1 / 68

Outlines Received due 8 October (local) 15 October (remote)

brina
Download Presentation

Outlines Received due 8 October (local) 15 October (remote)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ECEN5553 Telecom SystemsDr. George Scheets Week #5Read[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)

  2. OutlinesReceiveddue 8 October (local)15 October (remote) 22 %

  3. Exam #1 (90 points) • Friday, 24 September (Local)Remote Distant Learners, no later than 1 October • Work 3 of 4 pages • Closed Book & Notes • Calculators & phones are NOT allowed...Set up numerical problem for full credit • Most equations are provided (on 5th page) • Approximately 40% of upcoming exam will be lifted from the Fall 2013 Exam #1 • Anything in the notes, on Power Point, or in reading assignments is fair game

  4. On Short Answer or Essay Questions • Answer the Question! • Memory Dump in the space provided • Knowledgeable individual can write more • Grader will look for "Power Point bullets" • Same remarks as instructor's typically not required • To get "A" or "B", instructor needs to walk away with impression you could've said more • Got space? Anything else pertinent to add? • It is NOT necessary to write small or fill up allotted space to get a good score! • Lost points? No comments? → Insufficient info provided • Rule of Thumb: "X" point question needs > "X" facts

  5. The Internet • VAST collection of interconnected networks • Key Building Block:Routers running IP (Layer 3) • Router link speeds range up to 100 Gbps • Hierarchical Alpha-Numeric Namesusername@machine.institution.domain

  6. AT&T 1997 Internet Backbone

  7. UUNET 1998 Internet Backbone

  8. Washington D.C. Area - 2000

  9. OSU 2009 Internet Connectivity

  10. Traceroute to WWW.CISCO.COM • 4 Internal OSU-Stillwater routers • 3OneNet routers (all in OKC? Tulsa?) • 2 Qwest routersdal-edge-18.inet.qwest.net • 2 NTT routersae-19.r08.dllstx09.us.bb.gin.ntt.net • Akamai Technologies (Hosting Service) • (12:55 pm, 11Sept14, rtt = 9 msec, 11 routers)

  11. Traceroute to WWW.TULSA.COM • 4 Internal OSU-Stillwater routers • 3OneNet routers (Tulsa?) • 5 Cogent Communications routers • te4-4.1052.ccr01.tul01.atlas.cogentco.com • be2128.ccr21.den01.atlas.cogentco.com • be2126.ccr21.slc01.atlas.cogentco.com • 2 Ace Data Center routers (Hosting Service) • ve15.ar05.prov.acedc.net • End server (198.57.177.235) probably in Provo, Utah area • (1:20 pm, 11Sept14, rtt = 60 msec, 14 routers)

  12. ISP Routes Sometimes Roundabout Launched 13 September 2014, 2 miles from OSU campus • 1 Scheets' home router • 4 AT&T routers • adsl-70-233-159-254.dsl.okcyok.sbcglobal.net • ggr3.dlstx.ip.att.net • 4 Cogent Communications routers • Be2032.ccr22.dfw01.atlat.cogentco.com • te0-0-2-1.rcr12.okc01.atlas.cogentco.com • 3 ONENET routers • OKC? • 3 Oklahoma State routers • (12:30 pm, 11Sept14, rtt= 84 msec, 15 routers)

  13. Fall 2007 Weird TraceRoute Seen by StudentTulsa to OSU Stillwater • Tracert launched from Tulsa, hitAtlantaWashington, D.C.IllinoisKansas CityTulsaOklahoma CityOSU Stillwater

  14. Internet Service Provider Backbone Trunks Access Line Router Switched Network, full duplex trunks. Access lines attach to corporate routers & routers of other ISP's.

