CN102325088A - Path protection method for optimizing node sleep under delay and shared risk link group restraint - Google Patents

Abstract

The invention discloses a path protection method for optimizing node sleep in a green network under delay and shared risk link group restraint. By using the method, in path calculation, the influence of sleep or awakening delay on a node due to path delay before a sleep node is taken into consideration and the path end-to-end delay calculating precision is improved. A cost function used when the obtained path is selected not only ensures that the reliability of a combined path meets restraint, but also encourages link and sleep node resource share between the protecting paths through calculation of path occupied network link and node resources, therefore, the proportion of the sleep node in the network is increased and the awakening frequency on the sleep node is reduced. The complexity of the method approaches that of the traditional k shortest path calculation-based path protection method; and the invention has strong adaptability on the change of the data flow of the network and expresses excellent and stable performance.

Description

Delay and the constraint of shared risk link group be the trail protection of optimized nodes sleep down

Technical field

Under delay and shared risk link group (SRLG) constraint, seek one group of work, backup path fast; Satisfy under the prerequisite of quality of service requirement at end-to-end delay that makes combinatorial path and cumulative reliability; The path protecting method of optimizing node sleep in the network belongs to interconnection path by technical field, relates in particular under the dependability parameter constraint to reduce the green energy conservation network field that node energy consumes in the network.

Background technology

In recent years, the expansion of network size and the ability (list of references: Towards Green Broadband Access Networks, P.Chowdhury that causes that energy consumption of equipment constantly increases in the network; M.Tornatore, S.Sarkar, and B.Mukherjee; GLOBECOM; 2009 IEEE, pp.1-6,2009.).In order to tackle this trend; " GreenNet " (list of references: Greening of the Internet, M.Gupta and S.Singh, in Proc.ACM SIGCOMM; Vancouver; BC, Canada, in the research that idea Aug.2003.) is applied to new generation network gradually and the planning to reduce its energy consumption.Wherein, the most widely used strategy is: allow the part of nodes in the network when self being in low data traffic state, to close data transmitting/receiving equipment, get into sleep state.At this moment, need pass by the data of this node in the network, after the node that is in sleep is waken up again, just sent back to the continuous transmission of link trunking by the formation buffer memory of its upstream node.Therefore; Above-mentioned node sleep mechanism is in conserve energy; The required cost of paying is to increase the end-to-end total delay of data to introduce the mode that node sleep postpones, and the intermediate node quantity of available (being in waking state) when having reduced the routing algorithm calculating path.

Only needing under traditional routing mode of calculating individual paths, above-mentioned defective can not cause the remarkable rising of Route Blocking rate usually.This is because individual paths is less to the network resources demand resource, and the minimizing of available node resource is little to its influence in the network.As long as when Path selection,, avoid to introduce the node of big sleep delay with the sleep delay of node a part as path cost; Data still can satisfy normal transmission (list of references: An average velocity-based routing protocol with low end-to-end delay for wireless sensor networks, S.C.Choi, S.L.Gong under the constraint that postpones; And J.W.Lee; Communications Letters, IEEE, vol.13; Pp.621-623,2009).Yet along with data transmission credibility obtains paying attention in network day by day, but the reliability of individual paths often can not satisfy the modern requirement of paying attention to the network of survivability.Therefore routing algorithm need calculate the combination of paths (list of references of being made up of 1 operating path and 1 or multi-hop backup path: Subpath protection for scalability and fast recovery in optical WDM mesh networks, C.Ou, H.Zang with the mode of trail protection; N.K.Singhal, K.Zhu, L.H.Sahasrabuddhe; R.A.MacDonald; And B.Mukherjee, IEEE J.Sel.Area Commun., vol.22; Pp.1859-1875,2004.).And for combination is met the demands with the cumulative reliability of rear path, need to guarantee between operating path and the backup path enough separating degrees are arranged, its to the demand of available resources in the network much larger than traditional single path method for routing.Particularly in the WDM network for fear of by shared High-speed Optical Fiber Link fault (list of references: Survivable WDM mesh networks, S.Ramamurthy, L.Sahasrabuddhe; And B.Mukherjee; IEEE/OSA J Lightwave Technol, vol.21, pp.870-883; Apr.2003.) cause participating in many shared roads through inefficacy (being shared risk link group SRLG risk) simultaneously; Further require between the path not only link disjoint, also want shared risk link group (SRLG) to separate, this has just proposed the requirement more wanted to alternative number of nodes and end-to-end delay in the network.At this moment, the enabled node a resource shrinkage that GreenNet node sleep mechanism causes possibly badly influence the success rate that combinatorial path calculates, thereby the blocking rate of route is significantly risen.Though the local backup path of the use that proposes in some path protecting methods before this replaces complete backup path and between backup path, allows method (list of references: the A novel survivable routing algorithm with partial shared-risk link groups (SRLG)-disjoint protection based on differentiated reliability constraints in WDMoptical mesh networks of common sparing link; L.Guo and L.M.Li; J.Lightw.Technol.; Vol.25; Pp.1410-1415 Jun.2007.) can be alleviated above-mentioned contradiction to a certain extent.But its main target is the problem that solves the network link inadequate resource, and the effect of not enough network is not ideal enough too for enabled node, and bigger uncertainty is arranged.So where necessary, path protecting method is had to wake up a part and is in dormant node, lowers the probability that route requests gets clogged because of there not being enough Internet resources to guarantee the combinatorial path cumulative reliability.But do like this and can introduce another problem, except being in waking state for a long time, time and energy (list of references: Routing and Scheduling for Energy and Delay Minimization in the Powerdown Model that the frequent conversion between different conditions of node also can consumes considerable; M.Andrews, A.Fernandez Anta, L.Zhang; And W.Zhao, INFOCOM, 2010 Proceedings IEEE; Pp.1-5,2010.).According to existing; Path protecting method under Shang Weiyou delay, the SRLG constraint can be obtained balance preferably between reduction route requests blocking rate and optimized nodes sleep (comprising the average proportions of sleep node in the network and the average time that node state is changed).

