1. CS 6027 Advanced Computer Networking
Dr. Clincy
Professor of CS
Dr. Clincy
Lecture 1

2. Kick Off
Dr. Clincy
Lecture 1

3. Tentative Course Outline: Subject to Change
General Topic & Exam Coverage
Lecture Coverage
Chapters (in order)
Exam 1 - Introduction and Overview of Underlying Technologies:
Review critical concepts covered in foundation course, RFC’s; the importance of standards; underlying network technologies; OSI reference model & protocol layering, etc..
1 through 5
1, 2, and 3
Exam 2 - Addressing Issues:
IP, Internet addresses (classful and classless), subnetting and supernetting, ARP; RARP; BOOTP; DHCP; DNS, NAT, Mobile IP, etc..
6 through 11
7, 5, 8, 10, 18 and 19
Exam 3 - Network Layer Protocols:
ICMP; router functionality, dynamic versus static routing, routing tables, unicast routing (RIP, BGP, OSPF), routing algorithms (link state, distance vector)
12 through 14
4, 9, 6 and 11
Exam 3 – Multicast Routing
multicasting, routing algorithm (path vector), multicast routing protocols (MOSPF, DVMRP, CBT, PIM), MBONE, IGMP, End-to-end datagram delivery, and Flow control
15 through 16 12
Exam 4 – Transport Layer Protocols, Next Generation IP
UDP and TCP, IPv6, ICMPv6, transitioning from IPv4 to IPv6
17 through 20
13, 14, 15, 26, 27 and 28
Dr. Clincy
Lecture 1

4. Tentative Course Schedule: Subject to Change
Dr. Clincy
Lecture 1

5. Assessment
will curve GRADES if the SCORE AVERAGE is lower than 80 (curving vs bell-curve approach, TCP/IP new topic) (give example of curving concept – next bullet)
No make-up exams – last exam will count for missed exam – can miss only 1 exam
Dr. Clincy
Lecture 1

6. Explanation for curving
Explain why NOT force-fitting traditional 10-point grading approach
Heterogeneous student make up (vs homogeneous)
Gurus in class ?
Partially or Fully cover topic ?
A more demanding subject matter ?
Should the SD be dictated or flexible ?
Should the Avg be dictated or flexible ?
Students need not perceive the SCORE as their GRADE – but if they insist on doing so , think of the exam SCORE as an NATIONAL GRADE
Dr. Clincy
Lecture 1

7. Lesson in Stats – Example of Curving Grades – Raw Score to Final Grade
What is an Avg ?
What is the SD ?
This is the curve
Fitting raw scores to a curve
? = 90 + (RS-77)/1.4
? = 80 + (RS-63)/1.4
? = 70 + (RS-49)/1.4
? = 60 + (RS-35)/1.4
Dr. Clincy
Lecture 1

8. General Policies and Expectations:
Attendance at all classes is highly encouraged but NOT required. Concepts and ideas discussed in one class are used as building blocks for more concepts and ideas in the next class.
Any class session missed by the student is the student's responsibility to make up.
Makeup exams will NOT be given; instead, the last exam will count in place of the missed exam.
Exams should be returned to the Professor in class right after the review for the student to receive a grade. Grades are not logged until the students have reviewed the exams for grading mistakes. If students take the exam from the classroom, a grading penalty of 50% will be used due to the fact the Professor has no real way of determining if the exam was tampered with or not.
Project assignments MUST be turned in on time to receive full credit. Late project assignments will be graded severely – for each day the assignment is late, the assignment’s grade will be reduced by 20%.
Students will not be allowed to makeup missed project assignments.
It’s hard to teach a subject like TCP/IP from a single source. The Professor will use multiple sources to teach various concepts – multiple sources such as (1) text book, (2) lecture notes, (3) handouts, (4) URL’s, and (5) project assignments. Every topic detail WILL NOT necessarily be found in the our text.
Students are expected to read the text and any other supporting documentation the Professor distributes.
Dr. Clincy
Lecture 1

9. General Policies and Expectations:
In being successful in this subject, expect a minimum of 2-3 hours of study per hour of lecture (6-9 hours per week)
The Professor expects students to take advantage of office hours when needing clarification or help.
Purpose of class participation grade – no 2 students learn the same – no 2 Profs teach the same (or have the same expectations) – I feel constructive class participation is very important
The Professor greatly supports students sending s at any time – it will be the goal of the Professor to reply to s within a 24-hour time span (not counting weekends).
Be sure and provide the Professor a functioning personal address for you (on your Sign-up List) – already has KSU address
Lecture notes purpose: serve as a guide to the Professor – help organize and time lecture
Guarantee: current lecture notes will be posted before the next up-and-coming lecture (ie. lecture notes 1 will be posted before lecture 2 occurs)
See syllabus for withdrawal policy, enrollment policy, and the Academic Integrity Statement. Be sure and give me the signed copy at the next class meeting
Go to my website for a syllabus and lecture notes
Dr. Clincy
Lecture 1

