JP6457962B2 - Node device and redundant network communication method - Google Patents

Description

  The present invention relates to a communication method for a node device and a redundant network, and more particularly to a node device and a redundancy device that can increase the redundancy in a network that can be distributed to multiple output points by copying one input. The present invention relates to a network communication method.

  Conventionally, broadcast-type video distribution, a database replication mechanism among a plurality of data centers, and the like exist as applications in which the same data is distributed from a data distribution server to receiving terminals in a number of locations. (Hereinafter referred to as application group). A network for transmitting these data is configured by using a communication method (hereinafter referred to as unicast transmission) in which one transmitter and one receiver are paired in parallel as many as the number of receivers. it can. In addition, in a communication method in which a plurality of receivers correspond to one transmitter, a communication method for distributing data to a plurality of receivers by copying data as necessary within the network ( Hereinafter, it may be configured using multicast transmission).

FIG. 10 is a diagram schematically showing a conventional network 100 configured using multicast transmission. The network 100 is a network in a range provided to the user as a network service in which the same data is distributed to the user terminals 21a and 21b from the distribution server 11 of the user (for example, a distribution company).
The transmitter 31 installed at the transmission base T1 transmits the data input from the distribution server 11 from the user communication path 2. This data is copied (replicated) at the data copy point C, and the receivers 51 installed at the reception bases R1 and R2 respectively transfer the received data to the user terminals 21a and 21b.

Here, the transmitter 31 is, for example, a transponder device that converts a data signal input in an Ethernet (registered trademark, hereinafter the same) format into an optical signal in a format suitable for long-distance transmission and transmits the received data signal. The machine 51 performs the reverse conversion. The Ethernet format includes 10GBase-LR that uses optical signals, 10GBase-CX4 that uses electrical signals, etc. The format suitable for long-distance transmission is, for example, the OTN (Optical Transport Network) format. is there.
The data copy point C can be configured using an optical splitter or the like to perform copying at the optical level. If you want to copy at the electrical level, you can also implement an optical signal regenerative repeater (3R) device with a function that outputs the same data to multiple ports.

  As shown in FIG. 10, when the network 100 is configured using multicast transmission, the number of transmitters 31 can be suppressed to one and can be configured at low cost. In addition, since the transmission paths upstream from the data copy point C (on the side closer to the transmitter 31) are integrated into one, in many cases, the transmission paths can be configured at a lower cost than unicast transmission. .

The above-described application group is often required to have high availability. In this case, it is possible to provide a service with high availability by making the components of multicast transmission redundant.
As a method for increasing the redundancy of multicast transmission, for example, the method described in Non-Patent Document 1 can be cited. In this method, a plurality of multicast transmission paths are provided so that a base group and a transmission path group passing between the transmission base and the reception base are independent from each other. As a result, in this method, it is possible to configure multicast transmission (hereinafter referred to as multicast protection transmission) that continues normal data distribution in the event of a failure of an arbitrary base or transmission path.

  As one of the factors that lower the availability of the network, there is an event that occurs accidentally and independently, such as a natural failure of the device. Therefore, the device is made redundant in the transmission base, and multicast protection transmission from one transmission base is performed. It is preferable to configure. However, as another factor that lowers the availability of the network, there is an event that has geographical locality such as a great natural disaster and causes all the devices in the range to fail. For such an event, even if a device is made redundant in the transmission base, the transmission base is damaged by a disaster or the like, and the device in the transmission base fails at the same time. May stop.

  Therefore, in order to configure multicast protection transmission corresponding to natural disasters or the like, it is effective to install the transmission bases at a plurality of geographically separated locations (hereinafter referred to as different point input).

FIG. 11 is a diagram schematically showing a conventional redundant network 101 configured by using multicast protection transmission in which a plurality of transmission bases T1 and T2 are installed at geographically separated locations. The redundant network 101 includes switching means 52 installed at the reception bases R1 and R2. The switching means 52 selects one of the signals input at different starting points and distributes (transfers) the signal to the terminal 21a or the terminal 21b.
For this switching means 52, for example, a receiving end switching method used in Ethernet linear protection (Non-patent Document 2) or the like is implemented. The receiving end switching method itself can be configured not only for Ethernet format signals but also for arbitrary signals.

In the receiving end switching method, data is always copied and transmitted to different paths in the transmitter, and the same signal is received from the paths in the switching means built in the receiver or installed in front of the receiver. To do. Next, a normality determination is performed on each received signal, and only a system from which a normal signal has arrived is selected and actually received.
Receiving end switching method, in exchange for consuming the transmission capacity as many as the number of paths, with a short interruption from when an abnormality is detected to when switching is performed for an accidental failure of the transmission path, It is possible to obtain an effect that normal communication is automatically recovered at high speed.

  In the redundant network 101, for example, when the system starts to operate first, a signal system (referred to as an active system) to be received by the terminals 21a and 21b when the system is normal first flows into the network. Then, the switching means 52 performs normality determination between the system in which the signal is input and the system in which the signal is not input, selects the active system signal, and starts the operation. The signal system selected for the user terminals 21a and 21b is hereinafter referred to as a selection system. Thereafter, a signal of a system that is not the active system (referred to as a standby system) is caused to flow into the network. The switching means 52 recognizes that both systems are in a normal state, and in this case, the selection system of all the switching means 52 can be matched by mounting so as not to change the current selection system.

  In the redundant network 101, the transmitter 31 installed at the transmission site T1 transmits data input from the distribution server 11A from the user communication path 2, and the transmitter 31 installed at the transmission site T2 is a distribution server. Data input from 11S is transmitted from the user communication path 3. In this example, the redundancy is 2, and is composed of one active system and one standby system. The same data is sent to the active system and the standby system before the failure occurs, and after the failure of the active system By switching to the standby system, data loss is suppressed.

  In the redundant network 101, the switching means 52 distributes one selection system signal to the terminal 21a or the terminal 21b in the floor closest to the terminals 21a and 21b, so that the terminals 21a and 21b and the receiving bases R1 and R2 The last-stage transmission line between is not made redundant. Therefore, if a failure occurs in this section, the service of the terminal is stopped. However, the affected range of the service stop due to the failure is only the terminal. Therefore, the redundant network 101 has a network service compared to a system (multicast protection transmission from one transmission base) in which the entire system may be stopped due to a failure of the transmission base T1 as in the network 100 shown in FIG. Are often acceptable as reasonable quality. As in the redundant network 101, except for the final transmission line between the user terminals 21a and 21b and the receiving bases R1 and R2, the transmission line and the apparatus are all installed in a geographically redundant manner. In the following, a service using a set is referred to as a different starting point input multicast protection transmission.

  A transmission network using packet communication can be cited as a base for accommodating this different starting point input multicast protection transmission. A transmission network using packet communication, for example, a network that supports MPLS-TP (Non-patent Document 3), assigns a label to a packet in units of users and the like, thereby creating a virtual transmission path (Label Switched Path: LSP). This is because a multicast transmission path can be configured by creating a copy point.

Wang, S. et al., “Construction of Multicast Protection Tree based on Single Node Failure,” in Proc. Of Communications and Mobile Computing (CMC), 2010 International Conference on (Vol. 2, pp. 202-206), 2010 , April. Sato et al., “Standardization Trends of Ethernet Protection Switching,” IEICE Tech. Rep. CS2006-87, (2007-1). “MPLS-TP Layer Network Architecture”, G.8110.1, TTC Standard, 2013.05.23.

However, when providing different starting point input multicast protection transmission as a service, a method for sharing the communication network among the users and using the communication network efficiently has not been known.
The MPLS-TP described in Non-Patent Document 3 can be configured such that the label is recursively added and deleted, and the LSP is accommodated in the LSP. Therefore, according to MPLS-TP, it is possible to share a communication network by accommodating multicast transmission paths having the same route structure in one large multicast path having the same route structure. This large multicast path is hereinafter referred to as a multicast super path (hereinafter also referred to as MC super path for short). According to the network communication method using the MC super path, a cost reduction effect can be obtained by sharing the communication network of the user group. Here, in order to provide different starting point input multicast protection transmission as a service, a plurality of types of redundant networks that use MC superpaths in different ways are illustrated, and problems when they allow a group of users to use a communication network The point will be described.

