WO2011138470A1 - Method and system of associating virtual networks on a substrate consisting of mobile nodes - Google Patents

Method and system of associating virtual networks on a substrate consisting of mobile nodes Download PDF

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Publication number
WO2011138470A1
WO2011138470A1 PCT/ES2010/070305 ES2010070305W WO2011138470A1 WO 2011138470 A1 WO2011138470 A1 WO 2011138470A1 ES 2010070305 W ES2010070305 W ES 2010070305W WO 2011138470 A1 WO2011138470 A1 WO 2011138470A1
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virtual
physical
node
nodes
mobile
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PCT/ES2010/070305
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Spanish (es)
French (fr)
Inventor
Gorka HERNANDO GARCÍA
Susana PÉREZ SÁNCHEZ
José María CABERO LÓPEZ
Iñigo Arizaga Arcelus
Miguel Ángel MELCHOR MARTÍN
Fernando GÓMEZ GONZÁLEZ
Orlando PEÑA GONZÁLEZ
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Fundacion Robotiker
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Priority to PCT/ES2010/070305 priority Critical patent/WO2011138470A1/en
Publication of WO2011138470A1 publication Critical patent/WO2011138470A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/46—Interconnection of networks
    • H04L12/4641—Virtual LANs, VLANs, e.g. virtual private networks [VPN]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
    • H04W40/026—Route selection considering the moving speed of individual devices
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
    • H04W40/04—Communication route or path selection, e.g. power-based or shortest path routing based on wireless node resources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
    • H04W40/20—Communication route or path selection, e.g. power-based or shortest path routing based on geographic position or location
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W40/00—Communication routing or communication path finding
    • H04W40/24—Connectivity information management, e.g. connectivity discovery or connectivity update
    • H04W40/246—Connectivity information 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
    • H04L45/24—Multipath

Definitions

  • the present invention is encompassed in the field of Telecommunications. Within this area, in the virtualization of communications networks.
  • Virtualization of telecommunications networks is a key technique in the development of the future of the Internet, which consists of sharing (network) resources of one or different physical substrates by different network operators in a transparent and secure way [L. Peterson, S. Shenker, J. Turner. "Overcoming the Internet impasse through Virtualization”. ACM HotNets III, 2004 ⁇ , [N. Feamster, L. Gao, J. Rexford. "How to read the Internet in your spare time”. Georgia Tech Technical Report GT-CSS-06-10, August 2006 ⁇ . There are several open branches of research regarding this technique. One of them is the association method, which consists in the process of mapping the VNets virtual network requests (virtual networks) composed of virtual nodes and their respective virtual links optimally in the physical infrastructure trying to maximize the use of The available resources.
  • the virtual nodes request a specific CPU processing capacity (from the Central Processor Unit) and BW bandwidth (from the English Band Width) for their links that must be satisfied through the available physical resources. Sometimes it will not be possible to service these VNets so they must be postponed or rejected.
  • mapping problem can be approached from different points of view, depending on the metrics or optimization criteria that are of interest in each case.
  • Ammar apply a series of heuristic methods for resource allocation. They also divide the process of assigning virtual nodes and virtual links as different processes. From the utilization information of each physical element of the network, the system first assigns the central node of the VNet and continues the allocation process by dividing the requested network topology into small star topologies that will finally be linked.
  • Zhu & Ammar propose a migration method in which the VNets in critical situations, that is, those in which their physical resources are more saturated, are the first to try to reconfigure. [NM Chowdhury, M. Rahman and R. Boutaba. "Virtual Network Embedding with Coordinated Node and Link mapping ".
  • the present invention relates to a system and method for allocating resources for hosting virtual networks on a substrate formed by mobile wireless nodes.
  • the method and system focus on maximizing the number of VNets that live in the system simultaneously.
  • a method for the assignment of a virtual network in a communications network, wherein said communication network comprises a plurality of mobile physical nodes located in an area divided into location cells.
  • Each of the mobile physical nodes has a processing capacity, a location, a mobility factor and a movement speed and they communicate by means of physical routes where each of said physical routes comprises at least one link physical with a bandwidth, between two mobile physical nodes, available at a certain time.
  • the method comprises the following steps:
  • the resources of each mobile physical node are calculated as the ratio between the sum of the bandwidth of its links and the sum of the unit plus the product of its mobility factor by its movement speed.
  • the mobility factor takes the following values:
  • the virtual network cannot be allocated, the resources associated with it are released and said allocation request is maintained in the node memory mobile physicist with more resources for a future retry.
  • virtual nodes Periodically, and for a virtual network that remains assigned for a time greater than a certain threshold, virtual nodes reallocate their operational virtual link to a new physical route at a lower cost.
  • This process is called migration. Specifically, the cost of both routes is calculated: current and candidate, where said cost is calculated for each physical route as the sum of the bandwidth of each physical link multiplied by the number of hops of the route, and in case the candidate route is of lower cost, then the virtual link is migrated and the resources of the first physical route are released.
  • the node of said virtual network with higher CPU capacity and bandwidth requirements of its links is chosen as the main node n 0 of the virtual network and the numbering of the remaining virtual nodes to be assigned is performed consecutively in decreasing order of requirements CPU capacity and bandwidth of your links.
  • the Path Splitting technique is optionally used.
  • Mobile physical nodes use a communication protocol that comprises at least one of the following messages:
  • a request message which contains the resources required in the hosting request and the virtual node that must be assigned to the destination mobile physical node of said request message;
  • a hosting error message which is used to report an error during the hosting process of a virtual network due to the scarcity of resources in a mobile physical node or in its physical links where said hosting error message is sent to all mobile physical nodes that have already been assigned a virtual node or will be part of a virtual link of that virtual network;
  • a mobility error message which is sent from a mobile physical node when one of its physical links that has an assigned virtual link is broken, to the extreme physical node of the affected virtual link;
  • a reassignment message which is sent from a mobile physical node that changes location cell, and that has a virtual node assigned with location requirements, to a physical node located in the abandoned cell, where said reassignment message contains information to request a new virtual link to neighboring virtual nodes;
  • Migration message which is sent to a plurality of mobile physical nodes included in a new physical route candidate to replace a current virtual link assignment, for optimization reasons.
  • Migration release message which is sent from a physical node that has a virtual node assigned, in response to a previous migration message, to release the higher cost physical route.
  • a system comprising means adapted to carry out the method described above.
  • a computer program comprising computer program code means adapted to perform the steps of the method described above, when said program is executed on a computer, a digital signal processor, a programmable field gate arrangement, a circuit Integrated specific application, a microprocessor, a microcontroller, and any other form of programmable hardware.
  • Figure 1 shows a scenario of realization of the invention, where a communication network is illustrated comprising a plurality of mobile physical nodes and a virtual network with a plurality of virtual nodes requesting to be hosted in said communication network.
  • Figure 2 shows an example of assigning virtual links to physical routes using the Road Division technique (in English, Path Splitting).
  • Figure 3 shows an example of the proposed numbering for the virtual nodes of the virtual network.
  • Figure 4 shows the exchange of messages between the nodes of the network during the reallocation of a virtual node, with location requirements, in a new mobile physical node when the mobile physical node that hosted it changes location cell.
  • Figure 5 shows the exchange of messages between the nodes of the network during the reallocation of a virtual link to a new physical route when a mobile physical node detects the breaking of the physical link that housed said virtual link.
  • Figure 6 shows the migration of a virtual link to a new physical route when after a certain period of time a physical route is detected with a lower associated cost than the current physical route.
  • the present invention provides a system and method for allocating virtual resources oriented to mobile AdHoc networks MANets, which minimizes the problems arising from mobility and the loss of physical links.
  • Network operators are given the possibility of requesting a Approximate geographical location of its virtual nodes by dividing into cells of the surface covered by the physical infrastructure.
  • a distributed allocation protocol is presented that adapts to networks composed of nodes of similar characteristics where management is shared by all of them, as occurs in MANets networks.
  • the protocol minimizes the effects of the mobility of the nodes of the physical substrate during the allocation process, due to a priori ignorance of said mobility and its randomness there are continuous ruptures of the physical bonds and cell changes of location of the own physical nodes, which affect the proper functioning of the VNets.
  • the system uses two resource reallocation algorithms that allow reducing the number of VNets whose correct execution is interrupted due to the mobility problems mentioned.
  • the embodiment scenario of the invention shown in Figure 1 consists of a network of / V s mobile physical nodes 1 1 located in an infrastructure of size (x, y) divided into different location cells 12.
  • Each substrate link P e L s 13 is characterized by its bandwidth bw (P).
  • Each node of the rf e / V s substrate is also characterized by its CPU resources, its location on the map, its mobility factor a (rf) and its movement speed s (n s ).
  • the entries to the proposed system are VNets hosting requests, which are mapped or rejected depending on the state of the network and the resources available at the specific time of arrival.
  • G v (N v , L v )
  • N v represents the set of virtual nodes
  • L s represents the set of requested virtual links.
  • Each rf e N v 14 is characterized by its CPU capacity and its location; and each faith L v 15 is characterized by its bandwidth capacity.
  • the requests arrive at the system in an instant of a priori unknown time and indicate its duration.
  • the possible values of the mobility factor of the mobile physical nodes are:
  • the mobility index of a node is obtained as the product of its state and the speed of movement.
  • ⁇ is defined as the function that represents the set of physical links associated with a physical node, P ⁇ n s .
  • Equation 1 The equation that allows quantifying the resources, H (n s ), of each physical node is shown in equation 1.
  • the resources of a node are given by the remaining bandwidth capacity of its interfaces, the mobility factor and the speed of movement.
