The picture

CS70 Network Fundamentals & Architecture


David Morgan
Santa Monica College
see syllabus for email address
Our curious network:
Not any Damsel, which her vaunteth most
In skilful knitting of soft silken Twine;
Nor any Weaver, which his Work doth boast,
In Diaper, in Damask, or in Lyne;
Nor any skill'd in Workmanship emboss'd;
Nor any skill'd in Loups of Fingring fine;
Might in their diverse Cunning ever dare
With this so curious Net-work to compare.
       Edmund Spenser



Course outline

Zoom meeting recordings

Homework schedule

Grade information

Home network map


SMC dates/deadlines


Reading list, per chapter:
 6th edition
 5th edition

Remote Unix accounts


Textbook's website

RFC lookup

Remote Unix access with ssh

Protocols: non-cyber examples

MAC address assignments
 - listing
 - search

TCP/IP - Intro to the IP Protocols

TCP/IP Pocket
Reference Guide
 - IPv4 version
 - IPv6 version

Wireshark doc
html   pdf

Network calculators:
  here's one
  and another
  and a third

Real world DSL
  - a DSL order

commercial routers

Selected protocols






echo (port 7)

discard (port 9)

chargen (port 19)



FALL 2021
Section 1793 Online

This Website (  will be used extensively to communicate with you. Announcements, grade reports, and assignments will be posted here. You are responsible for awareness of the information posted here.

Announcements/grades/current topics

Homework - 
view and listen - to the several video and audio links in course outline section 4 homework column.
view, listen, read - about undersea cabling at the several links in the post below.
- get started, readings shown in the course outline through section 4; also read forward to succeeding sections as you have time, to prepare for upcoming topics.
do - the "ethernet frames" assignment in course outline section 4 homework column.
due on sputnik in the "assignments" subdirectory of your home directory end-of-day Wednesday 9/22 (9/16)

Undersea cabling - former student Philip Postovoit did the service of researching cabling quite thoroughly. Of the many links about it he sent me, I found particularly interesting:
submarine cable map (click individual cables)
manufacture, shipboard loading, seabed laying youtube video
Haut debit en eau profonde (French)
Transatlantic data cable by Microsoft/Facebook/Telexius completed.
"Contrary to conventional wisdom, satellites play a minimal role in the operation of the internet. Nearly 99% of international phone and data traffic goes through [submarine cables] like ours." Patricia Boulanger, Alcatel Submarine Networks 

Undersea fiberoptic cable landing point (Spain)


What other data link protocols besides ethernet are out there? You might instead have
  point-to-point protocol ("dial up")
  frame relay
  asynchronous transfer mode (ATM)
  802.11 ("wi-fi") in part  

What's the difference?
ARPANet, Leonard Kleinrock's network (now, the Internet), used dedicated connections between computer nodes. He made a phone call to Stanford from UCLA. The wire employed belonged to the phone company. The wire was not used by any other nodes, during the phone call. It was not shared. It was dedicated. Nodes that used it owned it and did not have to compete for it with any other nodes.
ALOHAnet, Norm Abrahamson's satellite based network among islands in Hawaii, used a satellite that could service only one connection at a time, and that all participating computer nodes had to use. So necessarily, nodes had to share it. It was non-dedicated. Nodes that used it did not own it and had to compete for it with all other nodes.
Ethernet was derived from ALOHAnet, and relied on a shared medium too. But while the ALOHAnet medium was radio to the satellite, the ethernet medium was a copper wire. (9/16)

Norm Abramson    4/1/1932 - 12/1/2020 


Grades - have been published, at the link entitled "Grade reports" at left. They include the "exercising wireshark" assignment in addition to the initial wireshark screenshot upload. There is a cumulative (weighted) average of these two. The cumulative average will be maintained to incorporate future work, assignment by assignment as they are completed, over the semester. Please look yourself up by the same anonymous 5-digit value you derived in calculating your sputnik remote server password. Please call any anomalies to my attention. (9/16)

Grades - have been published, at the link entitled "Grade reports" at left. Please look yourself up by the same anonymous 5-digit value you derived in calculating your sputnik remote server password. Please call any anomalies to my attention. (9/13)

By popular demand - at least 2 students in class tonight expressed interest in this bash cheat sheet (summary by a former student of things you can do using the command line in linux or mac). (9/9)

Green light - go ahead and download the vmconfigure scripts for your platform ("bash" version for linux/apple, "batch" version for Windows). In class tonight I had asked you to wait till I could test and confirm them. I did. They are OK. They serve to set up machines for your wireshark homework, below. (9/9)

upload - for homework this past week you made a screenshot of Wireshark after it had captured some network traffic. Please upload that file to the "assignments" directory under your home directory on the remote server, using your remote Unix system account. (This is how you will routinely submit homework.) due on sputnik in the "assignments" subdirectory of your home directory end-of-day Sunday, September 12
do - the exercise at the link on the course outline's section 3 entitled "wireshark" It is labeled as "in-class exercise" but becomes homework you will do outside of class.
When you perform it the result will be 3 screenshot files that you produce in the course of performing the exercise:

statistics-udp.jpg (or .png)

I ask you to place these into a zip file named "" and upload it to your assignments directory. (Please ignore the questions you will see at the bottom of the assignment page. They are not for you. I only want the screenshots.) due on sputnik in the "assignments" subdirectory of your home directory end-of-day Wednesday, September 15  (9/9)

RFC process - how protocols get created. Here is a current example, HTTP 2 which was published as an RFC in May, 2015. See in particular the development timeline that has led it to this point. (9/9)

Screenshot of Microsoft Network Monitor. Compare the interface with Wireshark's. It demonstrates the product category (network "sniffers") to which both products belong.

