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Basic Communication Systems
Finals Set
49
Computer Science
Graduate
06/08/2011

Additional Computer Science Flashcards

 


 

Cards

Term
Define Hertz
Definition
The unit of measurement of the frequency of a time-varying waveform.
Term
What is CAS (Circuit Associated Signaling/In-band Signaling)?
Definition
Circuit Associated Signaling is also known as In-band signaling where all signaling to manage the calls occurs within the same circuit that will be used for the call itself. CAS is less efficient than CCIS-based (Out of band) signaling.
Term
Are phone numbers associated with trunks themselves?
Definition
NO
Term
What did the 1968 carterphone decision allow?
Definition
It allowed non telephone company equipment to be connected to the AT&T network (via a protective coupling device).
Term
What is a loading coil and what does it do?
Definition
A loading coil is an induction device placed on a local loop longer than 18,000 feet that carries analog signals. The device compensates for wire capacitance and boosts the frequencies carrying voice information. Loading coils cause distortion at the higher frequencies used to carry digital information and so are not used on local loops that are supporting DSL service.
Term
Define MPLS
Definition
Multiprotocol Label Switching (MPLS) is a technology for speeding up network traffic flow and making it easier to manage. MPLS involves setting up a specific path for a given sequence of packets, identified by a label put in each packet, thus saving the time needed for a router to look up the address to the next node to forward the packet to.
Term
What is a connectionless transmission?
Definition
Communication between two network end points in which a message can be sent from one end point to another without prior arrangement
Term
What does the "asymmetric" in Asymmetric DSL mean?
Definition
Not as much bandwidth upstream as there is downstream. Less bandwidth provided upstream from the customer to the service provider. However, downloading and web surfing represent the majority of DSL activity. 7Mbps downloading and 640kbps uploading.
Term
What is Point of Presence (POP)/Point of Interface (POI)?
Definition
The physical point where the IEC (Long Distance Exchange Carrier) and the LEC (Local Exchange Carrier) are interconnected is called the point of presence or point of interface
Term
What are the 4 costs associated with the “edges”, or telecommunication links, between nodes?
Definition
1. Delay cost
2. Queue cost
3. Limited speed cost
4. Link use cost
Term
What did the modified final judgement of 1983 do?
Definition
Broke up AT&T into 7 Regional Bell Operating Companies
Term
What was the first operating system written in C language?
Definition
UNIX
Term
What did the Kingsbury commitment do?
Definition
Supported 4 decisions:
(a) It formalized AT&T’s monopoly of the U.S. telephone network
(b) It forced AT&T to divest itself of Western Union
(c) AT&T agreed to provide long-distance service to independent telephone companies (under certain conditions)
(d) AT&T agreed to refrain from purchasing any more independent telephone companies without Interstate Commerce Commission (ICC) approval.
Term
What did the 1969 MCI decision do?
Definition
(a) It granted MCI and any other phone company (i.e. other telcos) the right to offer long distance service to their customers.
(b) It granted MCI the right to connect to AT&T’s network for access to customer’s premises.
(c) It broke AT&T’s stranglehold on local phone service
Term
Where do 90% of all problems in a phone network occur?
Definition
In the local loop
Term
What are the upstream and downstream speeds for SDSL?
Definition
Up to 1.544Mbps in both directions.
Term
What is a API (Application Program Interface)?
Definition
Specific method prescribed by a computer operating system or by an application program by which a programmer writing an application program can make requests of the operating system or another application. Customers use the cloud provider's application program interface (API) to start, stop, access and configure their virtual servers and storage.
Term
What are the 3 characteristics of cloud computing?
Definition
(1) It is sold on demand, typically by the minute or the hour;
(2) It is elastic -- a user can have as much or as little of a service as they want at any given time
(3) The service is fully managed by the provider. The consumer / end user needs nothing but a personal computer and Internet access.
Term
What does DHCP do?
Definition
DHCP assigns IP addresses and routing information to LAN workstations
Term
What do cloud computing customers use to configure and access virtual servers and storage?
Definition
Application Program Interface (API)
Term

What are the symbols for router, switch, and AMP (Amplifier)?

Definition
[image]
Term

What is the maximum distance that ADSL will not work past the central office?

Definition

18,000 ft

Term

What is a LATA?

Definition
The U.S. federal court system had a dilemma related to defining local versus long distance service.  To solve, the US was broken down into 231 separate bounded areas for local calling based on the density of the population in the area.  These were called Local Access and Transport Areas, or LATAs
Term

What does the FTP protocol do?

Definition

A standard Internet protocol, and is the simplest way to exchange files between computers on the Internet.   It's also commonly used to download programs and other files to your computer from other servers.

