1. Public Switched System

2. Telecom Infrastructure Edge Connection –Terminal Equipment Phone Fax Modem DSL –Subscriber Loop Core Switching –Central office –Switching hierarchy –Circuit switching –Packet switching –Metro Area Network Long Haul Transmission –Coax and microwave links –Fiber optics Telephone Industry – The Economics Side of the Story http://elsa.berkeley.edu/~woroch/dance.pdf

3. Phone Electrical –Parts Carbon microphone, electromagnet speaker, bell, dial –Signaling DC AC: 300-3400 Hz Electronic –Dial tone and push button –DTMF http://en.wikipedia.org/wiki/DTMF http://en.wikipedia.org/wiki/DTMF

4. Analog Signaling Two Wires, Full Duplex –Ring, tip –Hybrid circuit, –Protection circuit http://www.epanorama.net/circui ts/teleinterface.htmlhttp://www.epanorama.net/circui ts/teleinterface.html On hook –DC: 48V –Ringing: 80V, 20 Hz Off hook –DC: 23-80 mA, 5-10V –Dial tone: 350+440 Hz –Pulse or tone dialing –Ring tone 440+480Hz, or line busy 480+620 Hz –Connection Indication of line status by tones! http://www.telephonetribute.com/signal_ and_circuit_conditions.htm

5. Subscriber Loop Twisted Wires –22-26 gauge –Frequency dependent loss –Loading –Splice and repeater –A tourA tour –http://www.epanorama.net/links/telephone. htmlhttp://www.epanorama.net/links/telephone. html DSL –www.iol.unh.edu/services/testing/dsl/training/ADS L_Tutorial.pdfwww.iol.unh.edu/services/testing/dsl/training/ADS L_Tutorial.pdf

6. Central Office Digitization Switching –http://www.dmine.com/phworld/network/http://www.dmine.com/phworld/network/ Multiplexing Inter Office Trunk Line Long Haul

7. Hierarchy Pre-Divestiture Local Exchange Carrier –LATA Interexchange Carrier –Long distance Common Channel Signaling (SS7) 585 http://www.pt.com/tutorials/ss7/

8. Digital Signaling Bandpass –4 kHz band limited filtering Digitization –8 kHz sampling –256 A-law companding –8-bit resolution –64 kb/s DS0 Time Division Multiplexing –x24 lines of 8 bits+1 bit; 1.544 Mb/s DS1 –DS2, 3; OC1, 3, 12, 48, 192, 768

9. Switching Space Switch –Historical electromechanical switch –Electronic switch http://en.wikipedia.org/wiki/List_of_telephone_switches

10. Switching Time Switch –Tim Slot Swapping Memory

11. Switching TMS Switch Switching Fabric –Contention –Queuing –Resource optimization http://www.ecs.umass.edu/ece/wolf/courses/ECE697J/slides/EC E697J-03-10-02.pdf http://www.cs.bham.ac.uk/~gkt/Teaching/SEM335/Queenie/prog ram/BatcherBanyanApplet.html

12. Circuit Switching Pre-Arranged Switches to Establish a Path –Fixed bandwidth –Low variance in delay –Set up overhead –Idle time

13. Data Flow Chart circuit establishment DATA data transmission circuit termination

14. Packet Switching Datagram –Multiple Routes to Send Demo –http://www.pbs.org/opb/nerds2.0.1/geek_glossary/packet_ switching_flash.htmlhttp://www.pbs.org/opb/nerds2.0.1/geek_glossary/packet_ switching_flash.html Flexible, efficient Variable delay, congestion Buffer, sequencing Virtual Circuit –Set up; data always in sequence Systems –ATM, Frame Relay, X.25 HeaderData Trailer

15. ISDN Digital Telephony With Voice and Data B Channel –Service at 64 kbs D Channel –Control at 16 kbs Speed –Basic: 144 kbs –Primary: 1.536 Mbps –B-ISDN: H channels Introduction to ISDN –http://www.ralphb.net/ISDN/index.htmlhttp://www.ralphb.net/ISDN/index.html

16. Frame Relay Characteristics –Resource sharing using packet switching –Dynamic bandwidth allocation supporting bursty data –Low latency, high throughput –WAN Protocol –Synchronization Flag Field –Destination Address Data link connection identifier – virtual connection –Flow Control Forward explicit congestion notification Backward explicit congestion notification Discard eligibility –Information Field Up to 16 kB –Error Handling Frame check sequence http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/frame.pdf http://www.mfaforum.org/frame/tutorials/40142.shtml

17. ATM Characteristics –Asynchronous –Efficient –Near real time response –Support multiple services Protocol –Header: 5 B Generic Flow Control Virtual Path Identifier Virtual Channel Identifier Payload Type Identifier Cell Loss Priority Header Error Control –Payload: 48 B http://www.uniforum.chi.il.us/slides/atmintro/ATM101.ppt.gz

18. Voice Over Digital Networks Digital Traffic >> Voice Traffic Voice Support by Digital Networks Conversion –Digitization –Compression Prioritization Fragmentation Other Issues –Jitter –Silence suppression –Echo cancellation Voice Over IP –http://www.solwise.co.uk/voiceoverip_intro.htmhttp://www.solwise.co.uk/voiceoverip_intro.htm Voice Over ATM, IP, and Frame Relay –http://www.protocols.com/papers/voe.htmhttp://www.protocols.com/papers/voe.htm

19. SONET or SDH Transport Synchronous Scalable –Fiber friendly http://www.cse.wustl.edu/~jain/cis777-99/ftp/g_9snt/sld001.htm

20. STS-1 Overhead and Payload Transport http://www.tek.com/Measurement/App_Notes/SONET/2RW_11407_2.pdf

21. Characteristics of SONET Synchronization –Accurate timing, no bit stuffing Data Compatibility –Direct mux or demux System Compatibility –Vendor, data rate Service Compatibility –ATM, IP, video, etc. Networking Capable

22. More on SONET Introduction –http://people.deas.harvard.edu/~jones/cscie129/nu_lectures/lecture12/son et/sonet.htmlhttp://people.deas.harvard.edu/~jones/cscie129/nu_lectures/lecture12/son et/sonet.html Chips –http://www.lightreading.com/document.asp?doc_id=56058http://www.lightreading.com/document.asp?doc_id=56058 Future –http://www.fujitsu.com/downloads/TEL/fnc/whitepapers/futureofsonet- wp.pdfhttp://www.fujitsu.com/downloads/TEL/fnc/whitepapers/futureofsonet- wp.pdf –http://img.lightreading.com/heavyreading/pdf/hr20031114_esum.pdfhttp://img.lightreading.com/heavyreading/pdf/hr20031114_esum.pdf