The synchronization method communication network

 

The invention relates to the synchronization of telecommunication networks, namely, to build systems network clock synchronization with a hierarchical structure, with a forced synchronization on the principle of “master-slave”. The technical result improved quality of synchronization signals and the reduction of bandwidth and equipment necessary for the operation of the synchronization system due to the formation of the totality of open routes of transmission of synchronization signals and selecting one of them the route with the best quality. For this purpose, the inventive method is implemented form a set of open routes of transmission of synchronization signals, forming a system synchronization. A new set of essential features is that the synchronization system is created as a single tree structure with defined for each route of transmission of synchronization signals private quality indicators, which allows for reconfiguration of the system synchronization without the use of tables of priorities and messages about the status of the synchronization sources and greatly simplifies the structure of the si communication without its structural complexity with a minimum expenditure of resource bandwidth communication network. 4 C.p. f-crystals, 11 ill.

The invention relates to the synchronization of telecommunication networks, namely, to build systems network clock synchronization with a hierarchical structure, with a forced synchronization on the principle of “master-slave”.

The known method synchronization network synchronous digital hierarchy. (Patent EP 0910189, CL H 04 J 3/06 3, H 04 J 3/14. 1999).

The method consists in the fact that the synchronization signal is passed from node to node and mark it in each node data that identifies this node. To synchronize this node, the synchronization signal is used only in case if it is not passed, and if the number of nodes, which passed through the synchronization signal does not exceed a certain number.

The disadvantage of this method is the relatively low quality of the synchronization signals (Interpretation of terms used in the description of the invention, are given in Appendix 1), due to the use for transmission of the synchronization signal routes, including lines of communication with the settings with lower istemi synchronization implemented by US patent 6185216, CL H 04 Q 7/280, 2001.

The method consists in the fact that the synchronization signals are passed from node to node, providing them a unique ID of the node transmitting the synchronization signal, and a message indicating the quality level of the generator of this site. The synchronization signal that arrive at the node, used for synchronization of the generator only if its unique ID does not match with the code included in the received signal, or if the quality level of the received signal is below the signal quality received by another synchronization input for this node.

The disadvantage of this method is also relatively low quality of the synchronization signals. This is because when an error occurs in an accompanying message, identify the route of the synchronization signal, it is possible the emergence of closed routes of transmission of synchronization signals, as well as the accumulation of phase errors, the larger the permissible limits.

The closest to the technical nature of the claimed is a method of synchronizing a telecommunications network according to patent US 6317475, CL H 04 L 7/00, published 13.11.2001.

Prototype method is that place the generator is Ormerod open routes of transmission of synchronization signals, forming a synchronization system for which the primary signal generator synchronization is one of the generators of the system synchronization with the highest level of the hierarchy of quality, choose the best route calculated by the identifier, determine priorities for the inputs of the nodes and the direction of propagation of the synchronization signal, selects the signal source synchronization, the following quality primary generator, find routes from the selected node to an already existing part of the system and an additional count the IDs for these routes, which include the best route in the synchronization system, determine the possibility of establishing a closed route, if not open, expect the IDs found for closed routes, choose the route with the best ID, after which the synchronization signals are transmitted to all nodes in the synchronization system.

The known method prototype partially eliminates the drawbacks regarding reduction of the quality of synchronization signals, due to the introduction of the priorities of the quality of synchronization signals. This allows comparison with the known methods of network synchronization Holy the Sabbath. the relatively low quality of synchronization signals at a considerable complication of the structure of the system synchronization;

requires additional bandwidth and additional equipment in order to keep the priority tables on each node and update them when changes occur in the network.

The purpose of this invention is to develop a method of synchronizing a communication network, ensuring a higher quality of synchronization signals and the reduction of bandwidth and equipment necessary for the operation of the synchronization system due to the formation of the totality of open routes of transmission of synchronization signals and selecting one of them the route with the best quality.

This objective is achieved in that in the known synchronization method communication network previously on the communication nodes included in structure of the communication network, place the generators of synchronization signals having n1 hierarchy levels the quality of the generated synchronization signals, form the set of open routes of transmission of synchronization signals, forming a synchronization system for which the primary signal generator synchronization is one of the generators of the system synchronization with the highest level of s is as open routes of transmission of synchronization signals choose N spanning trees of the network connection. Each of the spanning trees comprises ribs extending from its root node. The root vertex of all spanning trees are located in the setup of the primary generator of synchronization signals. Then, for each spanning tree calculate the total length of its edges Lithe largest number of nodes nimaxin one of his routes and the quality factor used routes hi. After that the entire set of spanning trees are ordered by the values of LinmAx, hi. Then calculate each ordered group spanning trees private quality indicators, respectively: lengthLi, the number of nodes kniand used lines khi. On the obtained values of partial indicators of the quality I expect the integral indicator of quality kfor each spanning tree according to the formula ki=kLi+kni+khi. After that spanning trees ranged largest kand then opt for the transmission of synchronization signals spanning tree with the smallest value of k. The number of spanning trees of N is calculated by the formula:

BT0- transposed matrix to0.