FIG. 12 is a diagram schematically showing a redundant network 102 configured to share a transmission path in the MC super path. Here, in addition to the distribution servers 11A and 11S and the terminals 21a and 21b for the user 1, the distribution server 12A, the distribution server 12S, and the terminal 22a for the user 2 are assumed.
The MC super path 4 accommodates a multicast transmission path for data from the distribution server 11A of the user 1 and a multicast transmission path for data from the distribution server 12A of the user 2.
The MC super path 5 accommodates a multicast transmission path for data from the distribution server 11S of the user 1 and a multicast transmission path for data from the distribution server 12S of the user 2.

  In this redundant network 102, it is assumed that the switching means 52 performs switching for each MC super path at the reception bases R1 and R2. Hereinafter, this method is referred to as a reception base super path unit switching method. At that time, the abnormality detection is performed by the receiver 51. If an abnormality occurs in any of the communication paths of the users 1 and 2 accommodated in the MC super path 4 (or the MC super path 5), switching for each MC super path is performed. It can be implemented to instruct the switching means 52 to perform. Similarly, in a transmission network that performs wavelength multiplexing, the wavelength having the same path structure is accommodated in a transmission path using the same optical fiber and optical splitter, and the transmission path is regarded as an MC super path. A network of the system can be configured.

  In the reception base super path unit switching method, the selection system is forcibly synchronized with the signal system accommodated in the MC super path 4 (or the MC super path 5) for the multicast transmission transmission service for different starting point input for each user. Means that That is, when the network operator switches the MC super path 4 to the MC super path 5, for example, the distribution server connected to the terminals 21a and 21b of the user 1 (distributor) is forcibly distributed from the distribution server 11A. 11S. Here, it is desirable for the provision of network services that the information on the selection system is held for each user independently of the system (MC super path) of the network operator. The reason is that if the information on the selection system is not held for each user, the service redundancy of other users may be lost depending on the service usage state of a certain user.

  Specifically, for example, when the signal system distributed to each user's terminal is in the state of being transmitted through the MC super path 4 as shown in FIG. 12, the user 1 maintains the distribution server 11A for maintenance. Suppose you stopped for that. In this case, for example, the receiver 51 detects the signal interruption from the distribution server 11A of the user 1, and instructs the switching means 52 to switch from the MC super path 4 to the MC super path 5. As a result, the terminals 21a, 21b, and 22a of each user can continue to receive services using the signals from the distribution servers 11S and 12S. However, if a failure further occurs in the distribution server 12S of the user 2 while using the MC super path 5, if the switching unit 52 switches from the MC super path 5 to the MC super path 4, the MC super path 4 Does not include a signal from the distribution server 11A under maintenance of the user 1, the service to be provided to the terminals 21a and 21b of the user 1 is stopped. As a result, although there is no failure in the redundant network 102, the failure of the distribution server 12S of the user 2 causes the communication disconnection between the terminals 21a and 21b of the user 1. Therefore, it is considered that the quality as a network service provided to the user is deteriorated in the reception base super path unit switching method.

  In FIG. 12, the terminal 22a of the user 2 has received two signal inputs from both the receiving bases R1 and R2. This is because the last-stage transmission path is not made redundant, but depending on the user's wish, it is possible to make all the floors geographically separated by receiving signal inputs from two systems. It shows that there is.

FIG. 13 is a diagram schematically showing a redundant network 103 configured such that information on the selection system is held independently for each user while sharing a transmission path in the MC super path.
In this redundant network 103, when an abnormality is detected in any of the user communication paths accommodated in the MC super path 4 (or MC super path 5), the switching means 52 transmits the signal at the receiving bases R1 and R2. A method is assumed in which switching is performed for each user. Hereinafter, this method is referred to as a receiving site user unit switching method.

  In the redundant network 103, the number and arrangement of the receivers 51 and the switching means 52 are different from those in the redundant network 102. Specifically, in the redundant network 103, the receiving bases R1 and R2 are equipped with the receivers 51 in parallel for the degree of redundancy, and the switching means 52 for each user is provided in parallel in the subsequent stage for the number of users. Equipped with. Therefore, the total number of switching means 52 is (the number of receiving bases) × (the number of users), and the cost for the multicast communication service increases. Due to the nature of the service, the number of receiving bases increases as the number of user terminals increases as compared to the transmitting bases installed for the redundancy, so that the influence of the cost increase becomes significant.

  Note that it is possible to reduce the cost by incorporating the switching means 52 in the receiver 51 as software. However, to that end, the receiver 51 must be designed in advance to have a performance capable of supporting the maximum number of users to be serviced, and the performance must be estimated in advance and manufactured. As a result, it increases the cost of such a receiver.

FIG. 14 schematically shows a redundant network 104 configured to share the transmission path in the MC super path and minimize the parallel installation of the switching means so that the information on the selection system is held independently for each user. FIG.
In the redundant network 104, the configuration on the receiving bases R1 and R2 side is the same as the configuration of the redundant network 102 in FIG. 12, and the switching means 52 can perform switching for each MC super path. In addition, on the transmission bases T1 and T2 side, there are installed crossover lines 6 and 7 that straddle the transmission bases T1 and T2 independently of the MC superpaths 4 and 5, and the number of users is equal to the number of users. Switching means 41 and 42 are provided.

  If there is only one path for the crossover line, if the crossover line breaks down, degeneration to the same state as in FIG. 12 occurs. Therefore, typically, the redundant network 104 installs a plurality of different paths in each of the crossover lines 6 and 7 to ensure redundancy, and the switching means 32 when a path with the crossover lines 6 and 7 fails. Use after switching to another route.

  In the redundant network 104, for example, at the transmission base T1, the switching means 41 corresponding to the signal of the user 1 receives the signal from the distribution server 11A and the signal transmitted from the transmission base T2 through the crossover line 7 (from the distribution server 11S). Signal), and one (here, the signal from the distribution server 11A) is copied and output. Note that the switching means 42 corresponds to the signal of the user 2. In this way, when the transmission base side switching means 41, 42 detects any abnormality of the input signal, the method of switching the signal for each user will be referred to as a crossover line using user unit switching method in the following. To do.

In this system, when signals for each user are accommodated in the MC super paths 4 and 5 using the transfer lines 6 and 7, only the selection systems of all users are copied to both the MC super paths 4 and 5. Assume that it is contained.
In the redundant network 104, the number of switching means 41, 42 provided at the transmission bases T1, T2 is (redundancy) × (number of users), and the number of switching means 52 provided at the reception bases R1, R2 is the reception base. Number. Therefore, it can be expected that the number of switching means is reduced as compared with the configuration of the redundant network 103 of FIG.
However, a separate transmitter 34 and receiver 35 for configuring the transfer lines 6 and 7 are required. In order to accommodate the bandwidth for all users, these require a configuration of the same scale as the transmitter 31 and the receiver 51 for the MC super paths 5 and 6, and the cost cannot be ignored.

Summarizing the above, when trying to provide the different starting point input multicast protection transmission as a service, although the receiving base super path unit switching method (redundant network 102: FIG. 12) can obtain the cost reduction effect by sharing the communication network, Since the information of the selection system cannot be held independently for each user, the quality as a network service provided to the user is deteriorated.
In addition, although the receiving base user unit switching method (redundant network 103: FIG. 13) can hold the information of the selection system independently for each user, the switching means 52 on the receiving base R1, R2 side is set to the number of users for each receiving base. Corresponding parallel equipment increases costs.
Further, the switching line using user unit switching method (redundant network 104: FIG. 14) maintains the number of the switching means 52 on the receiving bases R1 and R2 side while holding the information on the selection system independently for each user. Although it can be suppressed to the same level as the unit switching method, the cost increases due to the equipment for configuring the crossover lines 6 and 7.

