Chapter 14: Remote Connectivity Flashcards
Modulation Techniques
The various multiplexing and demultiplexing technologies and protocols, both analog and digital.
Multiplexer
A device that merges information from multiple input channels to a single output channel.
Frequency Division Multiplexing (FDM)
A process of keeping individual phone calls separate by adding a different frequency multiplier to each phone call.
DS0
The digital signal rate created by converting analog sound into 8-bit chunks 8000 times a second, with a data stream of 64 Kbps. This is the simplest digital data stream.
How many wires are used for sending and how many are used for receiving in a T1 line?
2 for each
What is the connector on a T1 line?
RJ-48C
CSU/DSU
A piece of equipment that connects a T-carrier leased line from the telephone company to a customer’s equipment (such as a router).
DS1
- The signaling method used by T1 lines.
- Consists of 25 pieces: a framing bit and 24 channels (each like a single DS0 data channel)
- 1.544 Mbps throughput
Time Division Multiplexing (TDM)
The process of having frames that carry a bit of every channel in every frame sent at a regular interval in a T1 connection.
Fractional T1 Access
Only buying some of the channels on a T1 line
Channels and Speed of T1
24 channels
1.544 Mbps
Channels and Speed of T3
672 channels
44.736 Mbps
Channels and Speed of E1
32 channels
2.048 Mbps
Channels and Speed of E3
512 channels
34.368 Mbps
Synchronous Optical Network (SONET)
- The primary fiber carrier standard for connecting long distance, high speed, fiber-optic transmission systems.
- Defines interface standards at the Physical layer.
Optical Carrier (OC)
Specification used to denote the optical data carrying capacity of fiber-optic cables in networks conforming to the SONET standard.
Dense Wavelength Division Multiplexing (DWDM)
Allows an individual single mode fiber to carry multiple signals by giving each signal a different wavelength by using different colors of laser light.
Coarse Wavelength Division Multiplexing (CWDM)
Relies on multiple wavelengths of light to carry a fast signal over long distances, but can only realistically go 60km.
Synchronous Transport Signal (STS)
The signal method used by SONET, consisting of the STS payload and the STS overhead.
For some SONET optical carrier OC-X, what is the line speed?
X times 51.85 Mbps (for example, OC-3 has a line speed of 3 times 51.85 ~= 155.52)
X.25
- The first generation of packet-switching technology, enables remote devices to communicate with each other across high-speed digital links without the expense of individual leased lines.
- Also referred to as CCITT Packet Switching Protocol
Frame Relay
An efficient data transmission technique used to send digital info such as voice, data, LAN, and WAN traffic quickly and cost-efficiently to many destinations from one port
Asynchronous Transfer Mode (ATM)
- A packet switching technology that runs at speeds between 25 and 622 Mbps.
- Integrates voice, video, and data on one connection.
Multiprotocol Label Switching (MPLS)
A router feature that labels certain data to use a desired connection.
4 parts of a MPLS header
1) Label (what kind of data)
2) Cost of Service (CoS) (importance of the packet)
3) A single bit value set to 1
4) Time to Live (TTL)
Forwarding Equivalence Class (FEC)
A group of devices that tend to send their packets to the same place.
Label Switching Router (LSR)
Looks for and forwards packets based on their MPLS label
Label Edge Router (LER)
An MPLS router that adds MPLS labels to incoming packets that do not yet have a label.
Label Distribution Protocol (LDP)
The protocol used by LSRs and LERs to communicate dynamic info about their state.
Permanent Virtual Circuit (PVC)
Enables the creation of a logical connection on top of a physical connection between nodes that communicate frequently or continuously (Used for VPNs, basically a permanent VPN that your ISP sets up for you)
Bit Error Rate Test (BERT)
An end to end test that verifies a T-carrier connection
Dedicated Line
A telephone line that is an always connected circuit, and don’t usually have telephone numbers because of that.
Dial-up line
Telephone line with a telephone number
Public Switched Telephone Network (PSTN)
The most common type of phone connection, which takes your sounds, translated into an analog waveform by the microphone, and transmits them to another phone.
Local Exchange Carrier (LEC)
The telephone company that provides local connections.
