Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L45/00—Routing or path finding of packets in data switching networks
  • H04L45/12—Shortest path evaluation
  • H04L45/124—Shortest path evaluation using a combination of metrics
• • 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
  • H04L45/18—Loop-free operations

Definitions

• the invention lies in the field of computer and telecommunications networks and relates to optimizing the routing of data flows in an IP network.
• the European Commission has issued a Code of Conduct (CoC) on the energy consumption of broadband equipment that indicates the maximum power consumption allowed for each link technology.
• CoC Code of Conduct
• each technology has its own energy consumption regardless of the associated bandwidth. For example, a point-to-point fiber with a bandwidth of 10 Gbps consumes about 8 Watts, while an EPON fiber with the same bandwidth consumes about 13.4 Watts.
• Figures 1a and 1b illustrate for the same network configuration (100), the power that is consumed on a routing path according to which criteria are taken into account to determine the routing path.
• the network (100) type 5G is composed of two parts: a so-called access network and aggregation portion (102), and a so-called core network portion (104).
• the two parts of the network are coupled via a router (103) also called edge node.
• the network comprises in each part, nodes or routers (106-1, 106-i, .... 106-n) which are connected to one another via links (108-1, 108-j, ... 108- m) may be of different technologies.
• each router involved in a routing path develops a power consumption on its network interface that is a function of the technology of the link.
• the values indicated in FIGS. 1a and 1b are given by way of example, and corresponding to actual values given in the aforementioned code of conduct, for fiber types of 1 Gbit / s and 10 Gbit / s, depending on the number of ports.
• a client terminal (1 10) is connected to a WiFi terminal (1 12).
• a user requests a streamed video from a server (1 14) of the content provider.
• the packet routing (path 1 1 6) is done based on the metric bandwidth. Thus, the links with the largest passerby are favored.
• This routing policy entails a total energy consumption of the path of 132W, corresponding to the sum of the energy consumption of each link involved in the path between the source and the destination.
• the packet routing (path 1 18) is made according to the bandwidth and the energy consumption of the links.
• links that provide adequate bandwidth and consume less in terms of energy are favored.
• This routing policy entails a total energy consumption of the path of 74W.
• This example illustrates the problem related to the need to have a routing protocol that reduces energy consumption.
• the first approach is to propose a new routing metric that considers energy related parameters, such as the remaining level of a device's battery.
• a routing algorithm calculates the paths using this metric.
• the second approach is to introduce changes to the routing protocol itself in order to achieve energy savings. In this second approach, the routing metric does not undergo any modification.
• the existing solutions target networks of nodes with limited energy power such as ad-hoc networks or sensors.
• the node energy is a critical resource that must be used effectively to increase network life. Therefore, a routing metric based on node battery level or link quality is most appropriate for preserving node energy.
• U.S. Patent Application 2013/0315257 A1 to Welin et al. presents a method that uses the power consumption metric when switching traffic in routers or switches.
• This metric can be based on the power consumption in the link interfaces, in the links and in the node.
• Each node receives energy consumption from the rest of the nodes that are in the same routing domain. It also sends its energy consumption to other nodes.
• This type of solution does not ensure a Quality of Service (QoS) required by the applications. Considering only energy as the only end-to-end selection criterion, this solution can choose to route latency-sensitive traffic (for example, emergency call, IPTV, etc.) by a path not respecting their need (for example, long path causing high latency).
• QoS Quality of Service
• U.S. Patent 6,301,244 B1 to Huang et al. describes a method for finding a path between a source node and each node in a communication network, so that the path delay does not exceed a path delay constraint or first metric and the cost of the path or second metric is minimized, each metric being additive.
• a first path that is the shortest path from a source node to each network node in terms of a first metric is selected using the Dijkstra algorithm. Nodes associated with paths whose metric exceeds the imposed constraint are eliminated.
• An accessibility graph is then constructed based on the remaining nodes. The Dijkstra algorithm is then applied to the accessibility graph to determine the shortest path between a source node and each node in terms of a second metric.
