CERIA Laboratory. LH* RS P2P : A Scalable Distributed Data Structure for P2P Environment. W. LITWIN. T. SCHWARZ. H.YAKOUBEN. Paris Dauphine University [email protected] Santa Clara University (USA) [email protected] Paris Dauphine University [email protected]
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CERIA Laboratory
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
W. LITWIN
T. SCHWARZ
H.YAKOUBEN
Paris Dauphine University
Santa Clara University (USA)
Paris Dauphine University
2
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Very Large Scalable Files
High availabilityto deal with churn
At mostone forwarding message for key search or insert or scan
(fastest known performance)
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
SDDS (1993)
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
SDDS (1993)
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
VBI-Tree
CHORD...
BATON
Structured P2P Schemes
LH*, DDH, EH*,
LH*sa
LH*s
Alg. Sign…
IH*…
LH*m LH*g
Data Structures
SDDS(1993)
Classics
Tree
Hash
m-d Tree
1-dimensional
1-d Tree
d-dimensional
k-RP*, SD-Rtree, DRT*,
RP*,
High Availability
k-Availability
Security
LH*rs
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Growth through splits under inserts
New Peer
SDDS Expansion
Peer
Clients
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Image Adjustment Messaging
SDDS Client Image Evolution
Clients
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
SDDS 2007 Prototypes
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P2P (1995 ?)
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LH*RSP2P Peer
Server Part
LH*RS
Client
LH*RS
DB
j
Candidate Peer
Client &
Spare Storage
Candidate Peer
i’
n’
Client Part
LH*P2P Peer
LH*RSP2P Peer
LH*RS
Client
LH*RS
PB
Pupils
Pupil’s IP = Its key C
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2P Addressing
hi (C ) = C mod 2i
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2P File Expansion
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LH*RSP2P File Expansion
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Peer & Pupil Image Adjustment After Peer Split
i’ = j - 1 ; /* j value after the split
n‘ = a + 1 /* ais the splitting bucket ; n = a + 1
if n’ = 2i’ then i’ = j + 1 ; n’ = 0 ;
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
j=1
j=2
j=2
j=2
j=2
j=2
j=2
i’=1
n’=0
i’=1
n’=1
i’=2
n’=0
i’=1
n’=1
i’=2
n’=0
i’=1
n’=1
i’=1
n’=1
P2
P0
P1
P0
P1
P2
P3
i=1
n=1
i=2
n=0
CP
Coordinator Peer (CP)
Before splitting
After splitting
Example
i’= j =1;
n’= m+1= 1+1;
If n’=21thenn’=0; i’= i’+1
and
(i’, n’)= (2,0)
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Server Address Calculus
a’ hj (C ) ;
if a’= a then exit/* Bucket a is the correct one
else send C to bucket a/* Forwarding to bucket a’
exit;
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Peer Image Adjustment by IAM
i’ j - 1, n’ a + 1 ;
if n’ >2i’then n’ 0 ; i’ i’ + 1 ;
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
j=4
j=4
i’=3
n’=2
i’=3
n’=2
P9
P1
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Peer Image Adjustment by IAM
Checking and forward the key using A2
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IAM
a = 1
j = 4
Pairs
j=4
j=3
i’=3
n’=1
i’=2
n’=1
i =3
n=2
P0
P4
PC
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
j=4
j=4
i’=3
n’=2
i’=3
n’=2
P1
P9
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Peer Image Adjustment by IAM
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IAM
a = 1
j = 4
Pairs
j=4
j=3
i’=3
n’=1
i’= 3
n’= 2
i =3
n=2
P0
P4
PC
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Peers
j=3
j=2
j=3
j=3
j=3
i’=2
n’=3
i’=2
n’=1
i’=1
n’=1
i’=2
n’=2
i’=2
n’=3
P0
P2
P5
P6
i’=2
n’=1
i=2
n=2
i’=0
n’=0
PC
Candidate Peer
Pupil
LH*RSP2P
TUTOR, Update Pupil
Assign a Tutor for Candidate Peer:
LH-hash of its IP Address
i=2
n=3
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Properties of LH*RSP2P :
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Proof Property 1
j = i’+1
j = i’
a
2i’
0
n
a’
n+2i’
a+2i’
No forwarding
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
j = i’+1
j = i’
a
2i’
0
n
n+2i’
a’
a+2i’
Proof Property 1
Forwarding possible for any address a’ between (a, n)
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
j = i’+2
j = i’+1
j = i’
n
a
2i’
0
n+2i’+1
2i’+1
a’
Proof Property 1
Forwarding possible for any address a’ beyond [n, a]
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Proof Property 2
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Proof Property 2
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Proof Property 2
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2PChurn Management
Bucket reliability group with k paritybucketsprotect against up to k bucket failures per group
Data Record
Parity Record
5
4
3
2
1
0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Tutoring records
Rank
Data Peer
Parity Peer
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2PChurn Management
Peer leaves with notice
Say that’s OK
j
j
j
… …
Coordinator Peer
i’,n’
i’,n’
i’,n’
i’,n’
Pm
P0
Pl
Candidate Peer
Notification
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2PChurn Management
Peer leaves without notice or fails
LH*RS Bucket Recovery
j
j
j
Forward
Coordinator Peer
i’,n’
i’,n’
i’,n’
i’,n’
Pl-1
Pm
Pl
Parity Peer
Query
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2PChurn Management
Peer leaves without notice or fails
LH*RS Bucket Recovery
j
j
j
i’,n’
Pl
Coordinator Peer
i’,n’
i’,n’
i’,n’
Pl-1
Pm
Parity Peer
Answer
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2PChurn Management
j
Sure Search : Protects against outdated server read (transient communication or peer failure)
i’,n’
j
j
j
Pl
Coordinator Peer
i’,n’
i’,n’
i’,n’
i’,n’
Pl-1
Pm
Pl
Parity Peer
Answer
Query
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2P require at most one forward message when addressing error occur
Is the fastest known SDDS and P2P key based addressing algorithm
Protects efficiently against churn
Allows to manage very large scalable files
Should have numerous applications
Google ??
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
Thank you for Your Attention
Work partly funded by the IST eGov-Bus project
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
References
LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment
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LH*RSP2P: A Scalable Distributed Data Structure for P2P Environment