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ECEN5553 Telecom Systems Dr. George ScheetsWeek #5 Read [7c] "How can the Internet have too many routes and not enough addresses?" [8a] "The Cognitive Net is Coming" [8b] "The Internet of Things" [9a] "Browse at your Own Risk" [9b] "The Data Brokers: Selling Your Personal Information" [10a] "Internet QoS: Pieces of the Puzzle" [10b] "Innovation on the Web Lives and Dies with Net Neutrality" Exam #1 Lecture 16, 24 September (Live) No later than 1 October (Remote DL) Outline 8 October 2014, Lecture 22 (Live) No later than 15 October (Remote DL)
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Outlines Received due 8 October (local) 15 October (remote) 22 %
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Exam #1 (90 points) Exam #1 (90 points) n Friday, 24 September (Local) Remote Distant Learners, no later than 1 October n Work 3 of 4 pages n Closed Book & Notes n Calculators & phones are NOT allowed...Set up numerical problem for full credit n Most equations are provided (on 5th page) n Approximately 40% of upcoming exam will be lifted from the Fall 2013 Exam #1 n Anything in the notes, on Power Point, or in reading assignments is fair game
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On Short Answer or Essay Questions n Answer the Question! n Memory Dump in the space provided u Knowledgeable individual can write more u Grader will look for "Power Point bullets" u Same remarks as instructor's typically not required n To get "A" or "B", instructor needs to walk away with impression you could've said more u Got space? Anything else pertinent to add? u It is NOT necessary to write small or fill up allotted space to get a good score! u Lost points? No comments? → Insufficient info provided u Rule of Thumb: "X" point question needs > "X" facts
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The Internet n VAST collection of interconnected networks n Key Building Block: Routers running IP (Layer 3) n Router link speeds range up to 100 Gbps n Hierarchical Alpha-Numeric Names username@machine.institution.domain
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AT&T 1997 Internet Backbone
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UUNET 1998 Internet Backbone
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Washington D.C. Area - 2000
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OSU 2009 Internet Connectivity
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Traceroute to WWW.CISCO.COM n 4 Internal OSU-Stillwater routers n 3 OneNet routers (all in OKC? Tulsa?) n 2 Qwest routers dal-edge-18.inet.qwest.net n 2 NTT routers ae-19.r08.dllstx09.us.bb.gin.ntt.net n Akamai Technologies (Hosting Service) n (12:55 pm, 11Sept14, rtt = 9 msec, 11 routers)
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Traceroute to WWW.TULSA.COM n 4 Internal OSU-Stillwater routers n 3 OneNet routers (Tulsa?) n 5 Cogent Communications routers u te4-4.1052.ccr01.tul01.atlas.cogentco.com u be2128.ccr21.den01.atlas.cogentco.com u be2126.ccr21.slc01.atlas.cogentco.com n 2 Ace Data Center routers (Hosting Service) u ve15.ar05.prov.acedc.net n End server (198.57.177.235) probably in Provo, Utah area n (1:20 pm, 11Sept14, rtt = 60 msec, 14 routers)
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ISP Routes Sometimes Roundabout Launched 13 September 2014, 2 miles from OSU campus n n 1 Scheets' home router n n 4 AT&T routers u u adsl-70-233-159-254.dsl.okcyok.sbcglobal.net u u ggr3.dlstx.ip.att.net n n 4 Cogent Communications routers u u Be2032.ccr22.dfw01.atlat.cogentco.com u u te0-0-2-1.rcr12.okc01.atlas.cogentco.com n n 3 ONENET routers u u OKC? n 3 Oklahoma State routers n (12:30 pm, 11Sept14, rtt = 84 msec, 15 routers)
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Fall 2007 Weird TraceRoute Seen by Student Tulsa to OSU Stillwater n Tracert launched from Tulsa, hit Atlanta Washington, D.C. Illinois Kansas City Tulsa Oklahoma City OSU Stillwater
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Internet Service Provider Backbone Switched Network, full duplex trunks. Access lines attach to corporate routers & routers of other ISP's. Router Trunks Access Line
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OSU Backbone Access lines attach to Ethernet switches, Onenet and other routers. Router Trunks Access Line
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ISO OSI Seven Layer Model n Layer 7 Application n Layer 6 Presentation Windows API n Layer 5 Session Windows TCP n Layer 4 Transport Windows TCP n Layer 3 Network Windows IP n Layer 2 Data Link PC NIC n Layer 1 Physical PC NIC
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Internet Protocal v4 (20 Bytes) TOS TTL Source Address Destination Address 4 Bytes
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Microsoft's Tracert
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802.3 Ethernet Packet Format MAC Destination Address MAC Source Address CRCData + Padding Bytes: 7 1 6 6 2 20 20 6-1460 4 IPv4TCP
