Ethernet Quiz
1) Suppose computer #1 begins to transmit a packet that is 1400 bytes long. After 1,200 bytes of transmitting, a collision is detected. What should computer #1 do? 
2)Is this an error, or a normal acceptable event? 
3) Ethernet has a theoretical efficiency of ~38%. What is the practical limit to how fast a 100 Mb ethernet can send data? 
      About 15 Mb/second 
About 30 Mb/second 
About 38 Mb/second 
About 90 Mb/second 
4) I've just invented a new network, the Thumpernet. It has a latency of 3 ms one way, and a bandwidth of 1 megabit/second. How long does it take to send a 300 kilobyte jpg file? 

5) Suppose a packet is sent on an ethernet. There are no collisions. Is the packet received by the receiver? 
     Yes, if there are no collisions the packet will be received. 
No, there is no guarantee. For example ... _______________________________________________ 
6) A normal ethernet might have a latency of 0.5ms, and a bandwidth of 100Mbit/second. What is the most time it can take to send a 1 kilo-byte file? 

7) Give one advantage of Token Ring over ethernet, and one disadvantage 

8) Normally, an ethernet card will wait a random amount of time after a collision before it begins to retransmit. Suppose I modify my card so this it retransmits immediatly after a collision. What will I, the user, notice? 

9)Suppose everyone in my department does the same thing. What will we notice? 

10) Will an ethernet receiver ever receive a packet other than the one transmitted. In other words, can corrupted data ever be received? Explain. 

11) Suppose two cards with the same MAC address were placed on different ethernets. What would happen? 

12) My ethernet serves two departments, each with it's own server. It's Tuesday, March 13th. Buffy the Vampire Slayer is on. Half the computers are Macs, the other half PC. Each department has 1/2 the Macs and 1/2 the PCs. I notice that my ethernet is very slow to send data. Further, there are LOTS of collisions. Most of the data sent are image files (we're a graphics workshop). Green iMacs are 10% faster than blue iMacs. What can I do to speed my network? Feel free to draw a picture, if that helps (or don't if it does not). 

13) Suppose I ethernet keep as it is, except that I double the maximum cable length. What else must I change (if anything)? 

14)  Suppose I have a 100 megabit/sec ethernet.  I want to send a CD-ROM full of data.  A CD holds 660 mega bytes.  How long with this take about.  Just be within 50% or so.

15) Suppose I have a very lightly loaded network. My one goal is to minimize the average latency of small messages. Which is the best type of 
network. Why? 
10 megabits/sec Ethernet. Why: _______________________________________________ 
10 megabits/sec Token Ring. Why: _____________________________________________ 
16) Batman and Wonder Woman are fighting over who has to do the dishes next. Batman throws the first punch. Who wins? Why?