  • the criterion that is applied looks for the rf node with a maximum value of H (n s ), that is, high values in the numerator, and low values in the denominator. In this way, the choice of those moving nodes is penalized.
  • the method used is based on the exchange of messages between neighboring nodes of the physical substrate so that the defined algorithm indicates the steps to be taken in the event of the occurrence of an event or the reception of a message.
  • the system assigns the virtual nodes rf and their respective virtual links fa the physical nodes rf and physical links P that make up the physical infrastructure and repairs the initial assignment in case of mobility failure during the lifetime of The virtual network
  • a new VNet hosting request arrives at any node of the physical network, this node queries the physical node in its routing table with more resources and retransmits the request for accommodation, so that node begins the process of resource allocation.
  • the central node stores the VNet request in memory until it is completed in case it is to be re-mapped later due to an error caused by mobility .
  • That physical node to which a new mapping request arrives first checks if it is capable of supporting the CPU requested by the virtual node and the bandwidths of the virtual links. If so, and as long as there are more virtual nodes to be mapped, the node forwards the request to the physical nodes with the greatest amount of resources, and, that meet the location requirements, at the request house, in charge of hosting the virtual neighbors of said node. If any of the physical nodes involved in the process cannot support the request due to the scarcity of resources, said node sends an error message backwards so that the rest of the nodes can release the request.
  • the physical nodes host the VNet until the time requested by the network operator, provided that it should not be released due to mobility problems that cannot be repaired through the reallocation algorithms of resources.
  • the method implements the known Path Division technique (in English, Path Splitting) shown in Figure 2.
  • Path Division technique in English, Path Splitting
  • the different nodes that make up the physical infrastructure 21 have several physical links 22.
  • the virtual link is divided into several physical paths, so that the sum of the bandwidths of all physical paths results in the bandwidth requested by the network operator for its virtual link.
  • the example in the figure shows a case where the virtual central node 23 needs to communicate with the virtual destination node 24 with a bandwidth of 40 units.
  • the nodes do not have several physical links there is no major problem in the execution of the allocation algorithm, it is simply a more restrictive mapping and the amount of VNets hosted in the system is probably smaller. It is the operator's decision to decide whether or not their virtual links allow the Road Division since this technology may not be interesting depending on the services offered.
  • by assigning virtual nodes in the physical nodes with the greatest amount of resources it is possible to balance the use of the network and facilitate the hosting of VNets that do not allow Path Splitting.
  • any type of topology is allowed to be requested, the numbering of virtual nodes is performed, as shown in Figure 3, assigning as node central ⁇ ⁇ 0 ⁇ the node that demands the greatest amount of resources and in ascending order completing neighbors rings rf ⁇ 32, n v 2 33 and n v 3 34.
  • a request cannot be accommodated, it is stored in the memory of the central node n v 0 31 that started mapping the request for a request. future attempt where the characteristics of the network are different, or is discarded, after a certain number of attempts, and therefore removed from the system.
  • a proactive routing protocol is used that allows to know the status of the entire network in an updated way.
  • the protocol provides the CPU, bandwidth and location information of each physical node.
  • the main innovation proposed by the method is the use of a MANet network as a VNets mapping infrastructure. This implies that movements of the physical nodes can cause ruptures of links or changes of location cells that affect the hosted VNets, therefore a method of adaptation to the new infrastructure situation is necessary. There are two reallocation situations considered:
  • a physical node 41 changes location cell 42 checks if it has any VNet assigned with location requirements. If so, in addition to sending the notification messages of this situation 43 to the virtual neighboring nodes 44, for the release of the affected routes, it selects a valid node 45 and sends a message 46 indicating the necessary information for reallocate affected links.
  • the neighboring nodes 44 informed of the situation enter into a state of repair, considering the VNet as not recoverable if after a while they have not received a message 47 indicating the information necessary to reallocate their affected links.
  • Request message this is the message used to complete the VNet hosting. It contains the resources requested by the network operator in addition to the virtual node to be assigned to the destination node of the message.
  • Embedding Error message reports an error during the hosting process due to the scarcity of resources at extreme or intermediate nodes of the physical path. The message is sent backwards so that the release is completed on all the nodes involved.
  • Mobility Error message 54 the node 51, 52 that is aware of the breaking of a physical link 53, sends this message 54 to the end node 55, 56 of the affected virtual link so that it can perform the appropriate reallocation operations. Since the link can be divided into several physical routes, each node relays the error message through all its interfaces except for the one where it received it.
  • Reallocate message 46 at the moment when a physical node to which a virtual node 41 with location restriction has been assigned changes location cell 42, it sends a reset message 46 to the selected physical node in the correct cell 45 with the information necessary to request a new virtual link to the neighboring virtual nodes.
  • the resources of the physical infrastructure nodes will vary due to the mobility and presence of VNets in the system.
  • the proposed method implements the technique known as migration, shown in Figure 6. From time to time, periodically, and for those VNets whose duration is longer than a defined threshold, the virtual nodes will try to migrate the operational virtual link to another physical path of lower associated cost, C (lv).
  • the cost of mapping a virtual link in the physical substrate as the sum of the bandwidth bw (l s ) multiplied by the number of hops hops (p) of all physical links I s , which make up the virtual link.
  • the communication protocol between the physical nodes also includes the following messages:
  • ⁇ Migration message allows the attempt to migrate a virtual link.
  • Migration Relay message the virtual node that receives a migration message responds through this message to release the previous assignment of resources of those nodes wrapped in the physical path not selected in the migration due to their higher cost.
  • Figure 6 shows the technique of migrating a VNet to another physical route of lower cost.
  • the VNet is assigned in the manner indicated in the upper part 61, using Path Spiitting, and, at the instant Tn + k, after the release of bandwidth in some of the physical links of the network of communications, due to the eviction of other virtual networks, the VNet migrates to a lower cost route and is assigned as indicated in the lower part 62 of the figure.

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Abstract

The invention relates to a method for repair assignments and attempts in the event of mobility failures of a virtual network in a communications network, where said communications network includes a plurality of mobile physical nodes (11) located on a surface divided into a plurality of localization cells (12), where each one of said mobile physical nodes (11) has a processing capacity, a localization, a movement speed and an associated mobility factor and where said mobile physical nodes (11) communicate with each other by means of physical paths where each one of said physical paths includes at least one physical link (13) with a bandwidth, between two mobile physical nodes (11), available at a predetermined time. The system includes mechanisms for dynamically repairing failures arising from the mobility of physical nodes that provide resources to the operative virtual networks.

Description

METODO Y SISTEMA DE ASOCIACIÓN DE REDES VIRTUALES SOBRE UN SUSTRATO COMPUESTO POR NODOS MÓVILES  VIRTUAL NETWORK ASSOCIATION METHOD AND SYSTEM ON A SUBSTRATE COMPOSED BY MOBILE NODES
D E S C R I P C I Ó N D E S C R I P C I Ó N
CAMPO DE LA INVENCIÓN FIELD OF THE INVENTION
La presente invención se engloba en el campo de las Telecomunicaciones. Dentro de este ámbito, en el de la virtualización de redes de comunicaciones.  The present invention is encompassed in the field of Telecommunications. Within this area, in the virtualization of communications networks.
ANTECEDENTES DE LA INVENCIÓN BACKGROUND OF THE INVENTION
La virtualización de redes de telecomunicaciones es una técnica clave en el desarrollo del futuro de Internet que consiste en compartir recursos (de red) de uno o diferentes sustratos físicos por diferentes operadores de red de manera transparente y segura [L. Peterson, S. Shenker, J. Turner. "Overcoming the Internet impasse through Virtualization". ACM HotNets III, 2004\, [N. Feamster, L. Gao, J. Rexford. "How to léase the Internet in your spare time". Georgia Tech Technical Report GT-CSS-06- 10, August 2006\. Existen varias ramas de investigación abiertas respecto a dicha técnica. Una de ellas es el método de asociación, que consiste en el proceso de mapear las solicitudes de redes virtuales VNets (del inglés Virtual Networks) compuestas por nodos virtuales y sus respectivos enlaces virtuales de manera óptima en la infraestructura física tratando de maximizar el uso de los recursos disponibles.  Virtualization of telecommunications networks is a key technique in the development of the future of the Internet, which consists of sharing (network) resources of one or different physical substrates by different network operators in a transparent and secure way [L. Peterson, S. Shenker, J. Turner. "Overcoming the Internet impasse through Virtualization". ACM HotNets III, 2004 \, [N. Feamster, L. Gao, J. Rexford. "How to read the Internet in your spare time". Georgia Tech Technical Report GT-CSS-06-10, August 2006 \. There are several open branches of research regarding this technique. One of them is the association method, which consists in the process of mapping the VNets virtual network requests (virtual networks) composed of virtual nodes and their respective virtual links optimally in the physical infrastructure trying to maximize the use of The available resources.
Varios son los puntos que hacen del algoritmo de asociación de VNets un problema difícil de solventar de cara a un mapeo óptimo y una mejor explotación de los recursos físicos disponibles: There are several points that make the VNets association algorithm a difficult problem to solve for optimal mapping and better exploitation of available physical resources:
- Los nodos virtuales solicitan una capacidad concreta de procesamiento CPU (del inglés Central Processor Unit) y ancho de banda BW (del inglés Band Width) para sus enlaces que han de ser satisfechos mediante los recursos físicos disponibles. En ocasiones no será posible dar servicio a dichas VNets por lo que deberán ser pospuestas o rechazadas.  - The virtual nodes request a specific CPU processing capacity (from the Central Processor Unit) and BW bandwidth (from the English Band Width) for their links that must be satisfied through the available physical resources. Sometimes it will not be possible to service these VNets so they must be postponed or rejected.
