CN105450738A - Price mechanism-based bandwidth allocation algorithm in P2P file sharing network - Google Patents

Abstract

Price mechanism-based bandwidth allocation algorithm in P2P file sharing network, and specific algorithmIt is each resource requestor r that initializes the price λ it can offer_r[t](ii) a Resource provider p initializes allocated bandwidth x for each resource requester_pr[t](ii) a The resource provider p uploads the bandwidth C according to the resource provider p_pBandwidth allocation x initialized for each resource requester r_pr[t]And the price lambda provided by each resource requester r_r[t]To obtain the expected price Cost_p[t](ii) a Resource provider p costs Cost according to expected price_p[t]And the price λ provided by the resource requester r_r[t]Adjust its allocated bandwidth x for resource requestor r_pr[t+1](ii) a Resource requester r adjusts its paid price lambda according to the obtained bandwidth_r[t+1](ii) a Each resource provider p iteratively reaches a balance point according to the steps, namely the optimal allocation of the uploading bandwidth of the resource provider; the resource provider and the resource requester complete data transmission according to the optimal bandwidth allocation; if a new node is added or the original node is withdrawn, the iteration process is carried out again until a new balance point is reached. The invention has the advantages of fair distribution, simple calculation and the like.

Description

A kind of based on bandwidth allocation algorithm in the P2P file sharing network of price mechanism

Technical field

The present invention relates to technical field of the computer network, especially a kind of P2P file sharing network bandwidth allocation algorithm based on price mechanism.

Background technology

Peer-to-peer network (Peer-to-Peer, P2P) is a kind of and the opposed network architecture of client/server (Client/Server, C/S) network.In a peer-to-peer network, the role of centralized servers is weakened even to cancel, each client node both can serve as server for other clients and provide services on the Internet, and can be again that common client obtains service, the such as service such as file download, video request program from other client node.Formed the overlay network (overlaynetwork) of a logic between node by the mode of self-organizing, work in coordination with the functions such as storage, index, calculating, Data dissemination together.Relative to the network of client/server structure, peer-to-peer network has that decentralization, self-organizing, extensibility and robustness are high, high without single point failure, cost performance, secret protection and the feature such as load-balancing performance is good.

Peer-to-peer network is emphasized playing an active part in of user and is shared cooperation achievement, has greatly transferred the enthusiasm of user's dedicate resources and service.All peer-to-peer network user applications are no longer only simple consumers as in legacy network environment, but act as the dual role of consumer and the producer simultaneously.Server ad hoc in traditional network application is the unable resources contribution person colony contending with so vast obviously, therefore the quality and quantity of internet content obtains considerable leap, it directly affects is exactly nowadays yield unusually brilliant results based on the application of peer-to-peer network: the file-sharing provided from initial peer-to-peer network and download service, representative is exactly that far-reaching file download tool BitTorrent (is called for short BT, be commonly called as BT to download), to employing IP network transferring voice significantly to reduce the networking telephone (VoIP of communications cost, VoiceoverIP), representative is exactly Skype, the flow medium live system of multimedia interaction application by now again, representative is exactly PPLive.The release of each new opplication of peer-to-peer network, federation causes the extensive concern of warmly pursuing of users and industry.

Due to the form that peer-to-peer network is a kind of self-organizing, therefore the management of Internet resources just becomes particularly important.At present, resource allocation mechanism in peer-to-peer network is mostly utilize incentives strategy, comparatively typical strategy comprises mechanism based on micropayments (as PPAY agreement, WhoPay agreement), based on directly reciprocal mechanism (as tit-for-tat method), based on the mechanism of prestige (as PeerTrust, SuperTrust method) etc., thus impel each user to share the resource of oneself, for other users provide services on the Internet.But these methods are mostly promote that the social utility realizing peer-to-peer network system maximizes, and seldom consider that resource obtains the fair allocat between the user of service in request.Unjust if there is Resourse Distribute, the use fairness of user certainly will be caused to be affected.Such as: when Internet resources price is too low, Internet resources are just easily consumed excessively, occur " Public Goods tragedy "; If but price is too high, although it is cold network to be avoided to a certain extent to gather around, this will cause Internet resources to can not get effective use, make network resource utilization too low, most of burden for users does not play the cost of use of Internet resources simultaneously, and the fairness of user be can not be guaranteed.