• the basic idea is to route the data packets over a given subset of network links during periods of low traffic, using a coordination strategy between the routers. In this way, interfaces that do not participate in traffic switching can be turned off, in standby mode, without causing problems with network availability.
• Zhang's US Patent Application 2015/0222537 A1 provides a method for aggregating traffic to disable or suspend network interfaces and thereby use as few links as possible in the network, thereby reducing the overall consumption of the network. network.
• This method uses a linear programming algorithm whose objective is to maximize the number of links to put on standby and taking as constraint the traffic state in the nodes of the network.
• the method needs the following parameters: the source node, the destination node, data on the topology of the network as well as data on the state of the traffic in each node.
• the method considers that the energy consumption of interfaces is the same regardless of the technology used.
• the method is not compatible with Open Shortest Path First (OSPF) distributed routing protocols. Indeed, once the interface is disabled, the OSPF protocol considers that the link is down and will flood the network with messages "Link-state advertisements" (LSA) to inform other routers.
• OSPF Open Shortest Path First
• the present invention meets this need.
• An object of the present invention is to propose a routing path determination method which reduces the total energy consumption in the networks, taking into account both the available bandwidth of the path and the energy consumption of the networks. nodes, and without degrading the quality of service offered to users.
• the present invention has the advantage of being able to be implemented on concave metrics, for example for the bandwidth where the metric of the end-to-end path is the minimum of the metric of the links, or to be implemented on metrics additives, for example for energy consumption where the end-to-end path metric is the sum of the link metrics.
• Another object of the present invention is to propose a method of determining an energy-efficient routing path while preserving the quality of service constraints required by the data streams, whatever the heterogeneity of the technologies of the networks used.
• the method of the invention relies on the implementation of an algorithm that comprises two levels of filtering: a first filtering to target all the best possible paths according to a first priority metric followed by a second filtering to select the best path according to a second metric.
• the invention will find advantageous applications in all areas where telecommunication network providers and operators are eager to reduce the energy consumption of the networks while ensuring the quality of service required by the data flows to transit.
• the invention can be implemented:
• the method of the invention is easy to implement, and adaptable according to the needs of the operator, depending on the priority performance sought, whether it is to ensure the quality of service for the flows, or to reduce energy consumption. .
• the method makes it possible to determine the paths having the best available bandwidth, and then to select among these, the one presenting the consumption. lowest energy level. If the priority is to reduce the energy consumption, in the case for example of flows that do not have a specific need in terms of quality of services as certain types of communications related to connected objects, the method makes it possible to determine the paths that have the lowest energy consumption, then select from those the one with the best available bandwidth.
• the method implements a Yen algorithm, which makes it possible to find the best k paths without a loop.
• a method of determining a data packet routing path between a source node and a destination node of a network comprising a plurality of nodes and links between the nodes, the links having at least first and second performance metrics, the method comprising the steps of:
• the ranking step consists in ordering the candidates according to an increasing or decreasing value of the second performance metric, and the selection step consists in selecting the candidate presenting the highest or lowest value;
• the calculation step consists in operating an algorithm for calculating 'k' shortest paths without a loop on a graph representative of the nodes of the network, 'k' being a predefined non-zero integer;
• the algorithm is the Yen algorithm
• the performance metrics are the available bandwidth and the energy consumption of each link
• the first metric is the available bandwidth and the second metric is the energy consumption
• the calculation step consists in determining a set of loopless paths having the highest available bandwidth and the selection step consists in selecting the path having the lowest energy consumption between the source node and the destination node;
• the first metric is the energy consumption and the second metric is the available bandwidth
• the calculation step consists in determining a set of loopless paths having the lowest power consumption and the selection step consists in selecting the path presenting the highest available bandwidth between the source node and the destination node;
• the method further comprises, after the calculation step, a step for filtering among the candidates a subset of candidates according to quality of service parameters for the data stream;
• the quality of service parameters are chosen from among the bit rate, the latency, the maximum loss rate of data packets, the jitter.
• the invention covers a data packet routing path determining device between a source node and a destination node of a network comprising a plurality of nodes and links between the nodes, the links having at least first and second links. metrics of performance, the device comprising means for implementing the steps of the claimed method.
