p.1service control technologies for peer-to-peer traffic in next generation networks part2: an...
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Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.1
Part2: An Approach of Passive Peer based Caching to Mitigate P2P Inter-domain Traffic
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.2
Motivation
• Widespread of P2P file sharing applications– Traffic Increase: more serious in inter-domain links
• P2P Traffic– Undesirable characteristics compared with Web traffic
• Transmission data size is huge• No traffic centralized point, e.g. servers in a data center,
because communications will occur among peers at any locations
– Most of such huge data transmissions become inter-domain traffic
• P2P traffic volume is a critical issue for ISPs– Analyze P2P traffic impact on inter-domain traffic– Control P2P traffic on inter-domain links
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.3
Related Works
• P2P Traffic control– Filtering / limiting P2P traffic
• How do we identify P2P connections?– Deep packet inspection is very powerful but …– How deep is an ISP allowed to inspect the packets?
– Introducing asymmetry along physical network topology
• Network-aware clustering / Cache servers• Some application’s protocol is closed
More general control methods should be considered
• P2P Traffic model– Mainly focusing on the scalability of overlay network
• Number of hops and search messages on overlay networks We need a model with physical network viewpoint
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.4
Our Research
• Analysis of inter-domain traffic– Considering pure P2P file sharing applications– Modeling inter-domain traffic amount
• Influence of additional passive peer
• P2P traffic control using passive peer– Resource cache equivalent function on P2P network
with closed protocol
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.5
Traffic Flow Model : Terminology
• My Domain / Other Domains– Set(s) of peers in the same administrative scope (e.g.,
ISP)– My Domain : A domain of interest– Other Domains : Others
• Passive peer– A native peer for corresponding P2P applications
• without any change• no active operations (resource creation / resource request)
– Added to My domain
• We analyzed the influence of a passive peer addition
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.6
Traffic Flow Model : Traffic
• Traffic Flow Model– Modeling traffic incoming to / outgoing from passive peer– Four kinds of traffic
• ‘out’ / ‘in’ : outgoing / incoming
• ‘m’ / ‘o’ : My Domain / Other Domains
• Inter-domain Traffic : To out + To inInter-domain Traffic
Tmin
TmoutPassive Peer
Toout
Toin
Other DomainsMy Domain
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.7
Traffic Flow Model : Selection Probability (1/2)
• Selection Probability– Probability that a peer selects destination peers in My Domain– We assume :
p : Selection Probabilitiesq : 1 - p
Tm
inpqTo
in
Tm
out
To
out
Tmin
TmoutPassive Peer
Toout
Toin
Other DomainsMy Domain
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.8
Traffic Flow Model : Selection Probability (2/2)
• What does this equation mean ?– Destination selection is regarded as random selection on a domain level scale
Tm
inpqTo
in
Tm
out
To
out
p : Selection Probabilitiesq : 1 - p
Tmin
TmoutPassive Peer
Toout
Toin
Other DomainsMy Domain
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.9
Traffic Flow Model : Without Passive Peer
• If the passive peer were not added– : disappeared– : transferred to alternative peers
– Alternative peers are selected according to the selection probability p
Tmin
TmoutPassive Peer
Toout
Toin
Other DomainsMy Domain
ToinTmin ,Tmout , Toout
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.10
Traffic Flow Model : Traffic Amount Change
• Inter-domain Traffic :
• Ratio: r =
– Traffic amount change caused by the passive peer
pTo out + qT
m out
To out + To inpTo out + qTm out
pToout
pTmout
qTmout
qToout
Other DomainsMy Domain
Inter-domain Traffic
with passive peer
without passive peer
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.11
Traffic Flow Model : Analyze
• Area of decreasing inter-domain traffic by passive peer– If p < 1/2,– additional peer rather increases inter-domain traffic
20
40
60
80
100
0.0 0.2 0.4 0.6 0.8 1.0
CachePerformance
Selection Probabilities
r < 1(decrease)
r > 1(increase)
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.12
Proposal
• To decrease inter-domain traffic without change p,q– To decrease r less than 1.0
– r =
• Method : Filtering
To out + To inpTo out + qTm out
To
out
Other DomainsMy Domain
Tooutδ TooutFilter
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.13
Proposal Method : Analyze
• Effective areas for several filter ratio:δ– The smaller δ is, the less the inter-domain traffic becomes– The smaller δ enlarges the effective area
20
40
60
80
100
0.0 0.2 0.4 0.6 0.8 1.0
CachePerformance
Selection Probabilities
Filter : 0.5Filter : 0.2Filter : 0.1
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.14
Discussion
• Validity of traffic flow model– Is destination selection really random even on a
domain level scale?
• Effectiveness of proposed method– Can this method decreases inter-domain traffic ?
• Measurement of real P2P network traffic– In order to discuss the above two topics
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.15
Discussion : Simulation Analysis
• Selection Probability : p– Simulation with 200,000 peers’ behavior
• Selection Probability gradually converges– Common p value can be applied to both incoming and outgoing
communications
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.16
Discussion : Experimental Analysis
• Selection Probability : p– Calculated from incoming and outgoing traffic
• Selection Probability gradually converges
0.5
0.4
0.3
0.2
0.1
00 5 10 15 20
outgoingincoming
SelectionProbability
Time (days)
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.17
Discussion : Cache Effectiveness
• Ratio of inter-domain traffic change by passive peer– become less than 1 after 12th day
• Successfully decreases inter-domain traffic
22
20
6
4
2
00 5 10 15 20 25 30
Time (days)
Ratio ofTraffic Amount
Service Control Technologies for Peer-to-peer Traffic in Next Generation Networks p.18
Conclusion
• We discuss a novel traffic model of P2P file sharing Application– To grasp inter-domain P2P traffic trend– Passive peer concepts– Selection Probability
• Analyze an impact of P2P traffic on inter-domain traffic– Passive peer rather increases inter-domain traffic in
the case of p<1
• Propose P2P traffic control method– decrease inter-domain traffic even in the case of p<1