In sum, user is sought after a kind ofly carrying out the algorithm that rationally effectively distributes for peer network resources, and the user satisfaction of the network service that makes to call request reaches optimum.

Summary of the invention

The object of the invention be to provide a kind of fairness in distribution rationally, calculate simple efficient, can avoid user with too low or extravagent price use Internet resources based on bandwidth allocation algorithm in the P2P file sharing network of price mechanism.

For achieving the above object, have employed following technical scheme: algorithm of the present invention mainly comprises Peer-to-Peer Network P2P, resource requestor r and resource provider p, in Peer-to-Peer Network P2P, resource requestor r download file needs the uploading bandwidth obtaining resource provider p, the expected price of the price that resource provider p provides according to each resource requestor r and resource provider p self is the bandwidth of resource requestor r Resources allocation supplier p oneself;

Described algorithm steps is as follows:

Step 1, in the shared file system of Peer-to-Peer Network P2P, each wants its price λ that can provide of resource requestor r initialization obtaining file download service _r[t];

Step 2, provides the resource provider p of download service to carry out allocated bandwidth, is the bandwidth x that each resource requestor r initialization distributes _pr[t];

Step 3, if the now bandwidth x that is assigned with of resource requestor r _pr[t] and the price λ provided _r[t] is all balance point, then algorithm terminates, and resource provider and resource requestor complete transfer of data;

If the now bandwidth x that is assigned with of resource requestor r _pr[t] and the price λ provided _r[t] is not balance point, then carry out step 4 downwards;

Step 4, resource provider p is according to the uploading bandwidth C of oneself _p, resource provider p is the initialized allocated bandwidth x of each resource requestor r _prthe price λ that [t] and each resource requestor r provide _r[t], obtains the expected price Cost of resource provider p _p[t];

Step 5, resource provider p is according to the expected price Cost of oneself _pthe price λ that [t] and resource requestor r provide _r[t], the bandwidth x of adjustment Resources allocation requestor r _pr[t+1];

Step 6, resource requestor r is according to the new bandwidth x obtained _pr[t+1] redistributes its price λ paid of adjustment _r[t+1];

Step 7, each resource provider p to go directly balance point, the i.e. optimum allocation of resource provider uploading bandwidth according to above-mentioned steps iteration;

Step 8, resource provider p and resource requestor r completes transfer of data according to optimal bandwidth allocation;

Step 9, if having new resource provider or resource requestor to add or original resource provider or resource requestor exit, then above-mentioned iterative process re-starts until reach new balance point.

In step 3, being analyzed as follows of balance point:

Suppose that the balance point of algorithm is (x ^*, λ ^*), then

Then $\underset{p:p\∈P}{\Σ}{C}_p=\underset{p:p\∈P}{\Σ}\frac{{\Σ}_{s:s\∈R\left(p\right)}{x}_{ps}^{*}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}}{{\mathrm{\λ}}_r^{*\frac{1}{\mathrm{\α}}}}=\frac{1}{{\mathrm{\λ}}_r^{*\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}\underset{p:p\∈P\left(s\right)}{\Σ}{x}_{ps}^{*}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}=\frac{y_r^{*}}{w_r^{\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}\underset{p:p\∈P\left(s\right)}{\Σ}{x}_{ps}^{*}=\frac{y_r^{*}}{w_r^{\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}{w}_s^{\frac{1}{\mathrm{\α}}}$

Wherein, P is all resource provider set; R is all resource requestor set; C _pit is the uploading bandwidth of resource provider p; w _rit is the expense that resource requestor r is ready to pay; it is the optimum total bandwidth that resource requestor r obtains; it is the best price that resource requestor r pays; w _sit is the expense that resource requestor s is ready to pay; it is the best price that resource requestor s pays; optimum bandwidth that resource requestor s distributes that to be resource provider p be; α >0 is fairness index;