  15. OSU Backbone Trunks Access Line Router Access lines attach to Ethernet switches, Onenet and other routers.

  16. ISO OSI Seven Layer Model • Layer 7 Application • Layer 6 Presentation Windows API • Layer 5 SessionWindows TCP • Layer 4 Transport Windows TCP • Layer 3 NetworkWindows IP • Layer 2 Data Link PC NIC • Layer 1 Physical PC NIC

  17. Internet Protocal v4 (20 Bytes) 4 Bytes TOS TTL Source Address Destination Address

  18. Microsoft's Tracert

  19. 802.3 Ethernet Packet Format Bytes: 7 1 6 6 2 MAC Destination Address MAC Source Address 20 20 6-1460 4 IPv4 TCP Data + Padding CRC

  20. IPv4 Header • Contains two addresses • 4B Source Address • 4B Destination Address • 4B = 32b = 4.295 G potential addresses • Example address • 10001011 01001110 01000010 11010011 • Dotted Decimal Format simplifies • x.x.x.x • Treat each byte as Base2 number, write in Base10 • Above number simplifies to 139.78.66.211

  21. IP Header • Alpha-numeric name simplifies further • es302.ceat.okstate.edu • Domain Name Servers convert to numerical • All OSU Stillwater addresses are of form • 139.78.0.0 to 139.78.255.255 • IP addresses & alpha-numeric names are effectively backwards • 139.78.66.211 mapped to es302.ceat.okstate.edu

  22. IP vs Ethernet Addresses • Ethernet has a flat address space • Similar to Social Security Number • Adjacent #'s nearby or on other side of globe? • Huge look up tables required to avoid flooding • Need 70.37 trillion entries • IP has a hierarchical address space • Packet delivery similar to Mail delivery • Adjacent IP addresses frequently nearby • Reduces size of look up tables • Don't need 4.295 billion entries

  23. 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

  24. ISP Router Overload • Core BGP entries as of 19 August 2014 • IPv4 about 520,400 • IPv6 about 18,300 • 2nd week of August • Caused some problems • Some routers had 512,000 entry limit source: bgp.potaroo.net Network World , 13Aug2014, "Internet outages expected to abate as routers are modified, rebooted"

  25. TCP Header 4 Bytes Source Port Destination Port Sequence Number ACK Number Window Checksum

  26. Wireshark Packet Capture • 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.

  27. ISO OSI Seven Layer Model MSS = 1460 B = Size of Layer 6 & 7 info per packet • Layer 7 Application • Layer 6 Presentation Windows API • Layer 5 Session Windows TCP • Layer 4 Transport Windows TCP • Layer 3 Network Windows IP • Layer 2 Data Link PC NIC • Layer 1 Physical PC NIC Ethernet Payload = 1500 B

  28. TCP Window Size (Layer 4) Effects End-to-End Throughput • Suppose • Window Size (set by PC) = 64 KB • Microsoft Windows XP • Maximum Segment Size = 1 KB • Server can send < 64 unACK'd packets PC Server 3,000 Km

  29. Throughput on 64 Kbps Line PC Server Packet #1 3,000 Km, 64 Kbps line • NPD = Prop Delay / Packet inject time • Prop Delay = distance / EM energy speed = 3,000,000 m / 200,000,000 m/sec = 0.015 seconds • Packet inject time = 8,376 bits / 64 Kbits/sec = 0.1309 seconds (7B PPP, 20B IPv4, 20B TCP) • NPD = 0.015 / 0.1309 = 0.1146 • Front end of packet arrives at far side prior to back end being transmitted.

  30. Throughput on 64 Kbps Line PC Server #1 Packet #2 #1 ACK • At this instant in time... • 2nd unACK'd packet is being transmitted • ACK for #1 enroute back to server • TCP+IP+Layer 2 → 47 bytes if PPP • When ACK#1 arrives at server, only packet #2 is unacknowledged. • Will 64 packet unACK'd limit be reached? • No. At most, 1 packet likely unACK'd. 3,000 Km, 64 Kbps line

  31. Throughput on 45 Mbps Line PC Server #3 #2 #1 3,000 Km, 45 Mbps line • NPD = Prop Delay / Packet inject time • Prop Delay = distance / EM energy speed = 3,000,000 m / 200,000,000 m/sec = 0.015 seconds • Packet inject time = 8,376 bits / 45 Mbits/sec = 186.1 μseconds (PPP, IPv4, TCP overhead) • NPD = 0.015 / 0.0001861 = 80.60 • 80.60 average sized packets will fit back-to-back on this line

