Transcript Connecting computers - Cambridge Regional College

Course ILT
Networking computers
Unit objectives
 Use the OSI model to determine the
levels of communication used in
networking
 Describe how different types of
addressing are used to identify
computers on a network
 Identify technologies for establishing
Internet connectivity
 Create wired and wireless network
connections
 Troubleshoot network connections
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Topic A
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Topic A: Network communications
Topic B: Addressing
Topic C: Internet connections
Topic D: Network installation
Topic E: Network troubleshooting
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The OSI model
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The OSI model applied to LAN
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Activity A-1
Analyzing the OSI model
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Topic B
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Topic A: Network communications
Topic B: Addressing
Topic C: Internet connections
Topic D: Network installation
Topic E: Network troubleshooting
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Addressing
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MAC address
IP address
Character-based names
Port address
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Identifying addresses
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MAC addresses
 Function at Data Link layer
 Host uses OS to discover MAC
address of another computer
 Can’t use MAC address across LANs
 MAC addresses are absolute
 All hosts on LAN must use MAC
address to communicate
 MAC addresses with IP addresses
used to communicate across LANs
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IP addresses
 32-bit long
 4-bytes separated by periods
 Largest possible IP address is
255.255.255.255
 Each byte is an octet
 4.3 billion possible IP addresses
 Not all IP addresses available for use
 IP address has two parts
1. Identifies the network
2. Identifies the host
IP classes
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 Three public IP classes
– Class A
– Class B
– Class C
 All assigned IP addresses in these
classes are unique
 Possible number of networks / hosts
– Class A – 127 / 16million
– Class B – 16,000 / 65,000
– Class C – 2,000,0000 / 254
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Parts of an IP address
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Character-based names
 TCP/IP supports Domain Name
Service (DNS)
– Resolves host names to IP addresses
 Windows supports NetBIOS names
– 16-character name
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Domain Name Service
 Match host names to IP addresses
 DNS names have three parts
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A computer name
A domain name
A top-level domain name
www.microsoft.com
 Possible to include subdomains
– www.corporate.microsoft.com
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Top-level domains
 The suffix of a DNS name
 Original specifications
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.com
.org
.edu
.gov
.mil
.net
.int
 TLDs added for each country
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Recent TLDs
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.biz
.name
.museum
.pro
.aero
.coop
.info
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NetBIOS names
 16-characters
 First 15-characters for name
 16th character specifies service or
function
 Allows special characters
!@#$%^&()-_'{}.~
 Doesn’t allow spaces or
\*+=|:;"?<>,
 Aren’t case-sensitive
 16th character expressed as <hex>
 Uses flat-namespace
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Resolving NetBIOS names
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WINS
 Broadcasts can’t go through network
devices such as routers
 WINS allows two computers on
separate networks to resolve NetBIOS
names
 A database with registered NetBIOS
names
 Primary name resolution service
starting with Windows 2000 is DNS
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Port addresses
 Transport layer protocols use port
addresses
 Each services listens on a port
 Port numbers 0 to 1024 are reserved
 Combination of IP address and port
number is a socket
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Activity B-1
Examining addresses
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Topic C
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Topic A: Network communications
Topic B: Addressing
Topic C: Internet connections
Topic D: Network installation
Topic E: Network troubleshooting
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Internet connections
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Dial-up networking
Virtual private network
Digital subscriber line
Cable
Satellite
Wireless
Local area network
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Connecting to the Internet
 Bandwidth
 Greater bandwidth = faster
communication potential
 Digital data transmission measured as
data bits per second (bps)
 One thousand bits per second = Kbps
 One million bits per second = Mbps
 Internet connections have varying
bandwidths
– Dependent on ISP service and physical
media
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Connecting LAN to ISP
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POTS
ISDN
DSL
Cable modem
Satellite link
Wireless
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Satellite ISP configuration
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Technology speeds
POTS — Up to 56 Kbps
ISDN — 64 Kbps to 128 Kbps
DSL — Up to 1.5 Mbps
DSL Lite or G.Lite — Up to 384 Kbps
upstream; up to 6 Mbps downstream
 ADSL — 640 Kbps upstream; up to
6.1 Mbps downstream
 SDSL — 1.544 Mbps
 HDSL — 1.5 Mbps
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continued
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Technology speeds, continued
 VDSL — Up to 52 Mbps downstream;
16 Mbps upstream
 Cable modem — 512 Kbps to 5 Mbps
 802.11b — 5.5 Mbps or 11 Mbps
 802.11g — Up to 54 Mbps
 802.11a — Up to 54 Mbps
 Ethernet — 10, 100, or 1000 Mbps
 Token ring — 4 Mbps or 16 Mbps
 T1 — 1.544 Mbps
 FDDI — 100 Mbps
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Remote access methods
 To a variety of systems
 Usually require
– Username
– Password
 Can use all LAN/Internet connection
methods to make a remote connection
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Activity C-1
Selecting the best Internet connection
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Topic D
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Topic A: Network communications
Topic B: Addressing
Topic C: Internet connections
Topic D: Network installation
Topic E: Network troubleshooting
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Installing a modem
1. Install and configure a modem
2. Install modem device driver
– Included with Windows
– From modem manufacturer
 External modem connects to serial
port
– 9-pin
– 25-pin
– EIA/TIA-232 standard
 Internal modem inserted in expansion
slot
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Serial ports for external modem
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Activity D-1
Installing a modem
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Dial-up connections
 Enables a computer to use a modem
and a telephone line to connect to a
network
 Modem behaves like a NIC
 Slower connection speeds
 Use New Connection Wizard to create
dial-up connection in 2000 and XP
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Activity D-2
Creating a dial-up connection
TCP/IP in dial-up
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 Needs
– An IP address
– IP address of the default gateway
– A subnet mask
 Know the answers to
– Static or dynamic IP addressing?