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IPv4 Header n Contains two addresses u 4B Source Address u 4B Destination Address u 4B = 32b = 4.295 G potential addresses n Example address u 10001011 01001110 01000010 11010011 n Dotted Decimal Format simplifies u x.x.x.x u Treat each byte as Base2 number, write in Base10 u Above number simplifies to 139.78.66.211
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IP Header n Alpha-numeric name simplifies further u es302.ceat.okstate.edu u Domain Name Servers convert to numerical n All OSU Stillwater addresses are of form u 139.78.0.0 to 139.78.255.255 n IP addresses & alpha-numeric names are effectively backwards u 139.78.66.211 mapped to es302.ceat.okstate.edu
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IP vs Ethernet Addresses IP vs Ethernet Addresses nEnEnEnEthernet has a flat address space uSuSuSuSimilar to Social Security Number FAFAFAFAdjacent #'s nearby or on other side of globe? uHuHuHuHuge look up tables required to avoid flooding FNFNFNFNeed 70.37 trillion entries nInInInIP has a hierarchical address space uPuPuPuPacket delivery similar to Mail delivery FAFAFAFAdjacent IP addresses frequently nearby uRuRuRuReduces size of look up tables FDFDFDFDon't need 4.295 billion entries
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ISP Router Overload Source: 1 October 2007 Network World Fall 2011 Level3 BGP entries 375,550 IPv4 7,210 IPv6 Peak Traffic 8.0 Tbps IPv4 500 Mbps IPv6
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ISP Router Overload n Core BGP entries as of 19 August 2014 u IPv4 about 520,400 u IPv6 about 18,300 n 2nd week of August u Caused some problems u Some routers had 512,000 entry limit source: bgp.potaroo.net Network World, 13Aug2014, "Internet outages expected to abate as routers are modified, rebooted"
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TCP Header Source PortDestination Port Sequence Number ACK Number Window Checksum 4 Bytes
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Wireshark Packet Capture n This interaction starts with a click on a Firefox bookmark to a distance calculator. Firefox then triggers a query to an OSU Domain Name Server asking for the IPv4 address of www.indo.com. This is next followed by a TCP 3 way handshake to open logical connections, an HTTP request to download the distance calculator page, and the beginning of the file transfer.
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ISO OSI Seven Layer Model n Layer 7 Application n Layer 6 Presentation Windows API n Layer 5 Session Windows TCP n Layer 4 Transport Windows TCP n Layer 3 Network Windows IP n Layer 2 Data Link PC NIC n Layer 1 Physical PC NIC MSS = 1460 B = Size of Layer 6 & 7 info per packet Ethernet Payload = 1500 B
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TCP Window Size (Layer 4) Effects End-to-End Throughput n Suppose u Window Size (set by PC) = 64 KB F Microsoft Windows XP u Maximum Segment Size = 1 KB u Server can send < 64 unACK'd packets Server PC 3,000 Km
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Throughput on 64 Kbps Line Server PC 3,000 Km, 64 Kbps line n NPD = Prop Delay / Packet inject time u Prop Delay = distance / EM energy speed = 3,000,000 m / 200,000,000 m/sec = 0.015 seconds u Packet inject time = 8,376 bits / 64 Kbits/sec = 0.1309 seconds (7B PPP, 20B IPv4, 20B TCP) u NPD = 0.015 / 0.1309 = 0.1146 u Front end of packet arrives at far side prior to back end being transmitted. Packet #1
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Throughput on 64 Kbps Line Server PC 3,000 Km, 64 Kbps line n At this instant in time... u 2nd unACK'd packet is being transmitted u ACK for #1 enroute back to server F TCP+IP+Layer 2 → 47 bytes if PPP u When ACK#1 arrives at server, only packet #2 is unacknowledged. n Will 64 packet unACK'd limit be reached? u No. At most, 1 packet likely unACK'd. Packet #2 #1 #1 ACK
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Throughput on 45 Mbps Line Server PC 3,000 Km, 45 Mbps line n NPD = Prop Delay / Packet inject time u Prop Delay = distance / EM energy speed = 3,000,000 m / 200,000,000 m/sec = 0.015 seconds u Packet inject time = 8,376 bits / 45 Mbits/sec = 186.1 μseconds (PPP, IPv4, TCP overhead) u NPD = 0.015 / 0.0001861 = 80.60 u 80.60 average sized packets will fit back-to-back on this line #1#2#3
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Throughput on 45 Mbps Line Server PC 3,000 Km, 45 Mbps line n At this instant in time, the Server... u Has transmitted 64 packets w/o ACK. u Has hit window limit. Halts. Packets 1 - 64
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Throughput on 45 Mbps Line Server PC 3,000 Km, 45 Mbps line n At this instant in time, u The PC has processed 1st packet & sent an ACK u The Server is still halted, waiting for ACK #1. F When ACK #1 arrives, server can then transmit one additional packet. F Other ACK’s arrive fast enough to allow back-to- back transmission of next group of 64 packets Packets 2 - 64 #1 ACK#1
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Can Estimate Throughput with a Time Line time t o = 0 n t o : Leading edge of 1st packet injected n t 1 : Trailing edge of 64th packet injected u t 1 = (64*1047B)(8b/B)/(45 Mb/sec) = 11.91 msec n t 2 : Leading edge of 1st packet hits far side u 15 msec (propagation delay) u If ACK injected right away... n t 3 :...ACK arrives at server at t = 30 msec n Process Repeats... t1t1 t2t2 t3t3
