📦 Packets
16 Nov 2016🎯 Learning Targets
- I can develop a packet-switching protocol.
- I can explain how the internet is a packet-switched system.
- I can explain the importance of standards for packets and routing include transmission control protocol/Internet protocol (TCP/IP).
Do Now
AP Practice question in Classroom!
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When we began this unit, we simulated the internet at a high level of abstraction, sending simple messages back and forth.
01000010 01110101 01101100 01101100
Then we went down another level of abstraction to expressing those messages using binary.
Then, we went 🆙 a level of abstraction to express those messages using hex.
Last time, we talked about how all of these abstractions are flawed, because they only depict 1:1 communication. Then we played Battleship and you developed your own protocol for simultaneous communication using bits.
Guess what?
Even the IP is a level of abstraction for what actually happens…
Routing
A router is a computer designed to receive and redirect packets of information based upon the IP address contained in the packet.
Routers will either deliver a packet to its final destination or forward it to one of several other routers it is connected to.
This picture is hilariously old looking, but it works:
Packet Switch Relay Race
We’re going to do a simplified packet-switching system. We have packets of information that need to travel across our “network” – this classroom.
Seven of you will be requesting data from the internet. The rest of you will be routers. Your router name is your initials, in ASCII. Mine would be:
42 53 4b
You can use the Unicode Converter to find yours:
As we switch packets, be sure to write your router ID on the ~packet~ envelope.
Packets
TCP Transfer Control…guess!
I’ll let Vint and Lynn explain:
Last time, we developed a protocol that included:
- Sender
- Receiver
- Message
- Success/failure
Assess!
Explain how IP/TCP and DNS are an example of abstraction.
AP Practice questions in Classroom.