Therefore

$y_r^{*}=\frac{w_r^{\frac{1}{\mathrm{\α}}}\underset{p:p\∈P}{\Σ}{C}_p}{\underset{s:s\∈R}{\Σ}{w}_s^{\frac{1}{\mathrm{\α}}}},{\mathrm{\λ}}_r^{*}={\mathrm{\λ}}_s^{*}={\left(\frac{\underset{s:s\∈R}{\Σ}{w}_r^{1/\mathrm{\α}}}{\underset{p:p\∈P}{\Σ}{C}_p}\right)}^{\mathrm{\α}}$

Can find, this balance point is exactly the optimum point of resource allocator model.

In step 4, the expected price Cost of resource provider p _p[t] is drawn by following formula:

${\mathrm{Cost}}_p\[t\]=\frac{{\mathrm{\Σ}}_{s:s\∈R\left(p\right)}{x}_{ps}\[t\]{\mathrm{\λ}}_s^{\frac{1}{\mathrm{\α}}}\[t\]}{C_p}$

In formula, C _pit is the uploading bandwidth of resource provider p; x _pr[t] is resource provider p is the bandwidth that resource requestor r distributes; α >0 is fairness index, for realizing α-fairness that bandwidth is distributed between resource requestor, during as α=1, then realizes proportional fairness; be resource provider p be the α-fairness realizing Resourse Distribute, the fairness price that the resource requestor s obtained provides; R (p) is then all requestor's set that resource provider p provides service, and then illustrate the expected revenus of resource provider p.

In steps of 5, according to following formula adjustresources supplier p be resource requestor r distribute bandwidth x _pr[t+1];

$x_{pr}\[t+1\]={(x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]\left)\right)}_{x_{pr}\[t\]}^{+}$

In formula, x _pr[t] is t resource provider p is the bandwidth that resource requestor r distributes; θ >0 is algorithm step-size; α >0 is fairness index; it is the fairness price that resource requestor r provides; Cost _p[t] is the expected price of resource provider p;

$x_{pr}\[t+1\]={(x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]\left)\right)}_{x_{pr}\[t\]}^{+}$ Mean,

If x _pr[t] >0, then $x_{pr}\[t+1\]=x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]);$

If x _pr[t]=0, then $x_{pr}\[t+1\]=max\{0,x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{cost}}_p\[t\])\}.$

In step 6, resource requestor r adjusts its price λ paid according to obtaining allocated bandwidth _r[t+1]

${\mathrm{\λ}}_r\[t+1\]=\frac{w_r}{y_r^{\mathrm{\α}}\[t+1\]},y_r\[t+1\]=\underset{p:p\∈P\left(r\right)}{\Σ}{x}_{pr}\[t+1\]$

In formula, λ _r[t+1] is the price that t+1 moment resource requestor r pays; y _r[t+1] is the total bandwidth that t+1 moment resource requestor r obtains; x _pr[t+1] is t+1 moment resource provider p is the bandwidth that resource requestor r distributes; P (r) is for resource requestor r provides the resource provider set of service; w _rit is the expense that resource requestor r is ready to pay; α >0 is fairness index.

Compared with prior art, tool of the present invention has the following advantages:

1, algorithm of the present invention effectively can converge to the optimum point of allocated bandwidth, realizes the fair allocat of uploading bandwidth between network resource request person of resource provider.

2, change Resource Allocation in Networks target the satisfaction of the network user that optimization request is served into by the optimizing user behavior that encourages, realize Resourse Distribute target that is service-oriented, customer-centric, more pressed close to the actual demand of user.

Accompanying drawing explanation

Fig. 1 is the flow chart of steps of algorithm of the present invention.

Fig. 2 is 6 user network topology diagrams of algorithm of the present invention.

Fig. 3 is the optimal bandwidth allocation figure that in Fig. 2, resource requestor r1 obtains.

Fig. 4 is the optimal bandwidth allocation figure that in Fig. 2, resource requestor r2 obtains.

