Additional questions about Conducted and Wireless Media

1
Additional questions about Conducted and Wireless
Media
School of Business Eastern Illinois University
2
Conduted and Wireless Media

• Why is twisted pair wire called twisted pair?
• Twisted pair wire often contains two or more
  pairs of wires. The wires in each pair are
  twisted around each other.
• How does crosstalk occur in twisted pair wire?
• Electromagnetic radiation is emitted from one
  wire, which is picked up by a second wire.
• What are Category 1, 2, 3, 4, 5 and 6 twisted
  pair wire used for?
• Cat 1 telephone lines Cat 2 T-1 and ISDN Cat
  3, 4, 5 and 6 LANs.

3
Conduted and Wireless Media

• What are the advantages and disadvantages of
  shielded twisted pair compared to unshielded
  twisted pair?
• The main advantage is that it provides a better
  level of isolation from interference. The
  primary disadvantage is cost.
• What is the primary advantage of coaxial cable
  compared to twisted pair?
• Coaxial cable has less noise and is more
  protected again interference.
• What is the difference between Baseband coaxial
  and Broadband coaxial cable?
• Typically, baseband carries digital signals
  through a single transmission channel. Typically
  broadband carries analog or digital signals using
  multiple channels.

4
Conduted and Wireless Media

• Is Category 1 the best wire for long distance
  transmissions? Explain.
• No. Cat 1 can go 2-3 miles, but only at very
  low data transfer rates.
• The local cable TV company is considering
  removing all the coaxial cable and replacing it
  with fiber optic cable. List the advantages and
  disadvantages of this plan.
• Higher data rates, less noise, but expensive.
• The local cable TV company has changed its mind.
  It is now going to replace all the existing
  coaxial cable with unshielded twisted pair. List
  the advantages and disadvantages of this plan.
• Noise used to be a huge problem when
  transmitting video signals through twisted pair,
  but new a technology (e.g. DVS) has solve that
  problem.

5
Conduted and Wireless Media

• Why is it attractive to use a wireless LAN to
  connect to a wired LAN?
• Servers normally are on a wired LAN, and in many
  businesses and Schools people who are moving
  need to access resources on the servers.
  Connecting a Wireless LAN to a wired LAN make it
  possible to access these resources.
• Can we implement a completely wireless LAN not
  connected to a Wired LAN? Explain.
• Yes. Using a switch with built-in Access Point,
  we can implement a Wireless LAN not connected to
  a Wired LAN. We can even implement a small
  completely wireless LAN without Access Point or
  Switch. In this case, Wireless NICs operate
  automatically in ad hoc mode, in which they talk
  directly to other wireless stations. This only
  works for small LANs. See next slide for
  illustration.

6
Ad Hoc 802.11 Wireless LAN

• No Access Points are used
• All stations must be Wireless (Wireless NICs)
• Stations broadcast to one another directly
• Not scalable but can be useful for SOHO use