ECE/CS 438: Communication Networks (Fall 2020)
    internet  
   
Description: This course will introduce students to the key concepts underlying wired and wireless networking. The layered architecture of the network protocol stack will be the focus of discussion. Alongside, a variety of case studies will be drawn from the Internet, combined with practical programming exercises. At the end of the semester, students will well understand several concepts, including the Internet architecture, HTTP, DNS, P2P, Sockets, TCP/IP, BGP, Routing protocols,
wireless and sensor networking, WiFi, cellular and satellite networks, security, etc.
 		  
     
Time and Location:   Tu/Th 3:30 to 4:45pm (zoom link here, password: "networks")
Instructor:                  Romit Roy Choudhury (croy@illinois.edu)
Office Hour:              After class
  
     
Course TA 1:               Yu-Lin Wei (Wally) <yulinlw2@illinois.edu>
                                                            - Office hour: Wed 10-11am, UIUC time.
Course TA 2:               Zhijian Yang <zhijian7@illinois.edu>
                                                            - Office hour: N/A
Course TA 3 (ZJUI):   Mingjia Huo <mhuo4@illinois.edu>
                                                            - Office hour: Fri 3-4pm, China time
Piazza:                        Here (mainly for student-to-student interaction)
  
   
 
Textbook:                  Computer Networking (A Top-Down Approach Featuring the Internet)
                                  J. F. Kurose and D. W. Ross, 3rd or later edition, Addison-Wesley.
                                  (Other editions are fine).
  
     
Grading Information:
Homework:                              15%
Programming assignments:      25%
1 mid-term exam:                     25%
Final Exam:                              35%

4 Credit Students: Need to complete a mini-project and submit a report at the end of the semester. Around K=3 topics for mini-projects will be suggested and students need to choose from one of them. Mini-project = 10% (while assignments and mid-term will be 20% each)

COVID requires us all to read this and conform to the university policies and standards
  

 
(Tentative) Course Calendar
The schedule may change over time due to unforeseen events, instructor travel, evolving student interests, etc.
 
Date/slides Video Topics of Discussion Homework, Prog. Assignments, etc.
Aug 25
0-logistics.ppt
 		 lecture1 Course Logistics, Course Overview.  
Aug 27
0-logistics_annotated.pdf		 lecture2 Overview continued
   - History and fathers of the Internet
   - End hosts and ISP hierarchy
   - Trans continental cables
   - Layering and encapsulation (end to end horizontal communication)
 		 Programming Assignment 0 (also called Machine Problem (MP))
Instructions  +  Beej's guide
No due date -- will not be graded
Sep 1
1-overview.pptx
 		 lecture3 Overview and Internet Terminology,
   - Introduction to Basic Terms and Concepts:
   - Internet: Hosts, apps, edge, core, routers, links, connection-less, infrastructure, service
   - Network edge: Client server, P2P, edge-fog-cloud, connection less/oriented, TCP, UDP
   - Network access and media: Notion of FFT and bandwidth, dial-up, ADSL, cable, LAN, wireless ...
 		 Programming Assignment 1 (MP1)
Instructions
Due date -- 11:59PM, Oct. 2, 2020
Sep 3

See this USA_ Spectrum_map

 		 lecture4 Overview Continued
   - Bandwidth, carrier frequency, notion of modulation and de-modulation, spectrum allocation in the US
   - Network core: Circuit switching, FDM versus TDM, throughput, latency
   - Packet switching: Statistical multiplexing, tradeoff between efficiency and guarantee.
 		  
Sep 8

1-overview-annotated.pdf

 		 lecture5 Overview
    - Datagram networks, Virtual circuit switching, Taxonomy of network core
    - Layered communication, End-to-End architecture
    - 4 kinds of delays (Processing, Queuing delay, Propagation, Transmit), Packet loss

Application
    - Introduction to Applications, client-server, peer-peer, services,
 
 
Sep 10
2-app-layer.ppt


 lecture6
 Application
    - Client-Server, Pure P2P, Hybrid P2P ... Overlay networks
    - Loss, Bandwidth, and Delay requirements
    - Introduction to HTTP, Non-persistent, Persistent, Cookies

  
Sep 15

 2-app-layer-annotated.pdf

2_app_optional_p2p.pptx		  lecture7 Application
    - Web caching
    - Email (SMTP, POP, IMAP)
    - DNS
    - P2P networks

Pointers: Inventor of the DNS system, Paul Mockapetris		 Homework 1 (on Gradescope)
Due date -- 5:00PM, Sep. 30, 2020




Sep 17

2_socket_programming.pptx

3-transport.ppt		  lecture8 Transport Layer
    - Socket programming
    - Reliability definition --> reliable wrapper over an unreliable channel
    - Multiplexing, Demultiplexing
    - UDP, checksums
    - State transition diagrams
    - Principles of reliability
         - Reliability definition
         - Building a reliable protocol from scratch (no errors, ACK/NACK, packet errors, seq. no.)