10. Break or Not To Break That is the question
Dr. Clincy
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11. CS 6027 Advanced Computer Networking
Lecture 1
Dr. Clincy
Lecture 1

12. Introduction and Overview
Just 50 years ago, networks were proprietary (ie. IBM, HP, DEC, etc)
Both the software (protocols or rules) and hardware used to make a network functional were proprietary.
Also, the networks’ technologies (components) were designed for a specific purpose in mind (ie. Business, manufacturing, high/low-speed, small/large capacity, etc..)
The certain applications could run on certain type networks
Larger corporations would typically have many different disjointed computer networks - company mergers caused this problem too (wasn’t perceived as a problem then)
Engineers and Scientists (or whomever) could have 3-4 terminals on his/her desk for different uses
Customer would have to go to a specific vendor for an application or network upgrade
Dr. Clincy
Lecture 1

13. Introduction and Overview
Back in the 70’s and early 80’s, there was a big push to make communication systems or networks “open”
“open” means “non-proprietary” - instead of the “specifications” being known only by the vendor, the specs would be be publicly known
By having publicly published specifications, all of the various vendors could design and manufacture network components that were compatible and interchangeable
Why was this a good thing ???? (Even if you were a network-component-producing company with a significant market share)
Dr. Clincy
Lecture 1

14. Introduction and Overview
Answer: would drive more (1) computer, (2) software application and (3) network usage - therefore, drive more revenue for all
Answer: more efficiency for businesses, government, etc..
Also, what happened with the computer industry as it relates to OS’s ???
Dr. Clincy
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15. Introduction and Overview
The idea behind having “open systems” is to have the ability to interconnect many different networks into a single network.
The technology that allows this is called “Internetworking”
Internetworking provides:
The Interconnection of heterogeneous (different) networks
Set of communication standards/protocols that make the interconnected heterogeneous networks interoperate
(river, language scenario)
Internetworking “hides” the details of the underlying hardware and allow the network nodes to communicate independent of their physical connection (or hardware)
Internetworking can be called “internet technology” – notice to lower case “i” on internet
Dr. Clincy
Lecture 1

16. Introduction and Overview
Some time ago, the government realized the benefit of internet technology and funded a research project through an agency called ARPA – Advanced Research Projects Agency
Through ARPA support, the “open” system specs were realized.
These open specs were called “TCP/IP Internet Protocol Suite”, commonly called “TCP/IP”
TCP – Transmission Control Protocol – dealt with higher level issues like segmentation, reassembly and error detection.
IP – Internetworking Protocol – dealt with datagram routing
TCP/IP was heavenly sent in that: (1) previously disjointed networks WITHIN companies could now function as a single network and (2) it facilitated communications amongst geographically dispersed sites
With TCP/IP, the Internet was born. Notice the “I” on Internet – called the Global Internet
Global Internet interconnects over 170 million nodes – testimonial for TCP/IP
Dr. Clincy
Lecture 1

17. Introduction and Overview
Bottom Line: what makes TCP/IP so great and unique from other network protocols ??:
Network Technology Independence – independent of a particular vendor’s hardware
Universal Interconnection – any 2 computers connected to the internet can communicate – each computer has a unique internationally recognized address
End-to-End Acknowledgements – acknowledgements between the source and destination versus intermediate nodes
Application Protocol Standards – TCP/IP provides services (or software) to applications needing lower level communication services
We will cover each of these attributes in detail throughout the course
Internet uses TCP/IP
Dr. Clincy
Lecture 1

18. Introduction and Overview
Read more details about the history in your book (Chapter 1)
Who is responsible the Internet ?. Internet Architecture Board (IAB)
IAB coordinates the research and development in relation to the TCP/IP protocols. The organization decides which protocols are required and sets policies
Each member of the IAB chaired an Internet Task Force responsible for investigating a set of problems or issues each (there were 10 task forces)
The chairman of the IAB was called the Internet Architect
Dr. Clincy
Lecture 1

