1. Vocabulary
Prototype: A preliminary sketch of an idea or model for something new. It’s the original drawing from which something real might be built or created.
Binary - A way of representing information using only two options.
Bit - A contraction of "Binary Digit". A bit is the single unit of information in a computer, typically represented as a 0 or 1.
Bandwidth - Transmission capacity measure by bit rate
Bit rate - (sometimes written bitrate) the number of bits that are conveyed or processed per unit of time. e.g. 8 bits/sec.
Latency - Time it takes for a bit to travel from its sender to its receiver.
Protocol - A set of rules governing the exchange or transmission of data between devices.

2. U1L3 Sending Binary Messages With the Internet Simluator
CS Principles
U1L3 Sending Binary Messages With the Internet Simluator

3. U1L3: Sending Binary Messages with the Internet Simulator Objective
SWBAT:
Explain how synchronization and coordination enable the transmission of binary messages.
Develop a protocol for exchanging binary messages in two directions.
Calculate the bit rate for a binary message exchange.
Provide a definition of "bit" and relate it to the binary messages they have seen so far.

4. U2L2 Activity Guide
Discussion

5. Vocabulary Bandwidth - Transmission capacity measure by bit rate
Bit rate - (sometimes written bitrate) the number of bits that are conveyed or processed per unit of time. e.g. 8 bits/sec.
Latency - Time it takes for a bit to travel from its sender to its receiver.
Protocol - A set of rules governing the exchange or transmission of data between devices.

6. Binary Messages Friday you all made your own binary message devices.
We learned that we could compose any number of messages by sending a sequence of states.
In order to interpret the message we needed to know
which signal meant A and which meant B and
some kind of mapping between sequences of signals and a possible message.
What we were really doing was beginning to develop a communication protocol
Today you’re going to develop a protocol to solve a problem.

7. Flashlight Test

8. Prompt
Did this new message make you think about your answer to the first question? Do you want to change your answer to the first question?
What assumptions did you make in interpreting these messages?
Is this protocol specific enough to allow useful communication of a binary message? If not what information would need to be added to it?

9. Internet Simulator
Today we will be using the Internet Simulator to explore some of the challenges of sending bits on the Internet.
This tool simulates a single wire connecting two people who cannot otherwise see or speak to each other.
The Internet Simulator helps to enforce “the binary rule” for sending messages – it will present challenges that they will need to problem solve around.

10. The Internet Simulator
The major challenge is that the wire is SHARED between the two people.
The wire can hold only a single state - A or B - and it can be set by either person at any time.
At any time either person can read the wire to see which state it’s in
misconception: that either partner is “sending” or “receiving” anything. Partners can set and see the current state of the wire.
The challenge of today’s activity is to figure out a way to coordinate actions with your partner to make this tool into a functioning two-way bit-sending device.

11. The 2-bit Message Exchange Challenge!
Students will practice relaying a 2-bit sequence with their partners. The goal is to exchange 2- bit messages (partner sends a 2-bit message, other partner sends a 2-bit message back) as quickly and accurately as possible. In other words, students are trying to get the fastest bit rate possible.
Each initial sender should be able to confirm that the message was received correctly and resent because the message that they have received is the same as the original.
As students iterate and perfect their protocol, they should try to extend their protocol to send more bits or send them more quickly, while maintaining accuracy. When each group has a working protocol and has time to practice (~10 minutes), have an all-class showdown to see who can do it the fastest.

12. Rules for the Challenge:
Student pairs can decide who sends first.
Teacher reveals sequence of bits to be sent. Partner A of each group may enter this sequence of bits into Internet Simulator but may not begin sending them.
Teacher will say “GO” and partners will exchange messages.
During the challenge students may not communicate with one another. (Note: feel free to put partners on opposite sides of a room or in separate rooms altogether.)
Students yell “STOP” once they have completed their exchange.
Teacher will verify that each partner received what the other sent by checking outgoing and incoming messages.