  Therefore, an object of the present invention is to provide a node device and a redundant network communication method capable of solving the above-described problems and configuring a redundant network accommodating multicast communication at low cost.

  In order to solve the above-described problem, the node device according to the present invention configures a redundant network for multicast transmission of a signal input by a user distribution server from the same number of transmission bases as a predetermined redundancy, A self-multicast super that is a node device installed at each transmission base, and that is a path that accommodates multicast transmission paths for each user having the same route structure from the self-transmission base to a plurality of reception bases. A transmitter which transmits to a plurality of receiving bases by a path and which branches from the own multicast superpath and transmits to other transmitting bases via a self-transmission line directed to another transmitting base, and a plurality of the receptions from other transmitting bases Other multi-keys are paths that accommodate multicast transmission paths for each user with the same route structure to the base. A receiver that receives a signal distributed via a crossover line that branches from the storage path to the transmission base, a signal that is provided for each user, and that is input by the distribution server; A plurality of signal switching means for monitoring the normality of the signal received via the crossover line, replicating one of the signals and outputting the duplicated signal to the transmitter, and switching the output signal according to the signal state; Prepare.

  In order to solve the above-described problems, the redundant network communication method according to the present invention is a redundant network in which a signal input by a user distribution server is multicast-transmitted from the same number of transmission bases as a predetermined redundancy degree. The node device installed in the transmission base includes a transmitter, a receiver, and a signal switching unit provided for each user, and the transmitter receives a signal input thereto. Are transmitted to a plurality of receiving bases by a self-multicast superpath that is a path accommodating multicast transmission paths for each user having the same route structure from the self-transmitting base to a plurality of receiving bases, and the self-multicast superpath Branching from the transmission step to the other transmission base via a self-transmission line to the other transmission base, and the receiver A signal that is distributed from another multicast super path that is a path accommodating multicast transmission paths for each user having the same route structure from a point to a plurality of the reception bases and distributed via a crossover line toward the self transmission base Receiving signal, and the signal switching means monitors the normality of the signal input by the distribution server and the signal received from the other transmission base via the other crossover line, and either one of them is monitored. A signal switching step of duplicating and outputting to the transmitter, and switching the output signal in accordance with the signal state.

According to the node device of such a configuration and the redundant network communication method of such a procedure, in the node device installed in the transmission base, the signal switching means provided for each user, the signal input by the distribution server, The normality of a signal received from another transmission base via a crossover line branched from another multicast superpath is determined. The signal switching means selects and duplicates one of the two input signals, and selects and duplicates the other signal according to the signal state. Then, the transmitter of the node device transmits the duplicated signal to a plurality of receiving bases through its own multicast superpath.
Therefore, since the branch of the multicast super path is also used as the transfer line between the transmission bases, the cost can be reduced by reducing the equipment necessary for installing the transfer line.

  According to the present invention, a redundant network that accommodates multicast communication can be configured at low cost.

It is a block diagram which shows typically the node apparatus which comprises the redundant network which concerns on embodiment of this invention. It is a flowchart which shows an example of the delivery operation | movement of the signal of the user 1 by the node apparatus N1 installed in the transmission base T1 of FIG. It is a flowchart which shows an example of the delivery operation | movement of the signal of the user 2 by the node apparatus N1 installed in the transmission base T1 of FIG. It is a flowchart which shows the operation example of the node apparatus N3 installed in receiving base R1 of FIG. It is explanatory drawing which shows the flow of the signal at the time of a failure of a delivery server. In Comparative Example 1 and Comparative Example 2, it is explanatory drawing which shows an example of the signal injection | throwing-in timing from a delivery server. It is a block diagram which shows typically the node apparatus which comprises the redundant network which concerns on other embodiment of this invention. FIG. 8A is a flowchart showing an example of the trigger signal generation process by the signal duplicating unit in FIG. 7, and FIG. 8B is a flowchart showing an example of the process by the priority determining unit in FIG. FIG. 9A is a flowchart showing an example of priority determination processing by the signal duplicating unit of FIG. 7, and FIG. 9B is a flowchart showing another operation example of the label attaching unit of FIG. It is a schematic diagram of the conventional network which provides multicast transmission as a service. It is a schematic diagram of the network which made the transmission line of FIG. 10 redundant. It is a schematic diagram of the structural example 1 of the conventional redundant network which shared a communication network. It is a schematic diagram of the structural example 2 of the conventional redundant network which shared a communication network. It is a schematic diagram of the structural example 3 of the conventional redundant network which shared a communication network.

The node device and redundant system communication method of the present invention will be described below in detail with reference to the drawings.
(First embodiment)
With reference to FIG. 1, the communication method of the node device and redundant system according to the first embodiment will be described. The redundant network 1 is provided as a network service that multicasts signals input from the user distribution servers 11A, 12S, 11S, and 12A from the transmission bases T1 and T2 to the reception bases R1 and R2.

[Sending location]
The transmission bases T1 and T2 are facilities of a communication carrier in which a node device including a transmitter of the communication carrier is installed. The transmission base T1 and the transmission base T2 have a remote relationship with each other so that a great natural disaster can be avoided. In FIG. 1, the number of transmission bases is two. However, the number is not limited to this, and may be the same number as three or more predetermined redundancy degrees.

[Receiving location]
The reception bases R1 and R2 are facilities of a communication carrier in which node devices including a receiver of the communication carrier are installed. In FIG. 1, the number of reception bases is two, but is not limited thereto, and may be three or more.

[Distribution server]
The distribution server 11A is an active (Active) distribution server for the user 1, and inputs a distribution signal to the transmission base T1.
The distribution server 11S is a standby distribution server for the user 1 and inputs a distribution signal to the transmission base T2.
The distribution server 12A is an active distribution server for the user 2 and inputs a distribution signal to the transmission base T2.
The distribution server 12S is a standby distribution server for the user 2 and inputs a distribution signal to the transmission base T1.

  These distribution servers 11A, 12S, 11S, and 12A are arbitrarily installed by the user, and are connected to the communication carrier devices at the transmission bases T1 and T2 using an arbitrary communication method. As a method for the user to arbitrarily install the user distribution server, a data center or the like may be constructed, or the facility may be installed in a telecommunications carrier facility.

[User's terminal]
The terminal 21a is the terminal of the user 1 and receives a signal transferred from the reception base R1.
The terminal 21b is the terminal of the user 1 and receives a signal transferred from the reception base R2.
The terminal 22a is a terminal of the user 2 and receives signals transferred from the reception bases R1 and R2.

  These users' terminals 21a, 21b, and 22a are arbitrarily installed by the user, and are connected to the communication carrier apparatus at the reception base using an arbitrary communication method. As a method of installing a terminal arbitrarily by a user, a data center or the like may be constructed, or it may be installed in a facility of a telecommunications carrier.

  For example, when the user 1 is a distribution company, for example, the distribution server 11A is installed at the Tokyo head office, the distribution server 11S is installed at the Osaka head office, and the terminals 21a and 21b are installed at a regional branch or a store. Good. A plurality of relay node devices (not shown) are connected between the transmission bases T1, T2 and the reception bases R1, R2.

  As shown in FIG. 1, the redundant network 1 is based on the configuration of the redundant network 104 shown in FIG. However, the redundant network 1 includes a transmitter 34 and a receiver that are used in the configuration of the transfer lines 6 and 7 (FIG. 14) for operating the switching units 41 and 42 in units of users at the redundant transmission bases T1 and T2. Instead of the device 35 (FIG. 14), a receiver 33 similar to the receiver 51 installed at the reception bases R1 and R2 of the multicast communication path is installed. Further, the redundant network 1 is set so that the multicast superpath (hereinafter referred to as MC superpath) 8 and the MC superpath 9 are also branched to the transmission bases T1 and T2, and also functions as a crossover line. These points are greatly different from the redundant network 104 shown in FIG.

