COMMUNICATION DEVICE, COMMUNICATION METHOD, AND PROGRAM

Abstract

A communication device (10) according to the present disclosure comprises: a selection list creation unit (12) that creates a selection list including respective identifiers and weight reference values of a plurality of communication devices constituting a multihoming, on the basis of the respective identifiers of the plurality of communication devices constituting the multihoming, notified from another device, and on the basis of the respective weight reference values which correspond to the respective communication states of the plurality of communication devices constituting the multihoming; and a selection unit (13) that selects a designated forwarder (DF) and a backup DF (BDF) from the created selection list, on the basis of a predetermined condition based on the weight reference values.

Description

[Technical field]

[0001] The present disclosure relates to a communication device, a communication method, and a program. [Background technology]

[0002] One of the technologies for realizing a Layer 2 Virtual Private Network (L2VPN) is an Ethernet Virtual Private Network (EVPN) described in Non-Patent Document 1.

[0003] In EVPN, by distinguishing customer traffic by EVI (EVPN Instance) within the carrier's communication network, it is possible to provide L2VPN services to each customer. In addition, Non-Patent Document 1 defines EVPM Multihoming (hereinafter simply referred to as "Multihoming") in which multiple PEs are connected to one CE, with the aim of improving the availability of PEs (Provider Edges), which are carrier communication devices connected to CEs (Customer Edges), which are customer communication devices.

[0004] In Non-Patent Document 1, in Multihoming, an ES (Ethernet Segment) is defined for a link connecting a PE and a CE. When there are multiple PEs with the same ESI (ES Identifier), which is an identifier for identifying an ES, in a communication network of a communication carrier, it indicates that the multiple PEs are connected to the same CE.

[0005] In addition, in Non-Patent Document 1, one PE is selected as a DF (Designated Forwarder) for each ESI, and only the DF forwards BUM (Broadcast, Unknown unicast, Multicast) traffic to the CE, while the other PEs (non-DFs) do not forward (drop) the BUM traffic to the CE. This prevents broadcast storms (loop failures) from occurring even if one CE is connected to multiple PEs. In addition, Non-Patent Document 2 defines the non-DF that becomes the new DF when a failure occurs in the DF as the BDF (Backup DF).

[0006] Next, the DF selection algorithm (Service Carving) described in Non-Patent Document 1 and Non-Patent Document 2 will be described.

[0007] When an ESI is set in the PE conforming to Non-Patent Document 1, the PE sets Layer 2 VPN (25) in the Address Family Identifier of MP-BGP (Multi-protocol Border Gateway Protocol), sets EVPN (4) in the Subsequent Address Family Identifier, sets Ethernet Segment Route (4) in the Route type of the Network Layer Reachability information field, and transmits the ESI set in the PE, the IP address set in the PE, and the like to the communication network.

[0008] A PE connected to a communication network starts selecting a DF when the ESI set in the device itself is the same as the ESI notified by MP-BGP EVPN Route type4 and the PE discovers the IP address of a new PE belonging to the ESI. Specifically, the PE waits for a predetermined time (Discovery Timer) for MP-BGP EVPN Route type4 to be notified from other PEs in the communication network. After the Discovery Timer ends, the PE creates a list of IP addresses for each ESI. The PE creates the list by sorting the IP addresses of multiple PEs belonging to the ESI in ascending order, starting with the IP address of the PE with the smallest value as 0. Next, the PE obtains the remainder i (modulo operation) of dividing the EVI with the smallest value among the EVIs belonging to the ES by the number of PEs participating in the ES, and selects the i-th PE in the list as a DF.

