CN104301214A - Routing method of overlay network - Google Patents

Abstract

Provided is a routing method of an overlay network. The routing method of the overlay network comprises the first step of constructing the overlay network, the second step of selecting candidate relay nodes, the third step of selecting relay nodes and the fourth step of carrying out flow cutting. The routing method of the overlay network achieves route relay in an end system to recover physical paths out of work, overcomes the defect that converge time delay of physical layer routing is too long, does not change a topology structure of a physical network and does not change a routing algorithm of the physical network. The routing method of the overlay network is a one-hop overlay network route mechanism which can quickly make a selection after a failure, does not need to backup routing paths, reduces routing loads, and has the advantages of being efficient and quick.

Description

A kind of coverage water method

Technical field

The present invention relates to a kind of coverage water method, belong to technical field of the computer network, particularly belong to Next Generation Internet technical field.

Background technology

The fault (as fracture or congested) of present the Internet interior joint or link is inevitable, and along with the increase based on internet, applications, this fault more frequently occurs.Because IP network Routing Protocol is (as open type shortest path priority protocol OSPF, Border Gateway Protocol (BGP)) feature, current IP network is that the route assemblage that this type of fault of solution is carried out need spend tens seconds, even tens minutes, often occurs data-bag lost phenomenon therebetween.

In order to solve this technical problem, many IP path failure restoration methods are suggested, and they roughly can be divided into three types: (1) acyclic method of substitution (LFA-based:loop-free alternate based scheme); (2) based on tunneling method (Tunnel-based:tunneling based scheme); (3) routing table backup method (BRT-based:backup routing table based scheme).In acyclic method of substitution, after route break occurs, the router adjacent with failed link shifts the flow that is affected to a predefined alternate router node, guarantees that heavy-route path is in without ring status.Research shows acyclic method of substitution inefficiency, is difficult to the fault point that prediction was lost efficacy, and provides backup link need spend larger maintenance cost for it.Based in tunneling method, when after a router detection to connected link generation failure of removal, Stochastic choice router, as via node, is redirected affected flow.This is the emergency mechanism after a kind of fault occurs, do not need to provide backup link or backup node in advance, but Iterim Change route direction, and to node, extra burden is brought to the time delay that Reseal and the decapsulation of packet bring, data flow even may be caused congested at this node secondary.Routing table backup method is that another kind provides route stand-by path mechanism, and it provides backup path for each routed path forwards in each router, but safeguards and upgrade the very large expense of these route stand-bies need.Therefore how effectively to solve the problem of IP network route recovery, become the technical barrier that next generation network technology field is badly in need of solving.

Summary of the invention

In view of this, the object of the invention is to invent a kind of IP network route recovery mechanism, it adopts the application layer route technology based on nerve of a covering, and uses nerve of a covering multipath mechanism to ensure reliability and the efficiency of network, and has the function of load balancing.

In order to achieve the above object, the present invention proposes a kind of coverage water method, described method comprises following operative step:

(1) building nerve of a covering: overlay network node is interconnected to form full mesh structure, is that a kind of full mesh logic connects;

(2) the choosing of candidate relay node: when breaking down in certain coverage water path, calculate overlay network node corresponding betweenness center in physical network, choosing a betweenness center higher specified quantity overlay network node is candidate relay node collection;

(3) the choosing of via node: source node detects the via node in described candidate relay node set, and final selection arrives destination node by this via node and k the via node formation set of relay nodes R making network congestion time delay minimum, builds k bar one and jumps coverage water path; Wherein k be greater than 1 natural number;

(4) flow cutting: source node to be jumped assignment of traffic on coverage water path to described k bar one according to the flow cutting method of setting, completes transfer of data to destination node and realizes minimizing of network congestion rate.

The calculating of betweenness center BC (v) of described step (2) interior joint v is carried out according to the following formula:

$\mathrm{BC}\left(v\right)=\underset{s,t\∈V}{\mathrm{\Σ}}\frac{{\mathrm{\σ}}_{\mathrm{st}}\left(v\right)}{{\mathrm{\σ}}_{\mathrm{st}}}$

In above formula, V is physical network nodes set, σ _strefer to the quantity from node s to the shortest path of node t, σ _stv () refers to the quantity from node s through via node v to the shortest path of node t.