[Multicast super path 8]
The multicast transmission path from the transmission base T1 for the distribution signal of the user 1 and arrival at the reception bases R1 and R2 is the same as the multicast transmission path from the transmission base T1 for the distribution signal of the user 2 and arrival at the reception bases R1 and R2. Has a path structure.
The MC super path 8 is a path accommodating multicast transmission paths for each user having the same route structure from the transmission base T1 to the plurality of reception bases R1 and R2.
In the state shown in FIG. 1 (active signal state), the MC super path 8 has a main line 8a, a base line 8b, a main line 8c, a base line 8d, and a crossover line 8e. A line 8f and a base line 8g are included.

The main line 8a connects the transmitter 31 of the node device N1 and the switching means 52 of the node device N3.
The intra-base line 8b connects the receiver 51 and the switching means 52 in the node device N3.
The main line 8c connects the transmitter 31 of the node device N1 and the switching unit 52 of the node device N4.
The base line 8d connects the receiver 51 and the switching means 52 in the node device N4.
The crossover line 8e branches from the main line 8a toward the transmission base T2, and connects the transmitter 31 of the node device N1 and the switching means 32 of the node device N2.
The crossover line 8f branches off from the main line 8c and goes to the transmission base T2, and connects the transmitter 31 of the node device N1 and the switching means 32 of the node device N2. The reason for setting a plurality of crossover lines is to ensure the redundancy of the crossover lines.
The base line 8g connects the switching means 32 and the receiver 33 in the node device N2.

[Multicast super path 9]
The multicast transmission path from the transmission base T2 for the delivery signal of the user 1 and arrival at the reception bases R1 and R2 is the same as the multicast transmission path from the transmission base T2 for the delivery signal of the user 2 and arrival at the reception bases R1 and R2. Has a path structure.
The MC super path 9 is a path accommodating multicast transmission paths for each user having the same route structure from the transmission base T2 to the plurality of reception bases R1 and R2.
The MC super path 9 includes a main line 9a, a main line 9b, a transition line 9c, a transition line 9d, and an intra-site line 9e in the state shown in FIG. Yes.

The main line 9a connects the transmitter 31 of the node device N2 and the switching means 52 of the node device N4.
The main line 9b connects the transmitter 31 of the node device N2 and the switching means 52 of the node device N3.
The transfer line 9c branches from the main line 9a toward the transmission base T1, and connects the transmitter 31 of the node device N2 and the switching means 32 of the node device N1.
The crossover line 9d branches from the main line 9b to the transmission base T1, and connects the transmitter 31 of the node device N2 and the switching means 32 of the node device N1.
The base line 9e connects the switching means 32 and the receiver 33 in the node device N1.

[Node equipment]
A node device N1 is installed at the transmission site T1, and a node device N2 is installed at the transmission site T2. A node device N3 is installed at the reception site R1, and a node device N4 is installed at the reception site R2. Each node device includes, for example, a CPU, a RAM, a ROM, an HDD, a NIC (Network Interface Card) for communication, and the like, and includes an optical cross-connect, a router, a switch, and the like.

[Configuration of Node Device N1]
The node device N1 includes a transmitter 31, a switching unit 32, a receiver 33, and a plurality of switching units (signal switching units) 41 and 42.
In the following, when the node device N2 side (other transmission base T2 side) is viewed from the node device N1 side (own transmission base T1 side), the MC superpath 8 is the own MC superpath and the MC superpath 9 is the other MC. The super path and the transfer lines 8e and 8f are also called own transfer lines, and the transfer lines 9c and 9d are also called other transfer lines.

  The transmitter 31 transmits an input signal (data) to a plurality of reception bases R1 and R2 through its own MC super path 8. This data is copied (replicated) at the data copy point C. The transmitter 31 is, for example, a transponder device that converts a data signal input in the Ethernet format into an optical signal in the OTN format suitable for long-distance transmission and transmits the data signal. The transmitter 31 transmits the input signal (data) to the node device N2 at the other transmission base T2 via the own connection lines 8e and 8f branched from the own MC super path 8. This data is copied (replicated) at the data copy point C. Note that the data copy point C can be configured using an optical splitter or the like to perform copying at the optical level.

  The switching means 32 selects one of the signals input from the other transfer lines 9c and 9d branched from the other MC super path 9, and transfers it to the receiver 33 via the in-site line 9e. Switch the crossover line accordingly. For this switching means 32, for example, a receiving end switching method used in Ethernet linear protection (see Non-Patent Document 2) or the like is implemented.

  The receiver 33 receives the signal distributed via the other transfer lines 9c and 9d branched from the other MC super path 9 via the switching means 32 and the intra-site line 9e. The receiver 33 is a device that performs a reverse conversion to the transmitter 31.

The switching means 41, 42 is provided for each user, and performs normality determination between a signal input to the own transmission base T1 and a signal distributed from the other transmission base T2 through the other MC super path 9. Then, one of them is copied and output. The switching means 41, 42 performs signal switching when any abnormality of the input signal is detected.
The switching unit 41 is a switching unit dedicated to the signal of the user 1, and is connected to the first port for signals input by the user 1's active distribution server 11A and the other transmission bases T2 via the crossover lines 9c and 9d. And a second port for received signals.
The switching means 42 is a switching means dedicated to the signal of the user 2 and is connected to the first port for signals input by the standby distribution server 12S of the user 2 and the other transmission bases T2 via the other transfer lines 9c and 9d. And a second port for received signals.
Here, the switching units 41 and 42 are illustrated as external devices installed in the preceding stage of the transmitter 31, but may be realized as a built-in mechanism of the transmitter 31.

  With the above configuration, the node device N1 is normal between the signal input to the transmission base T1 by the switching units 41 and 42 and the signal distributed from the other transmission base T2 through the MC super path 9. The multicast path for each user output after the determination is accommodated in the own MC super path 8 by the transmitter 31 and transmitted. Switching between user units is performed as necessary after the normality of the two-input signal is determined by the switching unit 41 or the switching unit 42.

[Configuration of Node Device N2]
Similarly to the node device N1, the node device N2 includes a transmitter 31, a switching unit 32, a receiver 33, and a plurality of switching units (signal switching units) 41 and 42.
In the following, the difference between the various signal flows and the node device N1 will be described.
When the node device N2 side (own transmission base T2 side) is viewed from the node device N1 side (other transmission base T1 side), the MC superpath 9 is the own MC superpath, the MC superpath 8 is the other MC superpath, The transfer lines 9c and 9d are also called own transfer lines, and the transfer lines 8e and 8f are also called other transfer lines.

  The transmitter 31 transmits the input signal (data) to the plurality of reception bases R1 and R2 through its own MC super path 9. This data is copied (replicated) at the data copy point C. The transmitter 31 transmits the input signal (data) to the node device N1 of the other transmission base T1 via the self-transfer lines 9c and 9d branched from the own MC super path 9. This data is copied (replicated) at the data copy point C.

The switching means 32 selects one of the signals input from the other transfer lines 8e and 8f branched from the other MC super path 8, and transfers the selected signal to the receiver 33 through the base line 8g.
The receiver 33 receives the signal distributed via the other crossover lines 8e and 8f branched from the other MC super path 8 via the switching means 32 and the intra-site line 8g.

The switching means 41 and 42 are provided for each user, and perform normality determination between a signal input to the own transmission base T2 and a signal distributed from the other transmission base T1 through the other MC super path 8. Then, one of them is copied and output.
The switching means 41 includes a first port for signals input by the standby distribution server 11S of the user 1, a second port for signals received from the other transmission base T1 via the other transfer lines 8e and 8f, It has.
The switching means 42 includes a first port for signals input by the active distribution server 12A of the user 2, a second port for signals received from the other transmission base T1 via the other connection lines 8e and 8f, It has.

