Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L45/00—Routing or path finding of packets in data switching networks
  • H04L45/28—Routing or path finding of packets in data switching networks using route fault recovery
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/12—Discovery or management of network topologies
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L45/00—Routing or path finding of packets in data switching networks
  • H04L45/02—Topology update or discovery
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L45/00—Routing or path finding of packets in data switching networks
  • H04L45/02—Topology update or discovery
  • H04L45/028—Dynamic adaptation of the update intervals, e.g. event-triggered updates
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/12—Discovery or management of network topologies
  • H04L41/122—Discovery or management of network topologies of virtualised topologies, e.g. software-defined networks [SDN] or network function virtualisation [NFV]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/40—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks using virtualisation of network functions or resources, e.g. SDN or NFV entities

Definitions

• the present invention relates to the determination and management of virtual networks on physical networks.
• the main benefit of these virtualization techniques is to juxtapose multiple machines and virtual systems on a single physical machine to facilitate data transfers, pool resources, facilitate backups, simplify administration and more.
• Virtual machines see the host machine as an independent machine and are driven by a virtualization manager from the host machine (Xen, Vmware, UML ).
• Xen, Vmware, UML There are different modes of virtualization adapted to different uses, for example operational: models, simulation, operational processes (servers, routers, etc.).
• the same physical network such as the network referenced 2 in FIG. 1, can serve as support for several virtual networks 4i ... 4 K.
• These virtual networks 4 realize the interconnection between sites that either provide services or are users of these services.
• Sites are connected through service access points or client access points on nodes in the physical network.
• the sites can themselves be sub-parts of a telecommunications network that includes virtual router support physical nodes.
• a virtual network architecture includes a superposition of different logical topologies established between virtual routers, these virtual topologies being supported by the physical network architecture 2.
• Each of virtual networks depending on the services it must support, will have to meet specific constraints in terms of quality of service, transit time, availability, etc.
• Such a structure makes it possible to assign a differentiated service to each of the superimposed networks.
• By virtualizing the networks it becomes possible to make a centralized administration for all the virtual networks from a physical platform of support, to share resources, in order to gain space and to reduce the energy consumption (machines, bays, air-conditioning etc. .), evolve virtual networks by installing new versions of operating systems without disrupting the operation of the router.
• the separation of virtual machines facilitates the differentiation of the various services supported by a physical machine (QOS, bandwidth reservation, security ).
• the mechanisms for managing the nodes of the physical network must make it possible to reconcile the connectivity between connection points of the virtual networks, a certain robustness of the virtual topology (resilience on cases of node failures or links physical) as well as the optimization of the sharing of resources of the physical network.
• Management and administration of these virtual networks are therefore particularly complex compared to conventional physical networks, especially in case of failure.
• Systematic manual management would be particularly burdensome and costly and would require human interventions on a large number of nodes of the physical network to make it possible to find the coherence of the virtual networks.
• it is used a centralized management of virtual networks. This poses security problems and leads to the simultaneous issuance of change orders to be made to several physical nodes in the event of network evolution.
• the present invention aims to improve this situation by providing a method for determining the topology of virtual networks as well as a program, a device and a corresponding network.
• the invention relates to a method for determining topologies of virtual networks, physical nodes being connected by a physical network and intended to support virtual nodes of said virtual networks.
• the method includes the following steps implemented by one of the physical nodes: a determination of resource parameters defining a physical configuration of the network and a physical configuration of the physical node and a determination of request parameters defining network service requests. and in case of modifications of at least one parameter belonging to the group comprising the resource parameters and the request parameters between a current instant and a previous instant, a diffusion of at least the modified parameters in the physical network, a Updating resource and request parameters based on changed settings and determining topologies for virtual networks using the updated settings.
• each node of the physical network has the same parameters and performs the same calculations to determine the topologies of virtual networks.
• said method can be automated and implemented by each node of the physical network independently. This improves the situation by allowing decentralized and autonomous management of virtual networks supported by the same physical network.
• said determination of resource parameters comprises at least one step selected from the group comprising taking into account predetermined configuration information, receiving information from other nodes of the physical network and an acquisition. local and distant resources.
• said determination of request parameters comprises at least one step selected from the group comprising taking predetermined configuration information into account, receiving information from other physical nodes and taking into account account of quality of service constraints.
• the nodes can determine the resources and requests from predetermined parameters or parameters transmitted by other nodes or acquired by interrogation. A node thus obtains the parameters modified by the other nodes and the determination of the topologies is coordinated between the different nodes of the physical network.
