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Course Admin Details

CS 218 Advanced Computer Networks Fall 2017 Course ID : CS218 Class hour : MW 8:00 - 10:00 pm Dodd 78. Course Admin Details. Prof Peter Reiher: BH 3532 F reiher@cs.ucla.edu Replacing Prof. Gerla, who was originally scheduled for the class Office Hrs: TTh 1-2 or by appointment

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Course Admin Details

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  1. CS 218Advanced Computer Networks Fall 2017Course ID : CS218Class hour : MW 8:00 - 10:00 pmDodd 78

  2. Course Admin Details • Prof Peter Reiher: BH 3532 F reiher@cs.ucla.edu • Replacing Prof. Gerla, who was originally scheduled for the class • Office Hrs: TTh 1-2 or by appointment • Teaching assistant: • Vince Rabsatt (rrabsatt@cs.ucla.edu ) • Prerequisites : CS 118 or equivalent • Course grading • Paper presentation 10% • Quizzes: 15% • Midterm : 25% • Term project/presentation : 50%

  3. Course objectives • Introduce active research areas in the field of networking • This year, we target: • Wireless networks • W-LANs, ad hoc nets, mobile P2P • Ad hoc routing and transport • Network Coding • Vehicular networks • Wireless health • Wireless security • Mobile Cloud Computing • Internet transport protocols • TCP congestion control; bandwidth estimation; • OpenFlow, SDN; • P2P applications • Term Projects: • Student teams investigate a specific topic in more depth (via analysis, simulation, implementation or measurements)

  4. Course Content • Wireless Networks • Wireless LANs (802.11, Bluetooth, ZigBee); MAC layer protocols • Wireless security • Vehicular networking • Internet protocols • Congestion control, TCP, streaming • OpenFlow; SDNs • Internet security • Securing BGP • Securing DNS • IP spoofing • DDoS

  5. Paper Presentations • Each student will be asked to present one research paper for one class • Chosen from a set I will provide • A 15 minute presentation of the paper’s content • Followed by leading a 15 minute class discussion on the paper • Presentation should briefly outline: • What the paper is about • What is interesting about the paper’s approach • Strong points of the research • Weak points of the research • We will schedule presentations at the end of the 1st week of class

  6. Quizzes Weekly During the recitation section Four to five short answer questions Covering material in the previous week’s readings and lectures Easy if you’ve read and attended class

  7. Class Projects • Substantial projects with research components • Original work on an advanced topic in networking • Not necessarily one the class lectures cover • Typically requiring simulation or implementation Not just a paper • Expected project outputs: • A written report covering all aspects of the project • Simulation or actual measurement results • An in-class presentation • Projects to be done in groups • 5-7 students per group • Outcomes should be commensurate with group size

  8. Project Membership • Choose your own teams • If you have trouble finding a team, consult our TA • Lists of team members required by Friday October 6 • No requirement to discuss subject of the project at this point • If you do not find your own team by then, you will be assigned a team at our discretion

  9. Project Proposal • A 3-5 page proposal of your project • Including: • Description of basic concept • Outline of your approach • A schedule • Description of criteria for evaluating it (which must include quantitative criteria measured directly or through simulation) • Breakdown of project responsibilities among team members • Insufficient detail in any of these will result in rejection of proposal • Requiring revision • Also losing points on the grade • Due Friday October 13

  10. CS 218 Term Project grading criteria: Class presentation style, clear delivery, organization, concise 15 Research value (say, if judged as a research paper to be published at some conference); 20 References. How careful is the review of prior work ; ie, how complete and consistent is the set of references? How appropriate are the citations? 5 Report (max 15 pg double spaced, including figures and tables); writing style; clarity; organization 10 Total: 50

  11. Previous CS 218 Class Projects •  Performance analysis of VANET Content Routing Based on Bloom Filter. • VANET Security project. • Cooperative Multimedia Distribution (CMD) scheme for Vehicular Networks • Cooperative crash prevention using human behavior monitoring

