Lab 7

Networking and Telecommunications

Goal

The purpose of this lab to review major network operations

Step 1 - HUBs

Review the following Animation: Understand Hubs through animation Answer the following questions: Answer the following questions:

  1. Why are hubs problematic?
  2. If hubs are so bad, why do they exist?

Step 2 - Switches

Review the following Animation: Understand Switches through animation

  1. Why are switches better than hubs? Give at least three reasons
  2. what does it mean that switches are contention free?
  3. Consider two switches that are linked, with each connected to several computers. What happens when a computer on one switch needs to talk to another computer connected to the other switch?
  4. At what OSI level are hubs and switches?

Step 3 - ARP (Address Resolution Protocol)

Review the following Animation: Understand ARP through animation

Answer the following questions:

  1. What is the purpose of ARP?
  2. If ARP did not exist, an alternative would be to manually provide all MAC addresses you need to communicate. Why is this not a good idea?
  3. If a computer needs to send a packet to a device not on the local LAN (e.g. on the other side of a router), what MAC address will the ARP process return? Why?
  4. At what OSI level are ARP packets?

Step 4 - Routing

Review the following Animation: Understand Routing through animation

Answer the following questions:

  1. What is the role of ARPing in the routing process?
  2. Is routing involved if the two computers communicating are on the same LAN?
  3. How does a computer figure out that a packet's destination is not on on the same LAN it is on?

Step 5 - OSI Model

Review the following Animation: ISO and TCP Routing

Answer the following questions:

  1. Why is TCP considered the lowest "end-to-end" protocol? What does this mean?
  2. What is congestion, and why does it cause packet loss?
  3. Why are the Datalink headers removed and then replaced at each intermediate router in the transmission process?
  4. What specifically is different about the data link packet header after it leaves a router from before it enters the router?

Step 6 - TCP Connections

Review the following Animation: TCP Connection Process

Answer the following questions:

  1. What is the purpose of the three-way connection handshake for TCP?
  2. What could happen if the connection process only involved just one, ot just two packets, rather than three?

Step 7 - UDP

Review the following Animation: UDP Animation

Answer the following questions:

  1. Why have a protocol like UDP if TCP is more reliable?
  2. What is the purpose of port numbers used in UDP?

Step 8 - TCP Flow Control

Review the following Animation: TCP Flow Control Animation

Answer the following questions:

  1. Why does TCP need Flow control? What could happen without it?
  2. How does limiting the window size act to "slow down" transmission from the send to the receiver?
  3. Is it possible for the receiver to completely stop the transmitter for awhile? How? Why would this need to happen?

Step 9 - SMTP

Review the following Animation: e-mai Animation

Answer the following questions:

  1. Why are email servers used rather than sending email directly to the destination computer?
  2. Why does the email server require authentication from the email client?
  3. Why is email encrypted between email servers?

Step 10 - Lab Assessment

  1. Did this lab help you understand or reinforce networking networking concepts?
  2. Which steps did you find the must beneficial? Which the least?
  3. Would this lab have been more beneficial earlier in the class. Or was this a good time for this lab?
Answer all question and turn into Moodle.
Topic revision: r4 - 2014-11-14 - JimSkon
 
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