[0009] Non-Patent Document 2 also describes a method for selecting DF and BDF. In this selection method, weights are calculated using variables such as a random function, ESI, Ethernet Tag (an identifier used to identify multiple BDs (Bridge Domains) existing in an EVI in a VLAN-Aware Bundle Service Interface, which is one of the three Service Instances defined in Non-Patent Document 1), and the IP address of a PE. Then, the PE with the smallest weight is selected as the DF, and the PE with the second smallest weight is selected as the BDF. [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] RFC7432 “BGP MPLS-Based Ethernet VPN” [Non-Patent Document 2] RFC8584 “Framework for Ethernet VPN Designated Forwarder Election Extensibility” Summary of the Invention [Problem to be solved by the invention]

[0011] The selection methods described in Non-Patent Documents 1 and 2 have the problem that they cannot flexibly select DF and BDF according to communication conditions such as bandwidth or delay because they use the settings of PEs in the communication network. For example, the selection methods described in Non-Patent Documents 1 and 2 may cause the bandwidth to be concentrated on the PE selected as the DF, resulting in congestion, and may cause a PE with a large delay to a certain CE to be selected as the DF.

[0012] In view of the above problems, an object of the present disclosure is to provide a communication device, a communication method, and a program that are capable of flexibly selecting a DF and a BDF according to the communication state. [Means for solving the problem]

[0013] In order to solve the above problem, a communication device disclosed herein is a communication device connected to a communication network, which forms a multihoming in which multiple communication devices are connected to a single customer network device, and is equipped with a selection list creation unit that creates a selection list including the identifiers and weight reference values ​​of each of the multiple communication devices that make up the multihoming based on the identifiers of each of the multiple communication devices that make up the multihoming notified from other devices and a weight reference value corresponding to the communication state of each of the multiple communication devices that make up the multihoming, and a selection unit that selects from the created selection list a DF (Designated Forwarder) that forwards traffic to the customer network device and a BDF (Backup DF) that becomes a new DF when a failure occurs in the DF, based on predetermined conditions based on the weight reference value.

[0014] In order to solve the above problem, a communication device disclosed herein is a communication device that is connected to multiple communication devices that form a multihoming with a single customer network device via a communication network, and is not part of the multihoming, and is equipped with a notification unit that notifies each of the multiple communication devices that form the multihoming of an identifier of each of the multiple communication devices that form the multihoming and a weight reference value corresponding to the communication state of each of the multiple communication devices that form the multihoming.

[0015] In addition, in order to solve the above problems, the communication method disclosed herein is a communication method by a communication device connected to a communication network, which forms a multihoming in which multiple communication devices are connected to a single customer network device, and creates a selection list including the identifiers and weight reference values ​​of each of the multiple communication devices that make up the multihoming based on the identifiers of each of the multiple communication devices that make up the multihoming notified by other devices and a weight reference value corresponding to the communication state of each of the multiple communication devices that make up the multihoming, and selects from the created selection list a DF (Designated Forwarder) that forwards traffic to the customer network device and a BDF (Backup DF) that becomes a new DF when a failure occurs in the DF, based on predetermined conditions based on the weight reference value.

[0016] In order to solve the above problem, a program according to the present disclosure causes a computer to function as the above-mentioned communication device. Effect of the Invention

[0017] According to the communication device, communication method, and program disclosed herein, it is possible to flexibly select a DF and a BDF according to the communication state. [Brief description of the drawings]

