Fault Detection, Isolation and Recovery Design for micro ...
Internet-based Fault Recovery for Home Wireless LANs
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Transcript of Internet-based Fault Recovery for Home Wireless LANs
Internet-based Fault Recovery for Home Wireless LANsAuthor: UnknownPresenter: Thomas Donahoe
EWLAN vs RWLANHigh speed wired backbone
Centralized controller
Admin coordinates wireless
No private wired connection
Not centralized
No coordination
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
RxIP: How will it work?
1. Detect hidden terminal problem
2. Isolate the hidden terminal
3. Recover by coordination (token system)
Is there a hidden terminal?
AP 1 AP 2
A B
Success!
Fail!
Collision!
Success!
Asymmetry delivery ratio or bitrate for upload vs download
Is there a hidden terminal?
AP 1 AP 2
A B
I hear A’s ACK
Where is
AP1’s DATA?
ACK
DATA
Which is the hidden terminal?
RxIP AP’s record timestamp
Challenge-response protocol via the internet
H.T.?
Which is the hidden terminal?
Loss + Concurrent (Collision)
Success + Concurrent (No Collision)
Loss + Not Concurrent
Success + Not Concurrent
Saturation Counter
H.T.?
Recovery By Coordination
Token passed back and forth
AP’s “purchase” transmission timeslot
Abstain notification
Recovery By Coordination
More HT = more complicated
Must purchase from every partner
RxIP: What else?
Ideal token passing (NP hard)
No deadlock
Token loss
Incrementally deployable
Internet latency
Evaluation
Evaluation
Evaluation
Questions?