- El desconocimiento previo de la llegada de nuevas peticiones hace de la asociación de recursos una tarea difícil de afrontar ya que se debe tratar de alojar la petición en función de los recursos físicos actuales tratando de maximizar la posibilidad de alojar futuras VNets si bien desconocemos los requerimientos que solicitarán. - The previous ignorance of the arrival of new requests makes the association of resources a difficult task to deal with since the request must be treated according to the current physical resources trying to maximize the possibility of hosting future VNets although we do not know the requirements they will request.
- No existe ninguna restricción respecto al tipo de topología a solicitar por el operador de red por lo que el sistema debe adaptarse en todo momento a las necesidades específicas de cada esquema de red.  - There is no restriction regarding the type of topology to be requested by the network operator, so the system must adapt at all times to the specific needs of each network scheme.
El problema del mapeo se puede abordar desde diferentes puntos de vista, dependiendo de las métricas o criterios de optimización que interese aplicar en cada caso. Son numerosas a día de hoy las soluciones que tratan de solventar el problema del alojamiento (del inglés "allocation"). [M. Yu, Y. Yi, J. Rexford and M. Chiang. "Rethinking Virtual Network Embedding: Substrate Support for Path Splitting and Migration". ACM SIGCOMM, April 2008\ y [ V. Zhu and M. Ammar. "Algoríthms for assigning substrate network resources to virtual network components" In Proceedings for IEEE GLOBECOM, 2003, pp. 3004-3008] muestran el proceso de asignación de recursos como un problema de complejidad computacional NP-complejo ó NP-hard (del inglés Non-Deterministic Polynomial- time hard) si bien lo afrontan desde una perspectiva diferente. Así M. Yu et al asumen la posibilidad de dividir el ancho de banda solicitado en diferentes rutas físicas mediante la técnica denominada División de Caminos (del inglés Path Splitting) y aplican otras técnicas de tiempo polinomial para resolver el mapeo de nodos y enlaces. Para ello, optan por la división del tiempo de ejecución en ventanas de tiempo de manera que durante el transcurso de una ventana varias son las solicitudes de alojamiento de VNets que llegan al sistema. Asimismo proponen la aplicación del concepto de migración para el balance dinámico de los recursos físicos cada ventana de tiempo. Sin embargo, Y. Zhu & M. Ammar aplican una serie de métodos heurísticos para la asignación de recursos. También dividen el proceso de asignación de nodos virtuales y enlaces virtuales como procesos diferentes. A partir de la información de utilización de cada elemento físico de la red, el sistema en primer lugar asigna el nodo central de la VNet y continua el proceso de asignación dividiendo la topología de red solicitada en pequeñas topologías en estrella que serán finalmente unidas. Zhu & Ammar proponen un método de migración en el cual las VNets en situación crítica, es decir, aquellas en las que sus recursos físicos se encuentran más saturados, son las primeras en tratar de reconfigurar. [N.M. Chowdhury, M. Rahman and R. Boutaba. "Virtual Network Embedding with Coordinated Node and Link mapping". Accepted for IEEE INFOCOM, 2009] por su parte trata de optimizar la solución considerando el alojamiento de nodos y enlaces virtuales de manera conjunta en vez del tradicional sistema separado. Para ello, se introduce el concepto de clusters, nodos situados dentro de una célula de localización, y meta-nodes, nodos encargados de gestionar dichos nodos del clúster. [/. Houidi, W. Louati and D. Zeghlache. "A Distributed Virtual Network Mapping Algorithm". IEEE International Conference on Communications (ICC 2008), 2008] propone un enfoque diferente a los análisis anteriores mediante un sistema de almacenamiento distribuido entre los nodos de la red. Con el objetivo de reducir el tiempo de asignación, divide la infraestructura en clusters compuestos por nodos de similares características. The mapping problem can be approached from different points of view, depending on the metrics or optimization criteria that are of interest in each case. Today there are numerous solutions that try to solve the problem of accommodation (in English "allocation"). [M. Yu, Y. Yi, J. Rexford and M. Chiang. "Rethinking Virtual Network Embedding: Substrate Support for Path Splitting and Migration". ACM SIGCOMM, April 2008 \ and [V. Zhu and M. Ammar. "Algoríthms for assigning substrate network resources to virtual network components" In Proceedings for IEEE GLOBECOM, 2003, pp. 3004-3008] show the process of resource allocation as a problem of computational complexity NP-complex or NP-hard (Non-Deterministic Polynomial-time hard) although they face it from a different perspective. Thus, M. Yu et al assume the possibility of dividing the requested bandwidth into different physical routes using the technique called Paths Division (in English Path Splitting) and apply other polynomial time techniques to solve the mapping of nodes and links. To do this, they choose to divide the runtime into time windows so that during the course of a window several are the VNets hosting requests that arrive at the system. They also propose the application of the concept of migration for the dynamic balance of physical resources every time window. However, Y. Zhu & M. Ammar apply a series of heuristic methods for resource allocation. They also divide the process of assigning virtual nodes and virtual links as different processes. From the utilization information of each physical element of the network, the system first assigns the central node of the VNet and continues the allocation process by dividing the requested network topology into small star topologies that will finally be linked. Zhu & Ammar propose a migration method in which the VNets in critical situations, that is, those in which their physical resources are more saturated, are the first to try to reconfigure. [NM Chowdhury, M. Rahman and R. Boutaba. "Virtual Network Embedding with Coordinated Node and Link mapping ". Accepted for IEEE INFOCOM, 2009] for its part tries to optimize the solution considering the accommodation of nodes and virtual links together instead of the traditional separate system. To do this, the concept is introduced of clusters, nodes located within a location cell, and meta-nodes, nodes responsible for managing said cluster nodes. [/. Houidi, W. Louati and D. Zeghlache. "A Distributed Virtual Network Mapping Algorithm." IEEE International Conference on Communications (ICC 2008), 2008] proposes a different approach to the previous analyzes through a distributed storage system between the nodes of the network.In order to reduce the allocation time, divide the infrastructure into clusters composed of nodes of similar characteristics.
A día de hoy, el problema de la asignación de recursos en la virtualización de redes se ha restringido a redes de telecomunicaciones estáticas y cableadas, si bien la Internet of Things [Internet Reports 2005: "The Internet of Things 2005, 7th edition":http://www.itu.int/publ/S-POLIR.IT-2005/e] prevé un nuevo paradigma de red compuesto, principalmente, por nodos móviles. To this day, the problem of resource allocation in network virtualization has been restricted to static and wired telecommunications networks, although the Internet of Things [Internet Reports 2005: "The Internet of Things 2005, 7th edition": http://www.itu.int/publ/S-POLIR.IT-2005/e] foresees a new network paradigm composed mainly of mobile nodes.
RESUMEN DE LA INVENCIÓN SUMMARY OF THE INVENTION
La presente invención se refiere a un sistema y método de asignación de recursos para el alojamiento de redes virtuales sobre un sustrato formado por nodos inalámbricos móviles.  The present invention relates to a system and method for allocating resources for hosting virtual networks on a substrate formed by mobile wireless nodes.
El método y sistema se centran en la maximización del número de VNets que conviven en el sistema simultáneamente. The method and system focus on maximizing the number of VNets that live in the system simultaneously.
En concreto, en una realización de la presente invención, se proporciona un método para la asignación de una red virtual en una red de comunicaciones, donde dicha red de comunicaciones comprende una pluralidad de nodos físicos móviles situados en una zona dividida en celdas de localización. Cada uno de los nodos físicos móviles tiene una capacidad de procesamiento, una localización, un factor de movilidad y una velocidad de movimiento y se comunican mediante unas rutas físicas donde cada una de dichas rutas físicas comprende, al menos, un enlace físico con un ancho de banda, entre dos nodos físicos móviles, disponible en un determinado momento. El método comprende los siguientes pasos: Specifically, in one embodiment of the present invention, a method is provided for the assignment of a virtual network in a communications network, wherein said communication network comprises a plurality of mobile physical nodes located in an area divided into location cells. Each of the mobile physical nodes has a processing capacity, a location, a mobility factor and a movement speed and they communicate by means of physical routes where each of said physical routes comprises at least one link physical with a bandwidth, between two mobile physical nodes, available at a certain time. The method comprises the following steps:
• recibir en un nodo físico móvil, perteneciente a dicha red de comunicaciones, una solicitud de asignación, por un tiempo determinado, de una red virtual que comprende una pluralidad de nodos virtuales que tienen una capacidad de procesamiento y una localización y se comunican mediante una pluralidad de enlaces virtuales con un ancho de banda determinado;  • receive in a mobile physical node, belonging to said communications network, a request for assignment, for a certain time, of a virtual network comprising a plurality of virtual nodes that have a processing capacity and a location and communicate by means of a plurality of virtual links with a certain bandwidth;
• retransmitir desde dicho nodo físico móvil la solicitud de asignación hasta el nodo físico móvil con la mayor cantidad de recursos, donde dichos recursos dependen en cada uno de los nodos físicos móviles del ancho de banda disponible de sus enlaces, su movilidad y de su velocidad de movimiento;  • retransmitting from said mobile physical node the allocation request to the mobile physical node with the greatest amount of resources, where said resources depend on each of the mobile physical nodes of the available bandwidth of their links, their mobility and their speed of movement;
• almacenar dicha solicitud de asignación en dicho nodo físico móvil con la mayor cantidad de recursos;  • storing said allocation request in said mobile physical node with the greatest amount of resources;
• asignar el nodo principal de la red virtual a dicho nodo físico móvil con la mayor cantidad de recursos;  • assign the main node of the virtual network to said mobile physical node with the greatest amount of resources;
• iniciar, a partir del nodo central de la red virtual, un proceso de asignación del resto de nodos y enlaces virtuales a otros nodos físicos móviles y rutas físicas pertenecientes a la red de comunicación, siguiendo un criterio de mayor disponibilidad de recursos, que los pondera en función de la cantidad y la movilidad de los nodos;  • initiate, from the central node of the virtual network, a process of assigning the rest of the nodes and virtual links to other mobile physical nodes and physical routes belonging to the communication network, following a criterion of greater availability of resources, than the weight based on the quantity and mobility of the nodes;
• una vez que la totalidad de nodos y enlaces virtuales han sido asignados, mantener dicha red virtual alojada durante el tiempo indicado en la solicitud de asignación.  • Once all the nodes and virtual links have been assigned, keep said virtual network hosted for the time indicated in the assignment request.
