Module 11: Intro to Wireless Networks Flashcards
Wireless network: base station
What is a Wireless Host?
Laptop, PDA, IP phone
Run applications
May be stationary or mobile
What is a Base Station?
What is network infrastructure?
Describe infrastructure mode.
What is Ad Hoc mode?
What are key differences between infrastructure and ad hoc?
Different types of wireless networks
Wireless links: high bit error rate
Dealing with bit errors
What are some limitations of wireless links?
Broadcast limitations
802.11 infrastructure
CSMA In Wireless
Exposed Terminal Problem
Maintaining Ongoing Transfers
What’s the issue?
changing IP addresses
Describe adv/dis of how routing protocol handles changing IP due to mobility
Home Network and Home Agent
3 true things about indirect routing
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
Describe the inefficiency in indirect routing
How do we solve the triangle routing problem?
caching
What are reasons for Packet loss in Wireless TCP?
Why does TCP’s normal response to packet loss make matters worse in the context of wireless networks?
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.
What is a solution to wireless TCP?
split connection protocols
What is the disadvantage for split connection protocols?
Solution 2: Transport aware link protocol
Solution 3: TCP wireless aware sender
What is the base station responsible for in TCP snoop?
- monitor traffic
- retransmit packets
- discard acknowledgements