• the links between the nodes of the network are wired and / or not wired; the data packets are packets of a multimedia data stream.
• the invention also covers a communication system able to route in a network data packets between a source node and a destination node among a plurality of nodes connected by links, the links having at least first and second performance metrics, the system comprising at least one device as claimed.
• the claimed device is implemented in at least one node of the network.
• the network is of the "Software-
• SDN Networking
• the claimed device is implemented in the SDN controller of that network.
• the invention also covers a method operated by an SDN controller in a Software-Challenge Networking (SDN) network, for constructing a data flow route, the network comprising a plurality of nodes and links between the nodes. the links having at least first and second performance metrics, the SDN controller being adapted to detect a stream routing request and identify the address of a source node and the address of a destination node for the stream, the method comprising the steps of the routing path determination method as claimed.
• SDN Software-Challenge Networking
• the execution of the steps of the data packet routing path determination method is done according to whether the quality of service for a data stream has priority or not
• the invention may operate in the form of a computer program product that includes code instructions for performing the claimed process steps when the program is run on a computer.
• Figures 1a and 1b illustrate the power that is consumed on a routing path according to which criteria are taken into account to determine the routing path;
• FIG. 2 illustrates a sequence of steps according to the method of the invention, to determine a routing path
• FIG. 3 details the steps of the method of the invention in one embodiment
• FIG. 4 details the steps of the method of the invention in another embodiment
• Figure 5 illustrates a sequence of steps according to a variant of the method of the invention in another embodiment
• Figure 6 illustrates a sequence of steps of the method of the invention in one embodiment for an SDN network
• FIG. 7 schematically shows an SDN environment in which the invention can be implemented.
• a major advantage of the process of the invention is to reduce energy consumption in networks when calculating a routing path, taking into account both the available bandwidth of links between nodes and their energy consumption.
• FIGS. 1a and 1b illustrate a sequence of steps (200) of the GoGreen process of the invention.
• the method makes it possible to determine a routing path in communication networks, such as, for example, the 5G cellular network as illustrated in FIGS. 1a and 1b.
• the Gogreen method can also be operated in networks implementing a distributed routing protocol, such as the OSPF protocol.
• the method is executed in each router of the network, and the router block "Router Link State Advertisment" (Router LSA) in the message “Link State Update” (LSU) which is used for each router announces its interfaces , its neighbors and metric values to reach these neighbors, is modified to include a field announcing the two metrics of bandwidth and energy consumption.
• Router LSA Route Link State Advertisment
• LSU Link State Update
• a source-destination pair corresponding to a transmitter of a data stream and a receiver of the stream
• 'k' varies between 1 and 5 for a graph with nodes that vary between 10 and 100.
• a first step (202) the method makes it possible to determine a non-zero set of candidates of 'k' paths between the source and the destination presenting the first performance metric 'w1', without impose a minimum constraint or restriction on this first metric.
• the method selects (206) directly the corresponding path.
• the method makes it possible to classify (204) the candidates according to the second performance metric 'w2'.
• the ranking step consists of ordering the 'k' candidates according to an increasing or decreasing value of the second performance metric.
• the method makes it possible to select
• the selection step consists of selecting the candidate with the highest or lowest value in the ranking to enable the transmission of the data stream between the source and the destination via this path.
• the selected candidate then corresponds to the path offering optimized performance with respect to the two metrics.
• the step of determining paths I having the best values of the performance metric considered further comprises the classification step, a step of sorting the candidates to keep as candidates only the paths without loop.
• the step of determining the best paths according to a performance metric is based on the well-known Yen algorithm (JK Yen, "Finding the Shortest Loop Paths in a Network", Management Science (Vol 17 , No. 1 1, pp. 712-71 6), 1971) which makes it possible to generate the 'k' shortest paths without loops in a graph, and the classification step is done directly on the candidates without loop.
• Such an implementation corresponds to the scenarios where the performance priority is given to the bandwidth.