  With the above configuration, the node device N2 is normal between the signal input to the transmission base T2 by the switching units 41 and 42 and the signal distributed from the other transmission base T1 through the MC super path 8. The multicast path for each user output after the determination is accommodated in the own MC super path 9 by the transmitter 31 and transmitted.

[Configuration of Node Devices N3 and N4]
The node devices N3 and N4 include a receiver 51 and a switching unit 52. These configurations are the same as those shown in FIG.
The receiver 51 is a device that performs a reverse conversion to the transmitter 31 of the node devices N1 and N2, and is a transponder device that converts an optical signal input in the OTN format into a data signal in the Ethernet format and sends it out. . The receiver 51 has the same configuration as the receiver 33 of the node device N1.
The switching means 52 selects one of the signals input at different starting points and distributes (transfers) the signal to the terminal 21a or the terminal 21b. For this switching means 52, for example, a receiving end switching method used in Ethernet linear protection (Non-patent Document 2) or the like is implemented.
Since these structures are the same as those shown in FIG. 12, further description thereof is omitted.

[User 1 signal distribution operation by node device]
The signal distribution operation of the user 1 by the node device will be described with reference to FIG. 2 (refer to FIG. 1 as appropriate). Here, as an example, the signal distribution operation of the user 1 by the node device N1 installed at the transmission base T1 in FIG. 1 will be described.
In this case, first, a signal from the active distribution server 11A of the user 1 is input to the switching unit 41 of the node device N1 (step S1). Thereby, the switching means 41 recognizes the signal from the distribution server 11A as an active signal. That is, the selection system at this time is a signal from the distribution server 11A. After that, in the node device N1, the switching unit 32 receives a signal from the branch transfer line (for example, the transfer line 9c) of the standby MC superpath 9 (step S2), and the signal from the transfer line 9c becomes normal. It is determined whether or not it is detected (step S3). If an abnormality is detected in the signal from the transfer line 9c (step S3: No), the switching unit 32 switches the route of the transfer line, for example, selects the transfer line 9d (step S4).

  In step S3, when the signal from the crossover line 9c is normal (step S3: Yes), this signal is input to the switching means 41 via the receiver 33. Then, the switching unit 41 determines whether both the input signal from the distribution server 11A and the input signal (two input signals) from the transfer line 9c are normal (step S5). If the two input signals are both normal (step S5: Yes), the switching means 41 selects and duplicates the signal from the current distribution server 11A, which is the current selection system (step S6).

In step S5, when an abnormality is detected in the selected system signal (current system signal from the distribution server 11A at this time) (step S5: No), the switching unit 41 selects the non-selected system signal (at this time). Switching is made so that the standby signal from the transfer line 9c is selected (step S7), and the signal is duplicated (step S8).
Subsequent to step S6 or step S8, in the node device N1, the transmitter 31 transmits the duplicated signal from the active MC super path 8 (step S9).

[Distribution operation of signal of user 2 by node device]
The signal distribution operation of the user 2 by the node device will be described with reference to FIG. 3 (refer to FIGS. 1 and 2 as appropriate). Here, as an example, the signal distribution operation of the user 2 by the node device N1 installed at the transmission base T1 in FIG. 1 will be described.
The processing in steps S11 to S13 is the same as the processing in steps S2 to S4 in FIG. However, if the signal from the crossover line 9c is normal in step S12 (step S12: Yes), this signal is input to the switching means 42 via the receiver 33. That is, a signal from the active distribution server 12A of the user 2 on the transmission base 2 side is first input to the switching unit 42 of the node device N1. As a result, the switching means 42 recognizes the signal from the connecting line 9c as an active signal. That is, the selection system at this time is a signal from the crossover line 9c. Thereafter, in the node device N1, a signal from the standby distribution server 12S of the user 2 is input to the switching unit 42 (step S14).

Then, the switching unit 42 determines whether or not both the input signal from the crossover line 9c and the input signal (two input signals) from the distribution server 12S are normal (step S15). When the two input signals are both normal (step S15: Yes), the switching means 42 selects and duplicates the signal from the transfer line 9c which is the current selection system (step S16).
In step S15, when an abnormality is detected in the selected system signal (the signal from the crossover line 9c at this time) (step S15: No), the switching unit 42 selects the non-selected system signal (at this time, the distribution server 12S). Is switched (step S17), and the signal is duplicated (step S18).

Subsequent to step S16 or step S18, in the node device N1, the transmitter 31 transmits the duplicated signal from the active MC superpath 8 (step S19).
As shown in FIGS. 2 and 3, the node device N1 determines that the multicast path of the user 1 is transmitted by the transmitter 31 when the two input signals are normal in the switching units 41 and 42 (both Yes in step S5 and step S15). (Active signal) and the multicast path (active signal) of user 2 are accommodated in the active MC superpath 8 and both signals are transmitted (step S9).

[Reception of user signal by node equipment]
The user signal reception operation by the node device will be described with reference to FIG. 4 (see FIGS. 1 to 3 as appropriate). Here, as an example, the reception operation of the signals of the users 1 and 2 by the node device N3 installed at the reception base R1 in FIG. 1 will be described.
In this case, in the node device N3, the switching unit 52 first receives a signal from the MC super path 8 (step S21), and recognizes the signal from the MC super path 8 as a working system signal. That is, the selection system at this time is a signal from the MC super path 8. Thereafter, the switching means 52 receives a signal from the spare MC super path 9 (step S22), and both systems recognize that they are in a normal state. In this case, the current selected system (active system) is not changed. The active MC super path 8 is selected (step S23), and the signal is transmitted to the receiver 51 via the intra-site line 8b. Here, the active MC super path 8 accommodates a signal from the active distribution server 11A of the user 1 and a signal from the active distribution server 12A of the user 2.

  In the node device N3, the switching unit 52 determines whether or not an abnormality has occurred in either the MC super path 8 or the MC super path 9 (step S24). When the signal interruption of the MC super path 8 of the selected system is detected (step S24: Yes), the switching unit 52 switches the operation so as to select the signal from the MC super path 9 (step S25). Here, the spare MC super path 9 accommodates a signal from the active distribution server 11A of the user 1 and a signal from the active distribution server 12A of the user 2. Therefore, services to the terminals of users 1 and 2 are continued. At this time, the intra-site line 8b (FIG. 1) of the MC superpath 8 connecting the receiver 51 and the switching means 52 in the node device N3 is the base of the MC superpath 9 as shown in FIG. It is replaced with the internal line 9f.

  In step S24, when the receiver 51 does not detect any abnormality in the selected active MC super path 8 (step S24: No), step S25 is skipped. Subsequent to step S25, the receiver 51 transfers a reception signal from one of the MC super paths 8 and 9 to the user terminal (step S26). Specifically, the receiver 51 transfers a signal from the distribution server of the user 1 to the terminal 21a of the user 1 and transfers a signal from the distribution server of the user 2 to the terminal 22a of the user 2. In the case of the node device N4 at the receiving base R2, the receiver 51 transfers a signal from the user 1 distribution server to the user 1 terminal 21b and also transmits a signal from the user 2 distribution server to the user 2 terminal 22a. Forward to.

As described above, according to the network communication method according to the present embodiment, by configuring a redundant network using the MC super path, the network can be shared among users who use multicast communication, so the service is inexpensive. Can be provided.
Moreover, since the switching means 41 and 42 switch a signal for every user, it can hold | maintain the information of a selection type | system | group independently for every user.
Further, since the switching means 41 and 42 are installed on the transmission bases T1 and T2 side, the cost can be reduced by reducing the number of switching means equipped in the network as compared with the reception base user unit switching method (FIG. 13). Can be reduced.
Furthermore, by using the branch of MC superpaths 8 and 9 as the transfer line between the transmission bases T1 and T2, the necessary equipment for installing the transfer line is provided compared to the switching line using user unit switching method (FIG. 14). By reducing the cost, the cost can be reduced.