• said step of determining topologies for the virtual networks includes, for each virtual network, a control of the availability of the resources.
• the method for determining the topology of the virtual networks verifies that the service requests and resource parameters set, in particular for maintaining the quality of service, are respected.
• said step of determining topologies for the virtual networks comprises, for each virtual network, a determination of metrics for each virtual link between the nodes of the virtual network, a determination of the shortest paths between the nodes of the virtual network, a union shortest paths to create a virtual network topology, and a link load determination between the nodes of the virtual network.
• the method further comprises, as a function of the topologies of the determined virtual networks, a creation of at least one virtual router on at least one physical node.
• the method thus comprises an active phase of automatic adaptation of the physical network to the topology of the virtual networks determined.
• said steps of updating the parameters and determining the topologies are repeated each time the request or resource parameters are modified.
• the method allows automatic adaptation of the virtual networks as soon as a modification is detected.
• the method further comprises a management of the virtual networks after the determination of the topology.
• the management of the virtual networks comprises, in the event of failure of a node of the physical network, a diffusion of information at the level of the physical network, a convergence of the graph of the physical network and network topologies. virtual appliances affected by the failure, an update of the resource and request parameters while retaining the parameters defining the links not affected by the failure and a reiteration of the method for the determination of the topologies.
• the management of the virtual networks comprises, in the event of a physical router stopping, a diffusion of information at the level of the physical network, a convergence of the graph of the physical network and the topologies of the networks. virtual machines affected by the failure, an update of the resource and request parameters and after the shutdown of the physical router, a reiteration of the method for determining the topologies of the virtual networks.
• the management of the virtual networks includes, in case of adding one or more access points to a virtual network, an update of the request parameters and a reiteration of the method for determining the topologies of the virtual networks. virtual networks.
• the invention also relates to a computer program comprising code instructions for the implementation of a method as defined above when said program is executed by a computer computer.
• the invention relates to a node of the physical network belonging to a physical network and adapted to support virtual nodes of virtual networks comprising a resource parameter determination unit defining a physical configuration of the physical network and a specific physical configuration of the physical network.
• a physical node a request parameter determining unit defining service requests relating to the virtual networks, a comparator between the request and resource parameters of a current instant and the parameters of a previous instant, means for broadcasting requests.
• resource and request parameters in the physical network means for updating resource and request parameters according to the modified parameters and a computer adapted for determining topologies for the virtual networks using the parameters set to day.
• the invention also relates to a physical telecommunications network comprising a plurality of physical nodes connected to each other and adapted to support virtual nodes of virtual networks, characterized in that at least two of said physical nodes are nodes as mentioned above.
• FIG. 2 is a flowchart of the method for determining topologies of virtual networks and for managing these topologies according to one embodiment of the invention
• FIG. 3 represents matrices used in one embodiment of the method of the invention.
• FIGS. 1 to 3 A method according to an embodiment of the invention will now be described with reference to FIGS. 1 to 3 in a configuration comprising K virtual networks on N network nodes.
• This configuration represented with reference to FIG. 1, comprises N real nodes, or physical network nodes, denoted O 1 to 6 N , connected by the physical network 2 and supporting the K virtual networks 4, at 4 ".
• N real nodes or physical network nodes, denoted O 1 to 6 N , connected by the physical network 2 and supporting the K virtual networks 4, at 4 ".
• N real nodes there are virtual routers rated 8 ,,.
• network graph the description of the physical network 2 and topology the structure of each of the virtual networks 4.
• the method of determining topology of virtual networks allows a determination of the topology and the subsequent implementation of the virtual networks.
• This method starts with an acquisition 10, by each node of the physical network 6, data defining the physical configuration of the network graph and that of the physical node.
• the transmission of this information is implemented at the level of the physical network 2, by an IGP (Interior Gataway Protocol) type routing protocol.
• IGP Interior Gataway Protocol
• the received data come from the broadcast from each physical node 6, elements concerning the description of the physical configuration and in particular:
• each node of the physical network has information describing its own physical characteristics, the physical characteristics of the other nodes of the network 2 and the physical characteristics of the links of the network graph 2.
• IGP Interior Gateway Protocol
• adjacency matrices are used which define the graph of the network 2 using metrics representing a "distance" between the nodes of the network.
• the metric is unique by adjacency.
• the situation is more complex in virtual networks. Indeed, for each node of each virtual network, it is necessary to define a matrix taking into account metrics determined from different constraints, for example the transit delay between the nodes of the virtual network, but also the constraints of the service, the physical network constraints such as available bandwidth and physical machine constraints.
