Capa De Acceso a La RED

Capa de Acceso a la RED

4.1 Physical Layer Protocols

1. What are two types of physical connections?

1. Which home device incorporates both types of physical connections?

1. Explain what happens to a wireless device’s signal as it is moved further away from the access point?

1. What happens to a wireless network as more devices use it simultaneously?

1. Does a wired device need to share its access to the network with other devices?

1. List the three types of network media commonly used.

1. What does the physical layer consists of?
2. What is bandwidth?
3. 12. The practical bandwidth of a network is determined by what combination of factors?
4. What factors influence throughput?
5. Define latency?

1. List the defined standards for copper media are:

1. Draw a line between the following terms with their descriptions.

SynchronousHardware devices, media, and connectors which transmit and carry bit signals

Signaling methodHow 1s and 0s are represented on the media – varies, depending on encoding scheme

Frame encodingEvenly spaced time duration for signals

AsynchronousA method for converting streams of data bits into groupings of bits - predefined

Physical componentsArbitrarily spaced time duration of signals

1. Draw a line between the following terms with their descriptions.

BandwidthHow much usable data is transferred over a given amount of time

Pulse-coded modulationAmount of data that is allowed by the medium to flow during a given set of time

GoodputThe actual measure of data bits over a given period of time

ThroughputA technique to convert voice analog to digital signals

Frequency modulationTransmission method where the carrier frequency varies according to the signals sent

4.2 Network Media

1. Why do networks use copper media?

1. What is copper media limited by?

1. How does signal attenuation effect transmitted data as it travels through a network.

1. The timing and voltage values of the electrical pulses are also susceptible to interference from two sources. List and explain both.

1. Electromagnetic interference (EMI) or radio frequency interference (RFI)–

1. Crosstalk–

1. What do some types of copper cable do to counter the negative effects of crosstalk?

1. List the three main types of copper media used in networking.

1. What type of cabling is the most common?

1. What are the advantages of using Shielded Twisted-Pair (STP) cabling?

1. UTP cable has essentially replaced coaxial cable in modern Ethernet installations. Where is coaxial cable still commonly used?

1. UTP, STP, and coaxial copper media characteristics are provided in the table. Check the appropriate field to match the characteristic to the media type.

1. Where is Category 3 cable (UTP) commonly used?

1. What are the recommended speeds for the following cables?
2. Cat5 –
3. Cat5e –
4. Cat6 –

1. Which standard describes the wire color codes to pin assignments (pinouts) for Ethernet cables?

1. List and explain the three main cable types that are obtained by using specific wiring conventions.
2. Ethernet Straight-through –

• Ethernet Crossover –

• Rollover –

1. What happens if a crossover or straight-through cable is incorrectly used between networking devices?

1. Why has using optical fiber become very popular??

1. What are the advantages of using fiber-optic cable over copper wires?

1. Where is fiber optic cable used in an Enterprise Networks?

1. Explain the purpose of each part of a fiber optic cable.
2. Core –

• Cladding –

• Buffer –

• Strengthening Material –

• Jacket –

1. Fiber-optic cables can be broadly classified into two types. List and explain each.
2. Single-mode fiber (SMF) –

• Multimode fiber (MMF) –

1. What is dispersion and how does it affect the signal?

1. Identify the following fiber optic connectors

______

______

______

______

1. Why are two fibers are required to support full duplex operation?

1. Explain how fiber optic cable are color coded.

1. How do most enterprise environments use optical fiber?

1. Descriptions of fiber-optic media are provided in the table. Check the appropriate field to match the description to the fiber-optic cable.

1. List and explain some of the concerns about using wireless networks.

• Coverage area –

• Interference –

• Security –

1. List the common data communications standards that apply to wireless media.

1. What two devices are required for wireless network?

1. List the maximum speed for each of the following wireless standards.

a. 802.11a______

b. 802.11b______

c. 802.11g______

d. 802.11n______

e. 802.11ac______

f. 802.11ad______

1. What is the distance range for the 802.11n standard?

4.3 Data Link Layer Protocols

1. What are the two Layer 2 or data link layer basic services?

1. The data link layer is actually divided into two sublayers. List and explain both.

• Logical Link Control (LLC) –

• Media Access Control (MAC) –

1. What is the media access control method?

1. Write in the correct data link protocols under their standards organization.

4.4 Media Access Control

1. List and explain the two different ways LAN and WAN topologies can be viewed.

• Physical topology –

• Logical topology –

1. List and explain the three common physical WAN topologies.

Point-to-Point –

Hub and Spoke –

Mesh –

1. What is a virtual circuit?

1. Explain the following terms.

Half-duplex communication –

Full-duplex communication –

1. Identify the following physical topologies.

a. ______

b. ______

c. ______

d. ______

1. List and explain the two basic media access control methods for shared media.

• Contention-based access –

• Controlled access –

1. What is the purpose of Carrier Sense Multiple Access (CSMA)

1. If the CSMA process fails, what happens?

1. Explain in detail how CSMA/CD and CSMA/CA work.

Carrier sense multiple access with collision detection (CSMA/CD) –

Carrier sense multiple access with collision avoidance (CSMA/CA) –

1. Controlled access can be inefficient because a device has to wait for its turn before it can use the medium. List two controlled access examples.

1. List and explain the three fields of an Ethernet frame header.

Start Frame field –

Source and Destination Address fields –

Type field –

1. Data link layer protocols add a trailer to the end of each frame. The trailer is used to determine if the frame arrived without error. List and explain the two sections included in the trailer.

Frame Check Sequence –

Frame Trailer –

1. Ethernet is the dominant LAN technology. Which IEEE standards define it?

1. PPP establishes logical connections, called ______, between two nodes.

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Cisco – Introduction to Networks 5.0 - Chapter 4