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
  • H04L45/121—Shortest path evaluation by minimising delays
• • 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
  • H04L45/22—Alternate routing
• • 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
  • H04L45/38—Flow based routing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/10—Flow control; Congestion control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/10—Flow control; Congestion control
  • H04L47/11—Identifying congestion
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/10—Flow control; Congestion control
  • H04L47/12—Avoiding congestion; Recovering from congestion
  • H04L47/122—Avoiding congestion; Recovering from congestion by diverting traffic away from congested entities

Definitions

• the present invention relates to the field of routing data between nodes of a communication network.
• a communication network conventionally comprises a plurality of nodes that are connected to each other to form a mesh network.
• Such nodes may be IP type computer terminals, for "Internet Protocol", core network equipment, home gateway, etc.
• a link links a source node to a destination node.
• a link is in the form of a data link that can be wired (Ethernet, optical fiber, Online Carrier Current called “CPL”, etc.) or wireless (for example based on the IEEE 802.1 radio network standard 1 and its evolutions, grouped under the name WiFi "Wireless Fidelity" (Wifi 802.1 1a, 802.1 1n, etc.)).
• each node of the communication network comprises a routing table which is updated by the routing protocol from the topology table of the network comprising all the links constituting the network.
• Link state routing protocols such as OSPF for Open Shortest Path First and OLSR for Optimized Link State Routing, known to those skilled in the art, make it possible to build the routing tables of the nodes in order to route correctly the data between the source node and the destination node.
• each link is characterized by at least two parameters: a state and a metric.
• a link has two states: an active state, called “UP” state, in which the link is usable to send data between two neighboring nodes, and an inactive state, called “DOWN” state, in which no data traffic is not possible.
• the link state allows a routing protocol to determine whether the link is usable to form a path.
• active links are referenced in the topology table of a node.
• an active link has a metric that characterizes it such as the rate, the delay or the jitter of the link.
• the link metric allows a routing protocol to compare paths between them and to select in priority the paths having a better metric end-to-end, that is to say, on all the links that constitute them.
• a node of the communication network conventionally comprises a topology table in which each active link of the network is listed with its metric, an inactive link not being listed.
• An algorithm of the Djikstra type known to those skilled in the art, makes it possible to determine the shortest path between a source node and a destination node from the topology table of the source node.
• the best paths for each destination node are grouped in the routing table of the source node, where the routing table indicates on which link the data must be routed for a given destination node.
• the routing table of the source node indicates for each destination node which link of the source node should be used for the routing of the data.
• the routing table is computed from the topology table that is updated by sending topology messages between nodes in the network.
• topology messages are broadcast by the nodes so that the information relating to the inactivity of the link is known to all the nodes.
• the topology and routing tables of the nodes are then updated. Following the broadcast of topology messages between the nodes, the nodes of the network have the same topology table.
• the home network includes a home gateway connected to the Internet and a plurality of computer terminals (laptop, desktop computer, TV decoder also referred to as "set-top box") which are connected directly to the home gateway.
• a home network is designated star network, the home gateway forming the center of the star.
• the link between the home gateway and the set-top box must not be saturated. It is considered that a link is saturated when the data rate at the output of the link is less than the rate at the entry of this link. Data is lost during transmission on the saturated link. For example, for the transmission of a video stream, a saturation of the link results in the loss of video frames which deteriorates the visualization of the video stream by the user. The greater the number of data streams transmitted on the same link, the higher the probability of saturation of the link.
• the disadvantage of current link state routing protocols is that they are not adapted to respond gradually to a saturation of a link.
• this link can be used according to the routing table of the node and data streams can be transmitted on said link. If a link is full, it is considered inactive and is removed from the node's topology table and routing table. No data flow can then be issued on this saturated link.
• a link state routing protocol using dynamic metrics could be used. According to this type of routing, the more a link is saturated, the lower its metric. In other words, the link metrics vary depending on the data traffic.
• the data streams of the first link are redirected to a second link whose metric is better than that of the first.
• the second link is of the same nature as the first link (similar technology, similar speed, etc.)
• the second link saturates in turn and its metric is penalized.
• the data streams of the second link are then redirected to the first link whose metrics have improved in the absence of data traffic. Over time, the data flow will be alternately switched between the first and second links. This results in a flow oscillation phenomenon.
• the problem of saturation is thus reported from link to link.
• a routing protocol with a dynamic metric therefore does not solve the problem of saturation of a link of a mesh network. Note that this problem is not specific to home networks, described here as a simple example, but may occur in any type of communication network.
