This document provides an overview of basic computer networks. It discusses LANs and their advantages such as simple and inexpensive connections. It describes common LAN topologies like bus, star, and ring configurations. Components of LANs such as hubs, switches, routers and their functions are explained. The document also covers wireless LANs, Wi-Fi standards, and wireless networking components including access points. Common network protocols like IP addressing, DHCP, DNS are summarized. Methods for configuring networks in Windows and connecting wireless devices are outlined.
2. 2
Basic Computer Network
LAN Overview
LANs were created to save time, money, and enable users to
share information and resources more easily. Some advantages
that LANs provide include
Simple and inexpensive connections
Support for multiple media protocols
Flexibility to provide any-to-any connections
Support for new applications
Ability to grow easily
7. 7
Basic Computer Network
MAC Addressing
• Aka Hardware address
• “Ethernet” (or 802.3) networks specify a 48-bit
physical “MAC address”
– 00-00-f8-75-5b-a6 -- Unique identifier for the network
interface card (NIC)
– Address ranges are assigned to specific vendors e.g.,
“00-00” is Digital Equipment corp.
– To find vendors MAC addresses
http://coffer.com/mac_find/
• Specific MAC address that means “broadcast”
– ff-ff-ff-ff-ff-ff (All 1s)
11. 11
Basic Computer Network
Router
• Router: F F F F F
F LANs – WANs WANs – WANs
F F Router F
F F F F F (Internetworking
Device)
• F F F Router F IP F
3 OSI Model
TOT’s NETWORK
15. 15
Basic Computer Network
Fast Ethernet
Twisted Pair
(UTP)
.........100 Mbps100baseT
Fiber Optic200010 Mbps10baseF
Twisted Pair
(UTP)
STAR10010 Mbps10baseT
Thick EthernetThick Coaxial50010 Mbps10base5
Thin Ethernet
Cheapernet
Thin CoaxialBUS185 - 20010 Mbps10base2
F
Cable
Topology
F
- F
F
- F
FF
F ETHERNET
16. 16
Basic Computer Network
IP Address
Internet Protocol Address ˈ F F F F
F F F Hardware F
– F F F (Host Address)
– F F (Network Address)
• 32 bit F ˈ 4 F F F F F 0- 255
18. 18
Basic Computer Network
IP Addresses – Class A
• Class A
– Start with binary 0
– All 0 reserved
– 01111111 (127) reserved for loopback
– Range 1.x.x.x to 126.x.x.x
– All allocated
• Private address 10.x.x.x
19. 19
Basic Computer Network
IP Addresses – Class B
• Start with binary 10
– Range 128.x.x.x to 191.x.x.x
– Second Octet also included in network address
– 214 = 16,384 class B addresses
– All allocated
• Private address range
172.16.x.x – 172.31.x.x
20. 20
Basic Computer Network
IP Addresses – Class C
• Start with binary 110
– Range 192.x.x.x to 223.x.x.x
– Second and third Octet also part of network address
– 221 = 2,097,152 class C addresses
– Near all allocated
• Private address range
192.168.x.x
22. 22
Basic Computer Network
Dynamic Host Configuration ProtocolDynamic Host Configuration Protocol
• DHCP Service F IP Address
F F F (Client) F F F F
F F F Client F
F F (Server) F Service F F
run F F Client F F F IP
F
23. 23
Basic Computer Network
Domain Name
(Domain Name) ˈ
F (IP Address) ˈ
F F F
F F IP 202.44.204.33
" " ˈ www.nectec.or.th
F F F F F IP Address
F ˈ Lookup ʽ
ˈ (Domain Name) F Domain Name
Server
41. 41
Basic Computer Network
Internet Protocol (TCP/IP) ˁ Properties F
General F Obtain an IP address automatically Obtain DNS
server address automatically.
