protocol stack through a role playing game Based on : Norman - - PowerPoint PPT Presentation
Introduction to the TCP IP protocol stack through a role playing game Based on : Norman Pendegraft. 2003. The TCP/IP game. In Current issues in IT education, Tanya McGill (Ed.). IGI Publishing, Hershey, PA, USA 117-124 Acknowledgment: Many
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Based on : Norman Pendegraft. 2003. The TCP/IP game. In Current issues in IT education, Tanya McGill (Ed.). IGI Publishing, Hershey, PA, USA 117-124
Acknowledgment: Many thanks to Ozden Nyiaz for assisting in the preparation of these slides
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Players are organized into four-person teams that represent different computers in the network.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Δρ. Χαράλαμπος Ζ. Πατρικάκης
2.2.2.2 22-22 1.1.1.1 11-11 3.3.3.3 33-33 4.4.4.4 44-44 5.5.5.5 55-55 6.6.6.6 66-66 7.7.7.7 77-77 8.8.8.8 88-88 9.9.9.9 99-99
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Each person in the team assumes the role of one layer.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Creates messages Breaks the message into several smaller messages if necessary Addresses and routes the message Formats the message and performs error control Transmits the message to the physical layer of the destination computer
Δρ. Χαράλαμπος Ζ. Πατρικάκης
SMTP From To Message Message (Continued)
_ _
ID of your computer ID of destination computer Type any message you wish to send up to 20 characters. Use a hyphen (-) to indicate spaces between words
message on the blank piece of paper. This will help you understand the responses you get to your messages.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
SMTP From To Message Message (Continued)
_
_
Break the SMTP message into smaller packets. Cut the SMTP packet into two parts at the dotted line.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
TC P Sequence Number User Data
_ of _
If there is only one part of the SMTP packet, write "1 of 1" in the Sequence Number box.
SMTP
From To
Message
If it’s blank
Message (Continued)
Find one or two blank TCP packets.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
TC P Sequence Number User Data
_ of _
If there are two parts of the SMTP packet, write "1 of 2" on the first TCP packet.
SMTP
From To
Message
TC P Sequence Number User Data
_ of _
"2 of 2" on the second TCP packet.
Message (Continued)
Δρ. Χαράλαμπος Ζ. Πατρικάκης
TC P Sequence Number User Data _ of _ SMTP From To Message Pass the message to the network layer. Tape the SMTP packet(s) to the TCP packet(s) over the User Data space.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
IP Final Destination Next Node User Data _ . _ . _ . _ _ . _ . _ . _ Put the IP address of the PC corresponding to the PC of the To box of the SMTP packet
SMTP
From To
Message
Next computer’s IP address in the network map
TC P Sequence Number User Data
SMTP
From To
Message
Find a blank IP packet.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Final Destination Your Computer
If your computer is directly connected to the final destination computer, the “Next Node” is the same as the final destination.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
If your computer is not directly connected to the destination, you must select the best route that the message should follow and specify one of the computers to which you are connected.
Your Computer Final Destination
Δρ. Χαράλαμπος Ζ. Πατρικάκης
IP
Final Destination Next Node User Data
_ . _ . _ . _ _ . _ . _ . _
TC P Sequence Number User Data
_ of _
SMTP From To Message _ _
Pass the message to the data link layer.
Tape the TCP + SMTP packet to the IP packet over the User Data space.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _ _ _
Your computer’s MAC address
IP Final Destination Next Node User Data _ . _ . _ . _ _ . _ . _ . _
TC P Sequence Number User Data
_ of _
SMTP
From To
Message
_ _
*
1st message 01 2nd message 02
Number of hyphens
Put the MAC address of the PC corresponding to the PC of the Next Node box of the IP packet.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _ _ _ IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
Pass the message to the physical layer. In a few moments, the physical layer will return the packet to you. Tape the SMTP + TCP + IP packet to the Ethernet packet over the User Data space.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _ * _ _ IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
Δρ. Χαράλαμπος Ζ. Πατρικάκης
error in transmission by tossing two coins; if they are both heads, you will introduce an error. Change the number in the error box to your new calculation.
the supervisor of the lab/course. He/she may decide to introduce an error (you will not know about it)
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _ _ _
IP Final Destination Next Node User Data TC P Sequence Number User Data
SMTP
From To
Message
Take a picture of the original packets via your mobile phone. Save the picture for next steps.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _ _ _ IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
Pass the original SMTP + TCP + IP + Ethernet packet back to the data link layer and make sure that that person understands that you are giving back the message that he/she just gave you to transmit.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _
ACK
NAK
_ _ IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
address is listed in the Destination box. Things are complicated enough without ACKs and NAKs getting destroyed.
