Capítulo 15 conexões de lans, redes backbone e lans virtuais
Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.
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Transcript of Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.
![Page 1: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/1.jpg)
Internet-based Fault Recovery for Home Wireless LANsAuthor: UnknownPresenter: Thomas Donahoe
![Page 2: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/2.jpg)
EWLAN vs RWLANHigh speed wired backbone
Centralized controller
Admin coordinates wireless
No private wired connection
Not centralized
No coordination
![Page 3: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/3.jpg)
EWLAN Benefits for RWLAN
Internet as the backbone
Decentralized approach
Automated (no admin)
RxIP: a decentralized network diagnostic and recovery tool, initially targeted at hidden terminal mitigation
![Page 4: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/4.jpg)
RxIP: How will it work?
1. Detect hidden terminal problem
2. Isolate the hidden terminal
3. Recover by coordination (token system)
![Page 5: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/5.jpg)
Is there a hidden terminal?
AP 1 AP 2
A B
Success!
Fail!
Collision!
Success!
Asymmetry delivery ratio or bitrate for upload vs download
![Page 6: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/6.jpg)
Is there a hidden terminal?
AP 1 AP 2
A B
I hear A’s ACK
Where is
AP1’s DATA?
ACK
DATA
![Page 7: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/7.jpg)
Which is the hidden terminal?
RxIP AP’s record timestamp
Challenge-response protocol via the internet
H.T.?
![Page 8: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/8.jpg)
Which is the hidden terminal?
Loss + Concurrent (Collision)
Success + Concurrent (No Collision)
Loss + Not Concurrent
Success + Not Concurrent
Saturation Counter
H.T.?
![Page 9: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/9.jpg)
Recovery By Coordination
Token passed back and forth
AP’s “purchase” transmission timeslot
Abstain notification
![Page 10: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/10.jpg)
Recovery By Coordination
More HT = more complicated
Must purchase from every partner
![Page 11: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/11.jpg)
RxIP: What else?
Ideal token passing (NP hard)
No deadlock
Token loss
Incrementally deployable
Internet latency
![Page 12: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/12.jpg)
Evaluation
![Page 13: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/13.jpg)
Evaluation
![Page 14: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/14.jpg)
Evaluation
![Page 15: Internet-based Fault Recovery for Home Wireless LANs Author: Unknown Presenter: Thomas Donahoe.](https://reader035.fdocuments.us/reader035/viewer/2022070403/56649f325503460f94c4e138/html5/thumbnails/15.jpg)
Questions?