Ch.3 Fundamentals of WANs and IP Routing

Question 1

Describe the major steps of internal network layer routing for each packet arriving in a router interface

Answer 1

1. Uses the data-link layer (FCS) to ensure the frame has no errors. If errors occured discard the frame
2. Discard the old data-link header and trailer, leaving the IP packet
3. Compare the IP packets destination IP address to the routing table and find the best route to the destination address
4. Encapsulate the IP packet inside a new data-link header and trailer

Question 2

What is the flag header in HDLC

Answer 2

Lists a recognizable bit pattern so that the recieving nodes relize that a new frame is arriving

Question 3

What is the address header in HDLC

Answer 3

Identifies the destination device

Question 4

What is the Control header in HDLC

Answer 4

Mostly used for puposaes no longer in use today for links between routers

Question 5

What is the type header in HDLC

Answer 5

Identifies the type of layer 3 packet encapsulated inside the frame

Question 6

What is the FCS in HDLC

Answer 6

Identifies a field used the error detection process

Question 7

What headers are in the IPv4 header

Answer 7

DS,Protocol, and Time to live