• the invention relates to a link state routing method for routing a data stream in a mesh communication network comprising a plurality of nodes connected by links, at least one node of said network.
• load parameter is meant the ratio of a measurement of the data rate to the maximum rate that can be supported by said link.
• the load parameter may correspond to the percentage of the bandwidth of said link being occupied by a data stream.
• a data stream is transmitted according to said routing table without taking into account the state of charge of the network.
• the overload status of a link can influence the routing of data on the network.
• the detection of an overload link by a node of the network is broadcast to the other nodes of the network which allows each node to adapt to avoid saturation of the link overload. For example, a node may continue to send overflows on the overloaded link and may send the new feeds to another link.
• the node implements a step of updating its topology table from said overload status information of said link.
• the node that detects a link in overload condition can directly update its topology table which allows to modify the formation of its routing table.
• the routing of data flows by said node can then take into account the state of overload of the link and avoid saturation of the link.
• the node of said network comprises a routing table, constructed from the updated topology table, comprising at least one path leading to a destination node, and the node implements a storage step of the overload state of said path in the routing table.
• the routes of the routing table that are overloaded are advantageously indicated in the routing table.
• the stream may be diverted to another path or not emitted.
• the saturation of the overloaded link is then avoided.
• the routing table having an overloaded path leading to a destination node the node adds in its routing table another path leading to said destination node.
• the node advantageously forms a bypass path of the overloaded path. So, if a flow of data must be routed on an overloaded path, the stream can be routed on an alternate path. The capacity of the network is then used optimally.
• the node implements a storage step in its routing table of an identifier of a data stream flowing on said path.
• Storing the flow of data flowing on a path advantageously makes it possible to prevent other flows from being carried on the path in overload, the latter being reserved for the flow or flows flowing therethrough (nt).
• the method allows a data flow admission control over the overloaded path.
• the node implements:
• the topology table is updated based on the load parameter measured on said link to determine if the link is still overloaded.
• the topology table indicates that the path is no longer overloaded and the transmission of the data stream by said method is no longer selective.
• the invention also relates to a link state routing method for routing a data stream in a mesh communication network comprising a plurality of nodes connected by links, at least one node of said network comprising a topology table which comprises at least a link, in which the node implements:
• the overload status information of said link is broadcast to certain nodes of the network which allows the nodes to update their topology table and to change the routing of the data over the mesh network to account for the overload link. .
• the set of nodes of the network can take into account the overload link, this information not being reserved for the node having detected the overload.
• the invention further relates to a node of a meshed communication network comprising a plurality of nodes connected by links, the node comprising a topology table comprising at least one link, means for measuring a load parameter on said node. link, means for comparing the measured load parameter with a predetermined overload threshold, an overload state being assigned to said link in case of exceeding said overload threshold by said load parameter and means for broadcasting to at least some nodes of said network of information relating to said state of overload of said link.
• the node of the mesh communication network makes it possible to define for a link three potential states (active, inactive, overloaded), the state of overload of a link making it possible to influence the routing of the data on the network.
• the node can thus prevent the other nodes so that they adapt to avoid saturation of the link overload.
• the invention also relates to a node of a meshed communication network comprising a plurality of nodes connected by links, the node comprising a topology table comprising at least one link, means for receiving an overload status information.
• said link sent by at least one other node of the network and means for updating its topology table from said overload status information of said link.
• the overload status information of said link is received by the node allowing it to update its topology table and change the routing of data over the mesh network to account for the overload link.
• the set of nodes of the network can thus take account of the overload link, this information not being reserved for the node having detected the overload.
• the invention further relates to a computer program comprising instructions for implementing a routing method when the program is executed by a processor and a recording medium in which the program is stored.
• the invention also relates to a signal transmitted by a source node of a meshed communication network, comprising a plurality of nodes connected by links, destined for at least one destination node of said network, the destination node comprising a topology table. with at least one link, the signal carrying a topology message for updating the table destination node topology, wherein the topology message includes a field specifying the overload status of the link of the topology table.
• the overload information being directly integrated into a topology message, the updating of the topology table of a node of the network is facilitated.
• the signal conveying the overload state of a link is unitary with the routing method since both are intended to communicate an overload state of a link to form a topology table to avoid overloading. overload link.
• the invention also relates to a topology table of a node of a meshed communication network which comprises at least one link, the topology table comprising a field in which the overload state of said link is defined.