• the GoGreen method calculates (step 304) a non-zero set of k best paths by considering as first metric the available bandwidth (w1) of the links, without imposing a minimum constraint or a restriction on this first metric. It determines the k loopless paths that have the highest available bandwidth, the bandwidth of a path being considered to be equal to the minimum bandwidths of the links that make up that path. If only one path is candidate (OUI branch of 306), the method makes it possible to select it (31 0) to make it possible to activate the transmission of the data flow between the source and the destination via this path. If several paths are candidates (branch NO of 306), the method makes it possible to classify (308) the candidates according to the value of the consumption
• the energy consumption of a path being calculated by summing the energy consumption of the links composing the path.
• the method makes it possible to select the path which has the smallest end-to-end energy consumption to enable the transmission of the data stream between the source and the destination via this process. path.
• the GoGreen method calculates (step 404) a non-zero set of k best paths by considering as first metric the energy consumption (w1) of the links, without imposing a minimum constraint or a restriction on this first metric. It determines the k loopless paths that have the lowest end-to-end energy consumption, the energy consumption of a path being calculated by summing the energy consumption of the links making up the path.
• the method allows to select it (410) to enable the transmission of data flow between the source and the destination via this path. If several paths are candidates (NOT branch of 406), the method makes it possible to classify (408) the candidates according to the value of the available bandwidth of each candidate, the bandwidth of a path being considered as being equal to the minimum of the bands passers of the links that make up this path. In the next step (410), the method makes it possible to select the path that has the largest bandwidth available to enable the transmission of the data stream between the source and the destination via this path.
• the calculation step (304, 404) applies a Yen-type algorithm that makes it possible to determine the k shortest paths without a loop.
• Figure 5 illustrates a sequence of steps (500) of a variant of the method of the invention in an embodiment where the traffic requirements to be routed in terms of quality of service (QoS) are considered.
• QoS quality of service
• the previously described GoGreen method operates without having to know beforehand the specific traffic requirements to be routed in terms of QoS (for example, the threshold rate required by the traffic of data).
• QoS for example, the threshold rate required by the traffic of data.
• the method makes it possible to generate the k paths, where 'k' is a non-zero integer having the best available bandwidth, without imposing a minimum constraint or a restriction on this first metric. Then, it selects, among these k paths, the one with the best value of energy consumption. However, in this mode, it may happen that the path ultimately selected is a path that reduces energy consumption but which however does not ensure the quality of service required by the traffic to route.
• An advantageous variant of the method of the invention in the embodiment according to FIG. 3 consists in taking into account the traffic requirements in the selection of the routing path.
• the method has a prior knowledge of the bit rate required by the data traffic to be routed (502).
• the method determines a group 'R' of k paths that offer the best bandwidth (504). If the group R contains only one path (YES branch of 506), the method selects (51 6) this path to initiate the transmission of data between the source and the destination.
• the method makes it possible to select (508) from among the candidates, a subgroup 'R_QoS' of candidates that make it possible to ensure the traffic requirements.
• the traffic requirements may include selected quality of service parameters among rate, latency, maximum data packet loss rate, jitter.
• the method makes it possible to classify (512) the candidates of the initial group R according to the second metric of energy consumption, and to select (51 6) from the group R the path presenting the best value according to the second metric of energy consumption.
• the method makes it possible to classify (514) the candidates of the subgroup R_QoS according to the second metric of energy consumption, and to select (516) among the group R_QoS the path presenting the best value according to the second metric of energy consumption.
• FIG. 6 illustrates a sequence of stream route construction steps (600) incorporating the routing path determination method of the invention, in one embodiment where the network is an SDN network, controlled by an SDN controller.
• Fig. 7 schematically shows an SDN environment in which the method of Fig. 6 can be implemented at the SDN controller (702).
• SDN controller One of the features of the SDN controller is its ability to have a global view of the network topology. This allows it to execute the method of the invention to calculate the optimal routing path while taking into account different objectives and constraints.
• the network (SDN) includes SDN switches for the transfer of traffic from the user in the data plane.
• the implementation of the method of the invention at the level of the SDN controller does not imply any modification or adaptation in the SDN switches or in the exchange protocol (ie Openflow) between the controller and the switch.