  In addition, in the switching line using user switching method, N × (N−1) × 2 transition lines must be installed for the number of transmission bases N, and the switching line cost increases in the order of N squared. There is a problem. On the other hand, according to the network communication method according to the present embodiment, it is not necessary to provide a separate crossover line even if the number of transmission bases increases, and the cost reduction effect compared with the crossover line user switching method increases as the transmission bases increase. Therefore, the cost reduction effect becomes more remarkable as the redundancy increases.

In the first embodiment, when the distribution servers 11A and 11S start distribution at the same time, the switching means 41 of the transmission bases T1 and T2 are directly connected before receiving signals from other transmission bases via the crossover line. Each distribution server is selected. Therefore, in this case, the signal of the distribution server 11A is distributed from the transmission base T1 to the reception bases R1 and R2, and the signal of the distribution server 11S is distributed from the transmission base T2 to the reception bases R1 and R2. The signal state at this time is shown as a redundant network 1B (Comparative Example 1) in FIG. In the first comparative example, the configuration subsequent to the transmitter 31 of the MC superpaths 8 and 9 is the same as that of the receiving end superpath unit switching method of FIG. 12, and does not satisfy the conditions for holding independent selection systems for each user. become.
Although not shown, the switching means 52 at the reception base R1 first receives a signal from the MC super path 8, and the switching means 52 at the reception base R2 first receives a signal from the MC super path 9. In this case, since the terminal 21b receives the signal from the distribution server 11S, the network selection systems in the terminals 21a and 21b of the user 1 become inconsistent.

  In order to solve this problem, the switching means 41 of the transmission base T2 to which the standby distribution server 11S of FIG. 1 is connected has a transmission delay of at least the transit lines 8e and 8f from the initial state with respect to the signal input of the first port. You may make it perform waiting control which does not receive a signal input only for the above predetermined time. That is, in the initial state where there is no signal input to both the first and second ports, even if there is a signal input from the distribution server 11S to the first port, the predetermined time is waited, and during that time, the second port receives the signal from the distribution server 11A. When there is a signal input, the second port is forcibly selected. Note that the switching means 41 of the transmission base T1 to which the active distribution server 11A is connected does not wait.

(Second Embodiment)
With reference to FIG. 7, a redundant network communication method and node device according to the second embodiment will be described. A redundant network 1C shown in FIG. 7 is an implementation example in a packet transmission network using label switching. In the redundant network 1C according to the second embodiment, the same components as those in the redundant network 1 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

[Configuration of Redundant Network 1C]
In the redundant network 1C, the node device N1 in FIG. 1 is configured by the transmitter 31, the switching unit 32, the receiver 33, the switching units 41 and 42, and the label providing units 71b and 71c installed at the transmission base T1. It is composed.
The node device N2 of FIG. 1 is configured by the transmitter 31, the switching unit 32, the receiver 33, the switching units 41 and 42, and the label providing units 71e and 71f installed at the transmission base T2. .
The node device N3 of FIG. 1 is configured by the receiver 51, the switching unit 52, and the label releasing units 72b and 72c installed at the receiving base R1.
The node device N4 shown in FIG. 1 is configured by the receiver 51, the switching unit 52, and the label releasing units 72e and 72f installed at the receiving base R2.

In the node device N1, the transmitter 31 includes a label attaching unit 71a, and the receiver 33 includes a label releasing unit 72a.
In the node device N3, the receiver 51 includes a label releasing unit 72a.
In the node device N2, the transmitter 31 includes a label attaching unit 71d, and the receiver 33 includes a label releasing unit 72d.
In the node device N4, the receiver 51 includes a label releasing unit 72d.

  As a premise, in the node device in which label switching is performed, it is not necessary to physically equip the transmitter 31, the receiver 33, the switching unit 32, the receiver 51, and the switching unit 52 by the number of users and the number of communication paths. .

The label assigning means 71b divides the signal input from the active distribution server 11A of the user 1 into packets, assigns labels to the divided packets, and inputs them to the first port of the switching means 41. This label assigning means 71b is a label indicating, for example, “path 1-1” for all packets input from the physical port to which communication from the distribution server 11A is connected. Add the number corresponding to “1”. Therefore, the packet length is extended as compared with the input time.
When the configuration of the packet input to the label attaching unit 71b and the configuration of the packet output from the label attaching unit 71b are arranged in order from the top in order, they can be expressed as follows.
Input packet: [Header] [Payload]
Output packet: [numeric value representing path 1-1] [header] [payload]

  The label assigning means 71e divides the signal input from the standby distribution server 11S of the user 1 into packets, assigns labels to the divided packets, and inputs them to the first port of the switching means 41. The label attaching unit 71e adds, for example, a label indicating “path 1-2” to all packets input from the physical port to which communication from the distribution server 11S is connected.

  The label assigning means 71f divides the signal input from the active distribution server 12A of the user 2 into packets, assigns labels to the divided packets, and inputs them to the first port of the switching means 42. The label attaching unit 71f adds, for example, a label indicating “path 2-1” to all packets input from the physical port to which communication from the distribution server 12A is connected.

  The label assigning unit 71c divides the signal input from the standby distribution server 12S of the user 2 into packets, assigns labels to the divided packets, and inputs them to the first port of the switching unit 42. The label attaching unit 71c adds, for example, a label representing “path 2-2” to all packets input from the physical port to which communication from the distribution server 12S is connected.

The label attaching unit 71a attaches a label representing, for example, “super path 1” to the head of the input packet. Specifically, a numerical value corresponding to “super path 1” is added to the head of the packet.
In the signal state shown in FIG. 7, when the configurations of two types of packets input to the label attaching unit 71 a are arranged in order from the top in order, they can be expressed as follows.
Packet 1: [numeric value indicating path 1-1] [header] [payload]
Packet 2: [numeric value indicating path 2-1] [header] [payload]
When the configuration of the packet output from the label assigning unit 71a corresponding to the above two types of packets is arranged side by side in order from the top, it can be expressed as follows.
Packet 1: [numeric value representing super path 1] [numeric value representing path 1-1] [header] [payload]
Packet 2: [Numeric value representing Super Path 1] [Numerical value representing Path 2-1] [Header] [Payload]
The label assigning unit 71d similarly assigns a label representing, for example, “super path 2” to the head of the input packet. Since the label applying unit 71d has the same configuration as the label applying unit 71a, description thereof is omitted.

The label canceling means 72a at the receiving base R1 cancels a label representing, for example, “super path 1” from the input packet. Specifically, the numerical value (label) corresponding to “super path 1” is removed from the head of the packet.
In the signal state shown in FIG. 7, when the configurations of the two types of packets input to the label releasing means 72a are arranged in order from the top in order, they can be expressed as follows.
Packet 1: [numeric value representing super path 1] [numeric value representing path 1-1] [header] [payload]
Packet 2: [Numeric value representing Super Path 1] [Numerical value representing Path 2-1] [Header] [Payload]
When the configuration of the packet output from the label releasing means 72a corresponding to the above two types of packets is arranged in order from the top in order, it can be expressed as follows.
Packet 1: [numeric value indicating path 1-1] [header] [payload]
Packet 2: [numeric value indicating path 2-1] [header] [payload]
The label releasing means 72a at the transmitting base T1 performs the same operation as the above-described operation of the label releasing means 72a at the receiving base R1.
The label releasing means 72d at the receiving base R2 similarly releases, for example, a label representing “super path 2” from the input packet. The label releasing means 72d operates in the same manner as the label releasing means 72a, except that the label type is different. The label releasing means 72d at the transmission base T2 performs the same operation as the label releasing means 72d at the receiving base R2.

