JP2015167365A - Networks having multiple paths between nodes and nodes for such a network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To select operation modes of a plurality of paths between nodes, on the basis of a requested level of traffic between the nodes and a fault occurrence in the paths.SOLUTION: A network 1 including a first node A, a second node B, and a plurality of nodes 4 which are connected via a first path 2 and a second path 3, the first and second paths being different has: a first operation mode in which traffic between the first node A and the second node B is transmitted via the first path 2, not the second path 3; and a second operation mode in which traffic is transmitted via the first path 2 and the second path 3. The network 1 includes a mode selector 10 configured to select the operation mode on the basis of a requested level of the traffic between the first node A and the second node B. Furthermore, the network 1 has a third operation mode in which traffic is transmitted via the second path 3, not the first path 2 when there is a fault in the first path.

Description

  The present invention relates to a network in which at least two paths are provided between two network nodes, a network node and a method of operating such a network.

  Network communications are well known. In a network, it is often desirable to transmit traffic from a source node to a destination node via the network. In order to guarantee the reliability of communication between such pairs of nodes, it is well known to protect the communication channel.

  In such a scheme, a primary connection through the network is established. Furthermore, the protected connection is established using different paths through the network. Protected connections are not used under normal usage conditions. The protection connection operates only when the main connection fails due to loss of signal, loss of continuity, increased error rate or dropped frames.

  A signal protection connection may be dedicated to a particular main connection (1: 1 protection) or may be shared between multiple main connections depending on the importance of maintaining a given connection ( 1: n protection). For such protection schemes, the International Telecommunications Union (ITU) Recommendation G., the contents of which are incorporated herein by reference. 808.1 and G841.

  According to the first aspect of the present invention, a network including a plurality of nodes including a first node and a second node connected through a network of nodes through a first path and a second path different from each other A first mode of operation in which traffic between the first node and the second node is transmitted through the first path instead of the second path, and the traffic is transmitted through the first path and the second path. A second mode of operation transmitted over two paths and configured to select the mode of operation based on a demand level of traffic between the first node and the second node A network including a selector is provided.

  Thus, this will primarily use the first path to transmit data, and will use the second path only when needed. In a particularly advantageous embodiment, the second path is such that the network has a third mode of operation in which traffic between the first node and the second node is sent only via the second path. And the mode selector is configured to select this mode if the first path is faulty. These means make it possible to use a well-known protection path that is normally idle when there is no failure and that operates when a failure occurs.

  The first pass and the second pass may be different. Those paths may go through different sets of intermediate nodes in the network. This is typical in the protection path.

  The selection of an operating mode that depends on the required level of traffic may depend on the rate at which data transmitted over the link is received. For example, a simple calculation of the rate at which data for the link is received is employed. Thus, the mode selector may include comparison means for comparing the rate with a threshold value. If the rate exceeds the threshold, the second operating mode may be selected. The threshold may be a percentage of the available bandwidth of the first path, such as 80% or 100%.

  The network may further include a priority allocator operable to assign a priority to the allocation of data between the first path and the second path. If the second path includes a protection path, data for the protection path that is potentially routed to the second path due to network failure is data that is potentially assigned to the second path due to traffic level May have a higher priority than the priority assigned to. The first node is preferably configured to assign data to the first path or the second path depending on the priority assigned to the data.

  According to a second aspect of the present invention, there is provided a network node that includes a first network interface and a second network interface and is used when sending data to a destination node in the network, A first operation mode in which data for the supply destination is transmitted using the first network interface instead of the second network interface, and data for the supply destination node is transmitted through the first network interface and the second network interface. A network node is provided that includes a mode selector configured to select an operation mode based on a requested level of traffic to a destination node.

  Thus, when the traffic between the network node and the supply destination node requests a secondary path, the secondary path can be selected. In general, in use, the first network interface is connected to a first path through the network to the destination node and the second network interface is connected to a second path through the network to the destination node.

  The network node may include a protection switch that, when a failure occurs, sends traffic to the supply destination node via the second network interface when there is a failure in the link from the first network interface to the supply destination node. In a particularly advantageous embodiment, the second path includes a protection path so that the second mode of operation is selected if the first path is faulty. These means make it possible to use a well-known protection path that is idle when there is no failure and that operates when a failure occurs.

  The first pass and the second pass may be different. Those paths may go through different sets of intermediate nodes in the network. This is typical in the protection path.

  The selection of an operating mode that depends on the required level of traffic may depend on the rate at which data transmitted over the link is received. For example, a simple calculation of the rate at which data for the link is received is employed. Thus, the mode selector may include comparison means for comparing the rate with a threshold value. If the rate exceeds the threshold, the second operating mode may be selected. The threshold may be a percentage of the available bandwidth of the first path, such as 80% or 100%.

  The network may further include a priority allocator operable to assign a priority to the allocation of data between the first path and the second path. If the second path includes a protection path, data for the protection path that is potentially routed to the second path due to network failure is data that is potentially assigned to the second path due to traffic level May have a higher priority than the priority assigned to. The first node is preferably configured to assign data to the first path or the second path depending on the priority assigned to the data.

