1
Q
SONET
A
Synchronous Optical Network
- WAN interconnections
- vast majority of long-distance connections that make up the internet
- most of the big long-distance optical pipes for the world are SONET rings
- defines interface standards at the Physical and Data Link Layers
2
Q
multiplexer
A
- takes a circuit and combines it with a number of other circuits into one complex circuit
- requires demultiplexer on the other end
3
Q
modulation techiques
A
converting a digital signal to analog, or pushing an analog signal to a higher frequency
4
Q
FDM
A
Frequency Division Multiplexing
- keeping each individiual signal in its own unique frequency range
5
Q
Can digital or analog travel farther?
A
Digital, because you can use repeaters
6
Q
T-carriers
A
digital trunk carriers used by the telephone industry
7
Q
T1
A
T-carrier Level 1
- T1 connection - the technology
- T1 line - the specific wire
- ends with RJ-48C
- uses signaling method DS1 (digital signal 1)
- no addressing necessary
- 24 channels 1.544 Mbps
8
Q
CSU/DSU
A
Channel Service Unit / Digital Service Unit
- at end of T1 line
- point-to-point, can only have 1 at each end
- has atleast 2 connections, one to demarc, other to router
- CSU - protects from lightning strikes, stores statistics, and has loopback function for testing
- DSU - supplies timing to each user port, converts signals, encapsualtes frames
9
Q
Connect 2 CSU/DSU boxes together
A
T1 Crossover Cable
10
Q
TDM
A
Time Domain Multiplexing
- process of having frames that carry a portion of every channel in every frame sent on a regular interval
11
Q
DS0
A
each 64-kbps channel in a DS1 signal
12
Q
Fractional T1 Access
A
purchasing individual T1 channels
13
Q
T3
A
- 672 channels, 44.736 Mbps
- sometimes called DS3
- mainly used by regional phone companies and ISPs
14
Q
E1
A
E-carrier Level 1
- European format for digial transmissions
- 32 channels, 2.048 Mbps
15
Q
E3
A
- 512 channels , 34.368 Mbps
16
Q
HDLC
A
High level Data Link Control
- E1 and Sonnet use a derivative protocol as the control channel
17
Q
OC standards
A
Optical Carrier Standards
- denote the optical data-carrying capacity in bps of fiber-optic cables in SONET networks
- speeds from 51.8 Mbps (OC-1)
- to 39.8 Gpbs (OC-678)
- can use WDM ro DWDM
18
Q
WDM
A
Wavelength Division Multiplexing
19
Q
DWDM
A
Dense Wavelength Division Multiplexing
- can create about 150 different signals
20
Q
CWDM
A
Coarse Wavelength Division Multiplexing
- lower cost
21
Q
STS Signal Method
A
Synchronous Transport Signal
- used by Sonet
- STS payload - data
- STS Overhead - signal and protocol information
- STS number will match OC number… ex OC-24 is STS-24
22
Q
First packet-switching technology
A
X.25 or CCITT packet switching protocol
- enabled remote devices to communicate with each other across high-speed digital links without the expense of individual leased lines
23
Q
packet switches
A
any machines that forwads and stoers packets using any type of packet-switching protocol
24
Q
Frame Relay
A
- efficient packet-switching standard
- designed for use primarily with T-Carrier lines
- works espeically well for off-again/on-again traffic typical of most LAN applications
- works at layers 1 & 2 using frames rather than packets
- switches frames quickly, but without any guarantee of data integrity
- will discard frames if there is network congestion
- replaced by MPLS
25
ATM
Asynchronous Transfer Mode
- network technology designed for high-speed LANs
- integrated voice, video and data on one connection using short and fixed-length frames called cells (53 bytes)
- speeds from 155.52 to 622.08 Mbps
26
MPLS
Multiprotocol Label Switching
- replacement for Frame Relay and ATM
- adds an MPLS label that sits between the layer 2 header and the layer 3 information
- avoids running IP packets through their full routing tables and instead use the header information to route packets quickly
- MPLS routers use existing dynamic routing protocols to send each other messages about their overhead, enabling QoS to span an entire group of routers
27
MPLS header
label - unique identifier
exp - experimental bits - relative value used to determine the importance of the labeled packet for prioritization
S - Bottom of Label Stack - a single packet may have multiple MPLS labels, this single bit value is set to 1 for the first initial label
TTL - Time to Live - value that determines the number of hops the label can make before it's eliminated
28
FEC
Forwarding Equivalence Class - a set of packets that can be sent to the same place, sunch as a single broadcast domain of computers connected to a router
29
LSR
Label Switching Router - looks for and forwards packets based on their MPLS label