internet
Protocol(TCP/IP)
obtain an IP address
obtain DNS
Click Properties
43. 43
Basic Computer Network
F PingF Ping
• F F F F
F F F ICMP
(Internet Control Message Protocol)
F F ˈ ICMP Echo
Reply ( F ˈ ICMP Echo Request)
• block ping F F Fire wall
F F F ˈ F F
F F
46. 46
Basic Computer Network
F Wireless LAN (Local Area Network) WLAN
ˈ F F F peer-to-
peer F F (station) F
F ˈ F F (point-
to-point) F (point-to-multi point)
F WLAN ˈ F F LAN
F ˈ F F
LAN F F
F Wireless LAN
48. 48
Basic Computer Network
F F F
Wireless LAN (Proprietary)
Wired LAN Network
IEEE Standard ETSI Standard
IEEE 802.11
IEEE: Institute of Electrical and Electronics Engineers
ETSI: European Telecommunications Standards Institute
HiperLAN/1
HiperLAN/2
HiperACCESS
IEEE 802.11b (Wi-Fi) IEEE 802.11a (Wi-Fi5)
IEEE 802.11g (Wi-Fi)
49. 49
Basic Computer Network
IEEE 802.11Specifications
2.4-2.497 GHz
5.15-5.35 GHz
5.425-5.675 GHz
2.4-2.497 GHz
Frequencies
CCK= 1,2,5.5,11
Mbps
OFDM=6,9,12,18,2
4,36,48,54 Mbps
6,9,12,18,24,36,
48,54 Mbps
1,2,5.5,11 Mbps
Data rates
OFDM and CCKOFDMCCKModulation
54Mbps54Mbps11MbpsMaximum
Data rate
June 2003July 1999July 1999Standard
Approved
802.11g802.11a802.11b
OFDM (Orthogonal Frequency Division Multiplexing)
CCK (Complementary Code Keying)
50. 50
Basic Computer Network
Wi-Fi
Wi-Fi F F Wireless Fidelity ˈ
F F F
IEEE 802.11 (Institute of Electrical and Electronic
Engineer 802.11)
F F F
F F (Wireless Local Area Network
(WLAN)) F F UHF (Ultra High
Frequency)
51. 51
Basic Computer Network
Wireless Network Components
RF interface for
iPAQ / Casiopia)
Access Point
………….……. …
…
…
…
…
…
…
.
…
…
…
…
…
…
…
…
.…
.
RF interface for
desktop PC
RF interface for
notebook
52. 52
Basic Computer Network
Access Point
ˈ F Wireless Network
ˈ
- F F
F F F F F
128
F F MAC
address
F F F
Client mode, Infrastructure, Repeater,
Multipoint repeater
53. 53
Basic Computer Network
RF Interface Card
F PCMCIA USB port
Card Compact flash
F PCMCIA F F PCI F PCI Wireless F F F PCMCIA
PCMCIA : Personal Computer Memory Card International Association
56. 56
Basic Computer Network
Peer to Peer Topology (AdPeer to Peer Topology (AdPeer to Peer Topology (AdPeer to Peer Topology (Ad hochochochoc))))
o F F F F Access Point
o F F ( F 3 )
o F F
AdAdAdAd----hoc network is a network typically created in a spontaneous mannhoc network is a network typically created in a spontaneous mannhoc network is a network typically created in a spontaneous mannhoc network is a network typically created in a spontaneous manner.er.er.er.
59. 59
Basic Computer Network
Channels - IEEE802.11 DS
o 3 F F F /
o Access Points F 3
o F F bandwidth F F 22 MHz.
o F F 11 Mb/s
1 2 3 4 5 6 7 8 9 10 11
2400
24722412
12 13
1
2
3
5
4
6
7
8
10
9
13
11
12
62. 62
Basic Computer Network
Local Area Network (LAN)
HubHubHubHub
ServerServerServerServer SwitchSwitchSwitchSwitch
InternetInternetInternetInternet
Access PointAccess PointAccess PointAccess PointHubHubHubHub
Wireless LAN (WLAN) as anWireless LAN (WLAN) as anWireless LAN (WLAN) as anWireless LAN (WLAN) as an
extension to wired LANextension to wired LANextension to wired LANextension to wired LAN
Ethernet ClientEthernet ClientEthernet ClientEthernet Client
63. 63
Basic Computer Network
1. F ( PC F ) F F
F
PCMCIA F PCI F PCI
Slot F
PCI Wireless F F F PCMCIA PCI Slot
F
USB F F USB F ( USB
F F F F F F )
F F F F
64. 64
Basic Computer Network
2. F F F F F F
PCMCIA F F F F F F Centrino
USB F F USB F F
3. F F F Centrino F ˈ F F F
F F Centrino F F F
F
4. F Palm Pocket PC F F F
F F F Palm Pocket
PC F F F
F F F F