Module 11: Intro to Wireless Networks

Question 1

Wireless network: base station
What is a Wireless Host?

Answer 1

Laptop, PDA, IP phone
Run applications
May be stationary or mobile

Question 2

What is a Base Station?

Answer 2

Question 3

What is network infrastructure?

Answer 3

Question 4

Describe infrastructure mode.

Answer 4

Question 5

What is Ad Hoc mode?

Answer 5

Question 6

What are key differences between infrastructure and ad hoc?

Answer 6

Question 7

Different types of wireless networks

Answer 7

Question 8

Wireless links: high bit error rate

Answer 8

Question 9

Dealing with bit errors

Answer 9

Question 10

What are some limitations of wireless links?

Answer 10

Broadcast limitations

Question 11

802.11 infrastructure

Answer 11

Question 12

CSMA In Wireless

Answer 12

Question 13

Exposed Terminal Problem

Answer 13

Question 14

Maintaining Ongoing Transfers

What’s the issue?

Answer 14

changing IP addresses

Question 15

Describe adv/dis of how routing protocol handles changing IP due to mobility

Answer 15

Question 16

Home Network and Home Agent

Answer 16

Question 17

3 true things about indirect routing

Answer 17

A mobile device can always be reached through the permanent address
The correspondent is the device that wishes to communicate with the mobile device
Foreign agent sends address of visited network to home network

Question 18

Describe the inefficiency in indirect routing

Answer 18

Question 19

How do we solve the triangle routing problem?

Answer 19

caching

Question 20

What are reasons for Packet loss in Wireless TCP?

Answer 20

Question 21

Why does TCP’s normal response to packet loss make matters worse in the context of wireless networks?

Answer 21

TCP assumes packet loss is due to:
1. Congestion
2. Reordering

If the loss is due to weak signal strength, then TCP will reduce its congestion window size and this will actually make the matter worse.

Question 22

What is a solution to wireless TCP?

Answer 22

split connection protocols

Question 23

What is the disadvantage for split connection protocols?

Answer 23

Question 24

Solution 2: Transport aware link protocol

Answer 24

Question 25

Solution 3: TCP wireless aware sender

Answer 25

Question 26

What is the base station responsible for in TCP snoop?

Answer 26

1. monitor traffic
2. retransmit packets
3. discard acknowledgements