Control Messages
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _
_ _ IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
If the Control box contains an asterisk (*), this is a data message. Perform error
TCP packet, and the IP packet [but not the Ethernet packet]). If this number is the same as the number in the Error box, no errors have occurred. If they are different, an error has occurred.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
If no errors have occurred in data message
Ethernet Source Destination Control Message# Error User Data
_ _ : _ _ _ _ : _ _ _ _
Find a blank Ethernet packet.
Your MAC address
Write the Ethernet address contained in the Source box of the incoming message
ACK
Write the two-digit number contained in the Message Number box of the incoming message in the Message Number box Pass the outgoing ACK message to the physical layer.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _
_ _ IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
Pass the incoming SMTP + TCP + IP packet to the network layer.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
If an error has occurred in data message
Ethernet Source Destination Control Message# Error User Data
_ _ : _ _ _ _ : _ _ _ _
Find a blank Ethernet packet.
Your MAC address
Write the Ethernet address contained in the Source box of the incoming message
NAK
Write the two-digit number contained in the Message Number box of the incoming message in the Message Number box Pass the outgoing NAK message to the physical layer. Throw away the incoming message containing the error.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _
ACK
_ _
Find the original message you sent, from the photo that you have taken for next steps, that has the same message number as the ACK. Destroy the original message and the ACK.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Ethernet Source Destination Control Message# Error User Data _ _:_ _ _ _:_ _
NAK
_ _ IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
If the Control box contains an NAK, this is an NAK message.
Find the original message you sent, from the photo that you have taken for next steps, that has the same message number as the NAK. Give the original message to the physical layer to transmit again. In a few moments, the physical layer will return the packet to you. Destroy the NAK.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
If it’s your IP address
Δρ. Χαράλαμπος Ζ. Πατρικάκης
IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
Remove the IP packet from the SMTP + TCP packet and throw the IP packet away Pass the SMTP + TCP packet to the transport layer
Δρ. Χαράλαμπος Ζ. Πατρικάκης
IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
If it’s someone else’s IP address
Δρ. Χαράλαμπος Ζ. Πατρικάκης
IP Final Destination Next Node User Data _ ._. _ ._ _ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
Scratch out or erase the address in the Next Node
computer in the network map to which the message should be sent and writing its data link layer address in the Next Node box.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
IP Final Destination Next Node User Data _ ._. _ ._ Old IP _ ._. _ ._
Remove the IP packet from the SMTP + TCP packet and throw the IP packet away Substitute the IP part with the new one Pass the message to the transport layer.
IP Final Destination Next Node User Data _ ._. _ ._
New IP
_ ._. _ ._ TC P Sequence Number User Data _ of _
SMTP From To
Message
_ _
Δρ. Χαράλαμπος Ζ. Πατρικάκης
TC P Sequence Number User Data _ of _ If the Sequence Number box says "1 of 1": The message is completed.
SMTP From To Message _ _
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Pass the SMTP packet to the application layer Take the TCP packet off of the SMTP packet and throw away the TCP packet TC P Sequence Number User Data _ of _
SMTP From To Message _ _
Δρ. Χαράλαμπος Ζ. Πατρικάκης
TC P Sequence Number User Data _ of _ If the Sequence Number box says "1 of 2": The message is not completed.
SMTP
From To
Message
_ _
TC P Sequence Number User Data _ of _ Wait for the second part of the message (2 of 2) to arrive.
Message (Continued)
Δρ. Χαράλαμπος Ζ. Πατρικάκης
TC P Sequence Number User Data _ of _
SMTP
From To
Message
_ _
TC P Sequence Number User Data _ of _
Message (Continued)
Take the TCP packets off of both SMTP packets and throw away the TCP packets
Δρ. Χαράλαμπος Ζ. Πατρικάκης
SMTP From To Message _ _ Message (Continued) Tape the two parts of the SMTP packet back together.
Δρ. Χαράλαμπος Ζ. Πατρικάκης
SMTP From To Message Message (Continued)
_ _
Pass the SMTP packet to the application layer
Δρ. Χαράλαμπος Ζ. Πατρικάκης
Eventually, you will receive an incoming message from the transport layer that was sent to you by some other computer asking you a question. To respond to the message, you will send a message that answers the question. Follow the same steps above to send a message write your answer in the Message box. For example, if the message you received asked what your favorite color was, you might write red or blue in the Message box.