– For static – what is the IP address,
subnet mask, default gateway address?
– DNS servers assigned?
– If not, what are the DNS server
addresses?
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Activity D-3
Configuring TCP/IP for a
dial-up connection
Cable, ISDN, DSL, and Satellite
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 All require TCP/IP settings
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IP address
Subnet mask
Gateway address
DNS server address
 Network cable attaches NIC card to
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Cable modem
DSL box
Satellite converter box
LAN switch or hub
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Cable and DSL broadband
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Broadband installations
1. Install NIC and drivers
2. Network cable from NIC to
– Cable modem
– DSL box
– Network hub
3. Configure TCP/IP
4. Install and configure Internet apps
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Cable modems
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Cable modem install steps
1. Determine NIC card’s MAC address
2. Configure TCP/IP for broadband
3. Connect the cables
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ISDN and DSL
 Provided by local telephone company
 For ISDN need a NT1 and aTA
 DSL needs a converter box
Satellite connection
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 Requires
– A satellite dish (usually around 2 ft. by 3
ft.)
– Two modems (upstream and
downstream)
– Cables to connect the computer and
modems
 Must locate satellite dish for best
signal
 Run cables from satellite into house
 Connect cables to modems
 Connect computer to modems
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Voice over IP
 Telephone calls over broadband data
network
 Converts voice from analog to digital
and back again
 Can use
– A regular telephone with an ATA
– An IP phone with an RJ-45 connector,
which plugs into your router
– Computer-to-computer using software
from your VoIP provider, a microphone,
speakers, and sound card
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Activity D-4
Configuring TCP/IP
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LAN connections
 Should be concerned about security
 All computers connect to Internet
through a gateway
 Three setups
– Protocol isolation
– Router security
– Proxy server security
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Protocol isolation
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Router security
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Proxy server security
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The gateway
 Gateway access can be any of the
Internet connection methods
 Dial-up would be slow for multiple
computers
 Select connection method for gateway
based on amount of traffic
 Gateway has two connections
– One to the LAN
– One to the ISP and the Internet
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Configuring LAN Internet connections
 Does the network use a proxy server?
If so, what is the IP address of the
server?
 If no proxy server is used, what is the
IP address of the default gateway?
 Is static IP addressing or dynamic IP
addressing used?
– If static IP addresses are used, what is
the IP address and subnet mask?
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Activity D-5
Describing LAN entry points
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Wireless nodes
 Infrared transceivers
 Wireless network adapters
 Useful for mobile users
– Print to a printer IR port
– Connect to the network with wireless NIC
– Share information between two
computers using IR ports
Wireless equipment
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 Need
– Wireless NICs
– Wireless router or wireless access point
 WAP connects WLAN to wired
network
 WAP includes firewall capabilities and
connection sharing
 Place WAP or wireless router in
central location
 WLAN needs a SSID
– Change the default for security
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Channel and SSID settings
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Security
 Enable WEP
 Alter the wireless access point’s
factory settings
– Change the default SSID
– Disable SSID broadcasts
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Use MAC filters
Enable 802.1x
Use Wi-Fi Protected Access mode
Disable the use DHCP on WAP
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Wireless authentication methods
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Unauthenticated access
Authorized MAC addresses
Wired equivalent protocol
WiFi Protected Access
The 802.1 protocol
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802.1x protocol authentication
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Activity D-6
Adding a wireless node to your network
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Topic E
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Topic A: Network communications
Topic B: Addressing
Topic C: Internet connections
Topic D: Network installation
Topic E: Network troubleshooting
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Network troubleshooting
 Identifying the scope of the problem
 Observing status indicator lights
 Checking TCP/IP communication
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Wireless network problems
 Determine network name
 Identify security configurations
 Check notebook wireless NIC power
switch
 Check wireless antenna position
 Check signal strength
 Test with another wireless card
Remote connection problems
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 Problem can be located with
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ISP
Communication line in building
Network cable to modem or transceiver
Network cable to NIC
NIC configuration
 For phone line – test for dial tone with
regular phone
 For cable – check for cable TV signal
 Swap out cables
 Use a surge protector or UPS
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Activity E-1
Troubleshooting network problems
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Unit summary
 Used the OSI model to determine the
levels of communication used in
networking
 Described how different types of
addressing are used to identify
computers on a network
 Identified technologies for establishing
Internet connectivity
 Created wired and wireless network
connections
 Resolved network connection
problems