  12. Previous CS 218 Class Projects (cont) • TCP Simulation for Iridium system • MPTCP on Wireless Networks • MP TCP over Satellite paths • Improve the Management of Wireless Access Network using Software Defined Networks (SDNs)/ OpenFlow (OF) • Neighbor Discovery Protocol Implementation in Wireless Mobile Sensor Networks • Social ties based content retrieval in mobile ad-hoc networks

  13. CS 218 Past Projects Vehicular Ad Hoc Networks • Enhancing geographic routing in VANET • Implementing a Tracer Program for Qualnet – vehicular net applications • GPSR and Infrastructure • CarTorrent/CodeTorrent Experiments

  14. Past Projects (cont) Mobile P2P / Mobile Security • BlueTorrent in Medical situation (HealthNet): Bluetooth-based patients data distribution system. • BlueTorrent in SmartPhones • Smart phone Bluetooth P2P • Survey on mobile ad-hoc network security. • Proof of Security of a Mesh Architecture

  15. Past Projects (cont) Ad Hoc Networking • Experiments on a Real Wireless Mesh Network (WMN) • Cross-Layer LANMAR Routing Protocol in MIMO System • Dynamic hybrid MAC protocol for 802.15.4 • Don’t Pass “Packets” to Your Neighbors • Multicast in Ad Hoc Networks (FairCast) • Under Water ad hoc routing

  16. Past Projects (cont) Security • Secure, legitimate profit sharing in P2P content distribution • Implementation of ANODR – Anonymous Ad Hoc Routing Vehicle comms • CarTorrent: Cooperative Downloading in Vehicular Ad Hoc Wireless Networks • FleaNet: Mobile Market Place on the Vehicular Network • Studying the Dynamics of P2P File Pollution • Online Games in Vehicular Networks

  17. CS 218 F17 – Class Schedule • Week 1 Oct 2 – M: Wireless LAN Intro; MAC Layer • Oct 4 - W: MAC Layer-BT - Zbee ( 6TISH) • Oct 6 – F: Group membership lists due • Week 2 Oct 9 - M: Wireless Ad Hoc Route + GeoRoute • Oct 11 – W: Multicast, Epidemic Dissemination •   Oct 13 – F: Project proposals due • Schedule of lectures for remaining weeks to be announced • Week 5 Nov 1 – Midterm exam • Weeks 9-10 – Presentations of projects

  18. Wireless Local Area Networks The core wireless technology used today Providing a limited area with networking capability Through use of various radio technologies Enabling mobile computing And easing even non-mobile computing

  19. The three mobile wireless “waves” • Wave #1: cellular telephony (1980) • Still, biggest profit maker • Wave #2 : wireless Internet access (2000) • Initially, Ethernet wireless replacement (late ‘90) • Now, most Internet access is wireless (Campus, home, office, etc) • Urban Hot Spots are rapidly proliferating (pedestrians, vehicles) • Cellular: 2.5 G, 3G trying to keep up; competitive edge ( -> LTE)? • Wave #3: ad hoc wireless nets (now) • Commercial “opportunistic” ad hoc apps happening now • Note: Military “wave” actually started in 1970, followed by civil emergency/disaster recovery appls

  20. The Wireless Internet Access: Cellular • 2.5 G • 1xRTT (EVDO): CDMA based; 144Kbps • GPRS: Time Division based (GSM); < 100Kbps • Packet oriented; “always on”; per packet (instead of per call) charge • 3G • UMTS: Wide Band CDMA from 384 Kbps to 2Mbps • Integrates packet service with connection oriented service (voice, video, etc) • LTE (Long Term Evolution) • New technology: OFDM, MIMO • Higher bandwidth: > 20Mbps • Femtocells

  21. Wireless Internet Access: 802.11 • Replacement for wired Ethernet • Unlicensed spectrum (ISM) • Several options and rates • 802.11 b: 11, 5.5, 2, 1 Mbps; @ 2.4 GHz • 802.11 a up to 54 Mbps in 5.7 GHz band • 802.11 n, up to 100Mps with MIMO and OFDM technologies • Range • Indoor 20 - 25 meters • Outdoor: 50 – 100 meters • Transmit power up to 100 mW