Fig. 5 is the optimal bandwidth allocation figure that in Fig. 2, resource requestor r3 obtains.

Fig. 6 is the optimal bandwidth allocation figure that in Fig. 2, resource requestor r4 obtains.

Fig. 7 is the graph of a relation of convergence of algorithm speed of the present invention and iteration step length.

Embodiment

Below in conjunction with accompanying drawing, the present invention will be further described:

Algorithm of the present invention mainly comprises Peer-to-Peer Network P2P, resource requestor r and resource provider p, in Peer-to-Peer Network P2P, resource requestor r download file needs the uploading bandwidth obtaining resource provider p, the expected price of the price that resource provider p provides according to each resource requestor r and resource provider p self is the bandwidth of resource requestor r Resources allocation supplier p oneself;

As shown in Figure 1, described algorithm steps is as follows:

Step 1, in the shared file system of Peer-to-Peer Network P2P, each wants its price λ that can provide of resource requestor r initialization obtaining file download service _r[t];

Step 2, provides the resource provider p of download service to carry out allocated bandwidth, is the bandwidth x that each resource requestor r initialization distributes _pr[t];

Step 3, if the now bandwidth x that is assigned with of resource requestor r _pr[t] and the price λ provided _r[t] is all balance point, then algorithm terminates, and resource provider and resource requestor complete transfer of data;

If the now bandwidth x that is assigned with of resource requestor r _pr[t] and the price λ provided _r[t] is not balance point, then carry out step 4 downwards;

Step 4, resource provider p is according to the uploading bandwidth C of oneself _p, resource provider p is the initialized allocated bandwidth x of each resource requestor r _prthe price λ that [t] and each resource requestor r provide _r[t], obtains the expected price Cost of resource provider p _p[t];

${\mathrm{Cost}}_p\[t\]=\frac{{\mathrm{\Σ}}_{s:s\∈R\left(p\right)}{x}_{ps}\[t\]{\mathrm{\λ}}_s^{\frac{1}{\mathrm{\α}}}\[t\]}{C_p}$

In formula, C _pit is the uploading bandwidth of resource provider p; x _pr[t] is resource provider p is the bandwidth that resource requestor r distributes; α >0 is fairness index, for realizing α-fairness that bandwidth is distributed between resource requestor, during as α=1, then realizes proportional fairness; be resource provider p be the α-fairness realizing Resourse Distribute, the fairness price that the resource requestor s obtained provides; R (p) is then all requestor's set that resource provider p provides service, and then illustrate the expected revenus of resource provider p.

Step 5, resource provider p is according to the expected price Cost of oneself _pthe price λ that [t] and resource requestor r provide _r[t], the bandwidth x of adjustment Resources allocation requestor r _pr[t+1];

$x_{pr}\[t+1\]={(x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]\left)\right)}_{x_{pr}\[t\]}^{+}$

In formula, x _pr[t] is t resource provider p is the bandwidth that resource requestor r distributes; θ >0 is algorithm step-size; α >0 is fairness index; it is the fairness price that resource requestor r provides; Cost _p[t] is the expected price of resource provider p;

$x_{pr}\[t+1\]={(x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]\left)\right)}_{x_{pr}\[t\]}^{+}$ Mean,

If x _pr[t] >0, then $x_{pr}\[t+1\]=x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{cost}}_p\[t\]);$

If x _pr[t]=0, then $x_{pr}\[t+1\]=max\{0,x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{cost}}_p\[t\])\}.$

Step 6, resource requestor r is according to the new bandwidth x obtained _pr[t+1] redistributes its price λ paid of adjustment _r[t+1];

${\mathrm{\λ}}_r\[t+1\]=\frac{w_r}{y_r^{\mathrm{\α}}\[t+1\]},y_r\[t+1\]=\underset{p:p\∈P\left(r\right)}{\Σ}{x}_{pr}\[t+1\]$

In formula, λ _r[t+1] is the price that t+1 moment resource requestor r pays; y _r[t+1] is the total bandwidth that t+1 moment resource requestor r obtains; x _pr[t+1] is t+1 moment resource provider p is the bandwidth that resource requestor r distributes; P (r) is for resource requestor r provides the resource provider set of service; w _rit is the expense that resource requestor r is ready to pay; α >0 is fairness index.