• the invention also relates to a routing table of a node of a meshed communication network which comprises at least one path, the routing table comprising a field in which is defined the overload state of said path.
• Figure 1 is a schematic representation of the data flow routing according to the invention in a first communication network
• FIG. 2 is a schematic representation of the routing of data streams according to the invention in a second communication network
• Figure 3 is a schematic representation of the data flow routing according to the invention in a third communication network which is a home network;
• FIG. 4 is a representation of a topology message with information relating to the overload status of a link.
• a meshed communication network 1 comprises six nodes N1 -N6, interconnected by wire links of the same nature of the ethernet type, each link having the same metric.
• the N1 node is connected to the Internet 5 by a link 6 of the FTTH type for "Fiber To The Home" which guarantees a high rate of the order of Gigabit / s.
• the nodes are in the form of computer terminals able to route data streams on the mesh network.
• Node N1 is for example a residential or home gateway, or more generally an input gateway in a local network, for example corporate.
• Each node N1 -N6 has its own topology table whose content is identical to that of the tables of the other nodes, in which the topology of the network is defined.
• each active link is listed with its metric in the topology table.
• the links between the nodes are all active.
• Each node N1 -N6 also has a routing table of its own, in which the paths to reach each node of the network are defined.
• a path is defined by the sequence of links and nodes through which data flows in the communication network.
• the routing table of a node is constructed from the topology table of said node.
• a route in the routing table includes the identifier of the first link to use, the end-to-end metric of the path, and the indication of an overload of any link on that path.
• a first data stream, designated F1 in FIG. 1, is sent by the node N5 of the mesh network 1 to the node N4.
• the routing table of the node N5 indicates that to reach the node N4, the first data stream F1 must be routed by the node N2 and that no saturated link is detected on the path leading to the destination N4.
• the first stream F1 is transmitted on this path by the node N5.
• each node N1-N6 measures on its links a load parameter of the link.
• load parameter is meant the ratio of a measurement of the capacity used to the maximum capacity that can be supported by said link.
• the load parameter may correspond to the percentage of the bandwidth of said link being occupied by a data stream.
• the node N5 measures the load parameter of the link [N5, N2] at regular time intervals.
• the node N1 measures the load parameter of the links [N1, N3] and [N1, N2].
• the load parameter measured for each of the links through which the first stream F1 passes is equal to 40%.
• the bit rate of the first F1 stream uses 40% of the maximum bit rate allowed on each link.
• a node compares the measured load parameter with a predetermined overload threshold M.
• the overload threshold is here equal to 75% so as to attribute to a link an overload state "OVERLOAD" when the overload threshold M is exceeded while avoiding that said link is saturated when the overflow is exceeded.
• overload threshold M if a link is considered saturated when its load parameter is equal to 95%, an overload threshold equal to 75% allows a load margin (of the order of 20%). With this margin, the link can accept an additional flow of data that changes the state of the link without saturating the link.
• a second data stream is sent by the node N2 of the mesh network 1 to the node N4.
• the routing table of the node N2 indicates that to reach the node N4, the second data stream F2 must be routed by the node N1. As all the links are active on the N2 / N4 path, the second stream F2 is transmitted on this path.
• the node N5 recalculates the load parameter on the link [N5, N2] which does not vary following the transmission of the second stream F2 since the second stream F2 does not circulate on this link.
• the node N1 recalculates the load parameter of the links [N1, N3] and [N1, N2]. As the first stream F1 and the second stream F2 flow on the link [N1, N3], a load parameter equal to 80% is measured by the node N1.
• the load parameter of each link is compared to the overload threshold M equal to 75%.
• the node N1 updates its topology table to indicate that the link [N1, N3] has an overload state "OVERLOAD". For this purpose, the state of the link [N1, N3] changes from "UP" to "OVERLOAD" in the topology table of the node N1.
• the node N1 also diffuses this information relating to the overload status of the link [N1, N3] to the other nodes of the network 1 so that the latter update their topology tables.
• all the nodes of the network have the same topology table.
• the node N1 broadcasts to the other nodes of the network 1 a topology message comprising a field identifying the link [N1, N3], a field relating to the metric of the link and a field relating to the state of overloading. of the link [N1, N3].
• the N2-N6 destination nodes of the topology message update their topology table in a manner similar to the NI node .
• the N1 -N6 node routing tables are then updated from the topology tables to indicate paths. overloaded.