19. Introduction and Overview
In 1989, the IAB was re-organized due to commercial usage increases
The original IAB researchers were moved under the Internet Research Task Force – their focus is longer term research
The Internet Engineering Task Force is more concerned about short-term issues and is mostly comprised of industry types
The Internet Engineering Task Force Chairman and managers of each “working group” forms the Internet Engineering Steering Group – this group is responsible for coordination
In 1992, a group called the Internet Society (ISOC) was form to encourage participation on the Internet.
Dr. Clincy
Lecture 1

20. Introduction and Overview
Documentation of TCP/IP is placed in online repositories and made available at no charge – you will be responsible for collecting some of this documentation
The final and official TCP/IP documents start out as an Internet draft (working document)
Upon recommendation from Internet authorities, the draft may be published as a Request for Comment (RFC)
Each RFC is edited, assigned a number and made available to all interested parties. RFC’s go through maturity levels and are organized according to their requirement level
The six maturity levels are: proposed standard, draft standard, Internet standard, historic, experimental and informational
RFC’s are classified into 5 requirements levels: required, recommended, elective, limited use and not recommended
You can secure RFC’s: regular mail, , ftp or Internet (
Dr. Clincy
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21. Introduction and Overview
Dr. Clincy
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22. Introduction and Overview
Protocols – set of rules that governs data communications – defines what is communicated, how it is communicated and when it is communicated
Protocol elements are:
Syntax – structure or format of the data (order of the bits)
Semantics – meaning of each section of bits – how to interpret the pattern of bits
Timing – deals with (1) when the data should be sent and (2) how fast it should be sent (ie. a Tx can overload a Rx and therefore data can be lost or mis-interpreted)
More clarity: the TCP/IP protocol allows one to specify data communications without understanding the details of the underlying hardware.
Dr. Clincy
Lecture 1

23. Why Study OSI?
Still an excellent model for conceptualizing and understanding protocol architectures
More granularity in functionality - more functional delineation
Key points:
Modular
Hierarchical (chain of command, pecking order)
Boundaries between layers (called interfaces)
NOTE: the protocols or functionality with in the layer could change however, the interface remains the same – this facilitates the flexibility
Dr. Clincy
Lecture 1

24. OSI Reference Model ? OSI – Open Systems Interconnection
Set of rules of how to transmit data across a network
at the lower levels of the model protocols define the electrical and physical standards
at the lower levels, the bit ordering, the transmission of the bits, and error detecting and correcting are defined
at the higher levels of the model, the protocols define the data formatting, message syntax, dialogue management, message sequences and info presentation
Dr. Clincy
Lecture 1

25. Advantages of Layering
Easier application development
Network can change without all programs being modified
Breaks complex tasks into subtasks
Each layer handles a specific subset of tasks
Communication occurs
between different layers on the same node or stack (INTERFACES)
between similar layers on different nodes or stacks (PEER-TO-PEER PROCESSES
Dr. Clincy
Lecture 1

26. OSI’s Layered Approach Example
Network A
Network B
Actual commands invoked, presentation
Top Layer
Some Intermediate Layer
Bottom Layer
Top Layer
Some Intermediate Layer
Bottom Layer
Facilitate the actual communications
Network interfaces, raw bits
How does peer-to-peer communication work ?
Dr. Clincy
Lecture 1

27. OSI Application Open Systems Interconnection Presentation Session
Transport
Network
Data Link
Physical
Open Systems Interconnection
Developed by ISO
(International Organization for Standardization)
Contains seven layers
Dr. Clincy
Lecture 1

28. OSI Reference Model ? Bottom 3 layers Top 4 layers
Bottom 3 layers responsible for getting the info to the destination
(Bottom 3 layers): at the lower levels of the model protocols define the electrical and physical standards
(Bottom 3 layers) at the lower levels, the bit ordering, the transmission of the bits, and error detecting and correcting are defined
Top 4 layers
at the higher levels of the model, the protocols define the data formatting, message syntax, dialogue management, message sequences and info presentation
Dr. Clincy
Lecture 1

29. Ch 2: TCP/IP and OSI
Lecture 2
Dr. Clincy
Lecture 2

30. OSI Physical Layer Responsible for transmission of bits
Always implemented through hardware
Encompasses mechanical, electrical, and functional interfaces
Encoding issues: how 0’s and 1’s are converted to signals
Transport medium: Coaxial, Twisted Pair, Optical, etc..
Transmission Rate/Data Rate – how fast to send bits
Transmission mode: transmission direction (simplex, duplex)
Physical Topology: network layout
Dr. Clincy
Lecture 2