[0018] [Figure 1]FIG. 1 is a diagram illustrating a configuration example of a communication system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating an example of the operation of the PE illustrated in FIG. [Diagram 3] 2 is a diagram showing an example of a selection list created by a selection list creation unit shown in FIG. 1. FIG. [Figure 4] FIG. 11 is a diagram illustrating another configuration example of a communication system according to an embodiment of the present disclosure. [Diagram 5] FIG. 5 is a diagram illustrating an example of the operation of the PE illustrated in FIG. [Figure 6] 5 is a diagram showing an example of a weight reference value list created by a weight reference value list creation unit shown in FIG. 4. FIG. [Figure 7] 5 is a diagram showing an example of a weight reference value matrix created by a selection list creation unit shown in FIG. 4. [Figure 8] 5 is a diagram showing an example of selection of a DF and a BDF by a selection unit shown in FIG. 4. [Figure 9] 5 is a diagram showing another example of the selection of a DF and a BDF by the selection unit shown in FIG. [Figure 10] FIG. 13 is a diagram illustrating yet another configuration example of a communication system according to an embodiment of the present disclosure. [Figure 11] 5 is a diagram illustrating another example of the configuration of the PE 10a illustrated in FIG. [Figure 12] 5 is a diagram illustrating another example of the configuration of the PE 10 illustrated in FIG. 4. [Figure 13] 2 is a diagram illustrating an example of a hardware configuration of a PE 10 illustrated in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0020] Fig. 1 is a diagram illustrating a configuration example of a communication system 1 according to an embodiment of the present disclosure. As illustrated in Fig. 1, the communication system 1 according to the embodiment includes a plurality of PEs (Provider Edges) 10-1, 10-2, and 10-3 connected to a communication network 2. Hereinafter, when there is no need to distinguish between the PEs 10-1, 10-2, and 10-3, they will be referred to as PEs 10.

[0021] PE10 is a communication device of a telecommunications carrier provided in an edge region of a communication network 2. PE10 is connected to a CE (Customer Edge) 3, which is a customer's communication device (customer network device), via a link. In the example shown in FIG. 1, PE10-1 and PE10-2 are connected to one CE3-1. The same ESI:XX is set for the link between PE10-1 and CE3-1 and the link between PE10-2 and CE3-1. Therefore, PE10-1 and PE10-2 configure a Multihoming for CE3-1. That is, PE10-1 and PE10-2 are communication devices that configure a Multihoming in which multiple PE10s are connected to CE3-1 (one customer network device) and are connected to the communication network 2. From among the multiple PEs 10 constituting the Multihoming for CE3-1, PE10-1 and PE10-2 select a DF (Designated Forwarder) that forwards BUM traffic to CE3-1 and a BDF (Backup DF) that becomes a new DF when a failure occurs in the DF. Note that in this disclosure, the term "link" includes a physical link and a virtual link such as Link Aggregation or a Virtual Local Area Network (VLAN), and is not limited to a specific technology.

[0022] PE10-3 is connected to CE3-3. That is, PE10-3 is a communication device that is connected to CE3-3 (a customer network device different from one customer network device) different from CE3-1 and does not configure Multihoming with CE3-1. Also, PE10-3 is a communication device that is connected to multiple PE10-1 and PE10-2 that configure Multihoming with CE3-1 (a customer network device) via communication network 2 and does not configure Multihoming.

[0023] In addition, in order to simplify the explanation, an example in which there are two PEs 10 constituting the Multihoming is shown in Fig. 1, but the present invention is not limited to this, and there may be three or more PEs 10 constituting the Multihoming. Also, in Fig. 1, an example in which one CE 3 is connected to each PE 10 via a link is shown, but the present invention is not limited to this, and two or more CEs 3 may be connected to one PE 10.

[0024] Next, the configurations of PE10-1 and PE10-3 will be described. The configuration of PE10-2 is the same as that of PE10-1, so the description will be omitted. First, the configuration of PE10-3 will be described.

[0025] As shown in FIG. 1, the PE 10-3 includes a notification unit 11.

[0026] The notification unit 11 notifies each of the PE10-1, 10-2, which are multiple communication devices constituting the Multihoming, of the identifiers of each of the PE10-1, 10-2 (e.g., IP addresses set in each PE10) and the weight reference values ​​of each of the PE10-1, 10-2. The weight reference values ​​are values ​​corresponding to information (hereinafter referred to as "network information") related to the communication state of the PE10 (e.g., delay, bandwidth, number of hops in the communication network 2, metrics of the routing protocol, priority, etc.).

[0027] Next, the configuration of the PE 10-1 will be described.

[0028] As shown in FIG. 1, the PE 10-1 includes a selection list creation unit 12 and a selection unit 13.