• the routing table of N1 indicates in particular that the path leading to node N4 is overloaded. Routes in the routing table that have a path with an overloaded link are called overloaded paths.
• the admission of the second data stream F2 makes it possible to exceed the overload threshold M (load parameter greater than 75%) without saturation (load parameter less than 95%).
• the node when a node routes a data stream on a path of its routing table, the node stores in its routing table the data flow by associating the identifier of the flow of data. data to the path on which it is routed.
• the routing table of N1 furthermore includes fields already presented, a column in which the data streams F1 and F2 sent are identified.
• the first stream F1 and the second stream F2, stored in the routing table of the node N1, circulate on the link [N1, N3] before the link is declared overloaded.
• the flows F1, F2 are considered as authorized flows and the change of state of the link does not affect the routing of the streams F1, F2.
• the packets are routed by the node N3 without taking into account the overload state of the link [N1, N3].
• a third data stream, designated F3 in FIG. 1, is sent by the node N1 of the mesh network 1 to the node N6.
• the routing table of the node N1 indicates that to reach the node N6, the third data stream F3 must be routed by the node N3. Since the link [N1, N3] is overloaded "OVERLOAD" and the mesh network 1 is a single-path network, no other path is available to bypass the overload link and the third stream F3 is not routed by the node N1. In other words, the third data stream F3 is rejected because it can not be routed to its destination without borrowing an overloaded path.
• the routing method according to the invention makes it possible, thanks to its state of overload, to control the admission of data streams into the mesh network. Only flows that circulated on a link prior to changing its state are allowed. Only authorized flows can flow over overload links, any unauthorized additional flows being rejected. Thus, the overload link [N1, N3] is not saturated and no data is lost on the overload link [N1, N3]. This increases the quality of service of the mesh network.
• a node compares the load parameter of said overload link with a predetermined active threshold N.
• the predetermined active threshold is equal to 60%. If the load parameter of said link is less than said active threshold N, the link is no longer considered overloaded "OVERLOAD" and found an active state "UP”.
• the node broadcasts a topology message to inform other nodes in the network that the link is in the active state. The topology and routing tables of said nodes are then updated.
• the active threshold N is distinct from the overload threshold M, it prevents the state of the link is inadvertently modified when the link has a load parameter close to the overload threshold M. Thanks to the active threshold N, once the link is no longer overloaded, it becomes operational again and the routing of new data streams on the mesh network via this link is allowed.
• the management of the overload condition is dynamic thanks to the overload threshold M and to the active threshold N. This advantageously avoids oscillatory tilting between the two link states.
• the active threshold N and the overload threshold M are identical.
• a meshed communication network 2 comprises four nodes Q1 -Q4, the links [Q1, Q2] and [Q2, Q4] being formed by an ethernet link (represented by a single continuous line), the link [Q3, Q4] being formed by a so-called CPL line link (represented by a continuous double line) while the other links are wireless links (represented by a single broken line) which are based on the standard radio network IEEE 802.1 1 and its evolutions, grouped under the name WiFi "Wireless Fidelity".
• the links do not have the same metric, an Ethernet link being better than a CPL link which is itself better than a WiFi link in the sense of the particular metric considered here.
• Each Q1-Q4 node has its own topology table and its own routing table in which the paths to reach each node of the network are defined with the overload status of each path.
• the links between the nodes are all active.
• a first data stream, designated F1 in FIG. 1, is sent by the node Q3 of the mesh network 2 to the node Q4. To reach the node Q4, the first data stream F1 can pass successively:
• nodes Q3, Q2 and Q4 via the WiFi link [Q3, Q2] and the Ethernet link [Q2, Q4] which are active.
• the routing table of the Q3 node indicates that to reach the node Q4, the data must be routed by the CPL link [Q3 , Q4] considered the best path.
• the node Q3 measures the load parameter on the link [Q3, Q4] following the transmission of the first stream F1.
• the flow rate of the first stream F1 uses 40% of the maximum flow allowed on the link [Q3, Q4].
• the load parameter of the link [Q3, Q4] is compared to the overload threshold M, equal to 75%.
• the identifier of the first stream F1 is stored and associated with the path leading to the node Q4 passing through the link [Q3-Q4].
• a second data stream F2 is sent by the node Q3 of the mesh network 2 to the node Q4. For the same reasons as mentioned above for the routing of the first data stream F1, as all the links are active, the second stream F2 is routed on the link [Q3, Q4].
• the first stream F1 and the second stream F2 circulate on the link [Q3, Q4] which modifies the load parameter which is now equal to 80%.
