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(P2P systems)

To Pastry

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P2P ,

2

(overlay network)

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P2P

3

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Pastry;

To Pastry P2P , DHT.

(keys) (values)

() .

, .

DHT , (lookup (key)),

. 4

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Pastry 128-bitGUID(global unique

identifier) IP public key

GUID 2b(b 2

4, GUID 4 16 ) GUIDs

namespace(0 21281 ).

O(log2bN) N:

: (Leaf Set, L)

(Routing table, R)

(Neighborhood Set, M)

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Pastry

Leaf set: L

( L

8 16)

Routing Table ( - prefix-

based)

Neighborhood Set:M

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log2bN

2b1 (N )

.

i GUID

GUID i, i+1 2b-1 GUID

.

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GUID: 10233102 (b= 2, L= 8)0 1 2 3

02212102 22301203 31203203

11301233 12230203 13021022

10031203 10132102 10323302

10200230 10211302 1022302

10230322 10231000 10232121

10233001 10233232

10233120

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()D leaf set, leaf

D prefix GUID GUID

, D prefix GUID , GUID

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A: GUID D: Li: i

th GUID leaf set LD

: lth D

shl(A, B): prefix GUID/A BRi

: (l, i)th

(1) D leaf set

(2) (

)

(3) ( )

: A. Rowstron and P. Druschel.

"Pastry: Scalable, decentralized object location and routing

for large-scale peer-to-peer systems".

IFIP/ACM Middleware Conference, Nov 2001 pp. 329-350.

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Pastry

11

0 FFFFF....F (2128-1)

65A1FC

D13DA

D471F1

D467C4

D46A1C

.

: 0

(2128-1).

65A1FC

D46A1C

8 (l = 4).

(-

).

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(1) A. Rowstron and P. Druschel, "Pastry: Scalable, distributed objectlocation and routing for large-scale peer-to-peer systems". IFIP/ACMInternational Conference on Distributed Systems Platforms(Middleware), Heidelberg, Germany, pages 329-350, November, 2001

(2) Jeff Odom slides:http://x1.cs.umd.edu/818/docs/pastry.ppt