MP3 / MM740 Strategy & Information Systems Module 3: Internet & Telecom Basics Fall 2001 How the Net Works Key Technologies IP Telephony Solving the Last Mile Problem Mobile & Wireless

What is the Internet? A Network of Networks –TCP/IP - standard protocol for routing & transport A medium of exchanging all form of digital data –text, graphics, audio, video, programs, faxes An infrastructure for various services – (electronic mail) –WWW (world wide web) –FTP (file transfer protocol) –UseNet newsgroups –Games, EDI, etc.

Transmission Speeds Bandwidth –measure of transmission speed / capacity Bits & Bytes –bit - smallest form of computer memory - 1 or 0 –byte - 8 bits, roughly 1 character (Latin alphabet) How do we measure speeds? –bps - bits per second –Kbps - kilobit, thousands of bits per second –Mbps - megabit, millions of bits per second –Gbps - gigabit, billions of bits per second

Anatomy of a URL URL –Uniform Resource Locator (web address) application protocol (http is assumed by current browsers). Others: FTP, NNTP host computer BC: agora, www) domain name, top level domain user ID directoryfile case sensitive

The DNS & IP Addresses IP Address –Unique number identifying Internet computers. Expressed as four numbers between 0 and 255. –ex: infoeagle.bc.edu = (32 bit address) –IPv6: 128 bit addressing, more efficient/faster, secure DNS - Domain Name Service –A distributed database used to translate domain names, into Internet Protocol (IP) Addresses. Registry of an Internet domain name: –for com, net, org, over 60 firms (see icann.org for list) –for country-specific domains (.jp,.uk,.tv) fees vary widely (see icann.org for list)

Network Interconnections dial-in users (56.6 Kbps) dorm users class/office users dorm LANoffice LANmodem pool web server www2.bc.edu BC Campus Network Backbone ( 10 Mbps) (IP #s xxx.xxx domain) Internet Leased Line through RCN ( 45 Mbps / T3) The Internet local ISP microsoft.com whitehouse.gov wireless

TCP/IP TCP/IP - the Internet’s common language TCP - Transmission Control Protocol. Breaks up transmissions ( messages, web pages, etc.) into packets of no more than about 1500 characters each, checks the integrity of incoming packets, and reassembles packets on the other end IP - Internet Protocol. Routes packets.

Packet Traffic What’s in a packet? –source address –destination address –error checking (checksum) –time to live –options (timestamp, record route, etc.) –your data!

A Packet Switched Network at Work message: Prof. Gallaugher, I just wanted to let you know that I got a job based on the stuff I learned in your class... packet1 packet2 packet3 message: Prof. Gallaugher, I just wanted to let you know... packet2 packet1 packet3 packet1 packet2 packet3 packet2 packet3 R R R R R R= router

US Internet Infrastructure Source: Watch Cable & Wireless’s backbone traffic at: traffic.cwusa.com

TraceRoute from BC to Hawaii 1 cs7513-honolulu.aloha.net ( ) ms ms ms ( ) ms ms ms 3 sl-gw4-sea-5-0-T3.sprintlink.net ( ) ms ms ms 4 sl-bb1-sea-0-0.sprintlink.net ( ) ms ms ms 5 core2-hssi3-0.Seattle.mci.net ( ) ms ms ms 6 bordercore1.Boston.mci.net ( ) ms ms ms 7 boston-college.Boston.mci.net ( ) ms ms ms 8 Infoeagle.bc.edu ( ) ms ms ms

1 be102 ( ) 2 ms 1 ms 1 ms 2 at-gw3-alb-1-0-T3.nysernet.net ( ) 2 ms 3 ms 2 ms 3 at-gw2-alb-0-0.nysernet.net ( ) 2 ms 3 ms 3 ms 4 at-gw1-syr-1-0-T3.nysernet.net ( ) 6 ms 4 ms 4 ms 5 at-gw1-ith-0-0-T3.nysernet.net ( ) 7 ms 7 ms 7 ms 6 at-gw2-ith-0-0.nysernet.net ( ) 7 ms 7 ms 7 ms 7 at-bb1-pen T3.nysernet.net ( ) 20 ms 20 ms 20 ms 8 sl-bb6-pen sprintlink.net ( ) 21 ms 23 ms 20 ms 9 core4-hssi5-0.WestOrange.mci.net ( ) 25 ms 26 ms 25 ms 10 bordercore1.Boston.mci.net ( ) 317 ms 54 ms 110 ms 11 boston-college.Boston.mci.net ( ) 36 ms 37 ms 36 ms 12 Infoeagle.bc.edu ( ) 36 ms 37 ms 36 ms TraceRoute from BC to Albany, NY

TCP vs. UDP TCP - perfect transmission is critical (e.g. ) TCP will request packets that are lost or damaged The Internet UDP - low latency is critical (e.g. RealAudio, Video, packet streaming) Latency matters - UDP will ignore packets that don’t arrive on time or in good shape The Internet UDP = User Datagram Protocol

Circuit vs. IP Telephony Circuit Switching Internet Telephony (e.g. Net2Phone) IP Telephony over Private Networks (e.g. Qwest) Guaranteed QoS (quality of service) packets over the Internet, variable QoS packets over private network, improved QoS The Internet Private IP Network

POP Goes the Modem POP = point of presence An access point to the Internet VoIP Gateways PC (Dialpad) Appliances (Applio) POP (Credit Cards)

87% Decline in International DS-3 Pricing over the past two years Source: BandXChange

67% Decline in Domestic DS-3 Pricing over the past two years Source: BandXChange

Transmission Speeds The last mile problem –access to many consumers & businesses may be slow (e.g. 56 Kbps modem speeds) The contenders –Cable Modems (e.g. AT&T, Mbps download) –DSL (e.g. Verizon, 384 Kbps-1.5 Mbps download) –Fixed Wireless LMDS (e.g. WinStar, 500 Kbps download) MMDS (e.g. Sprint, 2 Mbps download) –GEO Satellite (e.g. DirecDuo, 400 Kbps download; Starband, 500 Kbps download)

Satellite Schemes GEO –Spaceway from Hughes (2003, 2-6 Mbps) LEO –Teledesic (2005, 2 to 64 Mbps) Graphic from Byte

Fostering Speed & Ubiquity Edge networks –get content closer to customers –e.g. Akamai, iBeam Optical Advances –DWDM, Optical routing/switching Wireless Access –WAP, i-mode, emerging 3G standards Integration of Devices –Bluetooth, b

i-Mode’s Rocket Ride

Mobile Contrasts Europe poor technology “walled gardens” enormous capital outlays Japan packet-switched, always on, HTML standards open platform 3G licenses offered for free via “beauty contests”