CN111385680A - Spectrum allocation method based on mixed spectrum conversion resource pool in elastic optical network - Google Patents

Abstract

The invention discloses a spectrum allocation method based on a mixed spectrum conversion resource pool in an elastic optical network, belonging to the technical field of communication networks. Aiming at the problems of distribution and optimization of spectrum resources in an elastic optical network, the method provides a spectrum distribution method based on a mixed spectrum conversion resource pool of a full-range spectrum converter and a limited-range spectrum converter, and distributes spectrum and establishes connection for a service request. The method comprises the steps of firstly calculating the longest continuous spectrum section set on a service route in sequence, then preferentially adopting a limited-range spectrum converter to relax spectrum continuity constraint and calculating to obtain all feasible optical paths according to the spectrum conversion relation in the adjacent spectrum section set, and finally determining a unique optical path according to the low-frequency continuous spectrum section priority principle and allocating corresponding spectrum and spectrum converters. The invention can effectively reduce the use of the full-range spectrum converter in the network on the basis of maintaining lower service blocking rate, thereby reducing the configuration cost of network hardware resources.

Description

Spectrum allocation method based on hybrid spectrum conversion resource pool in elastic optical network

technical field

The invention belongs to the technical field of communication network. Specifically, it relates to a spectrum allocation method based on a hybrid spectrum conversion resource pool in an elastic optical network.

Background technique

With the continuous development of Internet technology and the continuous emergence of emerging network applications, the business traffic in the communication network has shown an explosive growth, which poses a huge challenge to the transmission capacity and hardware resource allocation in the backbone optical network. Compared with the traditional WDM optical network, the elastic optical network based on Orthogonal Frequency Division Multiplexing (OFDM) technology has more efficient spectrum resource utilization due to its dense carrier frequency slot, flexible bandwidth granularity, and flexible modulation method. , which has great application prospects.

However, in an elastic optical network, due to the inherent constraints of spectrum continuity and adjacency, the dynamic establishment and removal of service connections may generate a large number of spectrum fragments, resulting in an increase in the service blocking rate. Therefore, configuring a certain number of optical signal spectrum converters in elastic optical network nodes can effectively relax the spectrum continuity constraint and improve the utilization rate of spectrum resources.

Optical signal spectrum converters are mainly divided into two categories: full-range spectrum converters (FRSCs) and limited-range spectrum converters (LRSCs). The full-range spectrum converter can convert the input optical signal spectrum to any other available spectrum within the optical fiber spectrum range for output, while the limited-range spectrum converter can only convert the input optical signal spectrum to a nearby available spectrum within a certain range output. Compared with full-range spectrum converters, limited-range spectrum converters have a smaller spectral conversion range, but are less expensive. At present, the spectrum allocation method of all-optical network based on spectrum converter mainly adopts the network node configuration scheme of pure full-range spectrum converter or pure limited-range spectrum converter. The former relies too much on full-range spectrum converter and is difficult to control effectively. The cost of network hardware resources, and the latter reduces the flexibility of spectrum allocation of switching nodes, which is likely to cause a higher service blocking rate. Relatively speaking, the node configuration scheme that adopts the full-range and limited-range hybrid spectrum conversion resource pool will be more conducive to reducing the hardware resource cost of the network and improving the utilization rate of spectrum resources.

Aiming at the allocation and optimization of spectrum resources in elastic optical networks, a spectrum allocation method based on a hybrid spectrum conversion resource pool of full-range and limited-range spectrum converters is proposed to allocate spectrum for service requests and establish connections. The invention firstly calculates the longest continuous spectrum segment set in sequence on the service route, and then, according to the spectrum conversion relationship in the adjacent spectrum segment set, preferentially uses the limited-range spectrum converter to relax the spectrum continuity constraint and calculates to obtain all feasible optical paths, and finally obtains all feasible optical paths according to the The low frequency continuous spectrum segment priority principle determines the unique optical path and assigns the corresponding spectrum and spectrum converter. The invention can effectively reduce the use of full-range spectrum converters in the network on the basis of maintaining a lower service blocking rate, thereby reducing the configuration cost of network hardware resources.

