Chapter 1: IP and L3 Tech

Question 1

How large is the IP Header of an IP Packet?

Answer 1

• between 20 and 60 bytes

Question 2

What fields are in an IP Header?

Answer 2

• Version
• Internet Header Length
• Notification and Explicit Congestion
• Total Length
• Identification
• Flags and Fragment Offset
• Time to Live
• Protocol

Question 3

What does an IP Packet that is only 20 bytes long contain?

Answer 3

• Just the IP Packet Header

Question 4

What is the largest IP Packet that Ethernet can transport?

Answer 4

• 1500 bytes

Question 5

What is the Identification field used for?

Answer 5

• used when an IP packet needs to be fragmented due to constraint of Layer 2 (Ethernet) Packet size limits

Question 6

Which IP Header field provides Quality of Service?

Answer 6

• Notification and Explicit Congestion

Question 7

What does the TTL field do?

Answer 7

• prevents IP packets from looping indefinitely
  When the TTL goes to zero, the router discards the packet and sends a message to the sender to tell it that the packet was dropped