So the object of the present invention is to provide a kind of one group of work of searching fast under shared risk link group constraint, backup path; The combinatorial path cumulative reliability is satisfied under the prerequisite of quality of service requirement; Through increasing the ratio of sleep node in the network; And reduce the conversion times of node between different conditions, optimize node sleep in the network as far as possible.

Provide several important definition below by foregoing in order further to explain:

1, the sleep mechanism of node and the sleep-awake that causes thereof postpone in the GreenNet:

The given network G that constitutes by N node and E bar link (N, E).Arbitrary node u has clear-headed and the sleep two states in the network, and when node was in waking state, the data of passing by this node were by undelayed forwarding downstream link port; When node was in sleep state, data were buffered in the formation of its upstream node, waken up up to this node and could continue transmission, so this node can be uploaded defeated data to the path and caused sleep delay.For real network, when data begin on a paths, to transmit, arrive this road through on before certain node of sleeping, in fact experienced the delay that stretch before this directly causes, so the actual sleep delay del that causes of this sleep node _{Sleep_dyma}The wakeup time that [u] estimates for this node deducts current time (the i.e. sleep delay del of this node self _Sleep[u]), deduction falls before this source node S to time in the path delay del (P of this sleep node u again _S-u) later numerical value.Sleep delay del when this node self _Sleep[u] is less than the delay del (P of link before this _S-u) time, this numerical value is 0.Obviously, above-mentioned sleep delay is a dynamic value, and when same sleep node was in the diverse location of different paths or same paths, the numerical value of the sleep delay that it causes was different.

${\mathrm{del}}_{\mathrm{sleep}\_\mathrm{dyna}}\left(u\right)=\left[\begin{array}{cc}{\mathrm{del}}_{\mathrm{sleep}}\left(u\right)-\mathrm{del}\left(P_{S-u}\right)& {\mathrm{del}}_{\mathrm{sleep}}\left(u\right)\≥\mathrm{del}\left(P_{S-u}\right)\\ 0& \mathrm{otherwise}\end{array}\right]$

$\mathrm{wheredel}\left(P_{S-u}\right)=\underset{\mathrm{link}(a-b)\∈P_{S-u}}{\mathrm{\Σ}}{\mathrm{del}}_{\mathrm{basic}}(a-b)---\left(1\right)$

$+\underset{\mathrm{node}\left(m\right)\∈P_{S-u},m\≠u}{\mathrm{\Σ}}{\mathrm{del}}_{\mathrm{sleep}\_\mathrm{dyna}}\left(m\right)+\underset{\mathrm{node}\left(n\right)\∈P_{S-u},n\≠u}{\mathrm{\Σ}}{\mathrm{del}}_{\mathrm{awake}\_\mathrm{dyna}}\left(n\right)$

When network need wake certain sleep node wherein immediately up, this node up to the state that is in complete operate as normal, also needed a period of time from current time, has promptly caused and has waken delay up.Identical with the computational methods (formula 1) of above-mentioned sleep delay actual numerical value, can see that this wakes delay del up _{Awake_dyma}The dynamic value of [u] also is to postpone del with waking up of himself _Awake[u] deducts before this, and obtain path delay.