Programming Assignment 2 (MP2)
Instructions
Due date -- 11:59PM, Oct. 23,2020
3-transport-classwork.pdf  lecture9 Transport Layer
      - Building reliable protocol over unreliable link
      - Link error model:
            - No error
            - Forward bit error, backward bit error
            - Packet loss
            - Packet delay
      - Moving from correctness to performance (pipelining)

  
See 3-transport-classwork.pdf above
  lecture10 Transpor Layer
       - Correctness to performance: Pipelined protocols
       - Go back N (GBN) ... Tx window but no Rx buffer, hence sends cumulative ACKs
       - Selective ACK (SACK) ... Tx and Rx have buffers

  
See 3-transport-classwork.pdf above  lecture11 Transport Layer
      - Selective ACK (SACK) ... Tx and Rx have windows ... and Selective ACKs
      - Various T/F questions on SACK
      - TCP introduction
      - Notion of congestion and adaptive window size

  
 3-tcp-oct1-classwork.pdf  lecture12

 Transport Layer: TCP
      - Bottleneck and available bandwidth
      - TCP's knob = congestion window (CW)
      - Chemical factory analogy
      - TCP protocol (Rx buffer + cumulative ACK)
           - 3 way handshake
           - Slow Start
           - Congestion avoidance (after SS_Threshold)
          
 
 3-tcp-oct6-classwork.pdf


  lecture13 TCP
     - Congestion indication from packet drop (time out)
     - ACK drops
     - 3 DupACKs and fast recovery
     - Ensuring congestion window grows while DupACKs arrive

  
 3-tcp-oct8-classwork.pdf lecture14 TCP
     - Fast recovery
     - TCP timers and saw tooth behavior
     - TCP state diagram
 3-tcp-oct13-classwork.pdf lecture15 TCP
     - Timeout estimation (RTO) as a function of Estimated RTT and Deviation
     - Packets to bytes
     - AIMD and TCP throughput calculation
     - Flow Control
     - TCP fairness

 Homework 2 (on Gradescope)
Due date -- 11:59PM, Oct. 25, 2020
 3-tcp-oct13-classwork.pdf lecture16 TCP
     - TCP over wireless
     - TCP Random Early Detection (RED)
     - Bottleneck bandwidth estimation via packet pairs
       
4-network.ppt lecture17

 Network Layer
     - Introduction
     - Routing and Forwarding (and Connection set up)
     - Network service models (guarantees and best effort)
     - Virtual circuit and datagram networks
     - Forwarding table

  
Mid-term info. slides
  lecture18 Network Layer
     - Longest prefix matching
     - Router architecture
     - IP datagram, fragmentation and reassembly
     - Subnets and IP addressing
     - CIDR (Classless Inter Domain Routing)

MID-TERM Discussion


Midterm Oct 29, Thu
 Routing Algorithm Examples  lecture19 Network Layer
     - Prefix matching based routing across ISP
     - NAT
     - ICMP and Traceroute
     - IPv6

     - Routing algorithms: Link state and Distance vector
     - Link state: Dijkstra's algorithm

 Programming Assignment 3 (MP3)
Instructions
Due date -- 11:59PM, Nov. 18,2020

 lecture20 Network Layer
     - Distance Vector (Bellman Ford's algorithm)
     - Hierarchical routing
     - Internet case studies
     - Link state: RIP, OSPF

  
 


5-link.pptx		 lecture21 Network Layer:
     - Distance vector: BGP (eBGP and iBGP)
     - Policy decisions based on socio-economic factors

Link Layer:
     - Introduction to link layer
     - Local reliability as performance optimization, not correctness

  






Pointers: Hamming codes: 3Blue1Brown Part1
3Blue1Brown Part2		  lecture22 Link Layer:
     - Error detection and correction
     - Multiple Access Protocols (Centralized and Decentralized)
        - Listen before you Talk
        - Carrier sensing
        - Collisions
5-link-classwork-nov17.pdf
  lecture23 Link Layer:
     - Medium access control protocols
     - Channel partitioning
     - CSMA/CD
     - Taking turns
     - Ethernet

  
 5-link-classwork-nov19.pdf  lecture24 Link Layer:
     - Ethernet continued
     - Ethernet protocol flowchart
     - MAC Layer addressing
     - Address Resolution Protocol (ARP)
     - Interconnecting at Link Layer
     - Hubs and Switches
     - Zoom out: comparison between routers, hubs, and switches.

 Programming Assignment 4 (MP4)
Instructions
Due date -- 5:00PM, Dec. 6,2020

Mini project (4 credit students)
Instructions
Due date -- 5:00PM, Dec. 18, 2020

Homework 3 (on Gradescope)
Due date -- 5:00PM, Dec. 11, 2020


THANKSGIVING BREAK
6-wireless-CSMA-WiFi.ppt

6-wireless-classwork.pdf
  lecture25 Wireless Link Layer
      - Wireless channel
      - Decoding a packet over wireless (SNR and SINR)
      - SINR's relation to distance from transmitter and interferer
      - CSMA/CD not possible
      - HIDDEN and EXPOSED terminal problems
      - CSMA/CA (WiFi) --> RTS/CTS
      - Limitations of RTS/CTS
6-wireless.ppt
  lecture26 Cellular Networks and Mobility
      - Cellular network terminology -- 2G, 3G, LTE, PSTN, RNC, GGSN, SGSN
      - Mobility at different layers
      - Home network, foreign network, Care-of-addresses
      - Indirect Routing anddd triangular routing problem
      - Mobile IP, HLR, VLR
      - Handoff
8-security.ppt  lecture27

 Security
      - Confidentiality, Authentication, Integrity, Access and availability
      - Symmetric and Public key cryptography
      - RSA algorithm
      - Authentication, Nonce, Replay and Playback attack, Man in the middle attack
      - Digital signatures

  
last-class-scribbles.pdf
 lecture27 Security
      - Key distribution center
      - Certification authority
      - Applications in secure email, SSL/TLS/ HTTPS


- Course recap and wrap-up
- Next courses
Final exam date:
Wed, Dec 16, 2020, 8-11am
 		   ECE/CS 438 Final Exam