Screenshot, Microsoft's Network Monitor sniffer

(Network Monitor comes with the Server editions of Windows and won't be found in our consumer editions.)  (9/9)

Remote server access how-to video. Several programs that provide login connection to a remote server, file transfer connection, or both, are discussed and demonstrated. These are the tools for accessing (9/3)

Homework - 
1) read all the announcements below and follow all the links they contain. I will expect you to be familiar with the information they convey.
2) do the reading and homework shown in the "Reading" and "Homework" columns of the course outline's topic #1.
3) make progress in installing VirtualBox on your computer, and my delivered VM in VirtualBox (see link below entitled "Obtaining and installing". (9/2)

Opportunity - ICANN (Internet Corporation for Assigned Names and Numbers) "Shaping the Future of the Internet: ICANN's Newcomer Programs"   (8/30)

Opportunity - NASA community college aerospace scholars program (8/30)

Course outline - with rough weekly topic coverage corresponded to related readings, homework assignments, and in-class slides I will use. Please follow this outline as we move through the topics, for assignments and reading I want to assign.

A virtual machine (VM) for you - hands-on lab exercises will be performed on a virtual machine that you can run in your own computer.
- Obtaining and installing your VM
     (direct link to fedora31-spring21.ova file on Google Drive)
- Transferring files in and out of it if necessary (accompanying howto video)
- Your VM's configuration
- VirtualBox networking "complete guide" - a good website on the subject

A Remote Unix system account is available for your use.

Using ssh (secure shell). ssh is an important tool you will use for interacting with remote computers. For that you will need an ssh client. There are a number of ssh client alternatives.

Distributing files from sputnik to the class as a whole,  publicly - the above file transfer discussion describes file movement to and from your own home directory, exclusive to you. Sometimes I will want to have someplace to put a file so everybody can get to it and download it. When I do that, here's how to download them.

Dates and deadlines
Class Census Day: SEP 13, 2021
Class 60% Day: NOV 4, 2021
Last Day to Withdraw to Receive a Refund: SEP 12, 2021
Last Day to Withdraw to Avoid a "W": SEP 12, 2021
Last Day to Withdraw to Guarantee a "W": NOV 20, 2021
Last Day to Request for Pass/No Pass Grade: NOV 20, 2021

Cover art on Tannenbaum textbook:

Networking textbook cover graphic

What is it??

"Number please?" asks the switchboard operator. The switchboard is a board. It's for switching. Switching changes a circuit between you and somebody. It can complete a circuit to your Aunt Bheulah in Iowa City so you can thank her for the knit socks. After you hang up if you want to call your uncle in Waco you'll need to switch circuits, to get a circuit to him instead of her. That's what the operator does for you. The "switch"ing in "switch"board is circuit switching. Nowadays in computer networks it's not circuit switching anymore, it's packet switching.

Phone swithboard operators c. 1950s


Functional layering - the famous "Open Systems Interconnect" model is depicted below. Somebody once had the idea that maybe there could be a way to get independent computer systems of different types to be able to exchange information with one another. The diagram blueprints the idea for "how in the world are we going to make that work??" That idea is the subject of this course.

The 7 layers of the OSI model

First-day administrative information you will need to know:

Running linux at home.

Slides available online - for most if not all slides I will show in class. Links to them can be found in the "Slides" column of the course outline.

Course-long textbook reading - a chapter-by-chapter list ( 6th edition, 5th edition ). The textbook is divided into chapters and they in turn into numbered sections. The list tells you which sections to read for this course when chapters are assigned. For example if I assigned chapter 10 and it had 17 sections, if this list specifies "10.1-100.5, 10.7, 10.12-17" it means I didn't feel sections 10.6 nor 10.8-11 were relevant enough so I only list the balance of the chapter. Read unlisted portions for your own interest if you wish, but the listed sections are what's officially assigned to you.

Textbook - Computer Networks and Internets, sixth edition, Douglas Comer, Pearson Prentice Hall , 2015.

Wireshark - is an excellent free packet capture utility. What is a packet, and why caputre it? We'll talk about that later. I will ask you to install and use Wireshark later in the semester, assuming you have a linux or windows computer available on which to do so. Please visit Wireshark's home page.




First message by telegraph 1844

"What hath God wrought?"
May 24, 1844

First message by telephone 1876

"Mr. Watson come here, I want to see you."
March 10, 1876

First message by internet 1969

October 29, 1969