Network Layer

Question 1

How does routing work?

Answer 1

Each router has a forwarding table (maps destination address to outgoing interfaces)
Upon receiving the packet:
- inspects destination IP address in header
- determines outgoing interface
- forward the packet out that interface
(next router in path repeats the process)

Question 2

What does routing algorithm do?

Answer 2

Decides which output line and incoming packet should be transmitted

Question 3

What are some examples of routing algorithms?

Answer 3

Non adaptive: static decision making process

Adaptive: dynamic decision making process

Question 4

What is hierarchical routing?

Answer 4

As networks grow in size, routing tables expand - impacts on performance and memory requirements.
Dividing routers into regions allows efficiencies: each router knows

Question 5

Routing tables are based around triple

Answer 5

IP address
Subnet mask
Outgoing line (physical or virtual)

(longest mask always used when choosing route)