Transcript Chapter 4 2007

Connecting to the Internet through
an ISP
Networking for Home & Small Business
What this Chapter is About…
• Every day people are online
• We need to communicate
• Internet Service Providers (ISP)
– Make this possible
– Web of service providers
• You’ll see:
– Why ISP’s are necessary
– The Network Operations Centers
What is the Internet
• Worldwide collection of computer networks,
cooperating with each other to exchange
information using common standards
– Network of networks that connects users in
every country in the world
• Do this through:
– Wireless, fiber, telephone lines, satellite &
more
The Internet
• Who owns it?
– No one
• There are several organizations that help
manage it
– Standards
– Addressing
Internet Organizations
• ISOC Internet Society
– Central leadership organization
• IETF Internet Engineering Task Force
– Proposes solutions to Internet problems
– Recommends protocol standards
• IRTF Internet Research Task Force
– Researches future of Internet
– How to handle transmissions during disaster
• IANA Internet Assigned Numbers Authority
– Bookkeeper of who addresses are assigned to
ISP’s
• What’s an ISP?
– Company that provides access to the Internet
• Name yours & others
Connect to the ISP through POP
• Point of Presence
• Between your LAN & the ISP
• Where you get the ISP’s services- closest point of
connection
High Speed Backbone
Maps
• http://www.telegeography.com/maps/index.
php
Review
1. Describe the Internet.
2. What does ISP stand for?
– Internet Service Provider
3. What does an ISP do?
– Provides connection to the Internet
4. What is the connection point between the
ISP and your LAN?
– POP
Options for Connecting to the
ISP
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Dial-up- slowest, telephone lines
Cell Phone Modem- becoming fast
DSL- high speed over phone lines
Cable Modem- high speed over cable lines
Leased Line- high speed over dedicated digital
lines, for businesses, T1
• Satellite- medium speeds
Options for Connecting to the
ISP
• Modem is used to connect to ISP
• You may have an ISR to connect multiple
computers to the modem
ISP Service Levels
• Home Service
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Slower speed
Less expensive
Less web space
Fewer email addresses
• Business Class
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Faster speed
More expensive
More web space
More email addresses
SLA (Service Level
Agreements)
• Network availability
terms
• Service response time
Asymmetric Service
• Download transfer rate is
different from upload rate
– Common in homes, most
Internet users
– Download is faster
Symmetric Service
• Download transfer rate is
same as upload rate
– Common in businesses or
hosting servers
– Great for uploading lots of
video, data, graphics
Activity
• Complete 4.1.5-3
• Handout Research
• Go home & test your speed!
• http://reviews.cnet.com/7004-7254_70.html
End of Day One
Review
1. Name some features that a business
class ISP service would offer that home
service does not.
2. Describe asymmetric service.
3. Describe symmetric service.
4. What is a POP?
– Connection between LAN & ISP
5. What’s the high speed links that connect
ISPs called?
– backbone
The Importance of IP
• Internet Protocol
– Uses packets to carry data
– IP carries what you do on the Internet
– Contains source & destination IP address
IP Packet
• Header contains the IP addresses & control
info for routers
• IP addresses MUST be unique
• ISP gets blocks of addresses
– Then they manage & split them up
How an ISP handles Packets
• Before hitting the Internet, your message is
divided into small packets
– Downloading a 1 MB song requires over 600 packets
of 1500 bytes each
• ISP determines whether packet is for local or for
remote network
NOC
• Controls traffic flow
– Uses destination IP
• Has services (web hosting, email)
NOC- Monitoring
NOC- AT &T Monitoring
Network Utilities
• Ping
– End-to-end
connectivity
• Traceroute
– Traces path
from source to
destination
– Displays each
hop
Traceroute
• http://visualroute.visualware.com/
Activities
• Packet Tracer 4.2.3.2
• Lab 4.2.3.3
The Internet Cloud
• Many routes to a destination
– Bad router- take the back road!