• the network devices in the data plane for example, routers, switches, radio cells, etc.
• the OpenFlow protocol while the calculation of the routing path is performed in the SDN controller, for example in a "data center" or a server having high performance.
• the method (600) is triggered by the arrival of a new OpenFlow message "OF PACKETJN" from a given switch or router.
• This message allows the SDN controller to detect (602) the need to route a new stream within the network. From this message, the SDN controller identifies the source address, the destination address, the transport protocol used, the source and destination port number.
• the method allows the SDN controller to determine (604) whether the QoS quality of service has priority based on various parameters such as the transport protocol used, the port number that identifies the application, and the destination address. If the QoS has priority (YES branch of 604), the method executes the routing path selection steps according to the operating mode described when the priority is the bandwidth (according to FIG.
• the method executes the routing path selection steps according to the operating mode described when the priority is the energy consumption (according to FIG. 4).
• the SDN may decide to use different values of the parameter k for different flow subgroups.
• the choice of the parameter k makes it possible to limit the number of the best paths selected according to the first metric, for reasons of performance. Indeed, the fact of calculating a precise number of possible paths (in this case k) is more efficient in terms of computing time than calculating all the possible paths.
• the computation of the paths must be done in real time as soon as a new flow appears in the network, at the level of a router or input switch. This new stream is then detected by the SDN controller which must therefore quickly calculate the path for this stream and set up the corresponding routing configurations in the routers of the calculated path, in order to allow the routing of the stream.
• the SDN controller determines (610) the switches / routers that are part of this routing path. Then, it prepares (612) the "OF PACKET_OUT" messages which make it possible to configure (614) these switches / routers.
• SDN updates (61 6) the value of available bandwidth of links on which the stream was routed.
• the switch / router sends a message to the SDN controller to indicate the end of the transmission of the stream at its level. This allows the controller to update the bandwidth value available to the links.
• each switch rule in a switch / router is associated with a timer that expires when the switch / router no longer receives packet linked to the stream. In this case, the switch rule is removed and a notification message is sent to the SDN controller.
• the described stream route construction method makes it possible to coexist in the same network flows having different needs, by the execution of the method of the invention:
• the available bandwidth at initialization corresponds to the nominal bandwidth. After installing a new path for a given stream, the available bandwidth is then the nominal bandwidth minus the estimated load for that stream.
• the SDN controller initializes the available bandwidth to the nominal bandwidth value. After installing a path in the data transfer plan for a given stream, the controller updates this metric by subtracting the estimated load for this stream, and this for each link participating in the routing of this stream.
• the controller updates the bandwidth metric for each link in that path.
• the bandwidth of the first link 11 becomes 9Mbps
• that of the second link 12 becomes 8Mbps
• that of the third link 13 becomes 9Mbps.
• the X path then has an available bandwidth of 9Mbps. To determine the available bandwidth of a path, it is sufficient to determine the minimum of the values of the available bandwidth of the links that constitute this path.
• the present invention can be implemented from hardware and / or software elements and operate on a computer. It may be available as a computer program product on a computer readable medium.
• the support can be electronic, magnetic, optical, electromagnetic or be an infrared type of diffusion medium.
• Such supports are, for example, Random Access Memory RAMs (ROMs), magnetic or optical tapes, disks or disks (Compact Disk - Read Only Memory (CD-ROM), Compact Disk - Read / Write (CD-R / W) and DVD).
• ROMs Random Access Memory RAMs
• CD-ROM Compact Disk - Read Only Memory
• CD-R / W Compact Disk - Read / Write
• DVD Compact Disk - Read / Write

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• Data Exchanges In Wide-Area Networks (AREA)
• Mobile Radio Communication Systems (AREA)

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• 2017
  • 2017-02-13 FR FR1751146A patent/FR3062976B1/fr active Active
• 2018
  • 2018-01-30 EP EP18701196.0A patent/EP3580898A1/de not_active Withdrawn
  • 2018-01-30 WO PCT/EP2018/052216 patent/WO2018145945A1/fr active Application Filing

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