  32. Throughput on 45 Mbps Line PC Server Packets 1 - 64 • At this instant in time, the Server... • Has transmitted 64 packets w/o ACK. • Has hit window limit. Halts. 3,000 Km, 45 Mbps line

  33. Throughput on 45 Mbps Line PC Server Packets 2 - 64 #1 ACK#1 • At this instant in time, • The PC has processed 1st packet & sent an ACK • The Server is still halted, waiting for ACK #1. • When ACK #1 arrives, server can then transmit one additional packet. • Other ACK’s arrive fast enough to allow back-to-back transmission of next group of 64 packets 3,000 Km, 45 Mbps line

  34. Can Estimate Throughput with a Time Line to = 0 t1 t2 t3 time • to: Leading edge of 1st packet injected • t1: Trailing edge of 64th packet injected • t1 = (64*1047B)(8b/B)/(45 Mb/sec) = 11.91 msec • t2: Leading edge of 1st packet hits far side • 15 msec (propagation delay) • If ACK injected right away... • t3: ...ACK arrives at server at t = 30 msec • Process Repeats...

  35. Can Estimate Throughput with a Time Line to = 0 11.91 15.00 30.00 time (msec) • This system can transmit • 64(1,047) = 67,008 B = 536,064 bits • Every 30 msec (one round trip time) • Estimated throughput = 536,064/0.03 = 17.89 Mbps • Actual throughput a bit lower • 1st ACK not transmitted until packet #1 fully received... • ... and processed by PC • 65th packet not transmitted until ACK #1 fully received... • ... and processed by Server

  36. Can Estimate Throughput with a Time Line to = 0 11.91 15.00 30.00 time (msec) • Need to be able to fill the pipe for 1 RTT • 30 msec in our example • 45 Mbps * .030 sec = 1.35 M b = 168,750 B = 168,750/1,047 = 161.2 packets • Window Size needs to be = 161.2 segments*1,000 bytes/segment = 161,200 B • Actually would need another segment or two to cover source & sink processing

  37. TCP Header 4 Bytes Source Port Destination Port Sequence Number ACK Number Window Checksum

  38. UDP Header (8 Bytes) 4 Bytes Source Port Destination Port Checksum For interactive real-time traffic, usually used with Real Time Transport Protocol (12 bytes).

  39. Virtual Circuits • Routing decisions made once when circuit is set up • Concerned switches have internal Look-Up tables updated • All packets part of info transfer follow the same path • Allows option of setting aside switch resources (buffer space, bandwidth) for specific traffic flows • MPLS, Frame Relay, ATM, & Carrier Ethernet use VC’s

  40. Datagrams • IP uses Datagrams • Routing Tables updated independently of individual traffic flows • Routers continuously talking with each other • Packets may follow different paths • Routers get no advance warning of specific packet flows.

  41. IP is Connectionless 20 20 up to 1,460 IP TCP Data + Padding 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.

  42. TCP, UDP, and IP • 30+ year old Protocols Designed for dataOne Priority & “Best Effort” servicesNo QoS GuaranteesAvailable bandwidth depends on other users • TCP (Layer 4 & 5) provides reliable transfer • UDP (Layer 4 & 5) unreliable transfer • IP at Layer 3 • Arbitrary Protocols at Layers 1 & 2

  43. InternetTraffic2008 - 2009 Comparison source: http://www.sandvine.coms

  44. Fixed Access Internet Traffic Profile 2013 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

  45. 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

  46. 2013 Mobile Access Internet Traffic Profile source: www.sandvine.com/downloads/general/global-internet-phenomena/2014/1h-2014-global-internet-phenomena-report.pdf

  47. Internet Traffic Growth source: "The Road to 100G Deployment", IEEE Communications Magazine, March 2010

  48. Internet Traffic Growth source: www.cisco.com/c/en/us/solutions/collateral/service-provider/visual-networking-index-vni/VNI_Hyperconnectivity_WP.html

  49. Combining the Figures

  50. VoIP • PC to PC • Internet Phone to Internet Phone Commodity Internet

More Related