The computational methods of the network congestion time delay described in described step (3) are carried out according to the following formula:

$t=\underset{e\∈E}{\mathrm{\Σ}}\frac{{\mathrm{\Σ}}_{(p,q)}{\mathrm{\ξ}}_{\mathrm{pq}\left(m\right)}^e{d}_{\mathrm{pq}}}{C_e-{\mathrm{\Σ}}_{(p,q)}{\mathrm{\ξ}}_{\mathrm{pq}\left(m\right)}^e{d}_{\mathrm{pq}}}$

In above formula, t represents network delay, and p represents the source node in nerve of a covering, and q represents the destination node in nerve of a covering, and m represents the via node in a jumping coverage water path, representing link indicating device, is a Boolean variable, when a jumping coverage water path p → m → q comprises link e, otherwise be 0; d _pqrepresent the traffic demand of source node p to destination node q, i.e. the data volume of planned transmission between source node p to destination node q; it is the total load of link e; C _eit is the capacity of link e; E represents the set of bottom physical link;

The particular content of the flow cutting method described in described step (4) is: be a linear programming problem by flow cutting and assignment of traffic problem definition, and its target function is the congestion ratio μ minimizing worst case lower network, that is:

$\min \mathrm{\μ}=\min \underset{(i,j)\∈E}{\max }\left\{\frac{L_{\mathrm{ij}}}{C_{\mathrm{ij}}}\right\}$

In above formula, E represents the set of bottom physical link; (i, j) represents a bottom physical link, L _ijrepresent the load on bottom physical link (i, j), C _ijrepresent the capacity of bottom physical link (i, j);

Described above formula will carry out optimization meeting under following constraints:

$\underset{m\∈R}{\mathrm{\Σ}}{\mathrm{\δ}}_m^{\mathrm{pq}}=1$

$\underset{m\∈R}{\mathrm{\Σ}}({\mathrm{\ψ}}_{\mathrm{pm}}^{\mathrm{ij}}+{\mathrm{\ψ}}_{\mathrm{mq}}^{\mathrm{ij}}){\mathrm{\δ}}_m^{\mathrm{pq}}{d}_{\mathrm{pq}}+{\mathrm{\β}}_{\mathrm{ij}}\≤\mathrm{\μ}{C}_{\mathrm{ij}},p\≠q$

$\underset{q\∈Q}{\mathrm{\Σ}}{d}_{\mathrm{mq}}\≤b^{+}\left(m\right),m\∈R$

$\underset{p\∈Q}{\mathrm{\Σ}}{d}_{\mathrm{pm}}\≤b^{-}\left(m\right),m\∈R$

In above formula, δ represents that data traffic waiting for transmission jumps the allocation proportion on overlay network path at k bar one, i.e. flow cutting rate; represent and be assigned to source node p accounts for total flow ratio to destination node q and through a flow of jumping on the p → m → q of coverage water path of via node m formation; Set R refers to the set be made up of described interruption node, and the scale of R is k; (u, j) represents a bottom physical link; (i, u) represents a bottom physical link; representing link indicating device, is a Boolean variable, when coverage water path p → m comprises physical link (i, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path m → q comprises physical link (i, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path p → q comprises physical link (u, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path p → q comprises physical link (i, u), otherwise be 0; β _ijit is the background traffic on physical link (i, j); E ⁺(u) and E ^-u () represents outlet and the inbound link set of node u respectively; Q be described overlay network set of node and; b ⁺(m) and b ^-m () represents nominal outlet port and the ingress bandwidth of node m respectively; d _mqrepresent from node m to the flow of node q; d _pmrepresent from node p to the flow of node m;

Beneficial effect of the present invention is that coverage water method of the present invention applies coverage water technology, route relaying is realized in end system, to recover the physical pathway lost efficacy, avoid the defect that physical layer route assemblage time delay is long, and do not change physical network topology, do not need to change physical network routing algorithm yet; Method of the present invention selected one to jump coverage water mechanism fast after a kind of inefficacy, do not need route stand-by path, decrease routing overhead, have efficient, advantage efficiently.