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Can Estimate Throughput with a Time Line time (msec) t o = 0 n This system can transmit u 64(1,047) = 67,008 B = 536,064 bits u Every 30 msec (one round trip time) u Estimated throughput = 536,064/0.03 = 17.89 Mbps n Actual throughput a bit lower u 1st ACK not transmitted until packet #1 fully received... F... and processed by PC u 65th packet not transmitted until ACK #1 fully received... F... and processed by Server 11.9115.0030.00
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Can Estimate Throughput with a Time Line time (msec) t o = 0 n Need to be able to fill the pipe for 1 RTT u 30 msec in our example u 45 Mbps *.030 sec = 1.35 M b = 168,750 B = 168,750/1,047 = 161.2 packets u Window Size needs to be = 161.2 segments*1,000 bytes/segment = 161,200 B n Actually would need another segment or two to cover source & sink processing 11.9115.0030.00
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TCP Header Source PortDestination Port Sequence Number ACK Number Window Checksum 4 Bytes
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UDP Header (8 Bytes) Source PortDestination Port Checksum 4 Bytes For interactive real-time traffic, usually used with Real Time Transport Protocol (12 bytes).
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Virtual Circuits n Routing decisions made once when circuit is set up u Concerned switches have internal Look-Up tables updated n All packets part of info transfer follow the same path n Allows option of setting aside switch resources (buffer space, bandwidth) for specific traffic flows n MPLS, Frame Relay, ATM, & Carrier Ethernet use VC’s
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Datagrams n IP uses Datagrams n Routing Tables updated independently of individual traffic flows u Routers continuously talking with each other u Packets may follow different paths n Routers get no advance warning of specific packet flows.
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IP is Connectionless Data + Padding 20 20 up to 1,460 IPTCP I/O decisions based on IP address & look-up table. Tables updated independent of traffic, hence path thru network may suddenly change. TCP is connection oriented.
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TCP, UDP, and IP n 30+ year old Protocols Designed for data One Priority & “Best Effort” services No QoS Guarantees Available bandwidth depends on other users n TCP (Layer 4 & 5) provides reliable transfer n UDP (Layer 4 & 5) unreliable transfer n IP at Layer 3 n Arbitrary Protocols at Layers 1 & 2
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Internet Traffic 2008 - 2009 Comparison source: http://www.sandvine.coms
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Fixed Access Internet Traffic Profile Source: www.sandvine.com/downloads/documents/Phenomena_2H_2012/ Sandvine_Global_Internet_Phenomena_Snapshot_2H_2012_NA_Fixed.pdf & www.sandvine.com/downloads/general/global-internet-phenomena/2014/1h-2014-global-internet-phenomena-report.pdf 2013
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2012 Mobile Access Internet Traffic Profile http://www.sandvine.com/downloads/documents/Phenomena_2H_2012/ Sandvine_Global_Internet_Phenomena_Snapshot_2H_2012_NA_Mobile.pdf
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2013 Mobile Access Internet Traffic Profile source: www.sandvine.com/downloads/general/global-internet-phenomena/2014/1h-2014-global-internet-phenomena-report.pdf
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Internet Traffic Growth source: "The Road to 100G Deployment", IEEE Communications Magazine, March 2010
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Internet Traffic Growth source: www.cisco.com/c/en/us/solutions/collateral/service-provider/visual-networking-index-vni/VNI_Hyperconnectivity_WP.html
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Combining the Figures
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VoIP PC to PC Internet Phone to Internet Phone Commodity Internet
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VoIP PC to Wired Phone Internet Phone to Wired Phone Commodity Internet Gateway Phone System
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VoIP (Wired Phone-to-Wired Phone) Carrier prioritizes VoIP traffic (DiffServ) Paths nailed down (MPLS) Gateways control # of voice calls Good Quality Possible with this configuration "QoS Enabled" Internet Gateway Phone System Gateway Phone System
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Traditional Videoconferencing Camera Codec 384 Kbps fixed rate output (video + audio) Codec Audio Video Dedicated Bandwidth Network: Circuit Switched TDM 6 Bytes @ 8000 times/sec *State Owned Fiber *ISDN
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2002 Non-Traditional Videoconferencing Camera Codec 384 Kbps fixed rate output (video + audio) Now > 784 Kbps Codec Audio Video Packet Switched StatMuxed Prioritized *State Owned Fiber This is technique being used in this class for video to & from Tulsa & Stillwater.