Los recursos de cada nodo físico móvil se calculan como el cociente entre el sumatorio del ancho de banda de sus enlaces y la suma de la unidad más el producto de su factor de movilidad por su velocidad de movimiento. The resources of each mobile physical node are calculated as the ratio between the sum of the bandwidth of its links and the sum of the unit plus the product of its mobility factor by its movement speed.
El factor de movilidad toma los siguientes valores: The mobility factor takes the following values:
• 0, para un nodo físico móvil estático durante un determinado periodo de tiempo;  • 0, for a static mobile physical node for a certain period of time;
• 1 , para un nodo físico móvil que comienza a moverse o a detenerse tras un determinado periodo de tiempo; • 2, para un nodo físico móvil que se mueve durante un determinado periodo de tiempo. • 1, for a mobile physical node that begins to move or stop after a certain period of time; • 2, for a mobile physical node that moves for a certain period of time.
Si por falta de capacidad de procesamiento en dichos nodos físicos móviles o de ancho de banda en los enlaces físicos, la red virtual no puede ser asignada, se liberan los recursos asociados a la misma y se mantiene dicha solicitud de asignación en la memoria del nodo físico móvil con mayor cantidad de recursos para un futuro reintento. If, due to lack of processing capacity in said mobile physical nodes or bandwidth in the physical links, the virtual network cannot be allocated, the resources associated with it are released and said allocation request is maintained in the node memory mobile physicist with more resources for a future retry.
Si el movimiento de un nodo físico móvil que tiene asignado un nodo virtual con requerimientos de localización, causa el cambio de celda de localización, se reasigna dicho nodo virtual y sus enlaces virtuales correspondientes, a otro nodo físico móvil válido en la celda correcta (solicitada). If the movement of a mobile physical node that has been assigned a virtual node with location requirements, causes the change of location cell, said virtual node and its corresponding virtual links are reassigned to another valid mobile physical node in the correct cell (requested ).
Además, si el movimiento de un nodo físico móvil causa la ruptura de un enlace físico, que tiene asignado un enlace virtual, se reasigna dicho enlace virtual a otra ruta física válida de dicha red de comunicaciones. In addition, if the movement of a mobile physical node causes the breakdown of a physical link, which has a virtual link assigned, that virtual link is reassigned to another valid physical route of said communications network.
Periódicamente y para una red virtual que permanece asignada durante un tiempo superior a un umbral determinado, los nodos virtuales reasignan su enlace virtual operativo a una nueva ruta física con un coste menor. Este proceso se denomina migración. En concreto, se calcula el coste de ambas rutas: actual y candidata, donde dicho coste se calcula para cada ruta física como el sumatorio del ancho de banda de cada enlace físico multiplicado por el número de saltos de la ruta, y en caso de que la ruta candidata sea de coste inferior, entonces se migra el enlace virtual y se liberan los recursos de la primera ruta física. Periodically, and for a virtual network that remains assigned for a time greater than a certain threshold, virtual nodes reallocate their operational virtual link to a new physical route at a lower cost. This process is called migration. Specifically, the cost of both routes is calculated: current and candidate, where said cost is calculated for each physical route as the sum of the bandwidth of each physical link multiplied by the number of hops of the route, and in case the candidate route is of lower cost, then the virtual link is migrated and the resources of the first physical route are released.
Preferentemente se escoge como nodo principal n0 de la red virtual el nodo de dicha red virtual con mayores requerimientos de capacidad de CPU y ancho de banda de sus enlaces y la numeración de los restantes nodos virtuales a asignar se realiza consecutivamente en orden decreciente de requerimientos de capacidad de CPU y ancho de banda de sus enlaces. En el proceso de asignación de nodos y enlaces virtuales se utiliza, opcionalmente, la técnica de División de Caminos (Path Splitting). Preferably, the node of said virtual network with higher CPU capacity and bandwidth requirements of its links is chosen as the main node n 0 of the virtual network and the numbering of the remaining virtual nodes to be assigned is performed consecutively in decreasing order of requirements CPU capacity and bandwidth of your links. In the process of assigning nodes and virtual links, the Path Splitting technique is optionally used.
Los nodos físicos móviles utilizan un protocolo de comunicación que comprende, al menos, alguno de los siguientes mensajes: Mobile physical nodes use a communication protocol that comprises at least one of the following messages:
• Un mensaje de asignación, que se utiliza para notificar desde un nodo físico móvil al resto de nodos físicos móviles la asignación de un nuevo nodo virtual y el valor de sus recursos actualizado;  • An assignment message, which is used to notify from a mobile physical node to the rest of the mobile physical nodes the assignment of a new virtual node and the value of its updated resources;
• Un mensaje de solicitud, que contiene los recursos requeridos en la solicitud de alojamiento y el nodo virtual que se debe asignar al nodo físico móvil destino de dicho mensaje de solicitud;  • A request message, which contains the resources required in the hosting request and the virtual node that must be assigned to the destination mobile physical node of said request message;
• Un mensaje de error de alojamiento, que se utiliza para notificar un error durante el proceso de alojamiento de una red virtual debido a la escasez de recursos en un nodo físico móvil o en sus enlaces físicos donde dicho mensaje de error de alojamiento se envía a todos los nodos físicos móviles que tuvieran ya asignado un nodo virtual o formaran parte de un enlace virtual de dicha red virtual; • A hosting error message, which is used to report an error during the hosting process of a virtual network due to the scarcity of resources in a mobile physical node or in its physical links where said hosting error message is sent to all mobile physical nodes that have already been assigned a virtual node or will be part of a virtual link of that virtual network;
• Un mensaje de error por movilidad, que se envía desde un nodo físico móvil cuando se rompe uno de sus enlaces físicos que tiene un enlace virtual asignado, hasta el nodo físico extremo del enlace virtual afectado; • A mobility error message, which is sent from a mobile physical node when one of its physical links that has an assigned virtual link is broken, to the extreme physical node of the affected virtual link;
• Un mensaje de reasignación, que se envía desde un nodo físico móvil que cambia de celda de localización, y que tiene asignado un nodo virtual con requerimientos de localización, hasta un nodo físico ubicado en la celda abandonada, donde dicho mensaje de reasignación contiene información para solicitar un nuevo enlace virtual a los nodos virtuales vecinos;  • A reassignment message, which is sent from a mobile physical node that changes location cell, and that has a virtual node assigned with location requirements, to a physical node located in the abandoned cell, where said reassignment message contains information to request a new virtual link to neighboring virtual nodes;
• Mensaje de migración, que se envía a una pluralidad de nodos físicos móviles comprendidos en una nueva ruta física candidata a sustituir una asignación actual de enlace virtual, por motivos de optimización.  • Migration message, which is sent to a plurality of mobile physical nodes included in a new physical route candidate to replace a current virtual link assignment, for optimization reasons.
• Mensaje de liberación de migración, que se envía desde un nodo físico que tiene asignado un nodo virtual, como respuesta a un mensaje de migración previo, para liberar la ruta física de mayor coste.  • Migration release message, which is sent from a physical node that has a virtual node assigned, in response to a previous migration message, to release the higher cost physical route.
En otro aspecto de la presente invención se proporciona un sistema que comprende medios adaptados para llevar a cabo el método descrito anteriormente. Finalmente, se proporciona un programa informático que comprende medios de código de programa informático adaptados para realizar las etapas del método descrito anteriormente, cuando dicho programa se ejecuta en un ordenador, un procesador de señal digital, una disposición de puertas de campo programable, un circuito integrado de aplicación específica, un microprocesador, un microcontrolador, y cualquier otra forma de hardware programable. In another aspect of the present invention there is provided a system comprising means adapted to carry out the method described above. Finally, a computer program is provided comprising computer program code means adapted to perform the steps of the method described above, when said program is executed on a computer, a digital signal processor, a programmable field gate arrangement, a circuit Integrated specific application, a microprocessor, a microcontroller, and any other form of programmable hardware.
BREVE DESCRIPCION DE LOS DIBUJOS BRIEF DESCRIPTION OF THE DRAWINGS
Con objeto de ayudar a una mejor comprensión de las características del invento de acuerdo con un ejemplo preferente de realización práctica del mismo y para complementar esta descripción, se acompaña como parte integrante de la misma un juego de dibujos, cuyo carácter es ilustrativo y no limitativo. En estos dibujos: In order to help a better understanding of the features of the invention according to a preferred example of practical realization thereof and to complement this description, a set of drawings is attached as an integral part thereof, the character of which is illustrative and not limiting . In these drawings:
La figura 1 muestra un escenario de realización de la invención, donde se ilustra una red de comunicaciones que comprende una pluralidad de nodos físicos móviles y una red virtual con una pluralidad de nodos virtuales que solicita ser alojada en dicha red de comunicaciones. Figure 1 shows a scenario of realization of the invention, where a communication network is illustrated comprising a plurality of mobile physical nodes and a virtual network with a plurality of virtual nodes requesting to be hosted in said communication network.
