Chapter 16 - Supplement - Sheet1 Flashcards
Main way WAN differs from LAN
Generally own LAN infrastructure, lease WAN infrastructure
PSTN
Public Switched Telephone Network
Which layers of the OSI model to WAN protocols and technologies occupy?
Physical, Data Lihnk, sometimes network
CPE
Customer premises equipment. Equipment that’s owned by the service provided by located on teh subscriber’s property
Local Loop
Pair of copper wires connecting the demarc to the closest switching office, called the CO
CO
Central Office. AKA POP (Point of Presence). Phone company building that connects the customer’s network to the provider’s switching network.
Toll Network
Trunk line inside a WAN provider’s network. Collection of switches and facilities owned by the ISP
WAN Connection Types
Dedicated (Leased) Lines, Circuit Switching, Packet Switching
Dedicated (Leased) Lines
AKA Point-to-point or dedicated connections. These lines are direct and always open, reserved for the customer to use
Circuit Switching
uses the phone system - ISDN or Dial-up
Packet Switching
Packet switching involves breaking messages into chunks at the sending device.
Each packet can be sent over any number of routes on its way to its destination. The packets
are then reassembled in the correct order at the receiver.
T1 Line
Basic, first level in bandwidth or speed for leased, synchronous connections between sites (WAN). Serves up to 24 Digital Signal 0 (DS0) 64Kbps Channels. Digital connection typically over 2 copper wire pairs
Countries that use T1
US, Japan (Uses J1 - same tech and speeds), South Korea
European version of T1 and speed.
E1 or E Carrier Line. Serves 30 DS0 Channels – Slightly faster than T1 at 2.048Mbps
What bit patterns does T1 use to transmit packets
DS1 (Digital Signal 1)
Max speed of T1C
3.152Mbps
Max speed of T1
1.544Mbps
Max speed of T2
6.312Mbps
Max speed of T3, digital signal level, number of T1 circuits
44.736Mbps, DS3, 28 T1 circuits
Max speed of T4
274.176Mbps
Attenuation
Weakening of a signal as it travels
Standard for Synchronous Data Transmission on optical fiber
SONET. Synchronous Optical Network
International Equivalent of SONET
SDH - Synchronous Digital Hierarchy
SONET throughput (base data rate)
51.84Mbps
Optical Carrier Level
Multiples of SONET. OC-1, OC-2, etc
OC-1 data rate
51.84Mbps
OC-3 data rate
155.52Mbps
OC-12 data rate
622.08Mbps
OC-48 data rate
2.488Gbps
OC-192 data rate
9.953Gbps
WDM
Wavelength Division Multiplexing (WDM) is a technology that multiplexes several optical
carriers on a single optical fiber by using different wavelengths. Remember, fiber-optic signals
are light, so using different wavelengths of the light spectrum is somewhat like using different
frequencies in a radio wave.
Microwave radio relay
technology for transmitting digital and sometimes even analog
signals between two locations on a line-of-sight radio path through the atmosphere
Differences between DSL and Cable
Speed, security (each has different vulnerabilities), popularity, customer satisfaction
HDSL
High bit-rate digital subscriber line. HDSL was the first DSL technology to use
a higher-frequency spectrum of copper twisted-pair cables. HDSL was developed in the
United States as a better technology for high-speed, synchronous circuits
Types of xDSL
HDSL, SDSL, VDSL, ADSL
SDSL
Symmetric (same rate in both directions) digital subscriber line (SDSL) provides T1/E1 type speeds symmetrically for both uploading and downloading data but doesn’t allow low-frequency phone calls on the same line
VDSL
VDSL, or very high bitrate DSL
(VHDSL), provides faster data transmission over single, flat, untwisted or twisted pairs of
copper wires. This capacity for blazingly fast speeds mean that VDSL is capable of supporting
high-bandwidth applications like HDTV and telephone services like the popular Voice
over IP (VoIP) as well as general Internet access over a single connection. VDSL is deployed
over existing wiring used for POTS and lower-speed DSL connections
ADSL
Asymmetric (meaning different upload and
download speeds) DSL has become the most popular xDSL because it focuses on providing
reasonably fast upstream transmission speeds (768 Kbps) and very fast downstream transmission
speeds (up to 9 Mbps, although usually slower). works on a single phone line without losing voice
call capability
Headend
This is where all cable signals are received, processed, and formatted. The signals
are then transmitted over the distribution network from the headend
Distribution Network
These are relatively small service areas that usually range in size from
100 to 2,000 customers. They’re typically composed of a mixed, fiber-coaxial, or hybrid
fiber-coaxial (HFC) architecture
DOCSIS
Data over cable service interface specification (DOCSIS) This specification provides the
interface requirements for a data over cable system, including that of high-speed data transfer
to an existing cable TV system. All cable modems and similar devices have to measure
up to this standard.
1G
Voice-only analog network. Wireless WAN technology.
2G
Wireless WAN technology. Digital voice and simple data (text)
3G
Wireless WAN technology.. High-speed voice and data, internet
4G
Wireless WAN technology. Goal is to provide data rates far beyond 3G.
Two varients of 4G
LTE, WiMAX
HSPA+
Evolved High Speed Packet Access (HSPA+) is really considered a 3.5 generation technology. 3-4mbps down, 1-2mbps up
WiMAX
World Wide Interoperability for Microwave Access (WiMax) is considered a true 4G technology.
It is based on the IEEE 802.16 standard. It supports fixed (tower to tower) and mobile
applications. 5-6mbps down, 2-3mbps up
LTE
Long Term Evolution (LTE) is the most promising of the emerging 4G technologies. Compatible with 3G and WiMAX. Best indoor coverage. 7-12mbps down, 3-5 up
Frame Relay
Frame Relay is a WAN technology in which variable-length packets are transmitted by
switching.
Access rate
The maximum speed at which the Frame Relay interface can transmit.
Committed information rate (CIR)
The maximum bandwidth of data guaranteed to be
delivered. In reality, it’s the average amount that the service provider will allow you to
transmit, based on what you purchased.
ATM
Asynchronous Transfer Mode
What is the greatest advantage of PSTN (POTS)?
It’s readily available
Which technology uses the term HFC?
Cable. Hybrid Fiber Coaxial is a telecommunication industry term for a network that incorporates botht optical fiber and coaxial cable to create a broadband network
You have one serial port on your router but need to connect many remote sites. What
WAN protocol could you consider as an option?
Frame Relay.
What is the maximum speed for T1?
1.55Mbps
What does the acronym DSL stand for?
Digital Subscriber Line
Which WAN technologies are considered packet-switching networks?
Frame Relay and X.25
Which cellular technologies are considered 4G?
LTE and WiMAX
Which WAN technology is considered a cell-switching network?
ATM
What are the different flavors of xDSL?
HDSL, SDSL, VDSL, ADSL
What is another name for PON?
Fiber to the Premises