Term

Do some LATAs include entire states?

Definition

Yes. For example Wyoming and New Mexico are LATAs.

Term
Traditionally, what type of carriers were allowed to handle LATA to LATA traffic?
Definition

Traditionally, LATA to LATA traffic had to go through a long-distance carrier (IXC – Interexchange Carrier)

Term

How does the Central Office monitor “on-hook” and “off-hook” status?

Definition

The central office watches (loop) electrical currents to determine on hook and off hook status

Term

What type of tone is a trunk busy tone?

Definition

It is a fast busy tone

Term

What is DOCSIS?

Definition
DOCSIS is a standard interface for cable modems, which handle incoming and outgoing data signals between a cable TV operator and a personal or business computer or television set
Term

How does distributed routing work?

Definition

Each node maintains its own routing table with no central site holding a global routing table.  Somehow each node has to share information with other nodes so that the individual routing tables can be created so routing tables are created dynamically.

Term

Will your distance from the Central Office affect your speeds?

Definition

Yes.  The further you are from the Central Office, the lower your speeds will be

Term

Is all routed network traffic is connectionless?

Definition
YES
Term

Is this statement true or false: Significant innovations in virtualization and distributed computing, as well as improved access to high-speed Internet and a weak economy, have accelerated interest in cloud computing.

Definition
TRUE
Term

What is a channelized T-1 vs. unchannelized T-1?

Definition

Channelized T-1 is where is T-1 is utilized as 24 discrete DS-0 channels of 64 Kbps each. Each DS-0 can be allocated to carry any single service, such as CO trunk, DID trunk, WATS trunks, FX line, 56K data circuits

Unchannelized T-1 is where T-1 is utilized as a single 1.536 Mbps data circuit. Using this setup, the data circuit is also known as a “pipe”

Term

What is a femtocell and how does it operate?

Definition

A femtocell is a wireless access point that provides (or improves on) cellular reception inside a home or office building.  The device, which resembles a wireless router, essentially acts as a VoIP repeater. When connected to Internet broadband, it broadcasts the connection using radio waves

Term

What technology is sometimes referred to as layer 2.5 protocol?

Definition
Multiprotocol Label Switching (MPLS)
Term

What is the difference between in-band and out of band signaling?

Definition

In band signaling: all signaling to manage the calls occurs within the same circuit that will be used for the call itself.  Less efficient signaling technique.

Out of band signaling: the signaling required to manage calls (i.e. call setup, call teardown, etc.) occurs over a separate signaling path / line than the actual call.  More efficient signaling technique.

Term

In the classic PTSN switch hierarchy what was the second term used to refer to the end office?

Definition

A class 5 office

Term
What protocol is the foundation (underlies and supports) VoIP technology?
Definition

               Session Initiation Protocol (SIP)

Term

What is equal access?

Definition
The ability for customers to select their own long distance service providers, and the ability of any IXC (Long distance carrier) to serve these customers.
Term

What did the telecom act of 96 do?

Definition

Allowed long distances carriers (IXCs) to provide local phone service

Term

True or False:  Is a Numbering Plan Area (NPA) the same as an area code?

Definition
TRUE
Term

How does remote call forwarding work?

Definition

Example: Business in Chicago can advertise local phone number in New York. 

-Callers in New York dial a local New York phone number, they avoid long distance charges they otherwise would have paid to call to Chicago.

-Calls are automatically forwarded to the Chicago business when people call the New York phone number.

-The Chicago business pays for the long distance charges for calls forwarded from New York to Chicago

-May be cheaper than FX line.

-Used as a customer service tool

Term

Where are key (phone) systems most often used?

Definition

Small businesses use key systems most often

Term
Name 4 PBX features that are not on key systems
Definition

1. Private Dialing Plans

2. Automatic Route Selection

3. Voicemail

4. Automatic Call Distribution

5. Voice Response Unit (VRU)

6. Class-of-Service

7. Authentication Codes

Term

Name two advantage and disadvantages with cable tv service

Definition

Advantages

-Coaxial cable offers much greater bandwidth than copper pairs

-Cable is already installed to ~70% of U.S. homes

  Disadvantages

-Return signals are very noisy

-Not a great perception of reliability

Term

What are the 3 categories of cloud computing?

Definition

1. Infrastructure-as-a-Service (IaaS)

2. Platform-as-a-Service (PaaS)

3. Software-as-a-Service (SaaS)

Term
Define Cloud Computing
Definition
Cloud computing is a general term for anything that involves delivering hosted services over the Internet. The only thing the user's computer needs to be able to run is the cloud computing system's interface software, which can be as simple as a Web browser, and the cloud's network takes care of the rest.
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