2, the link cost under delay, the SRLG constraint:

The basic cost of link a → b of any connected node a and b comprises that himself postpones del in the network _Basic(a → b) and self reliability rel _Basic(a → b).

In the route of reality is calculated, the actual of link counted the sleep delay (or waking delays up) that himself postpones to cause with its endpoint node and.When its endpoint node was in waking state, the numerical value of sleep delay was 0.

$\mathrm{del}(a\→b)={\mathrm{del}}_{\mathrm{basic}}(a\→b)+{\mathrm{del}}_{\underset{\mathrm{awake}\_\mathrm{dyma}}{\mathrm{sleep}\_\mathrm{dyma\; or}}}\left(b\right)---\left(2\right)$

Consider the influence of the shared risk link group of link (SRLG), the achieved reliability rel of link _SRLG(a → b) is counted himself reliability and is in probability long-pending of non-malfunction with shared risk link group under it.When its endpoint node was in waking state, the numerical value of sleep delay was 0.Ω wherein _SRLG[j] represents the probability of malfunction of j shared risk link group under this link.

${\mathrm{rel}}_{\mathrm{SRLG}}(a\→b)={\mathrm{rel}}_{\mathrm{basic}}(a\→b)\·\underset{j=1,...,p}{\mathrm{\Π}}(1-{\mathrm{\Ω}}_{\mathrm{SRLG}}[j\left]\right),---\left(3\right)$

3, the feasible path under delay, the SRLG constraint:

In the k shortest path first, an i single sub path by source node S process intermediate node u buffer memory, the normalized nonlinear cost that extends to the path of another intermediate node v can use formula 4 to calculate.Wherein parameter q (q＞1) is the non linear coefficient of non-linear cost.PP _S-DWith a backup path BP _{S-D [1]}Total SRLG reliability of the combinatorial path of forming can use formula 4 to calculate, and wherein representes path P _S-DIn a part of zone from node a to node b.Special, when node v is destination node, if satisfy postpone and the cost numerical value of SRLG reliability respectively smaller or equal to separately constraint L _DelWith L _Rel, claim that then this path is a feasible path.

$l\left(P_{S-u\left[i\right]-v}\right)={[{\left(\frac{\mathrm{del}\left(P_{S-u\left[i\right]-v}\right)}{L_{\mathrm{del}}}\right)}^q+{\left(\frac{\log \left[{\mathrm{rel}}_{\mathrm{SRLG}}\left(P_{S-u\left[i\right]-v}\right)\right]}{\log \left[L_{\mathrm{rel}}\right]}\right)}^q]}^{\frac{1}{q}}---\left(4\right)$

4, the SRLG reliability of combinatorial path:

By an operating path PP _S-DWith a backup path BP _{S-D [1]}Total SRLG reliability of the combinatorial path of forming can use formula 5 to calculate, and wherein representes path P _S-DIn a part of zone from node a to node b.

${\mathrm{rel}}_{\mathrm{comb}}({\mathrm{WP}}_{S-D},{\mathrm{BP}}_{S-D})=\underset{{{\mathrm{Seg}}^{\′}}_{S-D}(a\→b)}{\underset{{\mathrm{Seg}}_{S-D}(a\→b)=}{\mathrm{\Π}}}\mathrm{rel}\left[{\mathrm{Seg}}_{S-D}(a\→b)\right]\×$

$\underset{{{\mathrm{Seg}}^{\′}}_{S-D}(a\→b)=\mathrm{\Φ}}{\underset{{\mathrm{Seg}}_{S-D}(a\→b)\∩}{\mathrm{\Π}}}\left(\frac{1-\{1-\mathrm{rel}[{\mathrm{Seg}}_{S-D}(a\→b)\left]\right\}\·\{1-\mathrm{rel}[{{\mathrm{Seg}}^{\′}}_{S-D}(a\→b)\left]\right\}}{\mathrm{rel}\left[{\mathrm{Seg}}_{S-D}(a\→b)\right]}\right)---\left(5\right)$

When having an operating path and many backup path BP _{S-D [1]}..., BP _{S-D [j]}The time, the SRLG reliability of combinatorial path can use following method to obtain: find out the local path that each bar backup path separates with operating path SRLG, the local path that uses each to be found out successively, the reliability (formula 6) of renewal operating path corresponding topical.Thereby every backup path all is superimposed upon in the reliability of operating path the contribution of combinatorial path cumulative reliability successively.Repeat aforesaid operations, all finish using up to all local paths of being found out, the SRLG reliability after this moment, operating path finally was updated is the cumulative reliability rel of combinatorial path _Comb

