The Web and the Internet

Question 1

How many bytes are in 1 Ethernet frame?

Answer 1

64 to 1526 bytes (Payload can be 46-1500 bytes)

Question 2

Why are ethernet frames important to the web?

Answer 2

• know the minimum packet sizes that can be sent
• know the potential waste in a transmission
• know sizes that aren’t fragmented or split
• know when you’ll incur latency due to split packets/frames

Question 3

Why was IPv4 created?

Answer 3

Ethernet is not routable, so we needed a way to communicate to many computers. IP was a compromise to address computers

Question 4

How many bits of address space do IPv4 addresses have?

Answer 4

32 bits

Question 5

Why was IPv6 created?

Answer 5

We ran out of IPv4 addresses

Question 6

How many bits of address space do IPv6 addresses have?

Answer 6

128 bits

Question 7

User Datagram Protocol (UDP)

Answer 7

A communications protocol that allows computers to communicate with each other.
- Data sent is lossy and not ordered
- No connections
- No guarantees that the data is received
- Used for voice calls and media streaming

Question 8

Domain Name Service (DNS)

Answer 8

Allows a name to be binded to another name, IP, or set of IPs

Question 9

What can DNS use to check names?

Answer 9

host, dig, or nslookup

Question 10

Transmission Control Protocol (TCP)

Answer 10

A communications protocol that allows computers to communicate with each other.
- Connections
- 3-packet handshake
- Maintains order
- Used by HTTP, most internet applications

Question 11

Firewalls

Answer 11

Usually prevent hosts from communicating on certain ports, or hosting services