  22. Personal networking: Bluetooth • 1998: Bluetooth SIG : Ericsson, IBM, Intel, Nokia, Toshiba • A cable replacement technology • Max rate 700Kbps @2.4 Ghz • Range 10+ meters • Single chip radio + baseband • at low power (1mw) & low price point ($5) • Convergence of 802.15 and Bluetooth in a single PAN standard

  23. ZigBee Radios and Body Area Network ZigBee connects body sensors to phone ** Photo Credits: MicroStrain, Inc.

  24. Body area network (BAN) sensors • Electrocardiogram (ECG) UCLA Smart Shoe Sensor connects to Phone via BT or ZigBee • Pulse Oximeter • UCLA Smart Cane

  25. Wireless Nets: Infrastructure vs Ad Hoc Infrastructure Network (cellular or Hot spot) Ad Hoc, Multihop wireless Network

  26. General Ad Hoc Network Characteristics • Instantly deployable, re-configurable (No fixed infrastructure) • Created to satisfy a “temporary” need • Node portability (eg sensors), mobility • Limited battery power • Multi-hopping ( to save power, overcome obstacles, enhance spatial spectrum reuse, etc.)

  27. Ad Hoc Network Applications Military • Automated battlefield Civilian • Disaster Recovery (flood, fire, earthquakes etc) • Law enforcement (crowd control) • Homeland defense • Search and rescue in remote areas • Environment monitoring (sensors) • Space/planet exploration

  28. Ad Hoc Network Applications (cont) Commercial • Sport events, festivals, conventions • Ad hoc collaborative computing (Bluetooth) • Sensors on cars (car navigation safety); sensors on cows • Networked video games at amusement parks, etc Opportunistic ad hoc extensions (of Wireless Internet) • Indoor W-LAN extended coverage • Indoor network appliances (Bluetooth, Home RF) • Hot spots (Mesh Networks) • Campus, shopping mall, etc • Urban grid

  29. The Battlefield • DoD was first to understand the value of ad hoc networks for the automated battlefield • In 1971 (two years after ARPANET), DARPA starts the Packet Radio project • ONR (Office of Naval Research) sponsors MINUTEMAN - a 5 year program at UCLA (2000–2005) • Goal: develop an “unmanned” , airborne ad hoc architecture

  30. SURVEILLANCE MISSION AIR-TO-AIR MISSION STRIKE MISSION RESUPPLY MISSION FRIENDLY GROUND CONTROL (MOBILE) SATELLITE COMMS SURVEILLANCE MISSION UAV-UAV NETWORK COMM/TASKING COMM/TASKING Unmanned UAV-UGV NETWORK Control Platform COMM/TASKING Manned Control Platform Minuteman: Algorithms and Protocols for Network of Autonomous Agents

  31. Transferring Battlefield technology to civilian applications Disaster recovery: • Flood, mud slide, eruption, chemical or nuclear plant disaster • Several rescue teams involved, with different functions • Autonomous vehicle swarms (ground/airborne) are deployed (with sensors/actuators) • Manned and unmanned teams cooperate in rescue • “Ad Hoc networking”will be central to make the operation work

  32. The Urban Vehicle Grid • Ad hoc networking to prevent/contain accidents

  33. Urban Ad Hoc net in action: Safe Driving Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 65 mphAcceleration: - 5m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 20m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Alert Status: None Alert Status: None Alert Status: Inattentive Driver on Right Alert Status: Slowing vehicle ahead Alert Status: Passing vehicle on left Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 45 mphAcceleration: - 20m/sec^2Coefficient of friction: .65Driver Attention: NoEtc. Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 10m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Alert Status: Passing Vehicle on left

  34. CS218 Fall 2017Wireless Nets – the MAC layerPart I • FDMA/TDMA/CDMA • MAC Protocols Overview • MAC layer in the DARPA Packet Radio testbed • MAC in wireless LANs (MACA and IEEE 802.11)

  35. Application Processing Application Setup Application RTP Wrapper RCTP Transport Wrapper TCP/UDP Control Transport RSVP IP Wrapper IP IP/Mobile IP Routing VC Handle Flow Control Routing Clustering Packet Store/Forward Network Link Layer Packet Store/Forward Ack/Flow Control Clustering MAC Layer Frame Wrapper RTS/CTS CS/Radio Setup Frame Processing Radio Status/Setup Radio Propagation Model Mobility Channel Wireless Protocol Layers Data Plane Control Plane

