Chapter 14: Remote Connectivity Flashcards
Describe SONET.
Makes up vast majority of long distance connections.
What is a local exchange?
-defined grouping of individual phone circuits served by a single multiplexer.
What is a central office:
handles one or more exchanges
What is the last mile?
connection from central office to individual users.
Describe DS0.
- digital signal rate
- 64 Kbps
What is a T-carrier?
- digital trunk carrier.
- T1: high speed digital networking technology.
- line is shielded two-pair cabling that connects to ends of a T-1. Two send, two receive.
- CSU/DSU: Channel service unit/digital service unit.
Describe DS1.
- digital signal one: special signaling.
- frame consists of 25 pieces; framing bit and 24 channels.
- channel: single 8 bit DS0 data sample. 193 bits per DS1 frame
- frame transmitted 8,000 ties per second for a throughput of 1.544 Mbps.
- TDM.
Describe fractional t1 access.
where you just but some of the channels.
Describe a t3
data rate of 45Mbps on dedicated telephone connection.
-672 individual DS0 channels. mainly used by regional telephone companies and ISPs.
Describe an E1.
- similar to T1
- 2.048 Mbps(32 channels at 64 Kbps)
Describe an E3.
16 E1 lines. 34 Mbps
What does a CSU/DSU perform?
-performs line encoding and conditioning functions.
What is the function of a CSU?
- protects t1/T3 line from lightening stikes and other electrical interference.
- stores statisticas and capabilities for loopback testing.
What is the function of a DSU?
- supplies timing to each user port.
- converts user’s data signal and converts to specificed line code and framing format for transmission.
Describe a T1.
24 channels, 1.544 Mbps
Describe a T3,
672 channels, 44.736 Mbps
Describe an E1.
32 channels 2.048 Mbps
Describe an E3 line.
512 channels 34.368 Mbps
What does SONET stand for?
Synchronous Optical Network (US)
What does SDH stand for?
Synchronous Digital Hierarchy(europe)
What does SONET do?
Defines inteface standard at physical and data link layers
-important standard for making WAN interconnections.
What are OC standards?
Optical Carrier Standards.
- denote optical data-carrying capacity in bps of fiber optic cables.
- OC speeds from 51.8Mbps(OC-1) to 39.8 Gbps(OC-768).
What is WDM?
Wavelength division multiplexing.
- newer version is Dense WDM
- can support approximately 150 signals. 7.7 gigabytes
What is STS?
Synchronous Transport Signals.
- STS payload: data
- STS overhead: signaling and protocol info.