SUMMARY OF THE INVENTION

The present invention aims to solve the problems in the prior art. A spectrum allocation method is proposed to maintain a low service blocking rate and reduce the cost of network hardware resources. The technical scheme of the present invention is as follows:

A spectrum allocation method based on a hybrid spectrum conversion resource pool in an elastic optical network, the elastic optical network model is set as G(V, L), where V is the set of nodes in the network, L is the set of bidirectional links in the network, and each Each node is equipped with a certain number of limited-range spectrum converters and full-range spectrum converters, and the spectrum allocation method on its service routing includes the following steps:

Step 1. On the service route, from the source node to the destination node, establish the longest continuous spectrum segment set that meets the service bandwidth requirements in turn, let S _i represent the i-th longest continuous spectrum segment set, I=max(i), and 1≤I≤H, where H is the total number of hops of service routing, F _i,j represents the j-th longest continuous spectrum segment in the set Si, and the initialization variable _i =0;

Step 2. Let i=i+1, if i<1, jump to step 3, otherwise, jump to step 5;

Step 3. If there are F _i,j (∈S _i ) and F _i+1,k (∈S _i+1 ) that satisfy the limited range spectrum conversion condition, and there is an idle limited range in the intermediate node v _i,i+1 spectrum converter, then add (F _i,j ,F _{i +1,k} ) to the conversion relation set C, and delete all spectrum segments in Si and Si ₊₁ that do not meet the conversion conditions, and jump to step 2, otherwise, go to step 4;

Step 4. If there is an idle full-range spectrum converter in the intermediate node v _i,i+1 , add all (F _i,j ,F _i+1,k ) to the conversion relation set C, and jump to Step 2, otherwise, go to Step 6;

在业务路由上优先选择低频连续频谱段确定唯一光路，并进行相应频谱和频谱转换器的配置；Step 5. In the transformation relation set C, pass

On the service route, the low-frequency continuous spectrum segment is preferentially selected to determine the only optical path, and the corresponding spectrum and spectrum converter configuration is performed;

Step 6, end.

Further, in the step 1, the longest continuous spectrum segment set S _i that meets the service bandwidth requirement is established, and the specific steps include:

1) Starting from the current node, find all available spectrum blocks FB that meet the service bandwidth requirements in the full spectrum range and put them into the temporary set T;

2) If |T|>0, according to the continuity of the spectrum blocks on the service routing, sort the spectrum blocks in T in descending order of hops and mark them as {FB _α }, where α represents the Sequence number, let D _α be the frequency spectrum continuous hop number of FB _α on the service route, let α=1, j=1 jump to step 4), otherwise, jump to step 5);

3) Let F _i,j =(FB _α , D _α ), put F _i,j into the set S _i ;

4) If D _α+1 =D _α , then α=α+1, j=j+1, jump to step 3), otherwise, jump to step 5);

5) End.

Further, the definition method of the available spectrum block FB in the step 1) is shown in formula (1), wherein FS _m represents the idle frequency slot with index number m, and FS _m+1 represents the adjacent idle frequency slot of FS _m . , r represents the number of frequency slots corresponding to the bandwidth required by the service.

FB={FS _m ,FS _m+1 ,...,FS _m+r-1 } (1)

和

分别表示频谱段F_i,j和F_i+1,k对应的频谱块，m与n为频隙索引号，且m∈[0,MAX]，n∈[0,MAX]，MAX表示最大频隙索引号。Further, in the step 3, it is determined that F _i,j (∈S _i ) and F _i+1,k (∈S _i+1 ) satisfy the conditions for spectrum conversion in a limited range, as shown in formula (2), where ε represents limited the conversion degree of the range spectrum converter,

and

represent the spectral blocks corresponding to the spectrum segments F _i,j and F _i+1,k respectively, m and n are the frequency slot index numbers, and m∈[0,MAX], n∈[0,MAX], MAX denotes the maximum frequency slot index number.

The advantages and beneficial effects of the present invention are as follows:

Aiming at the allocation and optimization of spectrum resources in an elastic optical network, the present invention proposes a spectrum allocation method based on a mixed spectrum conversion resource pool of full-range and limited-range spectrum converters to allocate spectrum for service requests and establish connections. Compared with the current common network node configuration schemes using pure full-range spectrum converters or pure limited-range spectrum converters, the node configuration scheme using full-range and limited-range hybrid spectrum conversion resource pools will be more conducive to reducing network hardware resources. cost and improve the utilization of spectrum resources. On this basis, the method first calculates the longest continuous spectrum segment set on the service route in turn, so that the total consumption of the spectrum converter on the route is the least; The limited-range spectrum converter relaxes the spectrum continuity constraint and obtains all feasible optical paths by calculation, so that the consumption of the full-range spectrum converter on this path is the least; finally, according to the principle of low-frequency continuous spectrum segment priority, the only optical path is determined and the corresponding spectrum and spectrum conversion are allocated. This reduces the probability of spectrum fragmentation on the route. Through the above steps, the present invention can effectively reduce the use of full-range spectrum converters in the network on the basis of maintaining a lower service blocking rate, thereby reducing the configuration cost of network hardware resources.

