Chapter 14 - Remote Connectivity Flashcards
Define SONET/SDH
Primary standard for connecting long distance high-speed fiber-optic transmission systems
Ring-Based topology
Package DS1, DS3, and E1 signals into huge frames
Synchronous Optical Netowork (North America)
Synchronous Digital Hierarchy (Euro)
Originally designed to handle heavy duty circuits
What was a switch board used for
Two wires created a physical circuit between two phones
Define Multiplexer
Combined a circuit with a few hundred other circuits into a single circuit
Define Demultiplexer
Splitting the individual connections back out
Define Modulation Techniques
Technically means converting a digital signal to analog or pushing analog to a higher frequency
What was a local exchange
A defined grouping of individual phone circuits severed by a single multiplexer by adding a certain frequency to a call. Connections between exchanges were carried over special multiplexed trunk
Define Frequency division multiplexing
Adding a certain freqency multiplier to each call to keep calls separate when passing through a multiplexer
What is the ‘last mile’
The connection from a central office to individual users
Define Modulator
A digital signal is converted into a analog signal
Define Demodulator
Converts an analog signal to a digital signal
What is another name for a modem
Modulator-Demodulator
Give an example explaining how digital signal rate is converted
A sound is split into 8-bit chunks 8000 times a second creates a datastream of 64 Kbps
What speed is DS0
64 Kbps
What is a T1 line
shielded two pair cabling connecting two T1 connections. Two wires are for sending data, two for receiving. The jack they use is RJ48C
What is a CSU/DSU
At the end of a T1 line is a box that connects a consumer location to a provider.
What speed is DS1
25 pieces, 24- channels and 1 framing bit.
1 channel = 8- bit DS0
= 193 bits per DS1 frame @ 8000/s
= 1.544 Mbps
Define Time division multiplexing
the process of having frames that carry a portion of every channel in every frame sent on a regular interval.
Define Fractional T1 access
Providers will sell individual channels to consumers
What speed does a T3 line run at and how many channels does it have
672 DS0 Channels @ 45 Mbps
Define E1 line
E-carrier is a european format\
32 channels @ 2.048 Mbps
Define E3 line
16 E1 (512 Channels) lines @ 34 Mbps
Define Optical Carrier
OC standards denote the optical data carrying capacity of fiber-optic cables in networks
OC-1 = 51.8 Mbps
OC-768 = 39.9 Gbps
Define Dense Wavelength Division
enables an individual single mode fiber to carry multiple signals by applying different wavelengths to signals
What two forms of packet switching does WAN use
Frame Relay and ATM
Define Frame Relay
designed for and used primarily with T carrier lines. Works well for off and on traffic. Discards frames when there is network congestion
Define ATM
Asynchronous Transfer Mode integrated voice video and data on one connection using short and fix-length frames (cells)
Speeds ranged 155.52 to 622.08 Mbps
Define MPLS
Multiprotocol Label Switching consists of four parts
- Label - unique identifier
- Cost - relative value to determine importance of packet
- S - used to increment lables (may be multiple labels
- TTL determines the number of hops it can make before being eliminated
MPLS Routers talk to each other about overhead
Ideal for end user VPNs
What does a MPLS header look like
Label | CoS | S | TTL
Define Forwarding Equivalence Class
FEC is a group of devices that tend to send packets to the same place
Define Label Switching Router
LSR looks for and forwards packets based on their MPLS label
Define Label Edge Router
LER is an MPLS router that has the job of adding MPLS labels to incoming packets that do not yet have a label. This is the entrance and exit for a MPLS network.
Define Label Distribution Protocol
LSRs and LERs used LDP to communicate dynamic information about their state
Define Bit Error Rate Test
BERT verifies the T-carrier connection from end to end
What are solutions for the ‘last mile’
Dial up DSL Broadband Satellite Cellular WAN Fiber BPL
What is a dedicated line
lines that are always off the hook. This creates a permenant hard-wired connection between the two locations
What is a dial up line
have phone numbers that must be dialed in order to make a connection
What is Public Switched Telephone Network
PSTN is a regular phone line the same line that used to run into everybody’s home telephone jacks to the LEC.