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Internet Video Streaming PC Disk Drive The Internet Quality of Received Stream depends on: (1) Size of your pipe. (2) Internet congestion. (3) Server congestion.
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Internet Video Streaming Stillwater Video Server generates packets. Fairly steady generation if server not swamped. Rate depends on pipe size. Disk Drive
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Internet Video Streaming Disk Drive Internet Video Server Packets exit at an irregular rate. Random delays. Non-Dedicated Bandwidth (Packet Switched, Stat Muxing)
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ISP Routes can be Roundabout Launched 30 January 2007, 2 miles from OSU campus n n 1 Dr. Scheets' home router n n 6 SBC routers u u adsl-70-233-191-254.dsl.okcyok.sbcglobal.net u u ex2-p11-0.eqchil.sbcglobal.net n n 7 Level3 routers u u Te-3-2.Chicago1.Level3.net u u kscymo2wcx010-pos9-0-oc48.wcg.net u u tulsok6wcx2-pos11-0-oc48.wcg.net n n 5 ONENET routers u u at least 1 in Oklahoma City n 3 Oklahoma State routers Using DiffServe, End-to-End performance on this 22 router path...
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ISP Routes can be Roundabout Launched 5 September 2008, 2 miles from OSU campus n n 1 Scheets' home router n n 4 SBC routers u u adsl-70-233-191-254.dsl.okcyok.sbcglobal.net u u bb1-g1-0-2.rcfril.sbcglobal.net n n 1 Equinix router n n 1 Transitrail router u u onenet.chcgil01.transitrail.net n n 3 ONENET routers u u at least 1 in Oklahoma City n 4 Oklahoma State routers n rtt = 55 msec...may be worse than End-to-End performance on this 14 router path when not using DiffServ.
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LAN Internet Service Provider Network Router Trunks Leased Line PC Corporate sites using Internet as WAN. Can pay ISP extra $$ → Traffic between sites gets preferential treatment.
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Interactive VOICE & VIDEO over the commodity INTERNET (Best Effort, No Priorities) n Is not ready for Prime Time n Delay & Quality problems difficult to solve under the current system... n...although throwing Bandwidth at the problem will alleviate n Has a place for the user whose main concern is $$$$ or convenience
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LAN Internet Service Provider Network Routers operate at Layers 1-3. PC’s operate at Layers 1-7. Routers do not monitor opening of TCP Logical Connections. RSVP would change this. Router Trunks Leased Line PC
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Multi-Protocol Label Switching n Enables Virtual Circuits u End-to-End Paths nailed down u Traffic Engineering Easier u Resource Reservation Easier n Seeing fairly widespread ISP deployment
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Internet QoS n Most every ISP is installing or testing one or more of following... u DiffServ u MPLS u Resource Reservation capability u Pricing structure to reflect different QoS... but they are not yet widely deployed. n As a result, currently the Commodity Internet remains mostly u Best Effort, FIFO Routing
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Thinking of moving large amounts of high quality, time sensitive traffic over the Commodity Internet? Check back in 2-3 years when... n Priorities Enabled (IPv6 and/or DiffServ) n Resources Guaranteed (Resource Reservation Protocol (RSVP) or equivalent is deployed) n Flat rate pricing is gone
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The Internet Is... A superb information source Sometimes difficult to separate wheat from chaff IEEE Communications or Proceedings Peer Reviewed IEEE Spectrum Reviewed by editor Jane Doe's Web site Reviewed by Jane Doe A good marketing tool
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The Internet Is... a Security Nightmare Any-to-Any connectivity is both strength and weakness Tracert yields Router IP Addresses Could Telnet or HTTP to many. Password? Espionage Read “The Cuckoo’s Egg” by Cliff Stoll Former #1 on New York Times Best Seller Recommended by Dr. Scheets’ Mom
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