Accompanying drawing explanation

Fig. 1 is the flow chart of a kind of coverage water method that the present invention proposes.

Fig. 2 is that the restoration route of one of the inventive method simulated experiment result increases the comparison schematic diagram of praising.

Fig. 3 is the comparison schematic diagram of the restoration path jumping figure punishment of one of the inventive method simulated experiment result.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the present invention is described in further detail.

See Fig. 1, introduce a kind of coverage water method that the present invention proposes, described method comprises following operative step:

(1) building nerve of a covering: overlay network node is interconnected to form full mesh structure, is that a kind of full mesh logic connects;

(2) the choosing of candidate relay node: when breaking down in certain coverage water path, calculate overlay network node corresponding betweenness center in physical network, choosing the higher specified quantity in betweenness center (determine according to overlay network node sum, generally choose the 5%-10% of overlay network node sum) individual overlay network node is candidate relay node collection;

(3) the choosing of via node: source node detects the via node in described candidate relay node set, and final selection arrives destination node by this via node and k the via node formation set of relay nodes R making network congestion time delay minimum, builds k bar one and jumps coverage water path; Wherein k be greater than 1 natural number;

(4) flow cutting: source node to be jumped assignment of traffic on coverage water path to described k bar one according to the flow cutting method of setting, completes transfer of data to destination node and realizes minimizing of network congestion rate.

The calculating of betweenness center BC (v) of described step (2) interior joint v is carried out according to the following formula:

$\mathrm{BC}\left(v\right)=\underset{s,t\∈V}{\mathrm{\Σ}}\frac{{\mathrm{\σ}}_{\mathrm{st}}\left(v\right)}{{\mathrm{\σ}}_{\mathrm{st}}}$

In above formula, V is physical network nodes set, σ _strefer to the quantity from node s to the shortest path of node t, σ _stv () refers to the quantity from node s through via node v to the shortest path of node t.

The computational methods of the network congestion time delay described in described step (3) are carried out according to the following formula:

$t=\underset{e\∈E}{\mathrm{\Σ}}\frac{{\mathrm{\Σ}}_{(p,q)}{\mathrm{\ξ}}_{\mathrm{pq}\left(m\right)}^e{d}_{\mathrm{pq}}}{C_e-{\mathrm{\Σ}}_{(p,q)}{\mathrm{\ξ}}_{\mathrm{pq}\left(m\right)}^e{d}_{\mathrm{pq}}}$

In above formula, t represents network delay, and p represents the source node in nerve of a covering, and q represents the destination node in nerve of a covering, and m represents the via node in a jumping coverage water path, representing link indicating device, is a Boolean variable, when a jumping coverage water path p → m → q comprises link e, otherwise be 0; d _pqrepresent the traffic demand of source node p to destination node q, i.e. the data volume of planned transmission between source node p to destination node q; it is the total load of link e; C _eit is the capacity of link e; E represents the set of bottom physical link;

The particular content of the flow cutting method described in described step (4) is: be a linear programming problem by flow cutting and assignment of traffic problem definition, and its target function is the congestion ratio μ minimizing worst case lower network, that is:

$\min \mathrm{\μ}=\min \underset{(i,j)\∈E}{\max }\left\{\frac{L_{\mathrm{ij}}}{C_{\mathrm{ij}}}\right\}$

In above formula, E represents the set of bottom physical link; (i, j) represents a bottom physical link, L _ijrepresent the load on bottom physical link (i, j), C _ijrepresent the capacity of bottom physical link (i, j);

Described above formula will carry out optimization meeting under following constraints:

$\underset{m\∈R}{\mathrm{\Σ}}{\mathrm{\δ}}_m^{\mathrm{pq}}=1$

(this formula represents that flow cutting rate summation is 1)

$\underset{m\∈R}{\mathrm{\Σ}}({\mathrm{\ψ}}_{\mathrm{pm}}^{\mathrm{ij}}+{\mathrm{\ψ}}_{\mathrm{mq}}^{\mathrm{ij}}){\mathrm{\δ}}_m^{\mathrm{pq}}{d}_{\mathrm{pq}}+{\mathrm{\β}}_{\mathrm{ij}}\≤\mathrm{\μ}{C}_{\mathrm{ij}},p\≠q$