Step 7, each resource provider p to go directly balance point, the i.e. optimum allocation of resource provider uploading bandwidth according to above-mentioned steps iteration;

Step 8, resource provider p and resource requestor r completes transfer of data according to optimal bandwidth allocation;

Step 9, if having new resource provider or resource requestor to add or original resource provider or resource requestor exit, then above-mentioned iterative process re-starts until reach new balance point.

Peer network resources is distributed the satisfaction of target by encouraging user's shared resource to change the network user that optimization request is served into by the present invention, realizes Resourse Distribute target that is service-oriented, customer-centric, is more close to the users to the actual demand of network service.Setting up the optimization utility model of bandwidth resource allocation, realizing bandwidth fair allocat between resource requestor by choosing suitable utility function.The present invention devises a kind of distribution type and width resource allocation algorithm based on price mechanism, effectively can converge to the optimum point of optimization utility model, i.e. the optimal bandwidth allocation of the uploading bandwidth of resource provider between resource requestor.

Wherein, resource allocator model:

$max\underset{r:r\∈R}{\Σ}{U}_r\left(y_r\right)$

$subjectto\underset{p:p\∈P\left(r\right)}{\Σ}{x}_{pr}=y_r,r\∈R$

$\underset{r:r\∈R\left(p\right)}{\Σ}{x}_{pr}=C_p,p\∈P$

overx _pr≥0,r∈R,p∈P

In formula, r is resource requestor; P is resource provider; R is the set of resource requestor; P is the set of resource provider; P (r) is for resource requestor r provides the resource provider set of download service; R (p) is the set that resource provider p provides all resource requestor of download service; x _prthe bandwidth that resource requestor r obtains from resource provider p, total then resource requestor r obtain bandwidth be exactly y _r, meanwhile, resource provider p is no more than the uploading bandwidth C of himself for bandwidth sum that all resource requestor provide _p; U _r(y _r) be utility function.

Utility function U _r(y _r) describe resource requestor r acquisition download bandwidth y _rafter satisfaction, and in order to realize resource fair allocat between requestor, choose following utility function

$U_r\left(y_r\right)=\left\{\begin{array}{c}{w}_r\log y_r,\mathrm{\α}=1\\ w_r\frac{y_r^{1-\mathrm{\α}}}{1-\mathrm{\α}},\mathrm{\α}\≠1\end{array}\right.$

Wherein, w _rdescribe the expense that resource requestor r is ready to pay, and α>=0 describes fairness index, if α=1, then realize the proportional fairness of Resourse Distribute between user, if α=2, then realize the harmonic average fairness of Resourse Distribute between user, if α → ∞, then realize the max-min fairness of Resourse Distribute between user.

Utilize the resources configuration optimization problem that Lagrangian method process is above-mentioned, each resource requestor r can be obtained and can obtain optimal bandwidth allocation value

$y_r=\frac{w_r^{1/\mathrm{\α}}{\mathrm{\Σ}}_{p:p\∈P}{C}_p}{{\mathrm{\Σ}}_{r:r\∈R}{w}_r^{1/\mathrm{\α}}}$

As can be seen here, the optimal bandwidth allocation that each resource requestor r obtains is only relevant with fairness index α, and the expense paid with this user accounts for the ratio of the summation of all user's defrayments relevant, during as α=1, achieve resource proportional fairness between users.