[0029] The selection list creation unit 12 creates a selection list based on the identifiers of the multiple PEs 10 constituting the Multihoming and the weight reference values ​​of the multiple PEs 10 constituting the Multihoming, which are notified from another device. The selection list is a list including the identifiers and weight reference values ​​of the multiple PEs 10 constituting the Multihoming, and is used for selecting a DF and a BDF. As described above, the identifiers and weight reference values ​​of PEs 10-1 and 10-2 are notified from PE 10-3. Therefore, in FIG. 1, the other device is PE 10-3 that is connected to a CE 3-3 other than CE 3-1 (one customer network device) and does not constitute a Multihoming with CE 3-1.

[0030] The selection unit 13 selects a DF and a BDF from the selection list created by the selection list creation unit 12, based on predetermined conditions.

[0031] Next, the operation of the PEs 10-1 to 10-3 will be described with reference to FIG.

[0032] FIG. 2 is a diagram showing an example of the operation of PEs 10-1 to 10-3, and is a diagram for explaining a communication method according to the present disclosure.

[0033] PE10-3 learns through a control protocol (e.g., BGP EVPN Route Type 1 described in RFC7432) that the EVI for communication is set on PE10-1 and PE10-2, and that the identifiers of PE10-1 and PE10-2 and the same ESI are set on PE10-1 and PE10-2.

[0034] The notification unit 11 of PE10-3 notifies PE10-1, 10-2 of the identifiers (e.g., IP addresses) of PE10-1, 10-2 and the weight reference values ​​of PE10-1, 10-2 held by PE10-3 when a link between PE10-3 and CE3-3 is added / deleted, when a new CE3 is connected / removed to PE10-3, when a new EVI is added / changed / deleted to PE10-3, etc. (step S11).

[0035] As a means for transmitting and receiving the identifiers and weight reference values ​​of PEs 10 between PEs 10, a number of protocols can be used other than BGP, such as an Interior Gateway Protocol (IGP) and Traffic Engineering (TE) metrics defined in RFC7471.8570.

[0036] Based on the identifiers and weight reference values ​​of PE10-1 and 10-2 notified by PE10-3, the selection list creation units 12 of PE10-1 and 10-2 create a selection list including the identifiers and weight reference values ​​of the multiple PE10 (PE10-1 and 10-2) constituting the Multihoming (step S12).

[0037] FIG. 3 is a diagram showing an example of the selection list created by the selection list creation unit 12. As shown in FIG.

[0038] As shown in Fig. 3, the selection list creation unit 12 creates a selection list in which the identifiers of the multiple PEs 10 constituting the Multihoming are associated with a Weight reference value for each ES. Note that, in Fig. 3, an example in which a selection list is created for each ES has been described, but the present invention is not limited to this. The selection list creation unit 12 may create a selection list for each combination of ES and EVI described in RFC7432, for each combination of ES and Ethernet tag, for each combination of ES, EVI and Ethernet tag, for each combination of ES, EVI and MAC address obtained from EVPN Route-Type2, or for each combination of ES, EVI, Ethernet tag and MAC address.

[0039] Furthermore, when there are multiple weight reference values ​​based on multiple network information, the selection list creation unit 12 may calculate one weight reference value by performing arithmetic operations on the multiple weight reference values. Furthermore, the selection list creation unit 12 may calculate one weight reference value by, for example, multiplying the weight reference value based on the first network information by the reciprocal of the weight reference value based on the second network information. Furthermore, the selection list creation unit 12 may calculate one weight reference value from a function that uses the weight reference value for each network information as a variable.

[0040] The selection unit 13 selects a DF and a BDF from the selection list created by the selection list creation unit 12, based on a predetermined condition based on the weight reference value (step S13). For example, the selection unit 13 selects the PE10 having the smallest weight reference value in the selection list as the DE, and selects the PE10 having the second smallest weight reference value as the BDF. In the example shown in FIG. 3, the selection unit 13 selects PE10-2 as the DB, and selects PE10-1 as the BDF. The condition for selecting the DF and the BDF is not limited to the above example. For example, the selection unit 13 may select the PE10 having the largest weight reference value as the DE, and select the PE10 having the second largest weight reference value as the BDF. In addition, the selection unit 13 may select the DF and the BDF by comparing the magnitude of a value obtained by multiplying or dividing a value previously determined for each PE10 by the weight reference value.

