Remote Connectivity Flashcards
dedicated lines used before the Internet; specific, shielded, two-pair cabling in a T1 connection
T1 lines
defined grouping of individual phone circuits served by one multiplexor
local exchange
method for separating calls on a single cables; as calls come in, a multiplexor adds a certain frequency multiplier, keeping each call within its own frequency range
frequency division multiplexing (FDM)
name by the telecommunications industry for the connection between a central office and individual users
last mile
the simplest data stream, at a slow rate of 64 Kbps
DS0
the first copper, digital trunk carriers, which are still popular today
T-carriers
the most common and basic T-carrier; digital network technology
T1/T1 connection
box located at either (but not both) termination in a single T1 line, it has a second connection that goes from the phone company (its location) to a customer’s equipment (router)
Channel Service Unit/Digital Service Unit (CSU/DSU)
signaling method used in T1, it uses a primitive frame consisting of 25 pieces - a framing bit and 24 channels; each channel has a single 8-bit DS0 data sample, totalling 193 bits per frame; these are transmitted at 8000 times/sec, giving it a throughput of 1.544 Mbps (64 Kbps channels)
digital signal 1 (DS1)
process of having a frame carry a portion of each channel in every frame on a regular interval
time division multiplexing (TDM)
process of selling only some individual channels in a T1 bundle by phone companies - due to being expensive and obsolete
fractional T1 access
dedicated line consisting of 672 DS0 channels, totalling 45 Mbps; mainly used by regional phone companies and ISPs
T3/DS3 line
European version of T1 line, it carries signals at 2.048 Mbps (32 64 Kbps channels)
E1 line
European version of T3 line, it carries 16 E1 lines for a total bandwidth of 34 Mbps
E3 line
protocol of which a derivative is used by E1 and SONET as the control channel
High-Level Data Link Control (HDLC)
international fiber optic standard in the US used by all primary carriers, improving international connectivity; used for long-distance, high-speed, fiber-optic transmission
Synchronous Optical Network (SONET)
the European equivalent for SONET
Synchronous Digital Hierarchy (SDH)
standards denoting fiber optic data-carrying capacity in bps, conforming to SONET standard; speeds are escalating, ranging from 51.8 Mbps (XX-1) to 39.8 Gbps (XX-768)
Optical Carrier (OC)
process that increases the throughput of a fiber line by allowing a cable to carry multiple signals; signals are given a different wavelength; not as many signals as the other
wavelength division multiplexing (WDM)
process that increases the throughput of a fiber line by allowing a cable to carry multiple signals; signals are given a different wavelength; this one can support ~150 signals, so an OC-1 line has a througput of 7.6 Gbps; limited at 60 km
dense wavelength division multiplexing (DWDM)
simpler than DWDM, it is not as limited in its distance; used in higher-end LANs with 10GBase-LX4 networks; has lower cost
course wavelength division multiplexing (CWDM)
signal method used by SONET; a number is added to the end of “XXX” to designate its speed, like OC-1
Synchronous Transport Signal (STS)
first gen of packet switch tech, it enabled remote devices to communicate using high speed digital links without the expense of leased lines
X.25/CCITT Packet Switching Protocol
any machine that forwards and stores packets using any packet-switching protocol
packet switches
dead packet switching protocol that uses frames rather than packets; it was used primarily for T-carrier lines, worked well for off and on traffic, was efficient, and switched frames quickly, though it was succeptible to losing data
Frame Relay
dead packet switching technology designed for high-speed LANs in early 90s; it integrated voice, video, and data on one connection using cells due to being able to handle delay and signal loss; transfer speeds ranged from 155.52 to 622.08+ Mbps
Asunchronous Transfer Mode (ATM)
replacement technology for Frame Relay and ATM that adds a label the layer 2 header and Layer 3 info
Multiprotocol Label Switching (MPLS)
a set of packets that can be sent to the same place (Ex. Single broadcast domain of computers)
Forwarding Equivalence Class (FEC)
an MPLS router, it looks for MPLS packets and forwards the packets based on their MPLS labels
Label switching router (LSR)
an MPLS router that adds MPLS label to incoming packets and removes them from outgoing packets
Label edge router (LER)
protocol used by LSR’s and LER’s to communicate dynamic info about their state
Label Distribution Protocol (LDP)
feature of MPLS for establishing an VPN; an ISP using MPLS sets up a connection to your network and leases it to you; they give you/you plug in an RJ-45 plug into the office switch
permanent virtual circuit (PVC)
most important test an end user will make on a telephony line; it verifies the T-carrier connection from end to end
Bit Error Rate Test (BERT)
