Chapter 9 - Test 3 Flashcards Preview

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Flashcards in Chapter 9 - Test 3 Deck (39):
1

What is the internet?

-a network of networks.
-a set of separate and distinct networks operated by various national and state government agencies, nonprofit organizations, and for-profit corporations.

2

Describe ISPs.

-internet service providers.
-att and sprint.

3

Describe national ISPs.

-also called tier 1 ISPs, connect together and exchange data at network access points (NAPs)
-provide services for their customers and also to regional ISPs(tier 2 ISPs)

4

Describe NAPs.

-originally designed to connect only large tier 1 ISPs.

5

Describe Tier-2 ISPs.

-rely on Tier 1 ISPs to transmit their messages to ISPs in other countries.
-provide services to their customers and to local ISPs.

6

Describe local ISPs.

-sell internet access to individuals.

7

Describe MAEs.

-metropolitan area exchange.
-smaller versions of NAPs. and typically link a set of regional ISPs whose networks come together in major cities.

8

What's a rule of thumb for ISPs?

-ISPs at the same level do not charge one another for transferring messages they exchange.
-called peering.

9

Describe Internet Exchange Points(IXPs).

-often run by a not-for-profit cooperative organization
-permits any ISP or large organization to connect to its network.
-some charge connection fees, others charge membership fees, and others don't charge at all.

10

What happens at IXPs?

-ISP negotiates peering agreements with other ISPs who are members of the IXP and then begin exchanging internet traffic.

11

What happens at IXPs?

-ISP negotiates peering agreements with other ISPs who are members of the IXP and then begin exchanging internet traffic.

12

Describe autonomous systems.

-network run by a single organization
-each ISP responsible for running its own interior routing protocols and for exchanging routing information via the Border Gateway Protocol(BGP) exterior routing protocols at NAPs, MAEs, IXPs and any other connection points between individual ISPs.

13

Describe POPs.

-point of presence
-place at which the ISP provides services to its customers.

14

Describe how DSL works.

-DSL modem or cable modem that connects to the DSL multiplexer at the ISP and from there to a remote-access server (RAS) which checks the user is a valid customer.

15

Describe how DSL works.

-DSL modem or cable modem that connects to the DSL multiplexer at the ISP and from there to a remote-access server (RAS) which checks the user is a valid customer.

16

What are example of broadband technologies?

-DSL and cable modems

17

What do internet access technologies do?

-connect from one location to an ISP
--can't be used for general-purpose networking from any point to any point.

18

Describe DSL.

-digital subscriber line
-family of point-to-point technologies designed to provide high-speed data transmission over traditional telephone lines.

19

What is the local loop?

-the actual cable from a home or office to the telephone company.

20

What is CPE?

-customer premise equipment
-installed at the customer location.

21

What is a line splitter?

-CPE
-used to separate the traditional voice telephone transmission from the data transmissions.
-directs the telephone signals into the normal telephone system so that if the DSL equipment fails, voice communications are unaffected.

22

What is a DSL modem?

-sometimes called a DSL router.
-modem and a FDM multiplexer.

23

What is a MDF?

-main distribution facility
-where the local loops from many customers enter
-works like the CPE line splitter, splits the voice traffic from the data traffic and directs the voice traffic to the voice telephone network and the data traffic to the DSL access multiplexer(DSLAM).

24

What does a DSLAM do?

-demultiplexes the data strems and converts them into ATM data, which are then distributed to the ISPs

25

What is ADSL?

-asymmetric DSL
-uses FDM to create three separate channels over the one local loop circuit.
-traditional voice circuit, relatively high-speed simplex data channel downstream from the carrier's end office to the customer, slightly slower duplex data channel primarilly used for upstream from the customer to the carrier's end office.

26

What is ADSL?

-asymmetric DSL
-uses FDM to create three separate channels over the one local loop circuit.
-traditional voice circuit, relatively high-speed simplex data channel downstream from the carrier's end office to the customer, slightly slower duplex data channel primarilly used for upstream from the customer to the carrier's end office.
-data channels are further multiplexed with TDM.

27

Describe cable modem.

-digital service offered by cable television companies

28

Describe DOCSIS.

-Data over cable service interface specification.
-dominant standard used by most vendors of hybrid fiber coax networks.

29

What is the difference between cable and DSL architectures?

-cable is a point to point technology whereas cable modems use shared multipoint circuits.
-all messages on the circuit go to all computers on the circuit.

30

Describe the cable modem architecture.

-enters customer premise through cable splitter that separates the data transmissions from the tv transmissions.
-data transmissions sent to cable modem(modem and FDM)
-translates cable data into ethernet packets which are directer into a computer to a router and hub for distribution.

31

By how many people is a typical segment of cable shared?

-anywhere from 300 to 1000 customers.

32

Describe how cable customers connect to the cable company office.

-coax cable runs to a fiber node which has an optical-electrical converter.
-fiber nodes connected to cable compnay distribution hub(headend) through an upstream circuit and a downstream circuit.

33

Describe the upstream connection to the cable companies distribution hub.

-connected into a cable modem termination system(CMTS) which has series of cable modems/multiplexers.
-converts from cable modem protocols into protocols needed for internet traffic
-passes them to router connected to an ISP POP.

34

Describe the downstream connection from the cable companies distirubtion hub.

-contains both ordinary video transmissions from cable TV video network and data transmissions.

35

Describe the downstream connection from the cable companies distirubtion hub.

-contains both ordinary video transmissions from cable TV video network and data transmissions from the internet.
-data traffic enters distribution hub from ISP POP and routed through the CMTS wich produces the cable modem signals.
-traffic sent to a combiner which combines the internet traffic with ordinary tv video traffic and sends it back to the fiber node for distribution.

36

What is FTTH?

-fiber to the home
-running fiber-optic cable into the home.
-data transmitted down fiber cable using Wavelength Division Multiplexing(WDM).
-provides hundreds or thousands of separate channels.

37

How does FTTH work?

-optical unit network(ONU) at each subscriber lockation.
-acts like a DSL modem or cable modem and converts the signals in the optical network into an ethernet format.
-Dedicated point-to-point service like DSL.

38

What is WiMax?

-worldwide interoperability for microwave access.
-developed by IEEE 802.16
-can be used as a fixed wireless technology to connect a house or an office into the internet.
-ability to connect mobile laptops and smart phones into the internet.

39

Describe the Wimax architecture.

-controlled access media access control with point coordination function (PCF)