La figura 2 muestra un ejemplo de asignación de enlaces virtuales a rutas físicas mediante la técnica de División de Caminos (en inglés, Path Splitting). Figure 2 shows an example of assigning virtual links to physical routes using the Road Division technique (in English, Path Splitting).
La figura 3 muestra un ejemplo de la numeración propuesta para los nodos virtuales de la red virtual. Figure 3 shows an example of the proposed numbering for the virtual nodes of the virtual network.
La figura 4 muestra el intercambio de mensajes entre los nodos de la red durante la reasignación de un nodo virtual, con requisitos de localización, en un nuevo nodo físico móvil cuando el nodo físico móvil que lo alojaba cambia de celda de localización. Figure 4 shows the exchange of messages between the nodes of the network during the reallocation of a virtual node, with location requirements, in a new mobile physical node when the mobile physical node that hosted it changes location cell.
La figura 5 muestra el intercambio de mensajes entre los nodos de la red durante la reasignación de un enlace virtual a una nueva ruta física cuando un nodo físico móvil detecta la ruptura del enlace físico que alojaba dicho enlace virtual. Figure 5 shows the exchange of messages between the nodes of the network during the reallocation of a virtual link to a new physical route when a mobile physical node detects the breaking of the physical link that housed said virtual link.
La figura 6 muestra la migración de un enlace virtual a una nueva ruta física cuando transcurrido un determinado intervalo de tiempo se detecta una ruta física con un menor coste asociado que la ruta física actual. DESCRIPCIÓN DETALLADA DE LA INVENCIÓN Figure 6 shows the migration of a virtual link to a new physical route when after a certain period of time a physical route is detected with a lower associated cost than the current physical route. DETAILED DESCRIPTION OF THE INVENTION
La presente invención proporciona un sistema y método de asignación de recursos virtuales orientado a redes AdHoc móviles MANets, del inglés Mobile AdHoc Networks) que minimiza los problemas derivados de la movilidad y la pérdida de enlaces físicos. Se dota a los operadores de red de la posibilidad de solicitar una localización geográfica aproximada de sus nodos virtuales mediante la división en celdas de la superficie cubierta por la infraestructura física. Se presenta un protocolo de asignación distribuido que se adecúa a redes compuestas por nodos de similares características donde la gestión es compartida por todos ellos, como ocurre en las redes MANets. Si bien el protocolo minimiza los efectos de la movilidad de los nodos del sustrato físico durante el proceso de asignación, debido al desconocimiento a priori de dicha movilidad y a su aleatoriedad se producen continuas rupturas de los enlaces físicos y cambios de celda de localización de los propios nodos físico, los cuales afectan al correcto funcionamiento de las VNets. Para solucionar este problema el sistema utiliza dos algoritmos de reasignación de recursos que permiten reducir la cantidad de VNets cuya correcta ejecución se interrumpe debido a los problemas de movilidad mencionados. The present invention provides a system and method for allocating virtual resources oriented to mobile AdHoc networks MANets, which minimizes the problems arising from mobility and the loss of physical links. Network operators are given the possibility of requesting a Approximate geographical location of its virtual nodes by dividing into cells of the surface covered by the physical infrastructure. A distributed allocation protocol is presented that adapts to networks composed of nodes of similar characteristics where management is shared by all of them, as occurs in MANets networks. Although the protocol minimizes the effects of the mobility of the nodes of the physical substrate during the allocation process, due to a priori ignorance of said mobility and its randomness there are continuous ruptures of the physical bonds and cell changes of location of the own physical nodes, which affect the proper functioning of the VNets. To solve this problem, the system uses two resource reallocation algorithms that allow reducing the number of VNets whose correct execution is interrupted due to the mobility problems mentioned.
El escenario de realización de la invención mostrado en la figura 1 , consiste en una red de /Vs nodos físicos móviles 1 1 situados en una infraestructura de tamaño (x, y) dividida en diferentes celdas de localización 12. Se caracteriza el sustrato como un grafo ponderado no dirigido Gs = (N8, Ls), donde /Vs representa el conjunto de nodos físicos y Ls representa el conjunto de enlaces físicos disponibles en cada momento, puesto que estos se establecen y se pierden de manera dinámica. Cada enlace del sustrato P e Ls 13 se caracteriza por su ancho de banda bw(P). Cada nodo del substrato rf e /Vs se caracteriza también por sus recursos de CPU, su localización en el mapa, su factor de movilidad a(rf) y su velocidad de movimiento s(ns). The embodiment scenario of the invention shown in Figure 1, consists of a network of / V s mobile physical nodes 1 1 located in an infrastructure of size (x, y) divided into different location cells 12. The substrate is characterized as a non-directed weighted graph G s = (N 8 , L s ), where / V s represents the set of physical nodes and L s represents the set of physical links available at all times, since these are established and lost so dynamic. Each substrate link P e L s 13 is characterized by its bandwidth bw (P). Each node of the rf e / V s substrate is also characterized by its CPU resources, its location on the map, its mobility factor a (rf) and its movement speed s (n s ).
Las entradas al sistema propuesto son las peticiones de alojamiento de VNets, que son mapeadas o rechazadas dependiendo del estado de la red y los recursos disponibles en el momento concreto de la llegada. Se modela cada solicitud de alojamiento de VNet como un grafo ponderado no dirigido Gv = (Nv, Lv), donde Nv representa el conjunto de nodos virtuales y Ls representa el conjunto de enlaces virtuales solicitados. Cada rf e Nv 14 se caracteriza por su capacidad de CPU y su localización; y cada f e Lv 15 se caracteriza por su capacidad de ancho de banda. Las peticiones llegan al sistema en un instante de tiempo a priori desconocido e indican su tiempo de duración. Los valores posibles del factor de movilidad de los nodos físicos móviles son: The entries to the proposed system are VNets hosting requests, which are mapped or rejected depending on the state of the network and the resources available at the specific time of arrival. Each VNet hosting request is modeled as a non-directed weighted graph G v = (N v , L v ), where N v represents the set of virtual nodes and L s represents the set of requested virtual links. Each rf e N v 14 is characterized by its CPU capacity and its location; and each faith L v 15 is characterized by its bandwidth capacity. The requests arrive at the system in an instant of a priori unknown time and indicate its duration. The possible values of the mobility factor of the mobile physical nodes are:
• 0 - Para nodos estáticos durante un periodo de tiempo;  • 0 - For static nodes for a period of time;
• 1 - Para nodos que recientemente han comenzado a moverse o detenerse; • 1 - For nodes that have recently begun to move or stop;
• 2 - Nodos en movimiento durante un periodo de tiempo. • 2 - Nodes in motion for a period of time.
Se obtiene el índice de movilidad de un nodo como el producto del estado del mismo y la velocidad de movimiento. The mobility index of a node is obtained as the product of its state and the speed of movement.
Se define † como la función que representa el conjunto de enlaces físicos asociados a un nodo físico, P† ns. † is defined as the function that represents the set of physical links associated with a physical node, P † n s .
La ecuación que permite cuantificar los recursos, H(ns), de cada nodo físico se muestra en la ecuación 1 . The equation that allows quantifying the resources, H (n s ), of each physical node is shown in equation 1.
∑bw (ls ) ∑bw (l s )
H (ns ) ~ H (n s ) ~
l + a(ns ) - s(ns ) l + a (n s ) - s (n s )
Como se puede observar, los recursos de un nodo vienen dados por la capacidad de ancho de banda restante de sus interfaces, el factor de movilidad y la velocidad de movimiento. El criterio que se aplica busca el nodo rf con un valor de H(ns) máximo, es decir, valores elevados en el numerador, y valores bajos en el denominador. De esta manera, la elección de aquellos nodos en movimiento se ve penalizada. As can be seen, the resources of a node are given by the remaining bandwidth capacity of its interfaces, the mobility factor and the speed of movement. The criterion that is applied looks for the rf node with a maximum value of H (n s ), that is, high values in the numerator, and low values in the denominator. In this way, the choice of those moving nodes is penalized.
El método utilizado se fundamenta en el intercambio de mensajes entre nodos vecinos del sustrato físico de manera que el algoritmo definido indica los pasos a realizar ante la ocurrencia de un suceso o la recepción de un mensaje. Mediante el intercambio de dichos mensajes, el sistema asigna los nodos virtuales rf y sus respectivos enlaces virtuales f a los nodos físicos rf y enlaces físicos P que componen la infraestructura física y repara la asignación inicial en caso de fallo por movilidad durante el tiempo de vida de la red virtual. The method used is based on the exchange of messages between neighboring nodes of the physical substrate so that the defined algorithm indicates the steps to be taken in the event of the occurrence of an event or the reception of a message. Through the exchange of said messages, the system assigns the virtual nodes rf and their respective virtual links fa the physical nodes rf and physical links P that make up the physical infrastructure and repairs the initial assignment in case of mobility failure during the lifetime of The virtual network
Si en un instante aleatorio de tiempo y para unos recursos específicos de la infraestructura, una nueva solicitud de alojamiento de VNet llega a un nodo cualquiera de la red física, este nodo consulta en su tabla de rutado el nodo físico con mayor cantidad de recursos y le retransmite la solicitud de alojamiento, de forma que dicho nodo comienza el proceso de asignación de recursos. Si bien los pasos a realizar definidos por el algoritmo son idénticos en todos los nodos, el nodo central almacena en memoria la solicitud de VNet hasta que ésta se completa por si ha de ser re-mapeada más adelante debido a un error causado por la movilidad.If, in a random moment of time and for specific infrastructure resources, a new VNet hosting request arrives at any node of the physical network, this node queries the physical node in its routing table with more resources and retransmits the request for accommodation, so that node begins the process of resource allocation. Although the steps to be performed defined by the algorithm are identical in all nodes, the central node stores the VNet request in memory until it is completed in case it is to be re-mapped later due to an error caused by mobility .