${\mathrm{rel}}_{\mathrm{SRLG}\_\mathrm{upda}}\left(\mathrm{link}\right)\underset{\mathrm{link}\∉{{\mathrm{Seg}}^{\′}}_{S-D\left[i\right]}(a\→b)\⋐{\mathrm{BP}}_{S-D\left[i\right]}}{\underset{\mathrm{link}\∈{\mathrm{Seg}}_{S-D}(a\→b)\⋐{\mathrm{WP}}_{S-D}}{=}}$

${\mathrm{rel}}_{\mathrm{SRLG}}\left(\mathrm{link}\right)\×\frac{1-\{1-\mathrm{rel}[{\mathrm{Seg}}_{S-D}(a\→b)\left]\right\}\·\{1-\mathrm{rel}[{{\mathrm{Seg}}^{\′}}_{S-D\left(i\right)}(a\→b)\left]\right\}}{\mathrm{rel}\left[{\mathrm{Seg}}_{S-D}(a\→b)\right]}---\left(6\right)$

5, the path takies link and the cost function of the node that wakes up in this method

List of references (A novel survivable routing algorithm with partial shared-risk link groups (SRLG)-disjoint protection based on differentiated reliability constraints in WDM optical mesh networks; L.Guo and L.M.Li; J.Lightw.Technol.; Vol.25, pp.1410-1415, the backup path that Jun.2007.) allows to belong to the different operating path is shared the link circuit resource of some; Thereby significantly do not reducing under the prerequisite of trail protection success rate, reducing the demand of trail protection algorithm effectively the network link resource.In the method that this paper proposes, cost function has further added the consideration of the node resource quantity that the path is newly waken up, thereby reduces the frequency that the sleep node is waken up as far as possible, improves the ratio of sleep node in the network.Specific practice is to use the function expression cons (P in the formula 7 _S-D), the link circuit resource cons that the reflection path takies _Link(P _S-D) and the node resource cons that wakes up _Node(P _S-D).Consider that number of links is much larger than number of nodes in the general networking; Operation parameter α (α＞1; Its numerical value equals the number of links that two ends in the network are clear-headed node; Divided by the number of nodes of sleeping) weight of node resource that path in the function is newly waken up carries out proportional amplification, and the link circuit resource that its weight and path are taken is in the same order of magnitude.

cons(P _S-D)＝cons _link(P _S-D)+α·cons _node(P _S-D) (7)

The link circuit resource cons that the path takies _Link(P _S-D) numerical value can use formula 8 to obtain:

${\mathrm{cons}}_{\mathrm{link}}\left(P_{S-D}\right)=\underset{(a\→b)\∈P_{S-D}}{\mathrm{\Σ}}{\mathrm{cons}}_{\mathrm{link}}(a\→b)$

${\mathrm{cons}}_{\mathrm{link}}(a\→b)$

$=\left\{\begin{array}{cc}\frac{1}{{\mathrm{FW}}_{a-b}}& \mathrm{current\; wavelength\; is\; unused}\\ \frac{1-\underset{i=1,...,y}{\mathrm{\Π}}{\mathrm{rel}}_{\mathrm{SRLG}}\left({\mathrm{WP}}_{S-D}\right)}{{\mathrm{FW}}_{a-b}}& \mathrm{current\; wavelength\; is\; shared}\end{array}\right.---\left(8\right)$

Wherein, the cost of each bar link of path process is calculated respectively: when a wavelength that never is used is before this monopolized on the link in the path, only consider the quantity FW of residue wavelength on this link _A-b, the residue wavelength bright remaining bandwidth of speaking more more is big more, and from the viewpoint of balanced flow, network encourages the path to use the big link of remaining bandwidth, becomes the bottleneck of flow to avoid some link.When sharing certain bar link (have only and allow shared link between the backup path), add total failare probability 1-∏ rel to the operating path under other paths in current path and other paths that has existed _SRLG(PP _S-D) consideration, this path of the high more expression of reliability is real because other operating paths lost efficacy, and needs occupied possibility low more.