Being analyzed as follows of balance point:

Suppose that the balance point of algorithm is (x ^*, λ ^*), then

Then $\underset{p:p\∈P}{\Σ}{C}_p=\underset{p:p\∈P}{\Σ}\frac{{\Σ}_{s:s\∈R\left(p\right)}{x}_{ps}^{*}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}}{{\mathrm{\λ}}_r^{*\frac{1}{\mathrm{\α}}}}=\frac{1}{{\mathrm{\λ}}_r^{*\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}\underset{p:p\∈P\left(s\right)}{\Σ}{x}_{ps}^{*}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}=\frac{y_r^{*}}{w_r^{\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}\underset{p:p\∈P\left(s\right)}{\Σ}{x}_{ps}^{*}=\frac{y_r^{*}}{w_r^{\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}{w}_s^{\frac{1}{\mathrm{\α}}}$

Wherein, P is all resource provider set; R is all resource requestor set; C _pit is the uploading bandwidth of resource provider p; w _rit is the expense that resource requestor r is ready to pay; it is the optimum total bandwidth that resource requestor r obtains; it is the best price that resource requestor r pays; w _sit is the expense that resource requestor s is ready to pay; it is the best price that resource requestor s pays; optimum bandwidth that resource requestor s distributes that to be resource provider p be; α >0 is fairness index.

Therefore

$y_r^{*}=\frac{w_r^{\frac{1}{\mathrm{\α}}}\underset{p:p\∈P}{\Σ}{C}_p}{\underset{s:s\∈R}{\Σ}{w}_s^{\frac{1}{\mathrm{\α}}}},{\mathrm{\λ}}_r^{*}={\mathrm{\λ}}_s^{*}={\left(\frac{\underset{s:s\∈R}{\Σ}{w}_r^{1/\mathrm{\α}}}{\underset{p:p\∈P}{\Σ}{C}_p}\right)}^{\mathrm{\α}}$

Can find, this balance point is exactly the optimum point of resource allocator model.

Utilize Lyapunov stability theory, can prove to obtain, this algorithm can global convergence to its point of safes

$y_r^{*}=\frac{w_r^{1/\mathrm{\α}}{\Σ}_{p:p\∈P}{C}_p}{{\Σ}_{r:r\∈R}{w}_r^{1/\mathrm{\α}}},{\mathrm{\λ}}_r^{*}={\mathrm{\λ}}_s^{*}={\left(\frac{{\Σ}_{r:r\∈R}{w}_r^{1/\mathrm{\α}}}{{\Σ}_{p:p\∈P}{C}_p}\right)}^{\mathrm{\α}},r,s\∈R$

And this point of safes is exactly the optimum point of resource allocator model, i.e. the optimal resource allocation of resource requestor, simultaneously, the price paid in each resource requestor of point of safes place is all identical, as when α=1, namely achieve the proportional fairness of Resourse Distribute between users $y_r^{*}=w_r{\mathrm{\Σ}}_{p:p\∈P}{C}_p/{\mathrm{\Σ}}_{r:r\∈R}{w}_r,$ ${\mathrm{\λ}}_r^{*}={\mathrm{\Σ}}_{r:r\∈R}{w}_r/{\mathrm{\Σ}}_{p:p\∈P}{C}_p.$

Convergence

Convergence is the important indicator of measure algorithm performance.Contemplated by the invention 2 resource providers p1, p2, the situation of 4 resource requestor r1, r2, r3, r4, as shown in Figure 2, the uploading bandwidth of resource provider p1, p2 is respectively 20Mbps, 30Mbps.

The present invention analyzes the mediation fair allocat (i.e. α=2) of uploading bandwidth between resource requestor of resource provider, each simulation result is as shown in Fig. 3,4,5,6, such as in figure 3, when iterations is only 40 times, algorithm has just converged to optimum point, now resource provider p1 is the optimum bandwidth that resource requestor r1 distributes is 2.7522Mbps, resource provider p2 is the optimum bandwidth that resource requestor r1 distributes is 5.3828Mbps, and the optimum total bandwidth that resource requestor r1 obtains is 8.1350Mbps.Therefore, algorithm effectively can converge to balance point in limited iterations, and this balance point is exactly the optimum point of resource allocator model.Convergence of algorithm speed depends primarily on the iteration step length θ of algorithm, and as shown in Figure 7, when θ is larger, algorithm the convergence speed is very fast, but θ again can not be too large, otherwise algorithm there will be fluctuation near balance point.

