3
MAN: A metropolitan area network (MAN) is larger than a LAN. It normally covers a
WAN: A wide area network (WAN) includes all networks. A WAN interconnects LASs that may be located in different countries.
Appendix B
Copper Pairs
1.Most LANs employing copper wires use two pairs: one pair in each direction and all
2.Pairs must be twisted. This minimizes the EMI interface and radiation.
3.Pairs must be shielded - IBM type 1 and 2 use shielded pairs.
4.Typical interface - unshielded twisted pair
5.For UTP, RJ45,
Coaxial Cable
Coaxial cable is used for both baseband and broadband LANs
1.Independence - the independence of coaxial cable is not based on size. That means, for example, that bib cables do not necessarily have a low impedance.
2.Three common values of impedance - 50 ohms (for baseband Ethernet/802.3 LANs),
75ohms (for broadband LANs/801.4) and 93 ohms (for ARCnet LANs)
3.EMI, radiation and bandwidth/bit rate
•EMI susceptibly and radiation are lower than TP.
•Conventional bandwidth is greater than 400mhz. It is usually limited by the attached equipment.
•Data bit:10Mbps
4.Advantage of using optical fiber are:
•Security: No radiation. Avoids tapping.
•EMI: Not susceptible to electromagnetic interference.
Appendix C
Ethernet Comparison Chart
| Thicknet | Thinnet | 10 BaseT |
Media | Coaxial | Coaxial | UTP |
|
|
|
|
Data Rate | 10 | 10 | 10 |
|
|
|
|
Maximum Segment Legth (m) | 500 | 185 | 100 |
|
|
|
|
Network Span (m) | 2500 | 925 |
|
|
|
|
|
Node Per Segment (m) | 100 | 30100 |
|
|
|
|
|
Topology | Bus | Bus | Star |
|
|
|
|