The node resource cons that wake up in the path _Node(P _S-D) numerical value can use formula 9 to obtain:

${\mathrm{cons}}_{\mathrm{node}}\left(P_{S-D}\right)=\underset{b\∈P_{S-D}}{\mathrm{\Σ}}{\mathrm{cons}}_{\mathrm{node}}\left(b\right)$

${\mathrm{cons}}_{\mathrm{node}}\left(b\right)$

$\left\{\begin{array}{cc}1+\frac{1}{{\mathrm{out}}_{\mathrm{deg}}\left(b\right)}& \mathrm{awaked\; node\; b\; is\; only\; used\; by\; one\; <figure-callout\; id="1"\; label="path"\; filenames="HDA0000090263350000021.png,HDA0000090263350000041.png"\; state="\{\{state\}\}">path</figure-callout>}\\ \frac{1}{{\mathrm{num}}_{\mathrm{share}}\left(b\right)}+\frac{1}{{\mathrm{out}}_{\mathrm{deg}}\left(b\right)}& \\ & \mathrm{awaked\; node\; b\; is\; shared\; by\; <figure-callout\; id="0"\; label="multiple\; paths"\; filenames="HDA0000090263350000032.png"\; state="\{\{state\}\}">multiple\; paths</figure-callout>}\\ 0& \mathrm{node\; b\; needs\; not\; to\; be\; awaked}\end{array}\right.---\left(9\right)$

Wherein, each node that wake up in the path has different costs: be in waking state, the node cost that need not to be waken up is 0.When the path need be waken in the network node that is never waken up by other paths before this separately up, only consider the out-degree out of this node _Deg(b) (number of links that promptly connects); This node of the big explanation of out-degree is in the position than core in network topology; Its behavior of waking up will provide more nodes and link circuit resource for other paths, and network encourages the path to wake such node up, so that more route requests benefits.When certain node is shared in current path and other paths that has existed, add this node is shared frequency n um _Share(b) consideration, waking up of high more same this node of expression of shared number of times can make more route requests benefit, thereby reduces the probability that other route requests are waken other sleep node up, reduces the quantity that whole network is waken up node, increases the sleep of network node.

The main target of the path protecting method under 6, delay in the GreenNet, the SRLG constraint:

Path protecting method under delay in the GreenNet, the SRLG constraint has 2 main targets:

Its primary goal is to provide by 1 feasible operating path PP for each route requests _S-D, with 1 feasible backup path BP that separates with the complete SRLG of operating path _{S-D [1]}, or many feasible backup path BP that separate with the local SRLG of operating path _{S-D [1]}..., BP _{S-D [j]}The combinatorial path of forming, and guarantee that total SRLG reliability of combinatorial path satisfies constraint L _{Rel_comb}Requirement.

relS _{RLG_comb}(PP _S-D，BP _S-D[1]，…，BP _S-D[j])≥L _{rel_comb} (10)

Guaranteeing on the basis that primary goal is met that trail protection also need be practiced thrift the energy of node in the network as far as possible through following 2 kinds of modes: the average sleep ratio [1] of node in the maximization network; Minimize the conversion times of node between clear-headed and sleep state in the network.

MAX→sleeping_percentage _average

MIN→state_transitions _average (11)

For the conversion times of node in the network between clear-headed and sleep state; Because the time and the energy that transfer the required consumption of waking state to from sleep state are far longer than from waking state and convert sleep state into; Therefore, hereinafter use the number of times that transfers waking state to from sleep state to reflect the state exchange number of times of this node.

7, the jumping figure in path:

The sum that node (comprising its destination node) is passed by in the path is called the jumping figure in this path.

8, the path list of node:

In path computing; Except the source node S of route requests; Sequence number, the cost of the preceding k paths that other node is minimum with the normalized nonlinear cost from source node S to this node of current discovery and the node of passing by thereof all are stored in the tabulation of this node, and we claim that this tabulation is the path list of this node.For example: the i paths P in the path list of node n (S → n [i]) (the i paths of the expression of 1≤i≤k) wherein from source node S to node n.

Summary of the invention

The invention discloses a kind of one group of work of searching fast under shared risk link group constraint, backup path, satisfy in the cumulative reliability that makes combinatorial path under the prerequisite of quality of service requirement, optimize the path protecting method of the quantity of sleep node in the network.It comprises following steps and content:

1, in program, import relevant parameter: comprise N node and E bar link network topological diagram G (N, E), any self delay del of link a → b of connected node a and b in the network _Basic(a → b) and self reliability rel _Basic(a → b) (a, b ∈ 1 ..., N), each is in the sleep delay del that the sleep state node causes in the network _Sleep[n] (n ∈ 1 ..., N), the probability of malfunction Ω of each shared risk link group in the network _SRLGThe source node S of the number of paths k of each intermediate nodes cache, route requests and destination node D in the path computing process.