For the graph of the communication network build all spanning trees (OD). The procedure and principles of OD for the graph of the communication network is known (see, for example, Christofides N. Graph theory: an Algorithmic approach. TRANS. from English. - M.: Mir, 1978.- 432 S.).

Private index kLifor the i-th spanning tree calculated by the formula kLi=Li/Lmaxwhere Lmax- the maximum length of the edges of all the Li.

Private index knifor the i-th spanning tree calculated by the formula kni=nmAh/nmaxwhere nmax- most important of all, nimax.

Private index khithe i-th spanning tree calculated by the formula khi=hi/hmaxwhere hmax- the greatest numerical value of all hi.

A new set of essential features, namely, that the synchronization system is designed as a single tree structure with defined for each route of transmission of synchronization signals private quality indicators, gives rise to reconfigure the system synchronization without the use of tables of priorities and status messages and is galow synchronization required quality level for all nodes in the network without regard to its structural complexity with a minimum expenditure of resource bandwidth of the network connections.

The analysis of the prior art allows to establish that the known sources of information analogs characterized by the set of characteristics is identical for all features of the proposed technical solutions are missing, which indicates compliance of the claimed invention to condition patentability of “novelty.”

Search results known solutions in this and related areas of technology in order to identify characteristics that match the distinctive features of the prototype of the characteristics of the claimed method, showed that they do not follow explicitly from the prior art. The prior art also revealed no known impact of the envisaged reforms for the achievement of the technical result. Therefore, the claimed invention meets the condition of patentability “inventive step”. The claimed method is illustrated by drawings, which show:

in Fig.1 - General structure of the communication network;

in Fig.2 - the option of constructing a communication network, which form the synchronization system;

in Fig.3 - a set of spanning trees of the graph of the communication network;

in Fig.4 - table of calculation of the private rate the quality of kLi;

in Fig.5 - calculation table private showing of the face of the calculation of the integral index of quality kand ranking OD.

The claimed method synchronization communication network is implemented as follows.

It is known that the system network clock synchronization digital network is used to establish and maintain a certain value of clock frequency digital signals, which are designed for digital switching, digital, transit and synchronous interconnection of digital signals so that the timing between these signals do not go beyond certain limits.

For synchronization in the network needs the best source synchronization-clock, or timer, for all nodes in the network. It is necessary to have not only high-precision clock generator, but also a reliable transmission system clock signal to all the nodes in the network, i.e., the synchronization system.

So the communication network (see Fig.1) in General includes nodes 1 with mounted generators synchronization signal 2, line communication network 4, lines synchronization system 5. Physically, the synchronization signals are passed through the lines of communication networks that carry information signals, i.e., line (dotted line) transmission of synchronization signals indicated conventionally. For the communication network based on the known method (see, for example, Frank Central located site (Fig.1 - CONDITION 3). In the analyzed example, he is one. On it place a primary signal generator synchronization with the highest level (n=1) hierarchy of quality of generated signals 3. Generators having different degrees of the hierarchy of quality (Fig.2 n=2 and n=3), set on other nodes 2.

The sequence of steps of the claimed method is considered a variant of the communication system shown in Fig.2. The communication network includes four nodes communication US - US. The primary generator with the hierarchy level of quality n=1 posted on US, and used lines of communication include:

a fibre optic connection (length L1and L2);

RRC - L4,

the wire - symmetric (Z/h) and coaxial (Ls) communication cables.

The claimed method synchronization communication network based on the structuring collectively spanning trees (AR), whose vertices are located at the communication node that hosts the primary generator (in this example, the CONDITION 2 (Fig.2)). Given the known graph theory (see, for example, Christofides N. Graph theory: an Algorithmic approach. TRANS. from English. - M.: Mir, 1978. - 432 C.) for the network in question pre-built set of OD (Fig.3 OD1- OD8). Each onii communication between adjacent nodes. The route may consist of one (for example, AR5, Fig.3) or collectively (e.g., AR1, Fig.3) series of ribs so that the last edge is open (with hanging top).

The total number of ML can be determined by various methods. In the proposed method, the total number of OD are using matrix incidence. For this form the matrix incidence graph under consideration (Fig.2) network connection. The number of rows of this matrix equals the number of nodes of the communication network, and the number of columns is the number of edges. If the edge of incidence node (i.e., an edge connected to this node, at the intersection of the given matrix column and row write “1”, otherwise “0”.

For the considered graph of the communication network matrix incidence is:

Further, removing any row of the matrix, for example, row 1, get matrix b0and transposed it BT0

The procedure for obtaining the transposed matrix is known and described (see, for example, G. Korn, T. Korn. Handbook of mathematics for scientists and engineers. - M.: Nauka, 1977

The number of AP obtained by �01210.gif">

Building routes synchronization signals based on spanning trees provides them nonclosure, i.e. excludes unacceptable in the synchronization system closed routes.

For justification and objective selection of the route that provides the best of all the routes of quality, then find the set of individual indicators of their quality.