Interexchange Carrier (IXC)
A company that provides long distance service.
Baud
One analog cycle on a telephone line.
Modem
- A device that converts both digital bit streams into analog signals and incoming analog signals back into digital signals.
- Most commonly used to connect telephone lines to computers
V standards
Standards established for modem manufacturers to follow to ensure compatible speeds, compression, and error connection.
Integrated Services Digital Network (ISDN)
The process of sending telephone transmission across fully digital lines end-to end.
B channels
Carry data and voice info using standard DS0 channels (64kbps)
D channels
Carry setup and config info at 16 kbps
Basic Rate Interface (BRI) setup
Two B channels and one D channel
Primary Rate Interface (PRI)
A full T1 line, carrying 23 B channels
Terminal Adapter (TA)
The most common interface used to connect a computer to an ISDN line.
Max Distance of ISDN
18,000 feet
Digital Subscriber Line (DSL)
A fully digital, dedicated connection over telephone lines.
Symmetric DSL (SDSL)
- Type of DSL connection that provides equal upload and download speed.
- In theory provides speeds up to 15 Mbps, but the majority actually range from 192 Kbps to 9 Mbps
Asymmetric DSL (ADSL)
- Provides theoretical max download speeds of 15 Mbps
- Upload speeds up to 1 Mbps
DSL Access Multiplexer (DSLAM)
A device located in a telephone company’s central office that connects multiple customers to the Internet.
3 information channels of a DSL line
1) High-speed downstream channel
2) Medium-speed duplex channel
3) POTS channel
POTS Filter
Makes sure only the POTS signals go down the POTS line in a DSL connection.
Point-to-Point Protocol over Ethernet (PPPoE)
- A protocol that was originally designed to encapsulate PPP frames into Ethernet frames.
- Used by DSL providers to force customers to log into their DSL connection.
Data Over Cable Service Interface Specification (DOCSIS)
The protocol used by cable modem networks
Cable modems have speeds between…
5-100 Mbps
One-Way Satellite Connection
You download via satellite but you must use a PSTN/dial-up modem connection for uploads.
Global System for Mobile (GSM)
- The first group of networking technologies widely applied to mobile devices.
- Uses Time Division Multiple Access (TDMA)
Evolved High-Speed Packet Access (HSPA+)
The final wireless 3G data standard, transferring theoretical max speeds up to 168 Mbps, but rarely passing 10 Mbps
Metropolitan Area Network (MAN)
Multiple computers connected within the same city.
A network available to all citizens of the city.
Long Term Evolution (LTE)
4G technology now dominating wireless service.
Up to 300 Mbps download, 75 Mbps upload
IEEE 802.16
-Wireless standard called WiMax with a range of up to 30 miles.
Hotspot
A device that connects via cellular and enables other devices to connect to the Internet.
Passive Optical Network (PON)
A fiber architecture that uses a single fiber to the neighborhood switch and the individual fiber runs to each final destination.
5 Things Dial-Up Requires
1) A modem
2) The phone number to dial (provided by ISP)
3) Username/Password (provided by the ISP)
4) Type of connection (PPP)
5) IP info (provided by ISP)
Private Dial-Up Connection
Connects a remote system to a private network, and does not use the Internet!
Remote Access Server (RAS)
The hardware and software of a remote access solution.
How decibels work
A solid signal is 0dB
When a signal degrades, a negative number
When a signal increases, a positive number
Remote Desktop Protocol (RDP)
A Microsoft-created remote terminal protocol.
Port 3389
VoIP
Using an IP network to transfer voice calls.
Real-time Transfer Protocol (RTP)
-Protocol that defines the type of packets used on the Internet to move voice or data from a server to clients. –Used by VoIP
Session Initiation Protocol (SIP) and H.323
- Protocols that handle initiation, setup, and delivery of VoIP sessions.
- SIP port 5060/5061
- H.323 port 1720
Real Time Streaming Protocol (RTSP)
- Runs on top of RTP and is used by many streaming video servers.
- TCP port 554
What to do if there is loss of Internet connectivity from the WAN
Your computer needs 1) A legit IP address 2) Subnet Mask 3) Default Gateway 4) DNS address Check them.
Before investigating the WAN…
Investigate the LAN