Aquel nodo físico al cual le llega una nueva solicitud de mapeo comprueba en primer lugar si es capaz de soportar la CPU solicitada por el nodo virtual y los anchos de banda de los enlaces virtuales. De ser así, y mientras existan más nodos virtuales a mapear, el nodo reenvía la petición a los nodos físicos con mayor cantidad de recursos, y, que cumplan los requisitos de localización, en casa de solicitarse, encargados de alojar los vecinos virtuales de dicho nodo. Si alguno de los nodos físicos involucrados en el proceso no puede soportar la petición debido a la escasez de recursos, dicho nodo envía un mensaje de error hacia atrás de manera que el resto de nodos puede liberar la petición. Una vez completado el proceso de alojamiento, los nodos físicos alojan la VNet hasta cumplir el tiempo solicitado por el operador de red, siempre y cuando ésta no deba ser liberada debido a problemas derivados de la movilidad que no se puedan reparar mediante los algoritmos de reasignación de recursos. Preferentemente, si se permite la solicitud, el método implementa la conocida técnica de División de Caminos (en inglés, Path Splitting) que se muestra en la figura 2. Para ello se considera que los diferentes nodos que conforman la infraestructura física 21 disponen de varios enlaces físicos 22. De esta forma, si en un momento dado un nodo virtual 23 que debe asignar un enlace virtual de cierto ancho de banda hacia otro nodo virtual de la red 24 no dispone de dicho ancho de banda en ninguno de sus enlaces físicos, el enlace virtual se divide en varios caminos físicos, de forma que la suma de los anchos de banda de todos los caminos físicos tiene como resultado el ancho de banda solicitado por el operador de red para su enlace virtual. En el ejemplo de la figura se muestra un caso en que el nodo central virtual 23 necesita comunicar con el nodo destino virtual 24 con un ancho de banda de 40 unidades. En el caso de que los nodos no dispongan de varios enlaces físicos no existe mayor problema en la ejecución del algoritmo de asignación, simplemente se trata de un mapeo más restrictivo y la cantidad de VNets alojadas en el sistema es, probablemente, menor. Es decisión del operador decidir si sus enlaces virtuales permiten o no División de Caminos puesto que esta tecnología podría no ser interesante dependiendo de los servicios ofertados. En cualquier caso mediante la asignación de nodos virtuales en los nodos físicos con mayor cantidad de recursos se consigue balancear la utilización de la red y facilitar el alojamiento de VNets que no permitan Path Splitting. That physical node to which a new mapping request arrives first checks if it is capable of supporting the CPU requested by the virtual node and the bandwidths of the virtual links. If so, and as long as there are more virtual nodes to be mapped, the node forwards the request to the physical nodes with the greatest amount of resources, and, that meet the location requirements, at the request house, in charge of hosting the virtual neighbors of said node. If any of the physical nodes involved in the process cannot support the request due to the scarcity of resources, said node sends an error message backwards so that the rest of the nodes can release the request. Once the hosting process is completed, the physical nodes host the VNet until the time requested by the network operator, provided that it should not be released due to mobility problems that cannot be repaired through the reallocation algorithms of resources. Preferably, if the request is allowed, the method implements the known Path Division technique (in English, Path Splitting) shown in Figure 2. For this, it is considered that the different nodes that make up the physical infrastructure 21 have several physical links 22. Thus, if at any given time a virtual node 23 that must assign a virtual link of a certain bandwidth to another virtual node of the network 24 does not have said bandwidth on any of its physical links, The virtual link is divided into several physical paths, so that the sum of the bandwidths of all physical paths results in the bandwidth requested by the network operator for its virtual link. The example in the figure shows a case where the virtual central node 23 needs to communicate with the virtual destination node 24 with a bandwidth of 40 units. In the event that the nodes do not have several physical links there is no major problem in the execution of the allocation algorithm, it is simply a more restrictive mapping and the amount of VNets hosted in the system is probably smaller. It is the operator's decision to decide whether or not their virtual links allow the Road Division since this technology may not be interesting depending on the services offered. In any case, by assigning virtual nodes in the physical nodes with the greatest amount of resources, it is possible to balance the use of the network and facilitate the hosting of VNets that do not allow Path Splitting.
Si bien se permite cualquier tipo de topología a ser solicitada, la numeración de nodos virtuales se realiza, como se muestra en la figura 3, asignando como nodo central ην 0 Ζλ el nodo que demanda la mayor cantidad de recursos y siguiendo un orden ascendente completando anillos de vecinos rf^ 32, nv 2 33 y nv 3 34. En el caso de que una petición no pueda ser alojada ésta se almacena en la memoria del nodo central nv 0 31 que inicio el mapeo de la petición para un futuro intento donde las características de la red sean diferentes, o es descartada, después de un número determinado de intentos, y por tanto eliminada del sistema. Although any type of topology is allowed to be requested, the numbering of virtual nodes is performed, as shown in Figure 3, assigning as node central η ν 0 Ζλ the node that demands the greatest amount of resources and in ascending order completing neighbors rings rf ^ 32, n v 2 33 and n v 3 34. In the event that a request cannot be accommodated, it is stored in the memory of the central node n v 0 31 that started mapping the request for a request. future attempt where the characteristics of the network are different, or is discarded, after a certain number of attempts, and therefore removed from the system.
Puesto que se trata de una red MANet, se hace uso de un protocolo de rutado proactivo que permite conocer el estado de toda la red de manera actualizada. Además de la ruta, el protocolo proporciona la información de CPU, ancho de banda y localización de cada nodo físico. Since it is a MANet network, a proactive routing protocol is used that allows to know the status of the entire network in an updated way. In addition to the route, the protocol provides the CPU, bandwidth and location information of each physical node.
Tal como se ha comentado anteriormente, la principal innovación propuesta por el método es la utilización de una red MANet como infraestructura de mapeo de las VNets. Esto implica que movimientos de los nodos físicos pueden causar rupturas de enlaces o cambios de células de localización que afectan a las VNets alojadas, siendo por tanto necesario un método de adaptación a la nueva situación de la infraestructura. Dos son las situaciones de reasignación consideradas: As previously mentioned, the main innovation proposed by the method is the use of a MANet network as a VNets mapping infrastructure. This implies that movements of the physical nodes can cause ruptures of links or changes of location cells that affect the hosted VNets, therefore a method of adaptation to the new infrastructure situation is necessary. There are two reallocation situations considered:
• Node Remapping como se muestra en la figura 4, en el instante en que, debido al movimiento, un nodo físico 41 cambia de celda de localización 42 comprueba si dispone de alguna VNet asignada con requerimientos de localización. Si es así, además de enviar los mensajes de notificación de esta situación 43 a los nodos vecinos virtuales 44, para la liberación de las rutas afectadas, selecciona un nodo válido 45 y le envía un mensaje 46 indicando la información necesaria para reasignar los enlaces afectados. Los nodos vecinos 44 informados de la situación entran en estado de reparación, considerando la VNet como no recuperable si tras un tiempo no han recibido un mensaje 47 indicando la información necesaria para reasignar sus enlaces afectados. • Remapping Node as shown in Figure 4, at the moment when, due to movement, a physical node 41 changes location cell 42 checks if it has any VNet assigned with location requirements. If so, in addition to sending the notification messages of this situation 43 to the virtual neighboring nodes 44, for the release of the affected routes, it selects a valid node 45 and sends a message 46 indicating the necessary information for reallocate affected links. The neighboring nodes 44 informed of the situation enter into a state of repair, considering the VNet as not recoverable if after a while they have not received a message 47 indicating the information necessary to reallocate their affected links.
• Link Remapping como se puede observar en la figura 5, en el instante en que, debido al movimiento, los nodos físicos 51 y 52 detectan la ruptura de un enlace 53, estos nodos 51 y 52 comprueban si dicho enlace se encuentra asignado a alguna VNet. En caso de que así sea, envían mensajes 54 notificando esta situación a los extremos involucrados en la asignación 55 y 56. Puesto que ambos extremos de la ruta física 51 y 52 se percatan del error, y con el objetivo de evitar problemas debido a la duplicidad de mensajes para asignar nuevos enlaces y/o nodos, solo aquel nodo virtual con identificador numérico más bajo 55 trata de reparar el enlace mediante el envío de un nuevo mensaje de asignación 57. El otro extremo 56 por su parte entra en un estado de reparación de forma que si transcurrido un tiempo no se ha recibido un mensaje de reasignación 57 para el enlace virtual dañado, se considera la VNet como no recuperable y se procede a su liberación mediante mensajes de error. • Link Remapping as can be seen in Figure 5, at the moment when, due to the movement, the physical nodes 51 and 52 detect the breaking of a link 53, these nodes 51 and 52 check if said link is assigned to any VNet If so, they send messages 54 notifying this situation to the extremes involved in assignment 55 and 56. Since both ends of physical route 51 and 52 are aware of the error, and in order to avoid problems due to the duplication of messages to assign new links and / or nodes, only that virtual node with the lowest numerical identifier 55 tries to repair the link by sending a new assignment message 57. The other end 56 in turn enters a state of repair so that after a while no reallocation message 57 has been received for the damaged virtual link, the VNet is considered non-recoverable and is released by error messages.
A continuación se resume el objetivo de los mensajes empleados en el algoritmo para alojar y gestionar las VNets de manera distribuida entre todos los nodos que componen la MANet: The objective of the messages used in the algorithm to host and manage VNets in a distributed way among all the nodes that make up the MANet is summarized below:
• Mapping message: similar al clásico mensaje Helio de rutado, este mensaje notifica al resto de nodos físicos la asignación de un nuevo nodo virtual y el valor de los recursos actualizado.  • Mapping message: similar to the classic Helio routing message, this message notifies the rest of the physical nodes of the assignment of a new virtual node and the value of the updated resources.
