HTTP and DNS
What service works like the Internet’s phonebook, turning a website name into an IP address?
DNS
What are the small numbered chunks a message is split into before it is sent?
Packets
What two addresses does IP put on every packet?
Source and destination IP addresses
What carries bits through a fiber optic cable?
Light
When a message arrives, in what direction are the layers unwrapped?
Bottom up
What protocol do browsers and servers use to request and send web pages?
HTTP
Which protocol numbers packets, checks that they all arrived, and resends any that are missing?
TCP
In the mail analogy, the post office sorting center that reads an address and sends mail onward is like this device.
Routers
What carries bits through a copper wire?
Electrical signals (electricity)
If the physical network fails, what happens to the layers above it?
Nothing gets delivered
What do we call a set of rules that lets devices communicate?
Protocol
Which protocol skips the checking, making it faster but less reliable?
UDP
Why can packets from the same message arrive out of order?
They can take different paths
What does Wi-Fi use to send bits through the air?
Radio waves
An IP address is like a mailing address. How is an Internet message different from a letter?
It is split into packets that take different routes
Before your browser can send an HTTP request, what must DNS give back so it knows where to send it?
An IP Address
Why might a video call choose UDP over TCP, even though some packets can be lost?
Speed matters more than perfect delivery
One router fails, but packets still reach the server by another route. What design feature is at work?
Redundancy
What idea says a layer only needs to know what the layer below it does, not how it does it?
Abstraction
What key property allows the Internet to grow and adapt easily, such as swapping a copper cable for Wi-Fi without redesigning HTTP?
Scalability