• Cloud represents Internet or another
network
Devices in the Cloud
• More than just routers
• Tech at home must match tech at ISP
– DSL connects to a DSLAM (access
multiplexer)
– Cable Modem connects to a CMTS
(termination system)
• Must have equipment to connect to other
ISPs
• Must handle lots of traffic, near 100%
uptime, redundant
Devices in the Cloud
Devices in the Cloud
Activity
Review
1. A DSLAM is needed at the ISP for which
technology?
– DSL
2. What does DSL stand for?
– Digital Subscriber Line
3. A CMTS is needed for which technology?
– Cable Modem
4. What do you need to connect to the
Internet?
– IP Address, default Gateway, connection to a
network, and an ISP to connect you
Home & Business Devices
Home & Business Environment
Cables
• What’s another name for cable?
– Medium
– Channel
• Copper
• Fiber Optic
Network Cables
Twisted Pair Cabling
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Electricity over the copper wires
Pairs twisted inside jacket
Can get EMI
Crosstalk on long runs
– Cat 5 has 3-4 twists per inch
– Makes it more resistant to interference
Kinds of Twisted Pair
• UTP
– Electricity
– Inexpensive
– Easy to install
– 4 pairs of wires, color coded
– RJ45 connector
• Cat 5 & 5e
– 100 & 1000Mbps
• Cat 6
– 1000Mbps & higher
Review
1. What connector is on UTP?
– RJ45
2. What is the high speed links called that
connect ISPs?
– Backbone
3. A router, switch & access point all in one
is called what?
– ISR
Coax Cable
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Transmits electricity
Better shielding than UTP
Harder to install than UTP
ISP uses these for CMTS
Fiber Optic Cables
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Transmits pulses of light
Used in big environments
Glass or plastic
No EMI
High speed
– LAN backbone
– Connect ISP to Internet
• 2 fibers
– Transmit & receive
Fiber Optic Cables
• Multimode
– Less $
– Used in LANs/Campuses
• 2000 meters
– LED
– Many paths of light
• Single Mode
– More $
– Connects backbone/NOCs
• 3000 meters
– LED laser
– Single path of light
Activity- Fiber or UTP?
Cabling Standards
• Specs for installing & testing cable
– Pinouts (order of wires)
– Wire sizes
– Shielding
– Cable lengths
– Connector types
– Performance limits
UTP Cables
• TIA/EIA
– 568A
– 568B
Straight-Through Cable
• 568B to 568B
• Connect unlike devices
– Computer to Hub/Switch
– Switch to router port
• On the PC NIC
– Pins 1 & 2 transmit
– Pins 3 & 6 receive
Crossover Cable
• 568A to 568B
• Like Devices
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Switch/hub port to switch/hub port
Router port to router port
PC to router port
PC to PC
UTP Termination
• RJ45 male connector
• Jack is female
Let’s make cables!
• Straight-through
• 568B to 568B
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White-Orange
Orange
White-Green
Blue
White-Blue
Green
White-Brown
Brown
Let’s make cables!
• Crossover
• 568B to 568A
• Change Oranges & Greens on ONE SIDE!
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White-Green
Green
White-Orange
Blue
White-Blue
Orange
White-Brown
Brown
Terminating
• Patch Panel
– Switchboard
– Quickly
rearrange
– RJ45
• Jacks
Lab
• Terminate to a jack
Testing Cables
• Open
– Wire not in connector
– Break in wire
• Short
– Copper touches another
• Reversed Pair
• Split Pair
Other Tests- Degredation
• Attenuation
– Measure of signal strength
– If message fades at destination, will not be
understood
• Crosstalk
– Signal leaks onto another pair of wires
– Can happen if cables are not terminated
properly or low quality connectors
Cabling Best Practices
• Cable Management
– Keeps wires neat & organized to easily find
problems
– Protected from damage
Review
• Which cable would you use:
– In your house?
• UTP
– Between buildings?
• Fiber
– To your cable modem?
• Coax
– Where you get a lot of EMI?
• Coax or fiber, NOT UTP!!