In the case of the label canceling means 72a at the receiving base R1, for example, a packet assigned with [Numeric value representing path 1-1] or [Numerical value representing path 1-2] is transferred to the label canceling means 72b. Note that [Numerical value representing path 1-2] is also included in the condition because the packet with the label representing "path 1-2" flows through the network due to the failure of the active system of user 1, etc. This is because the communication is continued even in the case of being.
Similarly, in the case of the label releasing means 72a at the receiving base R1, for example, a packet with [Numerical value representing path 2-1] or [Numerical value representing path 2-2] transferred to the label releasing means 72c. To do.
Further, in the case of the label releasing means 72d at the receiving base R2, further, for example, a packet assigned with [Numerical value representing path 2-1] or [Numerical value representing path 2-2] is transferred to the label releasing means 72e. .
Similarly, in the case of the label canceling means 72d at the receiving base R2, a packet to which, for example, [numeric value representing path 1-1] or [numerical value representing path 1-2] is given is transferred to the label canceling means 72f. To do.

The label releasing means 72b, 72f removes the label from the input packet and uses the label ([numeric value representing path 1-1] or [numeric value representing path 1-2]) as a clue to the node device 21a, 21b. Output to the corresponding physical port.
The label releasing means 72c, 72e removes the label from the input packet and uses the label ([numeric value representing path 2-1] or [numeric value representing path 2-2]) as a clue to the corresponding node device 22a. Output to the physical port.

The label assigning means and the label releasing means in FIG. 7 are logical functional blocks that add or delete the label data as additional data to the packet group in the form of storing the communication data and dividing it. The implementation is also possible with a computer equipped with a CPU, RAM and the like for reading and writing packets and software on it.
By doing this, even when the same device is physically processing packet input from different users, by using software that changes the operation by identifying the label attached to all packets, It can appear as if there are logically separated functional blocks.

  The switching units 41 and 42 for each user at the transmission bases T1 and T2 include a priority determining unit 61 and a signal duplicating unit 62. The signal duplicating unit 62 sets the first port and the second port as described above. Have.

  The priority determination means 61 determines the priority (it becomes the priority for the first port at the own transmission base) when a predetermined trigger signal is received. For example, the priority determination means 61 at the transmission base T1 randomly determines a priority using a random number for the input operation trigger, and notifies the determined priority to the signal duplicating means 62 at the transmission base T1. Then, the transmitter 31 notifies the switching means 41 of the transmission base T2 of the control packet including the determined priority through the transfer lines 8e and 8f (multicast path) which are branches of the active MC super path 8. To do. This determined priority is a priority for the second port at the other transmission bases.

  For the random number determination in the priority determination means 61, for example, a device that generates a true random number is separately installed, or a pseudo random number generator that can be input with any number determined at the time of production for each device as a seed is used. can do. As a result, the possibility of priority collision between the transmission bases T1 and T2 can be sufficiently reduced, and an early end of the active system selection can be expected.

The signal duplicating unit 62 outputs a trigger signal to the priority determining unit 61 (priority determining internal trigger) every time it detects a normal or abnormal state change of signals input to the first port and the second port.
The signal duplicating unit 62 compares the priority determined by the priority determining unit 61 (the priority for the first port) with the priority for the second port notified separately, and the higher priority is determined. The signal input to the port is duplicated and output to the transmitter 31. Here, the priority for the second port to be notified separately is included in the control packet to be notified through the crossover line that is a branch of another MC superpath after the priority determining means 61 at the other transmission base determines. It is a priority.

For example, the signal duplicating means 62 at the transmission base T1 determines the priority notified from the priority determination means 61 of the own transmission base T1 and the priority of the other transmission base T2 when the two input signals are both normal signals. The larger one of the priorities notified from the means 61 is selected as the active system.
At this time, if the priority notified from the priority determination means 61 of the self-transmission base T1 is larger, the signal duplicating means 62 selects the signal input from the first port as the active signal and selects the selected signal. Duplicate and output.
If the priority notified from the priority determining means 61 at the self-transmission site T1 is smaller, the signal duplicating means 62 selects the signal input from the second port as the active signal, and selects the selected signal. Duplicate and output.
If the two priorities have the same value, the signal duplicating unit 62 outputs a trigger signal for performing the priority determining operation to the priority determining unit 61 until the selection of the active system is completed. repeat.

  For example, the signal duplicating unit 62 at the transmission base T1 deletes the control packet for notifying the priority input from the second port without relaying it to the switched transmission path. As a result, the control packet transmitted to the transmission base T2 is returned at the transmission base T2, and is received by the signal duplicating means 62 of the self-transmission base T1 as a priority notification from the transmission base T2, whereby the own transmission base T1 is separately provided. The priority is notified to the signal duplicating means 62, and the priority determining means 61 is prevented from continuing to operate unnecessarily.

[Operation of Redundant Network 1C]
As shown in FIG. 8 (a), the signal duplicating means 62 included in the switching means 41, 42 for each user at the transmission bases T1, T2 continues to monitor the state of signals input to the first port and the second port. (Step S31: No) When a signal state change is detected (Step S31: Yes), a trigger signal is output to the priority determination means 61 (Step S32).

  As shown in FIG. 8B, when the priority determining means 61 provided in the switching means 41, 42 for each user at the transmission bases T1, T2 receives the trigger signal from the signal duplicating means 62 (step S41), the priority is determined. Determine (step S42). Then, the priority determination means 61 notifies the determined priority to the signal duplicating means 62 of the own transmission base and the signal duplicating means 62 of the other transmission base (step S43).

As shown in FIG. 9 (a), the signal duplicating means 62 included in the switching units 41 and 42 for each user at the transmission bases T1 and T2 receives the priority (priority for the first port) from the priority determination means 61 of the own transmission base. And the priority (priority for the second port) from the priority determination means 61 of the other transmission base (step S51), the two priorities are stored in the memory (step S52) and compared. (Step S53).
The signal duplicating unit 62 selects a signal to be input to the higher priority port, duplicates the selected signal, and outputs the duplicated signal to the transmitter 31 (step S54).

  The redundant network 1C according to the second embodiment includes a priority determining unit 61 and a signal duplicating unit 62 for each of the switching units 41 and 42 for each user at the transmission bases T1 and T2, and the signal duplicating unit 62 includes The normality of the signals input to the port and the second port is constantly monitored, and the operation of the priority determination means 61 is triggered (priority determination internal trigger) whenever there is a change in normality / abnormality. Therefore, the redundant network 1C reliably distributes the user's working signal to all the receiving bases R1 and R2, and reliably guarantees the interlocking operation of the switching means 41 and 42 for each user between the transmitting bases T1 and T2. be able to.

(Third embodiment)
With reference to FIG. 7, a redundant network communication method and node device according to the third embodiment will be described. In the redundant network 1D according to the third embodiment, not only can the priority be determined within each node device installed at the transmission bases T1 and T2, but also the user can manually input the priority in a format that is input from outside the node device. Is different from the redundant network 1C according to the second embodiment in that the distribution signal system can be selected. In this redundant network 1D, the same components as those in the redundant network 1C are denoted by the same reference numerals and description thereof is omitted.

  In the redundant network 1D, each node device installed at the transmission bases T1 and T2 includes a priority detection unit as a function that allows the user to manually set the priority. Here, the function of the priority detection unit is also used as the labeling unit. In other words, as a function other than the function of labeling, the labeling means is configured to read the priority specified by the user in the control packet and input it together with the trigger when detecting the control packet input by the user. Has been.

  Specifically, the label assigning means (priority detecting means) 71b of the node device N1 uses the first of the signal duplicating means 62 included in the switching means 41 of the user 1 at the transmission base 1 from the signal input by the distribution server 11A. A control packet designating the priority for the port and the priority for the second port is detected, and a trigger signal including each detected priority as the priority of the external input mode is output to the priority determining means 61.

  The label assigning means (priority detection means) 71c of the node device N1 determines the priority and the priority for the first port of the signal duplicating means 62 included in the switching means 42 of the user 2 at the transmission base 1 from the signal input by the distribution server 12S. A control packet designating the priority for the second port is detected, and a trigger signal including each detected priority as the priority of the external input mode is output to the priority determining means 61.