the oldest and slowest original phone connection; this dial-up network uses the same phone lines used to make calls; end users need a modem to convert analog signals to digital
public switched telephone network (PSTN)/plain old telephone service (POTS)
an individual cycle in an analog signal
baud
number of bauds per second, with PSTN lines limited to 2400
baud rate
device in a modem that convert a 8-bit wide (parallel) digital data and converts it into 1-bit wide (serial) digital data; vise versa
Universal Asynchronous Receiver/Transmitter (UART)
standards for modems defining the speeds at which modems can modulate as well as how they compress data and perform error checking
V standards
high-capacity line that connects a central office switch to long-distance carriers; usually T1
trunk line (PSTN)
dial-up phone service that sends data across fully digital lines, including in the last mile; need to be within 18,000 feet of a central office to use
Integrated Services Digital Network (ISDN)
ISDN channel that carries voice and data information using standard DS0 channels (64 Kbps); most ISDN providers choose either one or two of these
Bearer (B) channels
ISDN channel that carries setup and configuration information at 16 Kbps
Delta (D) channels
the most common ISDN setup, consisting of 2 B channels and 1 D channel; uses only one physical line, and throughput is 128 Kbps
Basic Rate Interface (BRI)
ISDN setup consisting of 23 B channels and 1 D channel, basically a full T1 line
Primary Rate Interface (PRI)
the most common ISDN physical interface for one’s computer, resembling a modem; they can even function as hubs for direct LAN connections; to use, to must configure the ISDN phone number to call and the SPID
terminal adapter (TA)
special number provided by your telephone company for use in ISDN TA setup
Service Profile ID (SPID)
a fully digital, dedicated line provided by phone companies without the need to dial a phone number, though it uses the same lines and RJ-11 jacks; limited to 18,000 feet from central office
digital subscriber line (DSL)
DSL that provides equal download and upload speeds, about 15 Mbps (though majority range from 192 Kbps to 9 Mbps); more expensive than ADSL
symmetric DSL (SDSL)
DSL that provides unequal download and upload speeds, providing theoretical download speeds up to 15 Mbps and upload speeds up to 1 Mbps (real world: 384 Kbps to 15 Mbps download, 128-768 Kbps upload); less expensive than SDSL
asymmetric DSL (ADSL)
AT&T (and others) offering of DSL that can provide upload and downloads speeds in excess of 100 Mbps, though only at short distances (~300 meters); typical speeds are 8-16 Mbps download and 1-2 Mbps upload
very-high-bit-rate DSL (VDSL)
unique protocol used by a cable company’s network
Data Over Cable Service Interface Specification (DOCSIS)
fiber architecture where a single fiber cable runs to a neighborhood switch, and then from there individual fiber cables run to each destination; used to make rollouts more affordable; uses WDM to send multiple signals down the same cable
passive optical network (PON)
server that accept incoming calls and handles password authentication in a private dial-up connection; client connects to it using a connection tool; must have at least one modem; has separate permissions for dial-up and local users
remote access server (RAS)
service that runs on an RAS with Windows; dedicated to handling remote users who are not directly connected to a LAN but need access to file and print services
Routing and Remote Access Service (RRAS)
a unit describing a ration between an ideal/reference point and the current state of a signal; the quality of a signal
decibel (dB)
Citrix Corporation products for terminal emulation, the first popular ones
WinFrame/MetaFrame
standard for remote access via terminal emulation created by Citrix; defines how terminal info is passed between client and server; it was so powerful that Microsoft licensed the code and created its own product called Windows Terminal Services
Independent Computing Architecture (ICA)
bedrock of VoIP standards, defines the type of packets used on the Internet to move voice or data from server to client; most solutions are either SIP/RTP or H.323/RTP
Real-time Transport Protocol (RTP)
VoIP standard that handles the initiation , setup, and delivery of VoIP sessions and multicasting; uses TCP ports 5060 and 5061
Session Initiation Protocol (SIP)
VoIP standard that handles the initiation , setup, and delivery of VoIP sessions and multicasting; uses TCP port 1720
H.323
VoIP solution that does not use RTP; incompatible with other VoIP solutions; uses peer-to-peer topology and a proprietary encryption method
Skype
protocol for streaming video that runs on top of RTP; uses on TCP port 554
Real-Time Streaming Protocol (RTSP)
capability that enables out-of-band management to address issues with in-band management - remote systems must be fully booted to OS and not as much security or control
lights-out-management (LOM) capability
DNS server that redirects your browser to an advertisement when an incorrect URL is entered
DNS helper