2, calculate feasible path candidate:

2-1 uses the k shortest path first based on the nonlinear path cost, calculates source node S to preceding k bar feasible path between the destination node D.On the road in calculating, that the actual of link is counted the sleep delay (or waking delays up) that himself postpones to cause with its endpoint node and (formula 2).The actual SRLG reliability rel of link _SRLG(a → b) is counted himself reliability and is in long-pending (formula 3) of the probability of non-malfunction with shared risk link group under it.The actual sleep delay del that causes of sleep node u in the path _{Sleep_dyma}[u] (or wakes delay del up _{Awake_dyma}[u]) counted wakeup time that this node estimates and deducted current time (the i.e. sleep delay del of this node self _Sleep[u] or wake up and postpone del _Awake[u]), deduction falls the path delay time del (P of data from source node S to this sleep node u again _S-u) later numerical value (formula 1).

2-2 is with all feasible paths that obtain among the step 2-1, according to the descending of individual paths SRLG reliability size.

3, selection work, backup path from path candidate:

3-1 is designated as PP with the operating path of the article one in the feasible path that obtains in the step 2 and sort as the candidate _{S-D [i]}Other paths are designated as BP as candidate's backup path _{S-D [1]}..., BP _{S-D [x]}

3-2 checks candidate's backup path BP successively _{S-D [1]}..., BP _{S-D [x]}, confirm its whether with candidate's operating path PP _{S-D [i]}End-to-end SRLG separates: if then use formula 11 to calculate and write down node and the link circuit resource that this path takies; If not, then check itself and PP _{S-D [i]}Total SRLG reliability of combinatorial path whether satisfy constraint.If satisfy constraint, then use formula 11 to calculate and write down node and the link circuit resource that this path takies; If not, continue next bar candidate's of inspection backup path.Work as BP _{S-D [1]}..., BP _{S-D [x]}All checked finish after, if find at least one and PP _{S-D [i]}It maybe can be the backup path that combinatorial path satisfies the SRLG constraint that end-to-end SRLG separates; Then choose minimum one of the node that wherein takies and link circuit resource; Candidate's operating path and this path respectively as the result of the operating path and the backup path of trail protection, are jumped to step 4; Otherwise, execution in step 3-3 then.

3-3 calculates every candidate's backup path BP successively _{S-D [1]}..., BP _{S-D [x]}Operating path PP with the candidate _{S -D [i]}The SRLG cumulative reliability (formula 5) of combinatorial path; The total link that takies with combinatorial path and the ratio of node resource (formula 7); Choose wherein maximum candidate's backup path of ratio, use formula 6 that its contribution to operating path SRLG reliability is converted into operating path PP _{S-D [i]}The increase of respective link reliability.Repeat said process; Satisfy constraint up to the SRLG of combinatorial path cumulative reliability (operating path that equals the candidate on the numerical value is updated later SRLG reliability); Or the total link that takies of all selected backup paths and node resource surpass candidate's operating path, or all candidates' backup path is all selected.If the SRLG cumulative reliability of final combinatorial path satisfies constraint, jump to step 4; Otherwise jump to step 3-4.

3-4 according among the step 2-2 to the ordering in path, if current candidate's operating path is not the last item in the tabulation, choose the operating path of next paths of current candidate's operating path, repeating step 3-2 and 3-3 as the candidate; Otherwise, jump to step 4.

4, if the trail protection algorithm obtains the one group of operating path from S to D and backup path that meets the demands at least, the operating path of then exporting trail protection then is with the result of backup path and finish calculating.Otherwise the result of outgoing route protection algorithm computation failure also finishes to calculate.

The present invention has the following advantages:

(1) method involved in the present invention; When calculating feasible path candidate; With simple, feasible mode; The sleep node is postponed to integrate with in the link cost with waking up to the sleep delay that data cause, carry out the road through calculating thereby can directly use existing breadth-first k shortest path first easily.Postpone to carry out in the calculation process with waking up in the sleep delay that the sleep node is caused data, taken into full account the influence of data elapsed delays in upstream path, obtained the predicted numerical value of the end-to-end total delay in path accurately.

(2) method involved in the present invention when selection work, backup path from path candidate, has been utilized the path candidate that obtains fully.Based on factors such as the surplus resources of path reliability, network topology structure, link and node or shared number of times, formulated the function that delegated path takies link circuit resource and node resource quantity, encourage between the path to carry out resource-sharing with mode more efficiently.And the trail protection that has prevented single route requests effectively takies too much Internet resources.