• Request message: se trata del mensaje utilizado para completar el alojamiento de la VNet. Contiene los recursos solicitados por el operador de red además del nodo virtual que ha de ser asignado al nodo destino del mensaje.  • Request message: this is the message used to complete the VNet hosting. It contains the resources requested by the network operator in addition to the virtual node to be assigned to the destination node of the message.
· Embedding Error message: notifica un error durante el proceso de alojamiento debido a la escasez de recursos en nodos extremos o intermedios de la ruta física. El mensaje se envía hacia atrás de forma que se complete la liberación en todos los nodos involucrados. • Mobility Error message 54: el nodo 51 , 52 que se percata de la ruptura de un enlace físico 53, envía este mensaje 54 al nodo extremo 55, 56 del enlace virtual afectado de manera que este pueda realizar las operaciones de reasignación oportunas. Puesto que el enlace puede encontrarse dividido en varias rutas físicas, cada nodo retransmite el mensaje de error por todas sus interfaces excepto por aquella donde lo recibió. · Embedding Error message: reports an error during the hosting process due to the scarcity of resources at extreme or intermediate nodes of the physical path. The message is sent backwards so that the release is completed on all the nodes involved. • Mobility Error message 54: the node 51, 52 that is aware of the breaking of a physical link 53, sends this message 54 to the end node 55, 56 of the affected virtual link so that it can perform the appropriate reallocation operations. Since the link can be divided into several physical routes, each node relays the error message through all its interfaces except for the one where it received it.
• Reallocate message 46: en el momento en que un nodo físico al cual ha sido asignado un nodo virtual 41 con restricción de localización cambia de célula de localización 42, este envía un mensaje de realojamiento 46 al nodo físico seleccionado en la célula correcta 45 con la información necesaria para solicitar un nuevo enlace virtual a los nodos virtuales vecinos.  • Reallocate message 46: at the moment when a physical node to which a virtual node 41 with location restriction has been assigned changes location cell 42, it sends a reset message 46 to the selected physical node in the correct cell 45 with the information necessary to request a new virtual link to the neighboring virtual nodes.
Tal como se explicó anteriormente, los recursos de los nodos de la infraestructura física variarán debido a la movilidad y la presencia de VNets en el sistema. Con el propósito de optimizar los recursos de la red y reducir el coste que supone el alojamiento de los recursos virtuales al gestor de la infraestructura el método propuesto implementa la técnica conocida como migración, mostrada en la figura 6. Cada cierto tiempo periódico, y para aquellas VNets cuyo tiempo de duración sea mayor que un umbral definido, los nodos virtuales tratarán de migrar el enlace virtual operativo a otra ruta física de menor coste asociado, C(lv). As explained above, the resources of the physical infrastructure nodes will vary due to the mobility and presence of VNets in the system. In order to optimize network resources and reduce the cost of hosting virtual resources to the infrastructure manager, the proposed method implements the technique known as migration, shown in Figure 6. From time to time, periodically, and for those VNets whose duration is longer than a defined threshold, the virtual nodes will try to migrate the operational virtual link to another physical path of lower associated cost, C (lv).
C(lv ) =∑bw(ls ) - hops (p) C (l v ) = ∑bw (l s ) - hops (p)
Como podemos observar en la ecuación, definimos el coste de mapear un enlace virtual en el sustrato físico como el sumatorio del ancho de banda bw(ls) multiplicado por el número de saltos hops(p) de todos los enlaces físicos Is, que conforman el enlace virtual . As we can see in the equation, we define the cost of mapping a virtual link in the physical substrate as the sum of the bandwidth bw (l s ) multiplied by the number of hops hops (p) of all physical links I s , which make up the virtual link.
Para llevar a cabo dicha migración el protocolo de comunicación entre los nodos físicos incluye también los siguientes mensajes: To carry out said migration, the communication protocol between the physical nodes also includes the following messages:
· Migration message: permite el intento de migración de un enlace virtual.· Migration message: allows the attempt to migrate a virtual link.
• Migration Reléase message: el nodo virtual que recibe un mensaje de migración responde mediante este mensaje para liberar la asignación previa de recursos de aquellos nodos envueltos en la ruta física no seleccionada en la migración debido a su mayor coste. • Migration Relay message: the virtual node that receives a migration message responds through this message to release the previous assignment of resources of those nodes wrapped in the physical path not selected in the migration due to their higher cost.
En la figura 6 se puede observar la técnica de migración de una VNet a otra ruta física de menor coste. Así en el instante Tn, la VNet es asignada del modo indicado en la parte superior 61 , haciendo uso de Path Spiitting, y, en el instante Tn+k, tras la liberación de ancho de banda en algunos de los enlaces físicos de la red de comunicaciones, debido al desalojo de otras redes virtuales, la VNet migra a una ruta de menor coste y es asignada como se indica en la parte inferior 62 de la figura. Figure 6 shows the technique of migrating a VNet to another physical route of lower cost. Thus at the instant Tn, the VNet is assigned in the manner indicated in the upper part 61, using Path Spiitting, and, at the instant Tn + k, after the release of bandwidth in some of the physical links of the network of communications, due to the eviction of other virtual networks, the VNet migrates to a lower cost route and is assigned as indicated in the lower part 62 of the figure.

Claims

REIVINDICACIONES
1 . Un método para la asignación e intento de reparación, en caso de fallos por movilidad, de una red virtual en una red de comunicaciones, donde dicha red de comunicaciones comprende una pluralidad de nodos físicos móviles (1 1 ) situados en una zona dividida en una pluralidad de celdas de localización (12), donde cada uno de dichos nodos físicos móviles (1 1 ) tiene una capacidad de procesamiento, una localización, una velocidad de movimiento y un factor de movilidad asociado y donde dichos nodos físicos móviles (1 1 ) se comunican mediante unas rutas físicas donde cada una de dichas rutas físicas comprende, al menos, un enlace físico (13) con un ancho de banda, entre dos nodos físicos móviles (1 1 ), disponible en un determinado momento, donde dicho método comprende los siguientes pasos: one . A method for assigning and attempting to repair, in case of mobility failures, a virtual network in a communications network, where said communication network comprises a plurality of mobile physical nodes (1 1) located in an area divided into a plurality of location cells (12), where each of said mobile physical nodes (1 1) has a processing capacity, a location, a movement speed and an associated mobility factor and where said mobile physical nodes (1 1) they communicate by means of physical routes where each of said physical routes comprises, at least, a physical link (13) with a bandwidth, between two mobile physical nodes (1 1), available at a certain time, where said method comprises the following steps:
• recibir en un nodo físico móvil (1 1 ), perteneciente a dicha red de comunicaciones, una solicitud de asignación, por un tiempo determinado, de una red virtual que comprende una pluralidad de nodos virtuales (14) donde dichos nodos virtuales (14) tienen una capacidad de procesamiento y una localización y se comunican mediante una pluralidad de enlaces virtuales (15) con un ancho de banda determinado;  • receive in a mobile physical node (1 1), belonging to said communications network, a request for assignment, for a certain time, of a virtual network comprising a plurality of virtual nodes (14) where said virtual nodes (14) they have a processing capacity and a location and communicate by means of a plurality of virtual links (15) with a determined bandwidth;
• retransmitir desde dicho nodo físico móvil (1 1 ) dicha solicitud de asignación hasta el nodo físico móvil (1 1 ) perteneciente a dicha red de comunicaciones con la mayor cantidad de recursos, donde dichos recursos dependen en cada uno de los nodos físicos móviles (1 1 ) del ancho de banda disponible de sus enlaces (13), de su movilidad y de su velocidad de movimiento;  • retransmitting from said mobile physical node (1 1) said allocation request to the mobile physical node (1 1) belonging to said communication network with the greatest amount of resources, where said resources depend on each of the mobile physical nodes ( 1 1) the available bandwidth of its links (13), its mobility and its movement speed;
• almacenar dicha solicitud de asignación en dicho nodo físico móvil (1 1 ) con la mayor cantidad de recursos;  • storing said allocation request in said mobile physical node (1 1) with the greatest amount of resources;
• asignar el nodo principal de la red virtual a dicho nodo físico móvil (1 1 ) con la mayor cantidad de recursos;  • assign the main node of the virtual network to said mobile physical node (1 1) with the greatest amount of resources;
• iniciar, a partir de dicho nodo central de la red virtual, un proceso de asignación del resto de nodos y enlaces virtuales (15) de la red virtual a otros nodos físicos móviles (1 1 ) y rutas físicas pertenecientes a la red de comunicación dando prioridad a los nodos físicos móviles (1 1 ) con mayor cantidad de recursos;  • starting, from said central node of the virtual network, a process of assigning the rest of nodes and virtual links (15) of the virtual network to other mobile physical nodes (1 1) and physical routes belonging to the communication network giving priority to mobile physical nodes (1 1) with more resources;
• una vez que la totalidad de nodos virtuales (14) y enlaces virtuales (15) pertenecientes a dicha red virtual han sido asignados, mantener dicha red virtual alojada durante dicho tiempo determinado indicado en la solicitud de asignación. • Once all the virtual nodes (14) and virtual links (15) belonging to said virtual network have been assigned, keep said virtual network hosted during said determined time indicated in the assignment request.
