L.O: STUDENTS WILL BE ABLE TO EXPLAIN HOW A HIEARCHY OF OPEN

PROTOCOLS MANAGES THE COMPLEXITY OF THE INTERNET.

15-30 minutes (<1 class period)

DO NOW:READ Unit 4 Lab 3: Communication Protocols, Page 3

When you use the internet , a lot of things are going on behind the scenes…

There are billions of devices connected to the Internet, and hundreds of different kinds of

devices: laptops, tablets, phones, refrigerators, handheld credit card readers, and so on.

How do they all know how to find and talk to each

other?

Protocols (standards) ensure that the variety of devices interact with

each other smoothly.There are many many many

internet protocols!

The Internet was designed with several layers of abstraction that sort the protocols according to what part

of the process they support.

Internet Abstraction HierarchyThis hierarchy of abstractions manages the

complexity of the Internet by hiding the details of lower levels of the system.

The highest level of abstraction includes the most general features of the Internet that have to work

the same across all devices. At lowers levels of abstraction, things get more device-specific.

Application Layer Protocols are the highest level of

abstraction because they manage how data

is interpreted and displayed to users.

These protocols give meanings to the bits sent

by the lower protocols.

This is abstraction

because: this is where the bits and bytes (the

ones and zeros of binary) are

turned into what you see on the

screen

HTTP and DNS are examples of application

layer protocols...

use HTTP (HyperText Transfer Protocol) is used by your internet browsers (Safari, Chrome, Internet Explorer) to interpret HTML instructions for page formatting (HTTP turns the ones and zeros into a

webpage)!

DNS (Domain Name System) converts the user friendly web addresses into IP addresses.

Example you type: Youtube.com….DNS turns what you typed into 128.68.111.01. then the internet looks for that IP

address

Your email inbox may use SMTP (Simple Mail Transfer Protocol) to send and IMAP (Internet

Message Access Protocol) to read email.

Transport Layer Protocols manage

the breakdown of a message into packets to be transmitted by lower level protocols

and also the reconstruction of the

message from the packets upon arrival.

Transport Layer protocol Examples: TCP (Transmission

Control Protocol and UDP (User Datagram Protocol)

TCP versus UDPTCP (Transmission Control Protocol) used for reliable, long-term connection between two

computers by only displaying data once all packets have arrived. When you want the sent data to be

accurate!

TCP versus UDPWhen speed is more important than accuracy, people use UDP (User Datagram Protocol), such as for real-time video streaming, where one missed

packet doesn't matter much.

Internet Layer Protocols manage the

pathways that the data packets travel

across networks.

These protocols treat the Internet like one large network even

though the physical reality on the lower level is one of many tiny

subnetworks.

Internet Layer Examples: Every device on the Internet needs an IP address so other devices can find it. IP

(Internet Protocol) addresses are upgrading from IPv4 to IPv6. Routers use Internet layer protocols to detect and

work around network congestion.

Network Interface Hardware (Link

Layer): All Internet devices connect

through a physical interface that uses

a protocol to manage the

connection to the local network.

These local protocols are

the least abstract

because they deal directly

with your physical

hardware.

Link Layer Examples: this is the layer of Ethernet cables and WiFi radio antenna inside the case. Both connects computers to a local network router which then connects to an Internet provider. Cell phones use a longer-range cellular connection to a phone

carrier.

Open Protocols• Before the internet, there were several

different network protocols….back then, a particular brand of computer or router could only talk to the SAME computer brand!!!• Today with open standards: all devices on the

internet can “cooperate”. ANY hardware device or software can talk to any other one WITHOUT having to ask permission….

Open protocols:Your T-Mobile can talk to verizon

Open protocols:You can send an email from the US to an enemy country

Open protocols:Your computer with Microsoft can talk to Apple computers.

Make sure you understand these important Internet protocols:

1. HTTP: HyperText Transfer Protocol—the protocol that your browser uses to access an HTML webpage

2. DNS: Domain Name System—the hierarchical addressing protocol that is human-readable

3. TCP: Transmission Control Protocol—the protocol that assures reliable transmission of data

4. IP: Internet Protocol—the hierarchical addressing protocol that manages routing of data between computers; we are upgrading from IPv4 to IPv6 for more addresses

Now: Read Blown to Bits pages 309-312.

Enduring Understandings:

• EU 6.1 The Internet is a network of autonomous systems.• EU 6.2 Characteristics of the

Internet influence the systems built on it.

Learning Objectives:

1. LO 6.1.1 Explain the abstractions in the Internet and how the Internet functions. [P3]

2. LO 6.2.1 Explain characteristics of the Internet and the systems built on it. [P5]

3. LO 6.2.2 Explain how the characteristics of the Internet influence the systems built on it. [P4]

Essential Knowledge:• EK 6.1.1B An end-to-end architectures facilitates

connecting new devices and networks on the Internet.• EK 6.1.1C Devices and networks that make up the

Internet are connected and communicate using addresses and protocols.

• EK 6.1.1D The Internet and the systems built on it facilitate collaboration.

• EK 6.1.1E Connecting new devices to the Internet is enabled by assignment of an Internet protocol (IP) address.

Essential Knowledge:• EK 6.1.1F The Internet is built on evolving standards,

including those for addresses and names.• EK 6.1.1H The number of devices that could use an IP

address has grown so fast that a new protocol (IPv6) has been established to handle routing of many more devices.

• EK 6.1.1I Standards such as hypertext transfer protocol (HTTP), IP, and simple mail transfer protocol (SMTP) are developed and overseen by the Internet Engineering Task Force (IETF).

• EK 6.2.1A The Internet and the systems built on it are hierarchical and redundant.

Essential Knowledge:• EK 6.2.1D Routing on the Internet is fault tolerant

and redundant.• EK 6.2.2B The redundancy of routing (i.e., more

than one way to route data) between two points on the Internet increases the reliability of the Internet and helps it scale to more devices and more people.

• EK 6.2.2D Interfaces and protocols enable widespread use of the Internet.

• EK 6.2.2E Open standards fuel the growth of the Internet.

Essential Knowledge:• EK 6.2.2F The Internet is a packet-switched

system through which digital data is sent by breaking the data into blocks of bits called packets, which contain both the data being transmitted and control information for routing the data.

• EK 6.2.2G Standards for packets and routing include transmission control protocol/Internet protocol (TCP/IP).

Essential Knowledge:• EK 6.2.2H Standards for sharing information

and communicating between browsers and servers on the Web include HTTP and secure sockets layer/transport layer security (SSL/TLS).

• EK 6.3.1M Certificate authorities (CAs) issue digital certificates that validate the ownership of encrypted keys used in secured communication and are based on a trust model.