Description of drawings

FIG. 1 is a flowchart of spectrum allocation based on hybrid spectrum conversion resource pools in an elastic optical network according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and in detail below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are only some of the embodiments of the invention.

The technical scheme that the present invention solves the above-mentioned technical problems is:

The concepts and models involved in the content of the present invention are as follows:

1. Network Model

Suppose the elastic optical network model is G(V,L), where V is the set of nodes in the network, L is the set of bidirectional links in the network, and each node is equipped with a certain number of limited-range spectrum converters and full-range spectrum converters device.

2. Description of symbols involved in the content of the present invention:

r: The number of frequency slots corresponding to the bandwidth required by the service

S _i : the i-th longest continuous spectrum segment set

F _{i,j :} the jth longest continuous spectrum segment in the set Si

C: Conversion relation collection

H: The total number of hops of service routes

FB: Available spectrum block to meet service bandwidth requirements

FS _m : Free frequency slot with index m

频谱段F_i,j对应频谱块的频隙范围

Spectrum segment F _i,j corresponds to the frequency slot range of the spectrum block

T: temporary collection

v _i,i+1 : transition node between F _i,j (∈S _i ) and F _i+1,k (∈S _i+1 )

ε: conversion degree of the limited-range spectral converter

The technical scheme of the present invention is described as follows:

1. A method for establishing the longest continuous spectrum segment set S _i that meets service bandwidth requirements

Step 1: Starting from the current node, find all available spectrum blocks FB that meet the service bandwidth requirements within the full spectrum range according to formula (1) and put them into the temporary set T;

Step 2: If |T|>0, according to the continuity of the spectrum blocks on the service route, sort the spectrum blocks in T in descending order of hops and mark them as {FB _α }, where α represents the spectrum block , let D _α be the spectrum continuous hop number of FB _α on the service route, let α=1, j=1 and jump to step 4, otherwise, jump to step 5;

Step 3: Let F _i,j =(FB _α , D _α ), put F _i,j into the set S _i ;

Step 4: If D _α+1 =D _α , then α=α+1, j=j+1, jump to step 3, otherwise, jump to step 5;

Step 5: End.

2. Available spectrum block Available spectrum block FB definition method

Formula (1) defines the available spectrum block FB, where FS _m represents the idle frequency slot with index m, FS _m+1 represents the adjacent idle frequency slot of FS _m , and r represents the frequency corresponding to the service demand bandwidth. number of gaps.

FB={FS _m ,FS _m+1 ,...,FS _m+r-1 } (1)

3. The method of judging that the limited range spectrum conversion conditions are met

和

分别表示频谱段F_i,j和F_i+1,k对应的频谱块，m与n为频隙索引号，且m∈[0,MAX]，n∈[0,MAX]，MAX表示最大频隙索引号。Formula (2) is to judge that F _i,j (∈S _i ) and F _i+1,k (∈S _i+1 ) satisfy the condition of limited-range spectrum conversion, where ε represents the conversion degree of the limited-range spectrum converter,

and

represent the spectral blocks corresponding to the spectrum segments F _i,j and F _i+1,k respectively, m and n are the frequency slot index numbers, and m∈[0,MAX], n∈[0,MAX], MAX denotes the maximum frequency slot index number.

A spectrum allocation method based on a hybrid spectrum conversion resource pool in an elastic optical network, the specific implementation method of which includes the following steps:

101. On the service routing, from the source node to the destination node, establish the longest continuous spectrum segment set that meets the service bandwidth requirements in turn, let S _i represent the i-th longest continuous spectrum segment set, I=max(i), and 1 ≤I≤H, where H is the total number of hops of service routing, F _i,j represents the jth longest continuous spectrum segment in the set Si, and the initialization variable _i =0;

102. Let i=i+1, if i<1, jump to step 103, otherwise, jump to step 105;

103. If F _i,j (∈S _i ) and F _i+1,k (∈S _i+1 ) satisfy formula (2), and there is an idle limited-range spectrum conversion in the intermediate node v _i,i+1 then add (F _i,j ,F _{i +1,k} ) to the conversion relation set C, and delete all spectrum segments in Si and Si ₊₁ that do not meet the conversion conditions, and jump to step 102, Otherwise, jump to step 104;