  36. MAC Layer • Media Access Control protocol: coordination and scheduling of transmissions among competing neighbors • Used when multiple potential senders use the same underlying link • Goals: low latency, good channel utilization; best effort + real time support • MAC layer clustering: aggregation of nodes in a cluster (= cell) for MAC enhancement

  37. Multiple Access Control (MAC) Protocols • MAC protocol: coordinates transmissions from different stations to minimize/avoid collisions • (a) Channel Partitioning MAC protocols: TDMA, FDMA, CDMA • (b) Random Access MAC protocols: CSMA, MACA • (c) “Taking turns” MAC protocols: polling • Goal: efficient, fair, simple, decentralized

  38. frame ….. TDMA • Time Division Multiple Access • Time frame divided in slots: one slot per user • Problem with TDMA?

  39. Channel Partitioning (CDMA) • CDMA (Code Division Multiple Access): exploits spread spectrum (DS or FH) encoding scheme • unique “code” assigned to each user; ie, code set partitioning • Used mostly in wireless broadcast channels (cellular, satellite,etc) • All users share the same frequency, but each user has own “chipping” sequence (ie, code)

  40. Frequency Hopping (FH) • Frequency spectrum sliced into frequency subbands (eg, 125 subbands in a 25 Mhz range) • Time is subdivided into slots; each slot can typically carry one packet (or fraction of it) • A Bluetooth packet covers up to 5 freq slots • Users are clock and slot synchronized • They frequency hop slot by slot according to unique, predefined sequence • Ideally, hopping sequences are “orthogonal” across networks (i.e., no overlap) • In practice, conflicts occur

  41. Bluetooth Frequency Hopping: 1pkt/frq slot f5 f1 f4 f3 f2 f6 m s1 s2 625 µsec 1600 hops/sec

  42. MAC protocols • (a) Channel Partitioning : TDMA, FDMA, CDMA • (b)Random Access : CSMA, MACA • (c) “Taking turns” : polling

  43. Random Access Protocols • A node transmits at random (i.e., no a priori coordination among nodes) at full channel data rate R • If two or more nodes “collide”, they retransmit at random times • The random accessMAC protocol specifies how to detect collisions and how to recover from them (e.g., retx) • Examples: (a) SLOTTED ALOHA (b) ALOHA (c) CSMA and CSMA/CD

  44. Slotted Aloha • Time is slotted (slot = full packet size) • A newly arriving station transmits at the beginning of the next slot • If collision occurs (assume channel feedback) the source retransmits the packet at each slot with probability P, until successful • Success (S), Collision (C), Empty (E) slots • Maximum throughput efficiency = 1/e (~37%)

  45. Unslotted ALOHA • Slotted ALOHA requires slot synchronization • Unslotted ALOHA requires no synch, no slots • A node transmits any time • Collision probability increases (packet can collide with packets transmitted in a “vulnerable” window twice as large as in S-Aloha) • Max throughput is reduced by one half, i.e. S= 1/2e (~18%)

  46. CSMA (Carrier Sense Multiple Access) • CSMA: listen before transmit. If channel is sensed busy, defer transmission • Persistent CSMA: retry immediately when channel becomes idle (this may cause instability) • Non persistentCSMA: retry after random interval • Note: collisions may still exist, since two stations may sense the channel idle at the same time ( or better, within a “vulnerable” window = round trip delay) • In case of collision, the entire packet is retransmitted

  47. CSMA collisions

  48. CSMA/CD (Collision Detection) • CSMA/CD: carrier sensing like in CSMA. Now, collisions are detected within a few bit times. • Transmission is then aborted, reducing channel OH, wastage • CSMA/CD can approach channel utilization = 1 in LANs (low ratio of propagation over packet transmission time) • Collision detection is easy in wired LANs (e.g., E-net): • Can measure signal strength on the line, or code violations, or compare transmit and receive signals • Collision detection cannot be done in wireless LANs (the receiver is shut off while transmitting, to avoid damaging it with excess power)

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