One of the indicators of the quality of the route of transmission of synchronization signals is its length. To assess spanning tree for this indicator calculate the total length of its edges. In this example, the edge lengths accept conditional, relative, dimensionless units. Moreover, the relative length of the more than longer than its physical length of the edge. In this example it is assumed: L1=1, L2=4, L3,=2, L4=4, L5=5 (Fig.4). For example, OD 1 the sum of the lengths of its constituent edges is equal to 11. This is the largest and, therefore, the worst value of all OD. Then all the values obtained for other spanning trees, normalized relative to this worst values according to the formula kLi=Li/Lmaxwhere Lmax- the greatest (worst) the length of the edges in OD]. The calculated Normicro is the motor features of the kLi(Fig.4-a).

The quality of the route used for the transmission of synchronization signals determine the number of nodes contained from the root node to the terminal in the route of transmission of synchronization signals. In this regard, in each spanning tree selects a route that contains the largest number of nodes (i.e., the worst for this indicator route). For example, OD 1 this is the next route US - US - US - US (Fig.5A). This route contains four communication node. It is the best result for the whole population of OD. Similarly choose the routes containing the maximum number of nodes for each spanning tree. Then all the values obtained for other spanning trees, normalized relative to the worst values according to the formula knj=nimax/nmaxwhere nmax- maximum number of nodes in the route OD] (nmax=4). The calculated normalized values of knipresented on Fig.5-b, provide a basis for ranking all OD on private indicator of the quality of kLi(Fig.5-a).

Next, to account for quality used types of communication lines (fiber optic, wired or radio) calculate the third private indicator of the quality of kh.

For e is e are high quality optical communication lines, they have the highest quality score (h=1). Worst on a range of indicators (including the noise) are radio-relay communication lines. That is why it has adopted a quality indicator h=4. For coaxial and symmetrical cable lines are taken, respectively, h=2 and h=3 (see Fig.6).

Taking into account these indicators are the quality of all of the routes included in the spanning tree (see Fig.6-b). For example, OD contains the following routes:

1: US - US - US - US;

2: US - OS;

3: US - US - US.

These routes include ribs with balanced cables (L3), with coaxial cable (L5and radio-relay line (L4). Taking into account the above figures for these lines is h data routes OD1equal to 10. Similarly calculate individual indicators of other routes for all OD, which are summarized in the table (Fig.6-b). The worst indicator hmin=10 has an OD of 1. Therefore, all the values obtained for other spanning trees, normalized to hmin. The calculated normalized values of khipresented on Fig.6-b, provide a basis for ranking all OD the quality of the used lines (Fig.6-a).

Thus, the calculated individual indicators of quality comprehensively the Finance for integral objective quality assessment of all OD which is determined by the integral index of quality kcalculated according to the formula ki=kLi+kni+khi.

The results obtained kall OD tabulated in Fig.7-a and ranked (Fig.7-b).

Thus, these data are the basis for selecting the best (i.e., the minimum numerical value of k) OD, ensuring the highest quality transmission of synchronization signals in these terms of functioning communication network. In the above example, the best route is the route OD5.

In case of failure of individual elements in the selected route of transmission of synchronization signals make a transition to the next as the route OD6then on OD6and so on

When using the claimed method of synchronization is assured under all operating conditions of the communication network, the transmission of synchronization signals along the routes of the best quality, i.e., implements the stated aim of creating inventive method.

Claims

1. The synchronization method communication network, namely, that previously to the nodes of the light is f">1 hierarchy levels the quality of the generated synchronization signals, form the set of open routes of transmission of synchronization signals, forming a synchronization system for which the primary signal generator synchronization is one of the generators of the system synchronization with the highest level of the hierarchy of quality, after which the synchronization signals are transmitted to all nodes in the synchronization system, characterized in that as open routes of transmission of synchronization signals choose N spanning trees of the graph of the communication network, each of which consists of ribs extending from its root node, and the root vertex of all spanning trees are located in the setup of the primary generator of synchronization signals, then for the i-th spanning tree, where i=1, 2, ..., N, calculate the total length of its edgesithe greatest number of nodes ni maxin one of his routes and the quality factor used routes hiafter which, the whole set of spanning trees are ordered by the values of LinmAhhicalculate in each sorted group spanning trees private quality indicators, respectively, of length kthe i-th spanning tree according to the formula ki=kLi+kni+khi, rank spanning trees in kthen opt for the transmission of synchronization signals spanning tree with the smallest value of k.

2. The method according to p. 1, characterized in that the number N spanning trees is calculated by the formula

B0=MK - matrix incidence communication network, where M=Mp-1, respectively the number of rows and columns of the matrix and Mp- the number of rows of the original matrix incidence;- transposed matrix to0.

3. The method according to p. 1 or 2, characterized in that the private indicator of the quality of kLifor the i-th spanning tree calculated by the formula kLi=Li/Lmaxwhere Lmax- the maximum length of the edges of all the Li.

4. The method according to any of paragraphs.1-3, characterized in that the private indicator of the quality of knifor the i-th spanning tree calculated by the formula kni=ni max/nmaxwhere nmax- most important of all ni max.

5. The method according to any of paragraphs.1-4, characterized in that the private indicator of the quality of khii.

 

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