• an extended adjacency matrix is defined to take into account the physical capacities of the network, the physical machines and the constraints relating to the superposition of the networks.
• This extended adjacency matrix, or resource matrix, of size NxN is denoted R with reference to FIG. 3 and describes the physical resources available between the nodes of the physical network connected according to the topology of the network.
• the resource matrix R is composed of elements R 1 , which are vectors describing the resources available between the nodes 6, and 6 j expressed from the criteria defined to describe the service requests of the virtual networks such as bandwidth, delay transit, availability factor, jitter factor, etc.
• each vector R 1 includes a metric-type indication intended to take into account the connectivity between the nodes and thus to take into account the physical topology.
• each physical node 6 is associated a vector defining the hardware capabilities of this node (processor, memory, etc.).
• the method also includes determining service requests such as minimum bandwidth, maximum end-to-end delay, maximum jitter factor, and other parameters between the virtual access routers to a virtual network for a given bandwidth. given customer.
• the requests include, in addition to the description of the service requests, data related to the topology of the virtual networks. This data determines the metrics attached to the virtual network links and describes the predetermined topology. It is also possible to receive data that only partially describes the topology and only provides metrics on certain links.
• a request to create a virtual network can be received from several sources.
• such a request can be:
• step 12 allows the determination of a request matrix of size NxNxK denoted by D with reference to FIG. 3.
• This matrix D is composed of K matrices NxN denoted D k which represent service requests between access points to virtual networks.
• Each demand matrix D ⁇ associated with the virtual network of rank ke [1, K] is of dimension NxN and has for index k in the demand matrix D: D k ⁇ (D 1 , ⁇ k .
• Each matrix D k describes on the one hand the demand for resources required between the access points to the virtual network, and on the other hand metrics m ,, for the links allocated to the virtual level k between the physical nodes N 1 and N 1 .
• the metric m is derived from a calculation by a metric allocation algorithm based on the characteristics of the physical network and the type of service requested.
• the metric is determined a priori. In particular, in the case of a request for topology or engineering predetermined by a client.
• the method has the contents, the vectors P n of the hardware capabilities of each physical node 6, the matrix R of the resources of the physical network and the matrix D of the requests.
• These matrices R and D are represented with reference to FIG.
• the matrix elements R ,,, R VJ , R, v and their symmetries with respect to the diagonal define the metrics of the graph of the network 2 at the physical level and the available capacities of the links between the nodes 6 ,, 6 ,, and (v
• the unconnected links are characterized by infinite metrics m ⁇ ⁇ and null abilities.
• lk express the demand for the capacities (C IJk T
• k is infinite, which means that, despite the existence of a physical link between these nodes, the virtual topology of rank k has not assigned a link between these virtual routers.
• k and D Jvk express the metrics of the rank k network paths between 8v and 8n nodes.
• the virtual node 8y is not an access point to the virtual network.
• the capacities are set to the limit values: for example for D vlk , the bandwidth capacity is at zero and the transit delay on the link is infinite, indicating that there has been no request for resources between these two points. It is the same for D v ⁇ k and
• these steps 10 and 12 correspond to the initialization of the graph and topology data for the management of the virtual networks. Subsequently, these steps result from changes in the physical configuration (failure, addition of a node %) or changes to service requests.
• the method then includes a test 14 to evaluate whether the resource or request data has changed.
• a test 14 to evaluate whether the resource or request data has changed.
• matrices and vectors being initially blank, the presence of data constitutes a change.
• the method goes to a management step 40 described later.
• the current data defining the topology of virtual networks and on which the management is based do not need to be modified.
• the process continues with a broadcast 16 of the modified information.
• This broadcast 16 is implemented at the level of the physical network 2, by a routing protocol of IGP type.
• the data is broadcast by each physical node 6, to all the other physical nodes 6 of the network.
• the data transmitted concern in particular the descriptive data of the physical configuration and in particular:
• the data related to the topology of the virtual networks are also transmitted during the broadcast 16. These data are defined in the following two ways.
• the resource request When creating a virtual network automatically, the resource request only applies to the virtual network access nodes.
• This request is expressed in the format defined for the vector D l
• the request for creation of a virtual network is described in the same format D 1 , and expresses in the same way resource requests.
• the request further includes a description of the topology of the virtual network. This topology is expressed by the "metric" coordinate of the vectors which describes the structure of the considered network.