Above-described embodiment is only be described the preferred embodiment of the present invention; not scope of the present invention is limited; under not departing from the present invention and designing the prerequisite of spirit; the various distortion that those of ordinary skill in the art make technical scheme of the present invention and improvement, all should fall in protection range that claims of the present invention determines.

Claims (5)

1. one kind based on bandwidth allocation algorithm in the P2P file sharing network of price mechanism, mainly comprise Peer-to-Peer Network P2P, resource requestor r and resource provider p, it is characterized in that, in Peer-to-Peer Network P2P, resource requestor r download file needs the uploading bandwidth obtaining resource provider p, the expected price of the price that resource provider p provides according to each resource requestor r and resource provider p self is the bandwidth of resource requestor r Resources allocation supplier p oneself;

Described algorithm steps is as follows:

Step 1, in the shared file system of Peer-to-Peer Network P2P, each wants its price λ that can provide of resource requestor r initialization obtaining file download service _r[t];

Step 2, provides the resource provider p of download service to carry out allocated bandwidth, is the bandwidth x that each resource requestor r initialization distributes _pr[t];

Step 3, if the now bandwidth x that is assigned with of resource requestor r _pr[t] and the price λ provided _r[t] is all balance point, then algorithm terminates, and resource provider and resource requestor complete transfer of data;

If the now bandwidth x that is assigned with of resource requestor r _pr[t] and the price λ provided _r[t] is not balance point, then carry out step 4 downwards;

Step 4, resource provider p is according to the uploading bandwidth C of oneself _p, resource provider p is the initialized allocated bandwidth x of each resource requestor r _prthe price λ that [t] and each resource requestor r provide _r[t], obtains the expected price Cost of resource provider p _p[t];

Step 5, resource provider p is according to the expected price Cost of oneself _pthe price λ that [t] and resource requestor r provide _r[t], the bandwidth x of adjustment Resources allocation requestor r _pr[t+1];

Step 6, resource requestor r is according to the new bandwidth x obtained _pr[t+1] redistributes its price λ paid of adjustment _r[t+1];

Step 7, each resource provider p to go directly balance point, the i.e. optimum allocation of resource provider uploading bandwidth according to above-mentioned steps iteration;

Step 8, resource provider p and resource requestor r completes transfer of data according to optimal bandwidth allocation;

Step 9, if having new resource provider or resource requestor to add or original resource provider or resource requestor exit, then above-mentioned iterative process re-starts until reach new balance point.

2. according to claim 1ly a kind ofly to it is characterized in that based on bandwidth allocation algorithm in the P2P file sharing network of price mechanism, in step 3, being analyzed as follows of balance point:

Suppose that the balance point of algorithm is (x ^*, λ ^*), then ${\mathrm{\λ}}_r^{*\frac{1}{\mathrm{\α}}}=\frac{{\Σ}_{s:s\∈R\left(p\right)}{x}_{ps}^{*}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}}{C_p}$

Then $\underset{p:p\∈P}{\Σ}{C}_p=\underset{p:p\∈P}{\Σ}\frac{{\Σ}_{s:s\∈R\left(p\right)}{x}_{ps}^{*}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}}{{\mathrm{\λ}}_r^{*\frac{1}{\mathrm{\α}}}}=\frac{1}{{\mathrm{\λ}}_r^{*\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}\underset{p:p\∈P\left(s\right)}{\Σ}{x}_{ps}^{*}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}=\frac{y_r^{*}}{w_r^{\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}{\mathrm{\λ}}_s^{*\frac{1}{\mathrm{\α}}}\underset{p:p\∈P\left(s\right)}{\Σ}{x}_{ps}^{*}=\frac{y_r^{*}}{w_r^{\frac{1}{\mathrm{\α}}}}\underset{s:s\∈R}{\Σ}{w}_s^{\frac{1}{\mathrm{\α}}}$