Baud rate of 2400
Define LEC
Local Exchange Office
Define IXC
Interexchange Carrier provides long distance service
Define Baud
When a telephone microphone converts the sounds into electrical waveforms that cycle 2400 times/s, the 2400 is the baud rate, one cycle is 1 baud
How does a PC connect over telephone lines
PCs need one device that converts 8-bit wide digital signal into a serial digital data and another device to convert the data into analog waveforms
What is a Universal Asynchronous Receiver/Transmitter
UART takes the 8-bit wide digital data and hands it to the modem for conversion
What are the common speeds for V standards
Define the speed at which a modem can modulate V.22 = 1200 bps V.22bis = 2400 bps V.32 = 9600 bps V.32bis = 14400 bps V.34 = 28,000 bps V.90 = 57, 600 bps V.92 = 57, 600 bps (upstream faster than V.90)
What are the standars for how modems compress data and perform error checking
V.42 Error checking
V.42bis Data Compression
V.44 data compression
MNP5 Both error checking and data compression
What is ISDN
Integrated Service Digital Network is the process of sending telephone transmissions across fully digital lines end to end
What are the two channels for ISDN
Bearer channels - carry data and voice info using DS0
Delta Channels - carry setup and configuration info
What is Basic Rate Interface Setup
Used two B channels and one D channels, uses only one line, and doubles the throughput to 128 kbps.
What is PRI
T1 line carrying 23 B channels
What is a terminal adapter
A modem for a ISDN network that also functions as a hub to support a direct LAN connection
What is a Service Profile ID
SPID is a special number used in a ISDN telephone.
What is DSL
Digital subscriber line manifests as just another PSTN connection using the same telephone lines and RJ11 jacks. Need to be within 18,000 meters of a switch
- Symmetric DSL
- Asymmetric DSL
- Very High Bit Rate DSL (VDSL) (AT&T), 100 Mbps, 300 meter max
What speeds does SDSL come in
192 Kbps to 1.5 Mbps
What speeds does ADSL come in
Upload: 128 Kbps to 768 Kbps
Download: 384 Kbps to 15 Mbps
What three information channels does DSL use
High-speed downstream channel
medium - speed duplex channel
POTS channel
What is a DSLAM
DSL Access Multiplexer allow multiple connections are once.
What cable and protocol do cable modems use
Coax Cable using Data over cable service interface specification (DOCSIS)
Broadband standard
What are the 6 common Cellular technologies
GSM/EDGE CDMA HSPA+ WiMAX LTE
Define GSM
Global System for Mobile reilied on type of time division multiplexing called TDMA (Time Division Multiple Access)
Current version is Enhanced Data Rates for GSM Evolution uses speeds up to 384 Kbps
Define CDMA
Code Division Multiple Access uses a spread spectrum form of transmission (changes the frequencies used by each user).
Define HSPA+
High Speed Packet Access provides theoretical speeds of 168 Mbps rarely passed 10 Mbps.
Define WiMAX
Speeds 30 Mbps to 1 Gbps
Provided the idea of rolling out wifi to entire cities.
Define LTE
Long Term Evolution
300 Mbps download, 75 Mbps upload
Coexist data and voice
Define WDM (Wavelength Division Multiplexing)
technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This technique enables bidirectional communications over one strand of fiber, as well as multiplication of capacity.
Define Passive Optical Network (PON)
Architecture that uses a single fiber to the neighborhood switch and then individual fiber runs to each final destination. WDM is allows multiple signals on one line and then passively splits it at the switch.
What is PLC
Power line communications encompasses everything from voice to high speed internet access by using the electrical power lines.
Example: Broadband over Power Lines (BPL)
What are the six common forms of remote access
Dial-Up to Internet Private dial-up Virtual Private Network Dedicated Connection Remote Terminal VoIP
What is required to start a dial up connection
Modem Telephone Number User name and password Type of connection (almost always PPP) IP info (usually just DHCP)
What is required for a private dial up connection
Requires two systems, one acts as a remote access server and the other, client, uses a connection tool.
What authentication methods does a RAS server use
PAP, CHAP, EAP… and so on (standard authentication methods
Define dedicated connection
connections that are never disconnected.
- connection between two locations
- connection to the internet
Explain the split cable problem
Every time a cable is split the signal degrades by half
RDP uses what port
Port 3389
What are the three important standards for VoIP
RTP - Real-time transport protocol
SIP - Session Initiation Protocol
H.323 - related to SIP
What is RTP used for
defines the type of packets used on the internet to move voice or data from a server to clients.
What is SIP/H.323 used for
Handle the initiaition, setup, and delivery of VoIP sessions and both run on top of RTP.
SIP = Port 5060 & 5061
H.323 = Port 1720
What is RSTP
Real Time Streaming Protocol runs on top of RTP and has a numbmer of feature that favor video streaming
Port 554