30
LER
Label Edge Router - MPLS router that adds MPLS labels to incoming packets that do not yet have a label, and strips labels off of outgoing packets
31
LDP
LSRs and LERs use LDP to communicate dynamic information about their state
32
PVC
Permanent Virtual Circuit
| - VPN sold by ISPs
33
Packet-switching vs circuit-switching
new networks use packet-switching, old networks use circuit switching
34
Two reasons to use telephony WAN
get LAN on internet
| make a private connection between two or more LANs
35
BERT
Bit Error Rate Test
| - verifies the T-carrier connection from end to end
36
City-wide Network
MAN (metropolitan area network)
37
Last Mile Technologies
```
Dial-up
DSL
Broadband Cable
Satellite
Fiber
```
38
Dial up lines
Dedicated lines - always off the hook, no phone number
| Dial-up lines - have phone numbers
39
PTSN
Public Switched Telephone Network
40
POTS
Plain Old Telephone Service
| - 2400 baud rate
41
LEC
Local Exchange Carrier - telco
42
IXC
Interexchange Carrier - long distance telco
43
Baud Rate
the number of bauds per second
44
UART
Universal Asynchronous Receiver/Transmitter
- takes 8-bit-wide digital signal and converts it to 1-bit-wide digital data and hands it to the modem for conversion to analog
- does reverse for incoming data
45
ISDN
Integrated Services Digital Network
- process of sending telephone transmission across fully digital lines end-to-end
- must be within 18,000 ft
46
ISDN channels
```
Bearer channels (B) - carry voice and data using standard DS0 channels at 64 kbps
Delta Channels (D) - carry setup and configuration information at 16 kbps
- typical setup is 2 B and 1 D for 128 kbps
```
47
ISDN PRI
Primary Rate Interface
| - just a full T1 line, carrying 23 B channels
48
DSL
- fully digital, dedicated connection
- no phone number
- DSL modem considered demarc
49
SDSL
Symmetric DSL
| - speeds up to 15 mbps
50
ADSL
Asymmetric DSL
| - different upload/download speeds
51
SDLAM
DSL Access Multiplier
| - connects multiple customers to the internet
52
PPPoE
Point-to-Point Protocol Over Ethernet
- originally designed to encapsulate PPP frames into ethernet frames
- made DSL users use a username/password
53
DOCSIS
Data Over Cable Service Interface Specification
- protocol used by cable modems
- current specification is 3.1
54
Two types of Satellite internet
One-way - download satellite, upload on dial-up
| Two-way - satellite downloads and uploads
55
PON
Passive Optical Network
- architechture that uses a single fiber run to a neighborhood switch, then individual fibers to each final destination
- uses WDM to enable multiple signals to travel on the same fiber then splits them at the switch
56
Remote access
uses WAN and LAN connections to enable a computer to log onto a network from another location
57
six most common forms of remote access
```
dial-up
private dialup
VPN
Dedicated Connection
Remote Terminal
VoIP
```
58
Private Dial-up
- Uses phones to connect two systems, not the internet
- One system acts as an RAS (remote access server)
- client runs connection tool
- In windows, RAS is RRAS (routing and remote access service)
59
VPN
Virtual Private Network
| - allow you to connect rhough a tunnel from a local computer to a remote network securely
60
Dedicated Connections
- remote connection that are never disconnected
- two types: private and to the internet
- expensive, but provide high bandwidth and high security
61
Remote Terminal
- a connection to a faraway computer that enables you to control that computer as if you were sitting in front of it
- require server and client
- microsoft uses RDP on 3389
62
RTP
Real-time Transport Protocol
| - defines the types of packets used on the internet to move voice or data from server to clients
63
SIP and H.323
Session Initiation Protocol and H.323
- handle the initiation, setup and delivery of VoIP standards
- SIP uses ports TCP 5060 and 5061
- H.323 uses ports 1720
- both have methods for handling mutlicasting
64
Skype
- doesn't use clients or servers, uses P2P
| - encrypted using proprietary encryption
65
RTSP
Real-time Steaming Protocol
- for streaming video, has features for running, pausing, and stoping videos
- runs on TCP 554
66
in-band management
software installed on both the client and remote system enables direct control over resources
67
DNS helper
some ISPs have DNS servers that redirect your browser to advertising when you type in an incorrect URL
68
What is the signal rate for DS0
64 Kbps
69
V.90 standard defines a modem speed of
56 kbps
70
What is SONET used for?
long-distance, high-speed, fiber-optic transmission
CompTIA - Network+
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