1. Homework n Final Exam Wednesday, 3 May, 5:30-7:20 pm n Readings: [26] “Cable It’s not just for TV” [27] “Battling for Local Phone Customers” [28] “IP/ATM Integrated Services over Broadband Access Copper Technologies”

2. Video... n n Uncompressed NTSC video requires about 90 Mbps n n Broadcast Quality compressed video requires 45 Mbps n n ‘VHS Quality’ compressed video requires 1.5 Mbps n n The OSU Teleconferencing system is running at 384 Kbps

3. MPEG 1 n n Compression of motion video & audio at about 1.5 Mbps n n Targeted at digital playback & storage n n Has Random Access capabilities n n Employs Motion Estimation Algorithms, Discrete Cosine Transforms, & Huffman Coding n n Codes frames as Intrapictures, Predicted Pictures, and Bidirectional Pictures n n Standard since 1992

4. MPEG 2 n n Targets higher quality compression, typically at 3-6 Mbps bit rates n n Being used for Direct Broadcast TV n n Large chunks of MPEG2 used in U.S. HDTV standard n n Standard since 1994

5. MPEG 4 n n Aimed at Multimedia Coding n n Bit rates from 8 Kbps - 35 Mbps n n Codes objects as opposed to 8x8 blocks u u Ability to interact & manipulate objects n n Standard in 1999

6. MPEG 7 n Ability to describe and search for multi- media objects (under development) u Audio clips u video images MP3 n Web audio clips n Uses audio compression from MPEG 1 u 12-1 typical compression ratio

7. H.261 (a.k.a. Px64) n n Subset of MPEG n n Targets real time videoconferencing n n Bit rates from 64 Kbps to 2.048 Mbps u u 64 Kbps - 128 Kbps: Face shot (video phone) u u 384 Kbps: considered to be minimum speed for decent full screen videoconferencing n n H.263 is a modified H.261 Offers better quality Requires more processing power

8. Channel Capacity (C) n C = W*Log 2 (1 + SNR) bps u W = channel bandwidth (Hz) u SNR = channel signal-to-noise ratio n Maximum bit rate that can be reliably shoved down a connection n EX) Analog Modem (30 dB SNR) C = 3500 *Log 2 (1 + 1000) = 34,885 bps n EX) 6 MHz TV RF Channel (42 dB SNR) C = 6,000,000 *Log 2 (1 + 15,849) = 83.71 Mbps

9. Local Loop Capacity about 34.8 Kbps due to filter at input of CO A/D converter Phone CO Fiber Optic Trunk Copper Local Loop Copper Local Loop 4 Wire 2 Wire ‘4 Wire’ Analog Digital TDM 64 Kbps

10. 56 Kbps Modem requires Digital Source Server Phone CO Fiber Optic Trunk Copper Local Loop Copper Local Loop 4 Wire 4 or 2 Wire 2 Wire‘4 Wire’ Analog Digital (ISDN, xDSL, etc.)

11. Delivery: Over the Air 300 m Analog FDM Digital by 2006 (FCC edict) 50-60 miles

12. Video Delivery Systems n n Satellite Older systems analog u u 1 channel per 6 MHZ of RF bandwidth Newer Systems digital u u MPEG2 & TDM allow 4-6 channels per 6 MHz of RF bandwidth n n Cable TV Distribution systems originally all coax Fiber deployed from Head End side moving out

13. Who will be your one-stop telecom provider? n n Cable TV Companies? Physical Tree with Large Bandwidth Simplex & No Switching Fair/Poor quality cable plant n n Solution: Cable Modems Re-engineer system for 2-way traffic Shared Access Install data switches at Head End Install voice switches at Head End

14. PC to ISP Connectivity: Cable Headend Voice Switch Cable TV Network Home Ethernet NIC ISP Router To Internet Cable Modem will use shared bandwidth to get to Cable TV Headend. Voice network Mux Voice Data PC Cable Modem Data Voice Video

15. Who will be your one-stop telecom provider? n n Local Telephone Companies? Physical Star with Narrow Bandwidth Full Duplex & Switched Good quality cable plant n n Solution: Digital Subscriber Lines Switched Access Install data switches at CO Install video switches at CO

16. Home PC to ISP Connectivity CO Voice Switch Local Loop Home Modem ISP Modem Bank To Internet This configuration causes call blocking problems at some CO switches due to longer than designed-for call holding times. Voice network PC

17. PC to ISP Connectivity: DSL CO Voice Switch Local Loop (Voice & Data) Home ADSL Modem ISP Router To Internet ADSL will off load data traffic from CO voice switches, & provide more CO-Home bandwidth. Voice network DSLAM Voice Data PC Splitter Data Voice

18. Who will be your one-stop telecom provider? n n The Typical Telco can get xDSL running on existing twisted pair cable plant with less re- engineering than the typical Cable Company requires to get Cable Modems running on existing coax/fiber networks. n n But Cable network has more bandwidth n n Whoever gets to market first, with a cost- effective solution, will be in the driver’s seat. n n Advantage ???