitors it can corrupt the signals. So cables should be placed away from these devices also proper shielding should be used.

  • Distance: Network design should consider distance between devices. If devices are connected using cables that are at a distance more limitation of Ethernet cables then can cause in errors in transmission.

  • Crosstalk: It occurs when two cables running close to each other and are carrying signals interfere with each other and creates undesired effect. This is usually experienced in analog phone calls. It can be minimized by using higher category of cabling.

3.7 Compare and contrast different LAN technologies.

  • Ethernet: It is IEEE 802.3 standard. Speed is upto 10 Mbps and distance is 100m.

  • 1000Base-T: Uses UTP cabling and supports up to 100 m. It has 4 pairs of cat 5e or higher cable.

  • 1000Base-SX: Uses MMF cabling and supports up to 550 m. It uses SC fiber connectors.

  • 1000Base-LX: It uses both MMF and SMF cabling. It can support up to 550 m in multi mode and up to 2000 m in single mode. Further, it uses LC and SC connectors.

  • 1000Base-CX: It uses balanced shielded copper, and can support up to a distance of 25 meters. It uses a special connector, the HSSDC.

  • 10Gbase-T: 10GbaseT uses UTP cabling and connect to networks using Fast Ethernet. The standard supports a maximum distance of 100 m.

  • 10GBASE-SR (802.3ae) - Supports up to 300 m, cable type used: Multi Mode Fiber (MMF)

  • 10Gbase-LR (802.3ae) – supports 10 km, cable type used: Single mode fiber (SMF)

  • 10GbaseER(802.3ae) – Supports up to 40 km, cable type used: Single mode fiber (SMF)

  • 10Gbase-SW(802.3ae)- Supports up to 300 m, cable type used Multi Mode Fiber (MMF)

  • 10Gbase-LW(802.3ae)- supports 10 km, cable type used: Single mode fiber (SMF), typically used with SONET

  • 10Gbase-EW(802.3ae)- supports 40 km, cable type used: Single mode fiber (SMF)

3.8 Identify components of wiring distribution.

  • IDF (Intermediate Distribution Frame) : It is connected to MDF using a backbone cable when multiple wiring closets are used.

  • MDF (Main Distribution Frame): It is a wiring point which is a reference point for telephone lines. It holds switches, routers, servers etc..

  • Demarc: It is a point in telephone network after which maintanance will be done by telephone company.

  • Demarc extension: This extens demarcation point to a more functional location.

  • Smart jack: It is also known as NID(Network Interface Device) and is a hardware at dearction point. It contains connection and electronic testing equipments fro loo[back testing and other troubleshooting.

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