• metric of the vectors which describes the structure of the considered network.
• the broadcast 16 of the data by a node of the physical network corresponds, from the point of view of the nodes of the physical network which receive these data, to a step determining resources or requests so that each node has the same matrices and vectors defining resources and requests.
• the method includes updating the matrices 18 to integrate the modified data.
• the transmitted data must be reformatted before being integrated in the matrices.
• the data is transmitted in a format corresponding to the format of the matrices.
• the broadcast 16 and update 18 steps may be performed simultaneously or in another order than the order described.
• the method then comprises a step 20 for determining the topology of the virtual networks. This step is performed by each physical node and for each virtual network. According to the embodiments, the set of topologies is determined simultaneously by performing step 20 in parallel for each virtual network or in sequence according to an arbitrary order or fixed by operating constraints.
• Each node of the physical network uses the previously exchanged data for the determination calculation of the topologies of the virtual networks.
• This determination begins with the search for a topology and a set of resource reservations compatible with both the resources available on the physical level and with the service requests.
• VX (Point) Its use in the form VX describes the X component of a vector V.
• the first calculation 22 consists in determining, for each link of the physical network 2, the metric associated with it in the virtual plane to be created from the matrix R. resources available on the links of the physical network and the vector P n of the resources available on the nodes of the physical network. If this metric is already defined in the matrix D k , it is the predefined value which must be taken into account.
• a transfer function ⁇ k of R ⁇ IR + is associated with each virtual network.
• the result of applying this function to the graph data is a metric expressed according to the IGP protocol for each link of the physical network.
• the transfer function is further adapted to the nature of the requested service and calculates the metric to be associated with the virtual links from the characteristics of the physical links, and possible statistical or commercial rules. This calculation will make it possible to determine the shortest paths in the physical network in the sense of the metric of the virtual network to be created.
• Metrics allow the choice of a virtual network topology that corresponds to the requested criteria. Metrics will be provided by default to virtual routers when they are created.
• the determination calculation of the topology of a network is then carried out according to the following algorithm:
• n shortest paths which makes it possible to determine the n shortest paths between two points
• union 26 of these shorter paths so as to create a topology for the virtual network that is sufficiently meshed and resilient; by union we mean a union in the mathematical sense or superposition;
• a new matrix is defined for the processing and the storage of the resources allocated to the virtual network of rank k created: the matrix R k of vectors R IJk whose structure is identical to that of the vectors R 1 , of the matrix R.
• the vector R (Jk describes the resources required and allocated for the virtual network of rank k on the link 4 k of the physical network.
• the calculation of the link load can be performed as described below.
• the topology determination process includes checking the availability of the resources. This control is performed for each virtual network at several levels: at the level of the nodes of the virtual network, verifying that for any node 8 n of the network and for any criterion X defining the processing capacity on the node the difference is positive or zero: P n . x - ⁇ R nk .x>0;
• the algorithm checks that the transit delay on any path e connecting two 8 U and 8 V access nodes virtual network k respects the end-to-end delay request: ⁇ / ee E ux , Y ⁇ R ⁇ T ⁇ D uvk T;
• the method performs a test 32 on the result of the control. If all the resources requested are available, the topology of the corresponding network is valid and the test is followed by an update 34 of the matrices defining the virtual networks and in particular:
• step 20 is implemented for each virtual network.
• a topology is determined for each virtual network.
• the method then comprises a test 36 to determine if one or more virtual routers belonging to these new topologies of the virtual networks must be created on the physical node. In the case where this test is positive, the method creates these virtual routers during a step 38. Each node of the physical network through which a path of the new topology determined for the virtual network of rank k must have a virtual router
• the creation 38 begins with the creation of a virtual machine and its operating system, such as, for example, Xen and Linux, or a process for supporting virtual processing management media known as "equipment manufacturers”.
• the virtual router itself will be created in this environment. Provisioning involves a set of operations that depend on how the corresponding virtual network is administered. In one embodiment, it is an automatic creation based on a specific protocol. As a variant, it is a creation administered by the client on the basis of the virtual machine provided to it.
• the process of determining the virtual network topology ensures that the requested resources are available on the paths determined by the creation algorithm.
• each virtual router activates its own routing protocol which distributes its data to the other routers of the virtual network 4 on which it is located and is naturally integrated in the topology of the virtual network. Indeed, on each node of the physical network, each virtual router has performed the same calculations with the same data and therefore knows the location of other routers. Consequently, the virtual network does not require any particular signaling of implementation on the part of the physical network,
• the determination of the topology is performed automatically and autonomously by each node of the physical network without requiring transmission of the descriptive parameters of the topologies of the virtual networks.