2. El método según la reivindicación 1 en el que los recursos de cada nodo físico móvil (1 1 ) se calculan como el cociente entre el sumatorio del ancho de banda de sus enlaces y la suma de la unidad más el producto de su factor de movilidad por su velocidad de movimiento. 2. The method according to claim 1 wherein the resources of each mobile physical node (1 1) are calculated as the ratio between the sum of the bandwidth of its links and the sum of the unit plus the product of its factor of mobility due to its speed of movement.
3. El método según cualquiera de las reivindicaciones anteriores en el que dicho factor de movilidad toma los siguientes valores: 3. The method according to any of the preceding claims wherein said mobility factor takes the following values:
• 0, para un nodo físico móvil (1 1 ) estático durante un determinado periodo de tiempo;  • 0, for a static mobile physical node (1 1) for a certain period of time;
· 1 , para un nodo físico móvil (1 1 ) que comienza a moverse o a detenerse tras un determinado periodo de tiempo; · 1, for a mobile physical node (1 1) that begins to move or stop after a certain period of time;
• 2, para un nodo físico móvil (1 1 ) que se mueve durante un determinado periodo de tiempo.  • 2, for a mobile physical node (1 1) that moves during a certain period of time.
4. El método según cualquiera de las reivindicaciones anteriores en el que si por falta de capacidad de procesamiento en dichos nodos físicos móviles (1 1 ) o de ancho de banda en los enlaces físicos (13) de dicha red de comunicaciones, la red virtual no puede ser asignada, se liberan los recursos asignados a la misma y se mantiene dicha solicitud de asignación en la memoria del nodo físico móvil (1 1 ) con mayor cantidad de recursos para un futuro reintento. 4. The method according to any of the preceding claims in which, due to lack of processing capacity in said mobile physical nodes (1 1) or bandwidth in the physical links (13) of said communication network, the virtual network cannot be allocated, the resources assigned to it are released and said allocation request is maintained in the memory of the mobile physical node (1 1) with greater amount of resources for a future retry.
5. El método según cualquiera de las reivindicaciones anteriores en el que si el movimiento de un nodo físico móvil que tiene asignado un nodo virtual (41 ) con requerimientos de localización, causa el cambio de celda de localización (42), se reasigna dicho nodo virtual (41 ) y sus enlaces virtuales correspondientes, a otro nodo físico móvil válido (45). 5. The method according to any of the preceding claims in which if the movement of a mobile physical node that has been assigned a virtual node (41) with location requirements, causes the change of location cell (42), said node is reallocated virtual (41) and its corresponding virtual links, to another valid mobile physical node (45).
6. El método según cualquiera de las reivindicaciones anteriores en el que si el movimiento de un nodo físico móvil (51 ) causa la ruptura de un enlace físico (53), donde dicho enlace físico (53) tiene asignado un enlace virtual, se reasigna dicho enlace virtual a otra ruta física válida de dicha red de comunicaciones. 6. The method according to any of the preceding claims in which if the movement of a mobile physical node (51) causes a physical link to break (53), where said physical link (53) is assigned a virtual link, it is reallocated said virtual link to another valid physical route of said communications network.
7. El método según cualquiera de las reivindicaciones anteriores en el que periódicamente y para una red virtual que permanece asignada durante un tiempo superior a un tiempo determinado, dichos nodos virtuales (63) reasignan su enlace virtual operativo a una nueva ruta física con un coste menor, donde se calcula el coste de la ruta actual y una ruta candidata como el sumatorio del ancho de banda de cada enlace físico multiplicado por el número de saltos de la ruta y en caso de que la ruta candidata sea de coste inferior, entonces se migra el enlace virtual y se liberan los recursos de la primera ruta física. 7. The method according to any of the preceding claims wherein periodically and for a virtual network that remains assigned for a period of time. over a certain time, said virtual nodes (63) reallocate their virtual operational link to a new physical route with a lower cost, where the cost of the current route and a candidate route are calculated as the sum of the bandwidth of each link physical multiplied by the number of jumps of the route and in case the candidate route is of lower cost, then the virtual link is migrated and the resources of the first physical route are released.
8. El método según cualquiera de las reivindicaciones anteriores en el que se escoge como dicho nodo central (31 ) de la red virtual el nodo de dicha red virtual con mayores requerimientos de capacidad de CPU y ancho de banda de sus enlaces. 8. The method according to any of the preceding claims in which said node of said virtual network is chosen as said central node (31) of the virtual network with higher CPU capacity requirements and bandwidth of its links.
9. El método según cualquiera de las reivindicaciones anteriores en el que la numeración de los nodos virtuales a asignar (31 , 32, 33 y 34) se realiza consecutivamente en orden decreciente de requerimientos de capacidad de CPU y ancho de banda de sus enlaces. 9. The method according to any of the preceding claims in which the numbering of the virtual nodes to be assigned (31, 32, 33 and 34) is performed consecutively in decreasing order of CPU capacity requirements and bandwidth of their links.
10. El método según cualquiera de las reivindicaciones anteriores en el que el proceso de asignación de nodos y enlaces virtuales utiliza la técnica de División de Caminos. 10. The method according to any of the preceding claims in which the process of assigning nodes and virtual links uses the Road Division technique.
1 1 . El método según cualquiera de las reivindicaciones anteriores en el que dichos nodos físicos móviles (1 1 ) utilizan un protocolo de comunicación que comprende, al menos, alguno de los siguientes mensajes: eleven . The method according to any of the preceding claims wherein said mobile physical nodes (1 1) use a communication protocol comprising at least one of the following messages:
· Un mensaje de asignación, que se utiliza para notificar desde un nodo físico móvil (1 1 ) al resto de nodos físicos móviles la asignación de un nuevo nodo virtual (14) y el valor de los recursos de dicho nodo físico móvil (1 1 ) y de sus enlaces físicos (13) tras dicha asignación; · An assignment message, which is used to notify from a mobile physical node (1 1) to the rest of the mobile physical nodes the assignment of a new virtual node (14) and the value of the resources of said mobile physical node (1 1 ) and its physical links (13) after said assignment;
• Un mensaje de solicitud, que contiene los recursos requeridos en la solicitud de alojamiento y el nodo virtual (14) que se debe asignar al nodo físico móvil (1 1 ) destino de dicho mensaje de solicitud;  • A request message, which contains the resources required in the hosting request and the virtual node (14) that must be assigned to the mobile physical node (1 1) destination of said request message;
• Un mensaje de error de alojamiento, que se utiliza para notificar un error durante el proceso de alojamiento de una red virtual debido a la escasez de recursos en un nodo físico móvil (1 1 ) o en sus enlaces físicos (13), donde dicho mensaje de error de alojamiento se envía a todos los nodos físicos móviles (1 1 ) que tuvieran ya asignado un nodo virtual (14) o formaran parte de un enlace virtual de dicha red virtual; • A hosting error message, which is used to report an error during the hosting process of a virtual network due to the scarcity of resources in a mobile physical node (1 1) or in its physical links (13), where said Hosting error message is sent to all mobile physical nodes (1 1) that have already been assigned a virtual node (14) or are part of a virtual link of said virtual network;
• Un mensaje de error por movilidad (54), que se envía desde un nodo físico móvil (51 y 52), cuando se rompe uno de sus enlaces físicos (53), donde dicho enlace físico (53) tiene un enlace virtual asignado, hasta el nodo físico extremo del enlace virtual afectado (55 y 56);  • A mobility error message (54), which is sent from a mobile physical node (51 and 52), when one of its physical links (53) is broken, where said physical link (53) has an assigned virtual link, to the extreme physical node of the affected virtual link (55 and 56);
• Un mensaje de reasignación (46), que se envía desde un nodo físico móvil (41 ) que cambia de celda de localización (42), donde dicho nodo físico móvil (41 ) tiene asignado un nodo virtual con requerimientos de localización, hasta un nodo físico (45) ubicado en la celda abandonada, donde dicho mensaje de reasignación (46) contiene información para solicitar un nuevo enlace virtual a los nodos virtuales vecinos (44);  • A reassignment message (46), which is sent from a mobile physical node (41) that changes location cell (42), where said mobile physical node (41) is assigned a virtual node with location requirements, up to a physical node (45) located in the abandoned cell, where said reallocation message (46) contains information to request a new virtual link to the neighboring virtual nodes (44);
• Mensaje de migración, que se envía a una pluralidad de nodos físicos móviles comprendidos en una nueva ruta física cuando dicha nueva ruta es reasignada.  • Migration message, which is sent to a plurality of mobile physical nodes comprised in a new physical route when said new route is reassigned.
• Mensaje de liberación en migración, que se envía desde un nodo físico que tiene asignado un nodo virtual, como respuesta a un mensaje de migración previo, para liberar la ruta física de mayor coste.  • Migration release message, which is sent from a physical node that has a virtual node assigned, in response to a previous migration message, to release the higher cost physical route.
12. Un sistema que comprende medios adaptados para llevar a cabo el método de cualquiera de las reivindicaciones anteriores. 12. A system comprising means adapted to carry out the method of any of the preceding claims.
13. Un programa informático que comprende medios de código de programa informático adaptados para realizar las etapas del método según cualquiera de las reivindicaciones de la 1 a la 1 1 , cuando dicho programa se ejecuta en un ordenador, un procesador de señal digital, una disposición de puertas de campo programable, un circuito integrado de aplicación específica, un microprocesador, un microcontrolador, y cualquier otra forma de hardware programable. 13. A computer program comprising computer program code means adapted to perform the steps of the method according to any one of claims 1 to 1 1, when said program is run on a computer, a digital signal processor, an arrangement of programmable field doors, a specific application integrated circuit, a microprocessor, a microcontroller, and any other form of programmable hardware.
PCT/ES2010/070305 2010-05-06 2010-05-06 Method and system of associating virtual networks on a substrate consisting of mobile nodes WO2011138470A1 (en)

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