(3) method involved in the present invention; Its computational complexity is similar with traditional path protecting method; And can be through changing the numerical value of 1 simple parameters k; Along with the load of router cpu and real-time the adjusting of variation of the network condition of reality, under the condition that the CPU ability allows, obtain the high as far as possible path computing and the accuracy of selection.Though this method is in design; Emphasis has been considered in the green WDM network to postpone and the constraint of shared risk link group SRLG reliability to path or combinatorial path, but its can be used for very easily also that more common GreenNet postpones and reliability constraint under trail protection.So the method has extensive applicability, especially be fit to be nested in the GreenNet with survivability in other complicated path protecting methods, in order to improve the comprehensive quality and the detection probability in protection path.

Description of drawings

Fig. 1: the present invention proposes the flow chart of method.

Fig. 2: the flow chart of selection work from path candidate, backup path algorithm in the proposition method of the present invention.

Fig. 3: the network topological diagram that the method that the present invention proposes is used in emulation.

Fig. 4: simulation result figure.Wherein:

(a), (b), (c) represent the shared percentage of sleep node in the network respectively, average each actual sleep node number of waking up of route requests.The probability that path request gets clogged because violating delay or SRLG reliability constraint.

Fig. 5: the function false code of the main program of the method that the present invention proposes is described:

Embodiment

The performance of the method that proposes for better checking the present invention is applied in it respectively in 25 meshed networks of rule topology structure and has carried out emulation.Each bar link in the network has 2 even distributions that generate at random and does not have the cost component of correlation (postpone in [0,1] interval, reliability is interval interior in [0.95,1]).The failure probability of each shared risk link group SRLG is in [0,0.05] interval.Every the road is set to 5 and 0.75 respectively through the constraint of end-to-end delay and SRLG reliability.The constraint of combinatorial path SRLG reliability is set to 0.9.

The performance of method is used the average effect of the execution of the route requests of the source that generates at random for 1000 times, destination node is assessed.Parameter as Performance Evaluation comprises: the shared percentage of sleep node in the network, average each actual sleep node number of waking up of route requests.The probability that path request gets clogged because violating delay or SRLG reliability constraint.The method that is used to contrast comprises: (a) do not consider energy-conservation, the SRLG path protecting method that node is in running order all the time; (b) consideration is energy-conservation, only uses the SRLG path protecting method of in running order node in the path computing; (c) consideration is energy-conservation, allows arbitrarily to wake up the SRLG path protecting method that is in the sleep state node in the path computing; (d) this paper method is promptly considered energy-conservationly, allows in the path computing to wake up and is in the sleep state node, and the SRLG path protecting method of the shared mechanism optimization wake-up times of sleep node.

Among Fig. 5; Increase along with expression data traffic size loads proportionality factor in the network; Although only use the method that is in the waking state node to obtain maximum sleep node ratio; The method that the present invention proposes has obtained immediate with it result on the sleep ratio, and is superior to traditional permission all the time and arbitrarily wakes up and be in the sleep state nodal method.Aspect the node wake-up times, this paper algorithm is equally than allowing random waking up to be in the sleep state nodal method remarkable advantages is arranged.The presentation of results of trail protection blocking rate; Though only use be in the waking state node method in front 2 demonstrate some advantages in relatively; But the situation of the resources in network wretched insufficiency that it causes greatly descends the route success rate, is that blocking rate is the highest in the several method.And this paper method is selected and the shared mechanism of the node of sleeping through rational more path; Obtained again than random the waking up of tradition and be in the better effect of sleep state nodal method, in addition approach all nodes in the network all be in do not consider that energy-conservation operating state (node of not sleeping) method obtains LIMIT RESULTS.

This shows that method that this paper proposes all has excellent and stable performance aspect network node sleep and the trail protection success rate optimizing, it is fit to be applied in the trail protection under postponing in the GreenNet to retrain with SRLG.

In sum, this method has reached its intended purposes.