  According to the third aspect of the present invention, a network including a plurality of nodes including a first node and a second node connected via a network of nodes through mutually different first and second paths In which the traffic between the first node and the second node is transmitted via the first path instead of the second path, and the traffic is the first Operation of the network in a second mode of operation transmitted over a second path and a second path, the mode of operation selected based on the level of traffic between the first node and the second node A method is provided.

  Thus, this mainly uses the first path to transmit data, but the second path will only be used when needed. In one particularly advantageous embodiment, the second path operates in a third mode of operation in which traffic between the first node and the second node is sent only via the second path. Thus, the third mode is selected when the first path is faulty. These means make it possible to use a well-known protection path that is normally idle when there is no failure and that operates when a failure occurs.

  The first pass and the second pass may be different. Those paths may go through different sets of intermediate nodes in the network. This is typical in the protection path.

  The selection of an operating mode that depends on the required level of traffic may depend on the rate at which data transmitted over the link is received. For example, a simple calculation of the rate at which data for the link is received is employed. Thus, the mode selector may include comparison means for comparing the rate with a threshold value. If the rate exceeds the threshold, the second operating mode may be selected. The threshold may be a percentage of the available bandwidth of the first path, such as 80% or 100%.

  The method may include assigning a priority to assigning data between the first pass and the second pass. If the second path includes a protection path, data for the protection path that is potentially routed to the second path due to the network is assigned to data that is potentially assigned to the second path due to traffic level. You may have a priority higher than a priority. The data is preferably assigned to the first path or the second path depending on the priority assigned to the data.

  According to a fourth aspect of the present invention, there is provided a method for operating a network including a first network interface and a second network interface to send data to a destination node in the network, wherein the network node is a second one. A first operation mode in which data for a supply destination is transmitted using the first network interface instead of the network interface, and data for the supply destination node is transmitted via the first network interface and the second network interface. Operating the network node in a second mode of operation wherein a mode is selected based on the level of traffic to the destination node.

  Thus, when the traffic between the network node and the supply destination node requests a secondary path, the secondary path can be selected. In general, in use, the first network interface is connected to a first path through the network to the destination node, and the second network interface is connected to a second path through the network to the destination node.

  The network node may include a protection switch that sends traffic to the destination node via the second network interface when there is a failure in the link from the first interface to the destination node. In a particularly advantageous embodiment, the second path includes a protection path so that the second mode of operation is selected if the first path is faulty. These means make it possible to use a well-known protection path that is normally idle when there is no failure and that operates when a failure occurs.

  The first pass and the second pass may be different. Those paths may go through different sets of intermediate nodes in the network. This is typical in the protection path.

  The selection of an operating mode that depends on the required level of traffic may depend on the rate at which data transmitted over the link is received. For example, a simple calculation of the rate at which data for the link is received is employed. Thus, the mode selector may include comparison means for comparing the rate with a threshold value. If the rate exceeds the threshold, the second operating mode may be selected. The threshold may be a percentage of the available bandwidth of the first path, such as 80% or 100%.

  The method may further include assigning a priority to assigning data between the first pass and the second pass. If the second path includes a protection path, data for the protection path that is potentially routed to the second path due to network failure is data that is potentially assigned to the second path due to traffic level May have a higher priority than the priority assigned to. The first node is preferably configured to assign data to the first path or the second path depending on the priority assigned to the data.

  Any node of any aspect of the invention may include multiple interfaces and associated equipment. Node interfaces may include both customer interfaces or network interfaces, and the network interfaces shown above may indicate any or all of such interfaces. Such an interface may represent an ingress interface or an egress interface to the network. The interface may be further connected to additional networks for network interconnection.

  The mode selector behavior or mode selection may be controllable from a network management device that may be located remotely with respect to the network node. Such a network management device may be configured to selectively disable the operation of the second mode so that the network operator returns the network, node or method to the operation of the conventional protection circuit. Can do.

It is the schematic which shows the network which concerns on one Embodiment of this invention. 2 is a flowchart illustrating how data is assigned to the various links of FIG.

  A network according to an embodiment of the invention is shown in FIG. 1 of the accompanying drawings. This includes two network nodes A and B connected via the network 1. Nodes are connected by two paths, a main path 2 and a secondary path 3. Each path 2, 3 includes a plurality of intermediate nodes 4. The two paths 2 and 3 differ in that they pass through various intermediate nodes. The main path starts from the main network interface 5 of the node A and ends at the main network interface 6 of the node B. On the other hand, the secondary path starts with the secondary network interface 7 of node A and ends with the secondary network interface 8 of node B.

  Nodes A and B may be connected by either SDH / SONET, Ethernet (registered trademark), MPLS, or any transmission protocol using packets.

  In a well-known network configuration, communication traffic from node A (source node) to node B (destination node) does not cause a failure in the path (eg, one of the intermediate nodes 4 or the main network interface). If one of them stops functioning, a failure occurs) and is generally sent via the main path 2. In the event of a failure, traffic is sent out via the secondary path 3. In such a case, the secondary path is considered a protection path.