  The label assigning means (priority detecting means) 71e of the node device N2 determines the priority and the priority for the first port of the signal duplicating means 62 included in the switching means 41 of the user 1 at the transmission base 2 from the signal input by the distribution server 11S. A control packet designating the priority for the second port is detected, and a trigger signal including each detected priority as the priority of the external input mode is output to the priority determining means 61.

  The label assigning means (priority detection means) 71f of the node device N2 determines the priority of the first port of the signal duplication means 62 included in the switching means 42 of the user 2 at the transmission base 2 from the signal input by the distribution server 12A. A control packet designating the priority for the second port is detected, and a trigger signal including each detected priority as the priority of the external input mode is output to the priority determining means 61.

  The priority determination means 61 performs trigger execution at an arbitrary timing from the outside (priority determination external trigger) instead of an operation (priority determination internal trigger) for generating priority by a random number from the trigger signal from the signal duplicating means 62 Can be set. When the priority determining means 61 is set in this way, when the trigger signal including the priority is notified from the label giving means (priority detecting means) 71b, 71c, 71e, 71f, the notified priority is given. Degree can be set as priority to use.

  The label assigning means (priority detection means) 71b, 71c, 71e, 71f continue to monitor the state of the packet input from the distribution server as shown in FIG. When a packet (control packet) designating the degree is detected (step S61: Yes), a trigger signal including the priority designated by the packet is generated and output to the priority determining means 61 (step S62).

  According to the communication method of the redundant network 1D according to the third embodiment, the user sets the priority numerical value of the system desired to be the active system high and sets the priority numerical value of the system desired to be the standby system low, and then from the distribution server. By inputting the priority numerical value to the network using the control packet, the selection system can be arbitrarily determined.

  Furthermore, according to the communication method of the redundant network 1D, when performing distribution server maintenance, etc., when switching the system during operation, a higher priority is set from the server currently in the standby system. By inputting the corrected control packet, the priority determination unit 61 can be operated again without stopping the data transmission from the distribution server, and switching can be performed.

  As mentioned above, although each embodiment of this invention was described, this invention is not limited to these, It can implement in the range which does not change the meaning. For example, in the configuration example of the redundant networks 1C and 1D shown in FIG. 7, after the user input is divided into packets as in MPLS-TP or the like, a label is added and accommodated in the MC super paths 8 and 9 using label stacking. However, it can also be configured by assigning a wavelength to a transmission path for each user and regarding a fiber or the like that accommodates the transmission path as an MC super path.

1,1C, 1D Redundant system 8 MC super path (multicast super path)
8e, 8f Crossover line 9 MC super path (multicast super path)
9c, 9d Crossover lines 11A, 11S, 12A, 12S Distribution server 21a, 21b, 22a Terminal 31 Transmitter 32 Switching means 33 Receiver 41, 42 Switching means (Signal switching means)
51 receiver 52 switching means 61 priority determining means 62 signal duplicating means 71a, 71b, 71c, 71d, 71e, 71f label attaching means 72a, 72b, 72c, 72d, 72e, 72f label releasing means C data duplicating means N1, N2 , N3, N4 Node equipment R1, R2 Reception base T1, T2 Transmission base

Claims (8)

A node device installed in each of the transmission bases, constituting a redundant network for multicast transmission of signals input by a user distribution server from the same number of transmission bases as a predetermined redundancy degree,
The input signal is transmitted to a plurality of receiving bases by a self-multicast superpath which is a path accommodating multicast transmission paths for each user having the same route structure from the self-transmitting base to a plurality of receiving bases. A transmitter for branching the input signal from the own multicast superpath and transmitting the signal to another transmission base via a self-transmission line directed to the other transmission base;
It is distributed via a crossover line that branches from another multicast superpath, which is a path accommodating multicast transmission paths for each user having the same route structure from another transmitting base to a plurality of receiving bases, and is directed to the transmitting base. A receiver for receiving signals,
Monitors the normality of a signal provided for each user and input by the distribution server and a signal received from another transmission base via the other crossover line, and copies one of them to the transmitter. A node device comprising: a plurality of signal switching means for outputting and switching an output signal according to a signal state. The signal switching means includes a first port for a signal input by the distribution server of a predetermined user and a second port for a signal received from another transmission base,
The signal switching means to which a signal is input by a distribution server defined as a standby system accepts a signal input for a predetermined time from the initial state at least more than the transmission delay of the crossover line from the initial state. In the meantime, the second port is forcibly selected when a signal input from a distribution server defined as an active system is detected from the other transmission base to the second port via the other transfer line. The node device according to claim 1, which performs waiting control. The signal switching means is
A first port for signals input by the distribution server of a predetermined user;
A second port for signals received from other transmission bases;
Priority determination means for determining a priority for the first port when a predetermined trigger signal is received;
A trigger signal is output to the priority determining means each time a normal state change and an abnormal state change of signals input to the first port and the second port are detected, and the determined priority for the first port is The signal duplication which compares the priority with respect to the said 2nd port notified from other transmission bases via the said other crossover line, duplicates the signal input into a port with a higher priority, and outputs it to the said transmitter Means,
The priority determining unit notifies the signal duplicating unit of the determined priority for the first port, and transmits a control signal including the priority for the first port to the other transmission base through the self-transmission line. The node device according to claim 1, wherein notification is made to the signal switching means for the user.   A control packet that designates a priority for the first port and a priority for the second port is detected from a signal that is provided for each user and is input by the distribution server, and each detected priority is set to the external input mode. The node device according to claim 3, further comprising priority detection means for outputting a trigger signal including the priority of the priority to the priority determination means. A redundant network communication method for multicast transmission of a signal input by a user distribution server from the same number of transmission bases as a predetermined redundancy degree,
The node device installed at the transmission base includes a transmitter, a receiver, and a signal switching unit provided for each user,
The transmitter transmits an input signal to a plurality of receiving bases by a self-multicast superpath that is a path accommodating multicast transmission paths for each user having the same route structure from the self-transmitting base to a plurality of receiving bases. A transmission step of transmitting the input signal to the other transmission base via a self-transmission line that branches from the own multicast superpath to the other transmission base;
Crossover line that branches from another multicast superpath, which is a path accommodating multicast transmission paths for each user having the same route structure from another transmission base to a plurality of the reception bases, toward the own transmission base A receiving step for receiving a signal distributed via
The signal switching means monitors the normality of the signal input by the distribution server and the signal received from another transmission base via the other crossover line, and duplicates one of them to the transmitter. A redundant network communication method comprising: a signal switching step of outputting and switching an output signal according to a signal state. The signal switching means includes a first port for a signal input by the distribution server of a predetermined user and a second port for a signal received from another transmission base,
A signal switching means for receiving a signal from a distribution server defined as a standby system accepts a signal input from the initial state for a predetermined time that is at least equal to or longer than the transmission delay of the crossover line from the initial state. In the meantime, the second port is forcibly selected when a signal input from a distribution server defined as an active system is detected from the other transmission base to the second port via the other transfer line. The redundant network communication method according to claim 5, comprising a step of performing waiting control. The signal switching means includes a first port for a signal input by the distribution server of a predetermined user and a second port for a signal received from another transmission base,
In the signal switching step,
The signal switching means is
A step of outputting a predetermined trigger signal each time a normal state change and an abnormal state change of signals input to the first port and the second port are detected;
Determining a priority for the first port in response to the trigger signal;
Notifying the signal switching means for the user at the other transmission base through the self-transmission line of a control signal including a priority for the first port;
The determined priority for the first port is compared with the priority for the second port notified from another transmission base through the other crossover line, and a signal input to the port with the higher priority is obtained. The redundant network communication method according to claim 5, wherein the step of copying and outputting to the transmitter is executed. The node device includes priority detection means provided for each user,
The priority detection means detects a control packet designating a priority for the first port and a priority for the second port from a signal input by the distribution server, and externally inputs each detected priority. The redundant network communication method according to claim 7, further comprising a step of outputting a trigger signal including a mode priority to the signal switching unit.

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