104. If there is an idle full-range spectrum converter in the intermediate node v _i,i+1 , add all (F _i,j ,F _i+1,k ) to the conversion relation set C, and jump to step 102, otherwise, jump to step 106;

在业务路由上优先选择低频连续频谱段确定唯一光路，并进行相应频谱和频谱转换器的配置；105. In the transformation relation set C, by

On the service route, the low-frequency continuous spectrum segment is preferentially selected to determine the only optical path, and the corresponding spectrum and spectrum converter configuration is performed;

106. End.

The above embodiments should be understood as only for illustrating the present invention and not for limiting the protection scope of the present invention. After reading the contents of the description of the present invention, the skilled person can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims (4)

1. A spectrum allocation method based on a mixed spectrum conversion resource pool in an elastic optical network is provided, an elastic optical network model is G (V, L), wherein V is a node set in the network, L is a bidirectional link set in the network, and each node is provided with a certain number of limited-range spectrum converters and full-range spectrum converters, and the spectrum allocation method on a service route comprises the following steps:

step 1, on the service route, establishing the longest continuous spectrum segment set satisfying the service bandwidth requirement from the source node to the destination node in sequence, and making S_iRepresents the ith longest contiguous set of spectrum segments, I ═ max (I), and 1 ≦ I ≦ H, where H is the total hop count for the traffic route, F_i,jRepresentation set S_iInitializing a variable i to 0 in the jth longest continuous spectrum segment;

step 2, making I equal to I +1, if I is less than I, skipping to step 3, otherwise, skipping to step 5;

step 3, if there is F_i,j(∈S_i) And F_i+1,k(∈S_i+1) Meets the limited range spectrum conversion condition and has an intermediate node v_i,i+1A limited range spectrum converter with a free space in it, will be (F)_i,j,F_i+1,k) Adding to the set of conversion relationships C, and deleting S_iAnd S_i+1Skipping to the step 2 for all the spectrum sections which do not meet the conversion condition, or else skipping to the step 4;

step 4, if the intermediate node v_i,i+1With a free full-range spectrum converter in it, all (F)_i,j,F_i+1,k) Adding the conversion relation set C, skipping to the step 2, otherwise, skipping to the step 6;

step 5, in the conversion relation set C, through

Preferentially selecting a low-frequency continuous spectrum band on a service route to determine a unique optical path, and configuring a corresponding spectrum and a spectrum converter;

and 6, ending.

2. The method according to claim 1, wherein the longest continuous spectrum segment set S satisfying the service bandwidth requirement is established in step 1_iThe method comprises the following specific steps:

1) starting from a current node, searching all available spectrum blocks FB meeting the service bandwidth requirement in a full spectrum range and putting the available spectrum blocks FB into a temporary set T;

2) if | T |>0, according to the continuity of the frequency spectrum blocks on the service route, sorting and marking the frequency spectrum blocks in the T as { FB ] according to the sequence from large hop number to small hop number_αWhere α denotes the sequence number of the spectrum block, let D_αIs FB_αContinuously skipping frequency spectrum on the service route, making α equal to 1, and making j equal to 1 skip to step 4), otherwise, skipping to step 5);

3) let F_i,j＝(FB_α,D_α) Will F_i,jPut into set S_i；

4) If D is_α+1＝D_αIf α is α +1, j is j +1, go to step 3), otherwise go to step 5);

5) and (6) ending.

3. The spectrum allocation method based on the mixed spectrum conversion resource pool in the elastic optical network as claimed in claim 2, wherein the definition method of the available spectrum block FB of step 1) is shown in formula (1), wherein FS is_mIndicating a free frequency slot, FS, with index number m_m+1Represents FS_mR represents the number of frequency slots corresponding to the service required bandwidth.

FB＝{FS_m,FS_m+1,...,FS_m+r-1} (1)

4. The method according to one of claims 1 to 3, wherein the step 3 determines F_i,j(∈S_i) And F_i+1,k(∈S_i+1) The condition for satisfying the limited-range spectral conversion is shown in equation (2), where e represents the degree of conversion of the limited-range spectral converter,

and

respectively representing a spectral portion F_i,jAnd F_i+1,kCorresponding spectrum block, m and n are index numbers of frequency slots, and m ∈ [0, MAX]，n∈[0,MAX]MAX denotes a maximum frequency slot index number;

Images