Claims (3)

1. the path protecting method that optimized nodes is slept under delay and the constraint of shared risk link group is characterized in that comprising following 2 key steps:

Calculate feasible path candidate: use k shortest path first (need in the path of trying to achieve, select because of this method based on the nonlinear path cost; So path candidate quantity k＞1 of each nodal cache in the k shortest path first), calculate source node S to the feasible path between the destination node D; In path computing, the actual of link by counted himself postpone the sleep delay that causes with its endpoint node or wake up delay with; Actual shared risk link group (hereinafter to be referred as the SRLG) reliability of link is counted himself reliability and is in probability long-pending of non-malfunction with shared risk link group under it; In the path sleep node actual sleep delay that causes with wake up delay counted this node continue to accomplish remaining sleep back is waken up and immediately disrupted sleep directly waken up; Time up to can operate as normal deducts the current time, deducts the numerical value of data after the time of delay on from source node S to this sleep node path again; All that path computing is obtained satisfy the path candidate of delay and SRLG reliability constraint, according to the descending of individual paths SRLG reliability size;

Selection work, backup path from path candidate: the article one in the feasible path after will sorting is as candidate's operating path; Other paths are as candidate's backup path; Check every candidate's backup path successively, confirm whether it separates with the end-to-end SRLG of candidate's operating path: if then calculate and write down node and link circuit resource that this path takies; If not, then check the SRLG reliability of combinatorial path of itself and candidate's operating path whether to satisfy constraint; If satisfy constraint, then calculate and write down node and link circuit resource that this path takies; If do not satisfy constraint, continue next bar candidate's of inspection backup path; When all candidates' backup path all checked finish after; If find that at least one separates the backup path that maybe can make combinatorial path satisfy the SRLG constraint with the end-to-end SRLG of candidate's operating path; Then choose minimum one of the node that wherein takies and link circuit resource, candidate's operating path and the backup path of picking out are exported as the operating path of the trail protection result with backup path respectively; Otherwise, because the cumulative reliability of combinatorial path can't protect the path to satisfy constraint requirements through wall scroll, so adopt the guard method of mulitpath or local path; Calculate every candidate's backup path and candidate's SRLG cumulative reliability and the total link that combinatorial path takies and the ratio of node resource of combinatorial path of operating path successively; Choosing maximum candidate's backup path of ratio wherein and operating path makes up (wherein; For every candidate's backup path and candidate's operating path SRLG separated portions; Calculate the ratio of its cumulative reliability and original this part reliability of candidate's operating path; The numerical value of every link reliability in this part of candidate's operating path multiply by above-mentioned ratio, recomputate the end-to-end SRLG reliability of candidate's operating path) as the SRLG cumulative reliability of combinatorial path; Repeat said process, satisfy constraint up to the SRLG of combinatorial path cumulative reliability, or all selected backup paths total link and the operating path of node resource above the candidate that take, or all candidates' backup path is all selected; If the SRLG cumulative reliability of final combinatorial path satisfies constraint, candidate's operating path and the backup path of picking out are exported as the operating path of trail protection and the result of backup path respectively; Otherwise; Change candidate's operating path into its next paths on path list; Repeat above-mentioned path and select process, up to selecting operating path from S to D and the backup path that meets the demands, or tabulation is gone up all paths and all was used as candidate's operating path.

2. the method for claim 1 is wherein selected the step of operating path, backup path from path candidate, when the link circuit resource that calculating path takies, total cost that the path takies link for the cost of each bar link of its process with; When a wavelength that never is used was before this monopolized on the link in the path, this link cost numerical value was 1 quantity divided by residue wavelength on this link (encourage the path to use the many links of residue wavelength resource, become the bottleneck of flow to avoid some link); When certain bar link is shared in path and other paths that has existed; This link cost numerical value is 1 to multiply by the total failare probability of the operating path under other paths; (encourage path and other to be used the less backup path shared link of probability divided by the quantity of residue wavelength on this link again; When damaging simultaneously to reduce operating path under it, the conflict that takes place because of the link of fighting for backup path).

3. the method for claim 1, the step of selection work, backup path from path candidate wherein, when the sleep node that calculating path wakes up, total cost that node is waken in the path up for the cost of its each node that wakes up with; Be in waking state, the node cost that need not to be waken up is 0; When the path need be waken in the network node of never being shared by other paths before this up; Cost numerical value is 1 to add 1 out-degree divided by this node (the i.e. number of links that connects of this node; This node of the big explanation of out-degree is in the position of core in network topology; Therefore bigger possibly in the path computing of other route requests after this, being used arranged; This method encourages the path to wake such node up, further wakes extra sleep node up with the route requests that reduces other, thus the node that minimizings need be waken up sum and to the wake-up times of node, the energy consumption of the whole network of reduction); When certain node is shared in path and other paths that has existed; Cost numerical value is 1 divided by the number of paths of participate in sharing; Add that (being shared waking up of high more this node of expression of number of times can avoid more multirouting request to wake extra sleep node up to 1 out-degree divided by this node; This method encourages the path to wake such node up, and reason is the same).

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