• the load parameter of each link is compared to the overload threshold M equal to 75%.
• the link [Q3, Q4] which has a load parameter equal to 80%, greater than 75%, is declared overloaded "OVERLOAD" while the other links remain active "UP”.
• the node Q3 sends a topology message to inform the other nodes that the link [Q3, Q4] is overloaded.
• Network nodes 2 update their topology table and their routing table.
• the routing table of the node Q3 is modified so that the path leading to the node Q4 passing through the link [Q3, Q4] is declared overloaded "OVERLOAD".
• the identifier of the second stream F2 is stored and associated with the path on which it flows.
• the first stream F1 and the second stream F2 already circulating on the overload link are considered as authorized flows in the routing tables of the nodes Q3 and Q4 and the state change of the link CPL [Q3, Q4 ] does not affect the routing of flows F1, F2.
• a third data stream, designated F3 in FIG. 2 is sent by the node Q3 of the mesh network 2 to the node Q4.
• the third stream F3 can not be routed by the link [Q3, Q4] because this would cause its saturation.
• the node Q3 By consulting its topology table, the node Q3 notes that another path is available to bypass the overload link, in particular, the path passing through the nodes Q3, Q2 and Q4. From its topology table, the node Q3 calculates a new path leading to node Q4 considering that the overload links of the topology table are inactive links.
• the path formation algorithm for example an algorithm of the type Djikstra, will be modified in order to keep in the routing table the paths on which a data flow circulates and calculate an overload link bypass path to reach a given destination. .
• the routing table of Q3 keeps the path leading to Q4 via the link [Q3-Q4]. Nevertheless, as this path is overloaded, the routing table also has a bypass path leading to Q4 via the link [Q3-Q2].
• the routing method according to the invention makes it possible, thanks to its overload state "OVERLOAD", to use all the capacity of the network to make it possible to take advantage of all the links and thus increase the volume and the data rate that can be transmitted.
• OVERLOAD overload state
• the method of the invention can integrate with any type of existing routing protocol to improve the quality of service of a mesh network.
• the method according to the invention finds an advantageous application in local networks (domestic or business) comprising different terminals of different natures (television, laptop, multimedia station, desktop computer, etc.) interconnected by the links of different natures (Ethernet, WiFi 802.1 1a, WiFi 802.1 1 ⁇ , CPL, etc.).
• OLSR is a network layer protocol (layer 3 of the OSI model) defined in RFC 3626.
• the OLSR protocol is defined to allow to interface with nodes with wireless interfaces which is a particularity of conventional local networks. However, other routing protocols could also be used for LANs. Conventionally, the OLSR protocol is based on two-state links: "UP” and “DOWN”. The two states “UP” and “DOWN” are integrated in the operation of the protocol in an implicit manner.
• the nodes broadcast topology messages, called TC messages for "Topolgy Control", to declare active links.
• a topology message TC is shown in Figure 4 and includes, a field with the MSN message sequence number for "Message Sequence Number", a field with the message sub-sequence number MSSN for "Message SubSystem Number”, a metric field corresponding here to a hop count HC for "hop count”, a reserved field “Reserve”, a field with the original address OA for "Originator Address” and fields d MRSA multipoint relay selection address for "Multipoint Relay Selector Address”.
• the set of fields of the TC topology message are defined in detail in section 9 of RFC 3626.
• the topology message further comprises an overload state of the "OVERLOAD" link which is entered in the reserved field as illustrated in FIG.
• a node of the mesh network can form its routing table.
• FIG. 3 a multipoint mesh communication network 3 installed in a home of an individual is shown in FIG. 3.
• the local network 3 comprises a home gateway T1 which is arranged to connect the home network 3 to the Internet network 5 by a link 6 of the FTTH type which guarantees a high rate of the order of Gigabit / s.
• the local network 3 further comprises a set-top box TV decoder T2 which is connected to the home gateway T1 by two links L1, L2 which respectively correspond to WiFi links 802.1 1 ⁇ and 802.1 1 a which are independent.
• the home gateway T1 and the set-top box T2 form two nodes of the local network 3 connected by two links L1, L2.
• the set-top box T2 is connected, on the one hand, to a desktop computer 9 located on the floor of the home and, on the other hand, to a television set 8 located on the ground floor. floor of the home.
• the home gateway T1 is, for its part, connected to a multimedia server 7 also located on the ground floor of the home.