• the method then comprises a step 40 for managing the virtual networks.
• the management 40 is performed after the determination of the topology of the virtual networks.
• the method goes directly to this step.
• the method optionally includes an emission 42 of an error message and then the management step 40.
• the method also goes directly to the management step 40 if the test 36 indicates that it is not necessary to create a new router.
• the management 40 manages the modifications of the physical network or the virtual networks, or events, before repeating all the steps 10 to
• the descriptive information of the new configuration is determined by a router or an administration platform and transmitted to all the nodes of the physical network using the physical level exchange protocol similar to that of a conventional IGP (ISIS, OSPF p eg) -
• the other routers receive the new configuration and perform the topology determination based on this configuration.
• the management 40 also includes an automatic recovery of a failure 44.
• This recovery on link failure or physical node has two aspects made independent.
• Recovery involves first transmitting fault information at the physical level and at the virtual network level.
• each IGP of an assigned virtual network converts the topology of the corresponding virtual network based on its resilience to ensure the transport of the data despite the failure. This is totally transparent for the physical network that is physically converging.
• resource and request parameters are updated and the process is reiterated on each physical node and for each of the virtual networks affected by the failure.
• the process resumes with the new parameters of resources and demand integrating the consequences of the breakdown.
• the modified matrix R is deduced from the new topology determined by I 1 IGP of physical level by concealing the links affected by the failure.
• the matrices D k are determined from the existing matrices D k by concealing these same links.
• the data attached to the possibly incriminated nodes are hidden from the vectors P and P n .
• the virtual topologies are recalculated on these new data by keeping the metrics determined in the matrices D k on the unassigned virtual links.
• the management of a failure is thus reduced to the creation of a virtual network whose topology is partially predetermined. Links that can not be used by the new topology will not be taken into account.
• the taking into account of the metrics, and therefore the links, already determined in the matrix D k prevents a complete overhaul of the virtual networks impacted by the failure since the management process recovers the links that maintain the connectivity of the networks. .
• the calculation of new networks only intervenes in addition to deteriorated networks in order to restore resilience and the requested capacities.
• the reserved resources that are attached to the links in the matrices R k and D k and the resource vectors P n are retained until the fault is repaired, that is to say that the machine restarts or that the machine restarts. the link is restored.
• the hidden elements will then be released and reintegrated into the recalculated topology.
• the management 40 also includes a maintenance stop 46 of a node of the physical network.
• stop 46 includes a declaration of an inoperative status for the node of the physical network before it is stopped.
• the affected virtual routers continue to switch the packets they receive.
• the IGP protocol broadcasts the information by causing a reconvergence of the physical network graph.
• the management process is restarted with the new resource parameters. The method makes it possible to determine the new paths and triggers the creation of replacement virtual routers without the virtual networks being disturbed.
• the physical machine is then stopped.
• the virtual network routing protocols take into account the modification by converging on a network that has kept resources in accordance with the initial request.
• the management step 40 includes an addition 48 of one or more access points to a virtual network.
• the method resumes directly at the acquisition step 10 with a new resource request.
• the application of the method automatically leads to a new topology taking into account these new access points.
• the calculation or recalculation of a topology for a virtual network uses in priority the links declared in the matrix D k by their metrics. These links are determined a priori for imposed topologies, or during operation by the calculation process. If a predetermined link does not fit the constraints established for a given path, the management process determines an alternative path. Once the calculation is complete, an installation option allows or does not allow the management software to eliminate the unnecessary links of matrices D k and R k .
• the method of the invention can be implemented by a physical node comprising computers, memories and conventional network management means including encoders, decoders, transmission units, IGP and others.
• a node also comprises specific means suitable for implementing the method as described above.
• such a node comprises a resource parameter determination unit defining a physical configuration of the physical network and a physical configuration of the physical router, a request parameter determination unit defining service requests relating to the virtual networks as well as a comparator between the parameters of a current instant and the parameters of a previous instant, means for broadcasting new parameters to each of the routers of the physical network, means for updating the parameters of resources and requests as a function of modified settings, a computer adapted for determining topologies for virtual networks using the updated parameters.
• such a node may include a resource availability control unit for a virtual network.
• the invention can also be implemented by a computer program loaded into a memory and adapted for implementing the steps of the method described above when the program is executed by a computer.

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