(this formula represents that the load flowing through physical link (i, j) must be not more than the heap(ed) capacity of this link)

(this formula represents will meet flow law of conservation)

$\underset{q\∈Q}{\mathrm{\Σ}}{d}_{\mathrm{mq}}\≤b^{+}\left(m\right),m\∈R$

(this formula represents that the flow flowing out node m is not more than its maximum rate of discharge b ⁺(m))

$\underset{p\∈Q}{\mathrm{\Σ}}{d}_{\mathrm{pm}}\≤b^{-}\left(m\right),m\∈R$

(this formula represents that the flow flowing into node m is not more than its maximum inlet flow rate b ^-(m))

In above formula, δ represents that data traffic waiting for transmission jumps the allocation proportion on overlay network path at k bar one, i.e. flow cutting rate; represent and be assigned to source node p accounts for total flow ratio to destination node q and through a flow of jumping on the p → m → q of coverage water path of via node m formation; Set R refers to the set be made up of described interruption node, and the scale of R is k; (u, j) represents a bottom physical link; (i, u) represents a bottom physical link; representing link indicating device, is a Boolean variable, when coverage water path p → m comprises physical link (i, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path m → q comprises physical link (i, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path p → q comprises physical link (u, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path p → q comprises physical link (i, u), otherwise be 0; β _ijit is the background traffic on physical link (i, j); E ⁺(u) and E ^-u () represents outlet and the inbound link set of node u respectively; Q be described overlay network set of node and; b ⁺(m) and b ^-m () represents nominal outlet port and the ingress bandwidth of node m respectively; d _mqrepresent from node m to the flow of node q; d _pmrepresent from node p to the flow of node m.

Inventor has carried out simulated experiment to method of the present invention, tests specific as follows: inventor generates the physical network of random network GT180 as bottom with topology generator GT-ITM, and GT180 is made up of 180 nodes and 502 links.Assess by restoration route increasing reputation (GAIN) and restoration path jumping figure punishment (RPHP:Recovery Path Hop Penalty) two Measure Indexes performances to nerve of a covering.Restoration route increases the inverse that reputation GAIN is defined as the congestion ratio of restoration route and the ratio of default route congestion ratio, and more macroreticular congestion ratio μ is less for GAIN value, and restoration path is more excellent.The punishment of restoration path jumping figure refers to the ratio of path jumping figure and the corresponding IP path jumping figure recovered via overlay network, and RPHP is less shows that overlay network hop count is less, shows that spent time delay is less in a way.Inventor has compared comparative analysis method of the present invention (representing with One-hop Overlay) and conventional stochastic selection algorithm RSM (Random Selection Method), and comparative result is see Fig. 2 and Fig. 3.The feasibility of experiment show the inventive method and validity.

Claims (4)

1. a coverage water method, is characterized in that: described method comprises following operative step:

(1) building nerve of a covering: overlay network node is interconnected to form full mesh structure, is that a kind of full mesh logic connects;

(2) the choosing of candidate relay node: when breaking down in certain coverage water path, calculate overlay network node corresponding betweenness center in physical network, choosing a betweenness center higher specified quantity overlay network node is candidate relay node collection;

(3) the choosing of via node: source node detects the via node in described candidate relay node set, and final selection arrives destination node by this via node and k the via node formation set of relay nodes R making network congestion time delay minimum, builds k bar one and jumps coverage water path; Wherein k be greater than 1 natural number;

(4) flow cutting: source node to be jumped assignment of traffic on coverage water path to described k bar one according to the flow cutting method of setting, completes transfer of data to destination node and realizes minimizing of network congestion rate.

2. a kind of coverage water method according to claim 1, is characterized in that: the calculating of betweenness center BC (v) of described step (2) interior joint v is carried out according to the following formula:

$\mathrm{BC}\left(v\right)=\underset{s,t\∈V}{\mathrm{\Σ}}\frac{{\mathrm{\σ}}_{\mathrm{st}}\left(v\right)}{{\mathrm{\σ}}_{\mathrm{st}}}$

In above formula, V is physical network nodes set, σ _strefer to the quantity from node s to the shortest path of node t, σ _stv () refers to the quantity from node s through via node v to the shortest path of node t.