31. OSI Data Link Layer
Responsible for error-free, reliable transmission of data
Framing, Flow control, Error control (detection/correction)
Makes use of physical address because with in the same network
Network Layer
Data Link Layer
Physical Layer
Actually sends the packets (groups of frames) from node to node using a routing algorithm
Takes raw data (bits) and transform them into frames, error control, etc.
Transmit and receive the raw data (bits)
Dr. Clincy
Lecture 2

32. OSI Data Link Layer
Dr. Clincy
Lecture 2

33. OSI Network Layer Responsible for routing of messages through networks
Concerned with type of switching used (circuit v. packet)
Handles routing among different networks
NOTE: with in the same network, only the DATA LINK layer is needed – amongst multiple networks, the NETWORK LAYER is needed
No need for routing with in the same network (LAN)
Routing across “internetworks”
Makes use of logical address vs physical address because not with in same network
Dr. Clincy
Lecture 2

34. OSI Network Layer Transport Network Layer Data Link Layer
Concerned with an error-free end-to-end flow of data
Actually sends the packets (groups of frames) from node to node using a routing algorithm
Takes raw data (bits) and transform them into frames
Dr. Clincy
Lecture 2

35. OSI Network Layer
Dr. Clincy
Lecture 2

36. OSI Transport Layer Isolates messages from lower and upper layers
Breaks down message size (segmentation) (down) and performs re-assembly (up)
Monitors quality of communications channel (oversee all hops)
Selects most efficient communication service necessary for a given transmission (could change over hops)
Flow and Error control for Source and Sink
Dr. Clincy
Lecture 2

37. OSI Session Layer
Establishes logical connections between systems (up/down)
Manages log-ons, password exchange, log-offs (up/down)
Terminates connection at end of session (up/down)
Dr. Clincy
Lecture 2

38. OSI Session Layer
Dr. Clincy
Lecture 2

39. OSI Presentation Layer
Provides format and code conversion services
Examples
File conversion from ASCII to EBDIC
Invoking character sequences to generate bold, italics, etc on a printer
The source and sink could operate using different encoding schemes – the presentation layer makes the translations
Security
Compression
Dr. Clincy
Lecture 2

40. OSI Application Layer
Provides access to network for end-user (end-user being a human being or software application)
User’s capabilities are determined by what items are available on this layer (ie. remote log-in, file transfer, service, directory service, etc.)
Dr. Clincy
Lecture 2

41. What happens at the End and Intermediate Nodes ?Rx Tx 7
Intermediate Nodes 3 1 1 B C Q T A Z
Dr. Clincy
Lecture 2

42. Recap - OSI’s Layered Approach
between different layers on the same node or stack (INTERFACE)
between similar layers on different nodes or stacks (PEER-TO-PEER PROCESSES)
Dr. Clincy
Lecture 2

43. An exchange using the OSI model
Explain encapsulation and decapsulation
Dr. Clincy
Lecture 2

44. COMPLEXITY TO CONSIDER
Any particular node in an internetwork can be functioning as follows simultaneously:
Tx to other internetwork nodes
Rx from other internetwork nodes
Intermediate node to some other internetwork nodes
Dr. Clincy
Lecture 2

45. OSI in Action: Outgoing File Transfer
The File Transfer Program issues a command to the Application Layer
Application passes it to Presentation, which may reformat, encrypt, encode, compress, passes to Session (adds overhead)
Session requests a connection, passes to Transport (adds overhead)
Transport breaks file into chunks, adds error-checking and flow-control info, process-to-process, passes to Network (adds overhead)
Network selects the data’s route (internetworking), passes to Data Link (adds overhead)
Data Link adds error-control and flow-control info, passes to Physical (adds overhead)
Physical translates bits to signal and transmits the signal, which includes information added by each layer
Dr. Clincy
Lecture 2

46. OSI in Action: Incoming File Transfer
Physical receives signal and translates to bits, passes to Data Link
Data Link checks for errors and performs flow control on bits, formulates bits into some formation (frames), passes to Network
Network verifies routing (if intermediate node, determines next hop), passes to Transport
Transport checks for errors and performs flow control on the chunks, reassembles the chunks, passes to Session
Session determines if transfer is complete, may end session, passes to Presentation
Presentation may reformat, perform conversions, decode, decrypt, decompress, pass to Application layer
Application presents results to user (e.g. updates FTP program display)
Dr. Clincy
Lecture 2

47. US Postal System Analogy
Illustrate how the US Postal System is very similar to how networking works
Will help students better understand (versus memorize) networking
Upper Layers – creating and interpreting the signal, data or info
Lower Layers – getting the signal from one place to the next
Dr. Clincy
Lecture 2