• the advantage of the WiFi links L1, L2 is that the T1 home gateway and the multimedia server 7 can be distant from the T2 set-top box. In particular, the terminals may be located in different rooms.
• the T1 home gateway and the T2 set-top box are provided by a telecommunication operator and implement a tri-state OLSR routing protocol according to the invention in the local network 3.
• the home gateway T1 comprises means arranged to measure the load parameter on the two wireless links L1, L2, means for comparing the load parameter measured at a predetermined overload threshold and means broadcasting to at least some nodes of said network information relating to said overload state of said link.
• the T1 home gateway has as IP address 192.168.0.1 and broadcasts TC topology messages to the other nodes of the home network 3 in order to build the network topology table.
• the topology message TC comprises information relating to the state of overload of said link which is defined in the reserved field of said message TC as represented in FIG. 4.
• the local network 3 comprises only two nodes T1, T2 which each comprise a topology table constructed by exchanging TC topology messages.
• the topology table of the T1 home gateway has one line per link.
• the first line of the topology table corresponds to the link L1 and indicates that the set-top box T2, of IP address 192.168.0.2, is connected to the home gateway by a network interface of address 10.0 .0.2 and whose status is active "UP".
• the topology table according to the invention is enriched by an additional column indicating the overload status of the link referenced "T link state" in Table 1.
• Table 1 Topology table of the T1 home gateway
• the home gateway T1 forms its routing table, shown in Table 2 below, in which a line corresponds to a path leading to a destination node of the network.
• the first line of the routing table indicates that to reach the set-top box T2, IP address 192.168.0.2, a data stream can be routed to the network interface 802.1 1 ⁇ d ' address 10.0.0.2 via link L1.
• the routing table according to the invention is enriched by two additional columns indicating, on the one hand, the overload status of the network paths ("Interface Status") and, on the other hand, on the other hand, the other hand, the identifier of the flows flowing on said paths ("Flow ID").
• Table 2 T1 home gateway routing table with link L1 in UP state A first F1 stream is sent from the T1 home gateway to the T2 set-top box. After consulting its routing table, the first F1 stream is routed by the T1 home gateway on the L1 link which has a better metric than the L2 link. The identifier of the first stream F1 is then stored in its routing table as shown in Table 3 below.
• Table 3 T1 home gateway routing table after memorizing F1 flow
• the home gateway T1 measures the load parameter of the link L1 which is then equal to 80%.
• the home gateway T1 compares the load parameter of the link L1 to the overload threshold M.
• the link L1 is declared overloaded "OVERLOAD" while the other links remain active "UP”.
• the home gateway T1 updates its topology table by indicating that the link is overloaded and broadcasts TC topology messages to indicate to the other nodes of the home network 3 that the link L1 is overloaded.
• the set-top box T2 comprises means for receiving TC topology messages comprising the overload status information of said link sent by the home gateway T1 and means for updating its topology table to from said overload status information of said link.
• the routing table of the T1 home gateway is recalculated and the path to the set-top box T2 using the link L1 is indicated in overload as shown in Table 4 below. below.
• Table 4 T1 home gateway routing table with link L1 in OVERLOAD state
• a second data stream, designated F2 in FIG. 3, is sent by the home gateway T1 to the set-top box T2.
• the home gateway T1 consults its routing table. Since the link L1 is overloaded and another path is available to bypass the overload link, the T1 home gateway routes the second stream F2 by the second link L2.
• the routing method according to the invention makes it possible, thanks to its overload state, to use all the capacity of the network to make it possible to increase the volume and the data rate that can be transmitted between the nodes T1 and T2.
• the home gateway T1 stores the identifier of the second stream F2 in its routing table as shown in Table 5 below.
• Table 5 T1 home gateway routing table after storing the F2 stream
• the home gateway T1 can communicate with the set-top box T2 without saturating one of the links L1, L2.
• the transmission of the first data stream F1 is not disturbed by the routing method, the second data stream F2 being transmitted independently.
• this home network 3 when a link is overloaded "OVERLOAD", a step of selecting the streams to be sent can be implemented, only the priority data streams can be sent over the overload link, with the lower priority streams being passed by the other paths that are not overloaded. Likewise, an active threshold can be set to update the state of the overloaded link.
• the method according to the invention has here been integrated into a routing protocol that corresponds to the third layer of the OSI model for "Open Systems Interconnection" but an integration of the method with a path selection protocol, which corresponds to the second layer of the OSI model, can be deduced from the above teaching.

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• 2011
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