3. a kind of coverage water method according to claim 1, is characterized in that: the computational methods of the network congestion time delay described in described step (3) are carried out according to the following formula:

$t=\underset{e\∈E}{\mathrm{\Σ}}\frac{{\mathrm{\Σ}}_{(p,q)}{\mathrm{\ξ}}_{\mathrm{pq}\left(m\right)}^e{d}_{\mathrm{pq}}}{C_e-{\mathrm{\Σ}}_{(p,q)}{\mathrm{\ξ}}_{\mathrm{pq}\left(m\right)}^e{d}_{\mathrm{pq}}}$

In above formula, t represents network delay, and p represents the source node in nerve of a covering, and q represents the destination node in nerve of a covering, and m represents the via node in a jumping coverage water path, representing link indicating device, is a Boolean variable, when a jumping coverage water path p → m → q comprises link e, otherwise be 0; d _pqrepresent the traffic demand of source node p to destination node q, i.e. the data volume of planned transmission between source node p to destination node q; it is the total load of link e; C _eit is the capacity of link e; E represents the set of bottom physical link.

4. a kind of coverage water method according to claim 1, it is characterized in that: the particular content of the flow cutting method described in described step (4) is: be a linear programming problem by flow cutting and assignment of traffic problem definition, its target function is the congestion ratio μ minimizing worst case lower network, that is:

$\min \mathrm{\μ}=\min \underset{(i,j)\∈E}{\max }\left\{\frac{L_{\mathrm{ij}}}{C_{\mathrm{ij}}}\right\}$

In above formula, E represents the set of bottom physical link; (i, j) represents a bottom physical link, L _ijrepresent the load on bottom physical link (i, j), C _ijrepresent the capacity of bottom physical link (i, j);

Described above formula will carry out optimization meeting under following constraints:

$\underset{m\∈R}{\mathrm{\Σ}}{\mathrm{\δ}}_m^{\mathrm{pq}}=1$

$\underset{m\∈R}{\mathrm{\Σ}}({\mathrm{\ψ}}_{\mathrm{pm}}^{\mathrm{ij}}+{\mathrm{\ψ}}_{\mathrm{mq}}^{\mathrm{ij}}){\mathrm{\δ}}_m^{\mathrm{pq}}{d}_{\mathrm{pq}}+{\mathrm{\β}}_{\mathrm{ij}}\≤{\mathrm{\μC}}_{\mathrm{ij}},p\≠q$

$\underset{q\∈Q}{\mathrm{\Σ}}{d}_{\mathrm{mq}}\≤b^{+}\left(m\right),m\∈R$

$\underset{p\∈Q}{\mathrm{\Σ}}{d}_{\mathrm{pm}}\≤b^{-}\left(m\right),m\∈R$

In above formula, δ represents that data traffic waiting for transmission jumps the allocation proportion on overlay network path at k bar one, i.e. flow cutting rate; represent and be assigned to source node p accounts for total flow ratio to destination node q and through a flow of jumping on the p → m → q of coverage water path of via node m formation; Set R refers to the set be made up of described interruption node, and the scale of R is k; (u, j) represents a bottom physical link; (i, u) represents a bottom physical link; representing link indicating device, is a Boolean variable, when coverage water path p → m comprises physical link (i, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path m → q comprises physical link (i, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path p → q comprises physical link (u, j), otherwise be 0; representing link indicating device, is a Boolean variable, when coverage water path p → q comprises physical link (i, u), otherwise be 0; β i _jit is the background traffic on physical link (i, j); E ⁺(u) and E ^-u () represents outlet and the inbound link set of node u respectively; Q be described overlay network set of node and; b ⁺(m) and b ^-m () represents nominal outlet port and the ingress bandwidth of node m respectively; d _mqrepresent from node m to the flow of node q; d _pmrepresent from node p to the flow of node m.