P2P

4.1 4.2 4.3 4.4 4.5 4.6

4.1 P2PIPP2PPlaxton MeshP2PGeometries' NatureFNSFRSPerformanceResilienceLatency

Geometries considered

Geometry => Flexibility => PerformanceGeometry captures flexibility in selecting algorithmsFlexibility is important for routing performance

Flexibility in selecting routes leads to shorter, reliable paths

Flexibility in selecting neighbors leads to shorter paths

Metrics for flexibilityFNS: Flexibility in Neighbor Selection= number of node choices for a neighbor

FRS: Flexibility in Route Selection= avg. number of next-hop choices for all destinations

Constraints for neighbors and routes

select neighbors to have paths of O(logN) select routes so that each hop is closer to destination

Summary of flexibility analysisHow relevant is flexibility for DHT routing performance?

Static ResilienceTwo aspects of robust routing

Dynamic Recovery : how quickly routing state is recovered after failuresStatic Resilience : how well the network routes before recovery finishescaptures how quickly recovery algorithms need to work

depends on FRS

Evaluation:Fail a fraction of nodes, without recovering any stateMetric: % Paths Failed

Does flexibility affect Static Resilience?Tree

Geometrys impact on ProximityBoth FNS and FRS can reduce latencyTree has FNS, Hypercube has FRS, Ring & XOR have both Metric: Overlay Path Latency

Which is more useful: FNS or FRS?Plain

FRSresilenceFNSlatencytradeoff[Gummadi et al.03] K. P. Gummadi, R. Gummadi, S. D. Gribble, S. Ratnasamy, S. Shenker and I. Stoica. The Impact of DHT Routing Geometry on Resilience and Proximity. In SIGCOMM 2003, pp. 381-394.

4.2 (DHTDistributed hash table)P2PnodelDobjectIDDHT

P2P

P2PDHTP2PDHTP2PP2PPut(Key, Value)KeyValueRemote(Key)KeyValue=Get(Key)KeyValue

P2PAPIKarpIPTPS04OpenHashRheaSIGCOMM05OpenDHT(www.opendht.org )DHT

OpenDHTOpenDHTDHThttp://opendht.orgBamboo DHTPastryDHTOpenDHTDHTP2PAPIPut(K, V, t)OpenDHTtGet(K)KOpenDHT

OpenDHT

Examples:Here is an example usage scenario: $ ./put.py colors red Success $ ./get.py colors red $ ./put.py --secret donttell colors blue Success $ ./get.py colors red blue $ ./rm.py colors blue donttell Success $ ./get.py colors red

hash functionsecure hash functionconsistent hash functionMD5,SHA-1,HMAC(secret keyhash functionMAC)(2^n)2^(n/2)

4.3 P2PID

P2PP2PO(1)

P2PTTLP2P(guided routing)

FreenetFreenet

Freenet

P2PP2PIDO(logN)

P2PKaashoek & KargerIPTPS03P2P Nd(logdN-1)(logdN-O(1))(logdN-1)Moore Bound()Ah1+d^1+d^2++d^h=d^(h+1)/(d-1)d^(h+1)/(d-1)=NhO(logN)

4.4 P2P

P2PVSMvector space modeLSI latent semantic indexRefer to [Tang et.al.2003]&[Zhu et.al.,2003]

P2Prouting indicesP2PP2P [Crespo & Garcia-Molina, 2002]CRIHRIERIDHTP2P[Harren, 02][Ramabhadran, 2004]

ADatabaseLanguagesB100*(20/100)*(30/100)=6C1000*(0/1000)*(50/1000)=0D200*(100/200)*(150/200)=75BCDGoodness6,0,75ADGoodnessCRISi)iSi

DHTP2PN-gramsBeethovens 9th123:Bee eet eth tho hov ove ven ens ns_ s_9 _9t 9th23(thoventho,hov,oev,ven43concatenation

4.5 P2P

P2P

P2PGnutellaNGnutellaNPINGPONGPINGPeerPINGPONG

KaZaAKaZaAP2PKaZaA

eDonkeyKaZaAFreenet

P2PJoin Step1NGJoin Step2NGNIDNZNZJoin Step3

Join Step3TapestryCANP2P

4.6 P2P

1/2(logN)IPTPS03[Kaashoek&Karger,2003]

P2PP2PP2P

(static resilience)P2P(routing recovery resilience)

(flexibility)

P2P(churn)P2PP2PP2P

P2P(overlay partitioning)P2P

Crash Point50%(50%)

P2P

1PHTDHTDHT2overlay partition

IDEASearching Similarity Documents unstructured overlay Structured overlayInterest-Cluster PAIS: A Proximity-Aware Interest-Clustered P2P File Sharing System,CCGrid 2009,Haiying ShenRouting IndicesAdaptive Resource Indexing Technique for Unstructured Peer-to-Peer Networks,CCGrid2009,Sumeth Lerthirunwong, Naoya Maruyama, and Satoshi Matsuoka Range QueryRange Query Using Learning-Aware RPS in DHT-Based Peer-to-Peer Networks,CCGrid2009,Ze Deng, Dan Feng, Ke Zhou, Zhan Shi, and Chao Luo

OpenDHT(anycast)

[Cohen and Shenker.02] Edith Cohen and Scott Shenker. Replication Strategies in Unstructured Peer-to-Peer Networks. In SIGCOMM 2002, pp. 84-95. Rao et al.03] Ananth Rao, Karthik Lakshminarayanan, Sonesh Surana, Richard Karp, Ion Stoica. Load Balancing in Structured P2P Systems. In IPTPS 2003, pp. 68-79. Balancing Locality and Randomness in DHTs Shuheng Zhou, Gregory R. Ganger, Peter Steenkiste. Carnegie Mellon University Technical Report CMU-CS-03-203, November 2003.