  However, this embodiment of the present invention relies on the fact that in most cases the secondary path is unused, thus indicating that the bandwidth is not fully utilized. Therefore, when the bit rate of traffic for node B increases at node A until it exceeds the threshold, a secondary path is used. This uses a secondary path when there is no failure, and uses unused bandwidth when there is a failure. This may be achieved by counting the number of data output to the main network interface 5 at node A and switching the data to the secondary path 3 when the threshold is reached.

  In order to ensure that a reasonable fault tolerance is still maintained, a high priority is assigned to protection against specific defective devices (nodes or interfaces). Accordingly, the priority order in which data is switched from the main path 2 to the secondary path 3 may be set lower than the priority order when a failure occurs in the main path 2. Such priorities are given in ITU Recommendation G. It may be implemented in compliance with an automatic protection switching protocol as described in 808.1 and G841. Such priorities are not necessarily required in a simple embodiment as shown in FIG. 1 of the accompanying drawings, but those skilled in the art will understand their need in larger networks.

  Accordingly, the allocation of data between the various connections is demonstrated as shown in FIG. 2 of the accompanying drawings. When data for node B is received at node A, software executing on processor 10 in node A allocates data to primary link 2 or secondary link 3 using the illustrated method. The first step 100 determines whether the main link is functioning correctly. If not functioning correctly, all data is sent over the secondary link at step 102. If the primary link is functioning, the software determines in step 104 whether the bit rate of data from node A to node B is greater than a threshold. If greater than the threshold, in step 106 both links are used. On the other hand, if not greater than the threshold, at step 108, only the main link is used.

Claims (17)

  A network comprising a plurality of nodes including a first node and a second node connected through a network of nodes through different first paths and second paths, wherein the first node And a second mode of operation in which traffic between the second node and the second node is transmitted through the first path instead of the second path, and the traffic is transmitted through the first path and the second node. A second mode of operation transmitted over a path, and configured to select the mode of operation based on a requested level of traffic between the first node and the second node A network comprising a mode selector.   The second path includes a protection path that provides the network with a third operation mode in which traffic between the first node and the second node is transmitted only through the second path. The network of claim 1, wherein the mode selector is configured to select the third mode of operation when the first path is faulty.   The network according to claim 1 or 2, wherein the selection of the operation mode depending on the demand level of the traffic depends on a rate at which data transmitted via the link is received.   The network further comprises a priority allocator operable to assign a priority to data allocation between the first path and the second path. 4. The network according to any one of items 3.   A network node having a first network interface and a second network interface, and used for sending data to a supply destination node in the network, wherein the first network interface is not the second network interface but the first network interface is used. A first operation mode in which data for the supply destination is transmitted using a network interface; and a second mode in which the data for the supply destination node is transmitted via the first network interface and the second network interface. And a mode selector configured to select the operation mode based on a request level of traffic to the destination node.   The first network interface is connectable to a first path through the network to the supply destination node, and the second network interface is a second path through the network to the supply destination node. The network node according to claim 5, wherein the network node is connectable to the network node.   The network node includes a protection switch that transmits traffic to the supply destination node via the second network interface when a failure occurs in a link from the first network interface to the supply destination node in the event of a failure. The network node according to claim 5, wherein the network node is a network node.   The selection of the operation mode depending on the demand level of the traffic depends on a rate at which data transmitted via the link is received. The described network node.   The network node further comprises a priority allocator operable to assign a priority to data allocation between the first path and the second path. 9. The network node according to any one of 8. A method of operating a network comprising a plurality of nodes including a first node and a second node connected via a network of nodes through different first paths and second paths,
A first mode of operation in which traffic between the first node and the second node is transmitted via the first path instead of the second path; and the traffic is the first path And operating the network in a second mode of operation transmitted via the second path, the mode of operation being at a level of traffic between the first node and the second node. A method characterized by being selected based on.   The second path protects the network to operate in a third mode of operation in which traffic between the first node and the second node is sent only through the second path. The method of claim 10, comprising a path, wherein the third mode is selected when the first path is faulty.   12. A method according to claim 10 or 11, wherein the selection of the operating mode depending on the demand level of the traffic depends on the rate at which data transmitted over the link is received.   The method of claim 12, wherein the selection is made depending on whether the rate exceeds a threshold.   The method of claim 13, wherein the threshold is a percentage of available bandwidth of the first path.   15. The method according to any one of claims 10 to 14, wherein the method includes assigning a priority to data assignment between the first path and the second path.   Data that is potentially routed on the second path due to a failure in the network has a higher priority than the priority assigned to data that is potentially assigned to the second path due to traffic levels. 16. A method according to claim 15 when dependent on claim 11, characterized in that is assigned.   A method of operating a network comprising a first network interface and a second network interface to send data to a destination node in the network, wherein the network node is not the second network interface but the second network interface. A first operation mode in which data for the destination is transmitted using one network interface, and the data for the destination node is transmitted via the first network interface and the second network interface. Operating the network node in a second mode of operation, wherein the mode is selected based on a level of traffic to the destination node.

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