Wherein, P is all resource provider set; R is all resource requestor set; C _pit is the uploading bandwidth of resource provider p; w _rit is the expense that resource requestor r is ready to pay; it is the optimum total bandwidth that resource requestor r obtains; it is the best price that resource requestor r pays; w _sit is the expense that resource requestor s is ready to pay; it is the best price that resource requestor s pays; optimum bandwidth that resource requestor s distributes that to be resource provider p be; α >0 is fairness index;

Therefore

$y_r^{*}=\frac{w_r^{\frac{1}{\mathrm{\α}}}\underset{p:p\∈P}{\Σ}{C}_p}{\underset{s:s\∈R}{\Σ}{w}_s^{\frac{1}{\mathrm{\α}}}},{\mathrm{\λ}}_r^{*}={\mathrm{\λ}}_s^{*}={\left(\frac{\underset{s:s\∈R}{\Σ}{w}_r^{1/\mathrm{\α}}}{\underset{p:p\∈P}{\Σ}{C}_p}\right)}^{\mathrm{\α}}$

Can find, this balance point is exactly the optimum point of resource allocator model.

3. according to claim 1ly a kind ofly to it is characterized in that based on bandwidth allocation algorithm in the P2P file sharing network of price mechanism, in step 4, the expected price Cost of resource provider p _p[t] is drawn by following formula:

${\mathrm{Cost}}_p\[t\]=\frac{{\mathrm{\Σ}}_{s:s\∈R\left(p\right)}{x}_{ps}\[t\]{\mathrm{\λ}}_s^{\frac{1}{\mathrm{\α}}}\[t\]}{C_p}$

In formula, C _pit is the uploading bandwidth of resource provider p; x _pr[t] is resource provider p is the bandwidth that resource requestor r distributes; α >0 is fairness index, for realizing α-fairness that bandwidth is distributed between resource requestor, during as α=1, then realizes proportional fairness; be resource provider p be the α-fairness realizing Resourse Distribute, the fairness price that the resource requestor s obtained provides; R (p) is then all requestor's set that resource provider p provides service, and then illustrate the expected revenus of resource provider p.

4. according to claim 1ly a kind ofly it is characterized in that: in steps of 5 based on bandwidth allocation algorithm in the P2P file sharing network of price mechanism, is the bandwidth x that resource requestor r distributes according to following formula adjustresources supplier p _pr[t+1];

$x_{pr}\[t+1\]={(x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]\left)\right)}_{x_{pr}\[t\]}^{+}$

In formula, x _pr[t] is t resource provider p is the bandwidth that resource requestor r distributes; θ >0 is algorithm step-size; α >0 is fairness index; it is the fairness price that resource requestor r provides; Cost _p[t] is the expected price of resource provider p;

$x_{pr}\[t+1\]={(x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]\left)\right)}_{x_{pr}\[t\]}^{+}$ Mean,

If x _pr[t] >0, then $x_{pr}\[t+1\]=x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\]);$

If x _pr[t]=0, then $x_{pr}\[t+1\]=max\{0,x_{pr}\[t\]+{\mathrm{\θx}}_{pr}\[t\]({\mathrm{\λ}}_r^{\frac{1}{\mathrm{\α}}}\[t\]-{\mathrm{Cost}}_p\[t\])\}.$

5. according to claim 1ly a kind ofly to it is characterized in that: in step 6 based on bandwidth allocation algorithm in the P2P file sharing network of price mechanism, resource requestor r adjusts its price λ paid according to obtaining allocated bandwidth _r[t+1]

${\mathrm{\λ}}_r\[t+1\]=\frac{w_r}{y_r^{\mathrm{\α}}\[t+1\]},y_r\[t+1\]=\underset{p:p\∈P\left(r\right)}{\Σ}{x}_{pr}\[t+1\]$

In formula, λ _r[t+1] is the price that t+1 moment resource requestor r pays; y _r[t+1] is the total bandwidth that t+1 moment resource requestor r obtains; x _pr[t+1] is t+1 moment resource provider p is the bandwidth that resource requestor r distributes; P (r) is for resource requestor r provides the resource provider set of service; w _rit is the expense that resource requestor r is ready to pay; α >0 is fairness index.