[0041] Thus, in this embodiment, the PE 10-3 includes a notification unit 11. The notification unit 11 notifies each of the communication devices constituting the multihoming of the identifiers of each of the communication devices constituting the multihoming and a weight reference value according to the communication state of each of the communication devices constituting the multihoming. In addition, the PEs 10-1 and 10-2 include a selection list creation unit 12 and a selection unit 13. The selection list creation unit 12 creates a selection list including the identifiers and weight reference values ​​of each of the communication devices constituting the multihoming based on the identifiers of each of the communication devices constituting the multihoming and the weight reference value according to the communication state of each of the communication devices constituting the multihoming notified from another device. The selection unit 13 selects a DF and a BDF from the created selection list based on a predetermined condition based on the weight reference value.

[0042] By creating a selection list including weight reference values ​​according to the communication states of multiple communication devices (PE10-1, 10-2) that make up the multihoming, and selecting DF and BDF from the created selection list based on predetermined conditions based on the weight reference values, it is possible to flexibly select DF and BDF according to the communication states.

[0043] In FIG. 1, an example has been described in which identifiers and weight reference values ​​of multiple PEs 10 (PE10-1, PE10-2) constituting the Multihoming are notified from one PE 10 (PE10-3), but the present disclosure is not limited to this.

[0044] Fig. 4 is a diagram showing yet another configuration example of the communication system 1 according to an embodiment of the present disclosure. In Fig. 4, the same components as those in Fig. 1 are denoted by the same reference numerals, and description thereof will be omitted.

[0045] The communication system 1 shown in Fig. 4 includes a plurality of PEs 10a (10a-1, 10a-2) and PEs 10 (10-3, 10-4) connected to a communication network 2. The communication system 1 shown in Fig. 4 differs in that PEs 10-1, 10-2 are changed to PEs 10a-1, 10a-2 and that a PE 10-4 is added.

[0046] The PEs 10a-1 and 10a-2 are connected to one CE 3-1, and the same ESI:XX is set in the link between the PEs 10a-1 and CE 3-1 and in the link between the PEs 10a-2 and CE 3-1. Therefore, the PEs 10a-1 and 10a-2 configure Multihoming with respect to the CE 3-1.

[0047] PE10-4 is connected to CE3-4. That is, PE10-4 is a communication device that is connected to CE3-4 different from CE3-1 and does not form a multihoming with CE3-1. Also, PE10-4 is a communication device that is connected to multiple PEs 10a-1 and 10a-2 that form a multihoming with CE3-1 via a communication network 2 and does not form a multihoming. The configuration of PE10-4 is the same as that of PE10-3. Like PE10-3, PE10-4 notifies PE10a-1 and 10a-2 of the identifiers and weight reference values ​​of PEs 10a-1 and 10a-2 that form a multihoming.

[0048] 4, PE10-3 and 10-4, which are multiple communication devices connected to CE3-3 and 3-4 other than CE3-1 (one customer network device) and not forming a multihoming with CE3-1, notify PE10a-1 and 10a-2 of the identifiers and weight reference values ​​of PE10a-1 and 10a-2 forming a multihoming. PE10a-1 and 10a-2 select a DF and a BDF based on the identifiers and weight reference values ​​notified from PE10-3 and 10-4.

[0049] In addition, in order to simplify the explanation, Fig. 4 shows an example in which there are two PEs 10a constituting Multihoming, but the present invention is not limited to this, and there may be three or more PEs 10a constituting Multihoming. In addition, in Fig. 4, an example in which there are two PEs 10 not constituting Multihoming, but the present invention is not limited to this, and there may be three or more PEs 10 not constituting Multihoming. In addition, in Fig. 4, an example in which one CE3 is connected to PE10, 10a via a link, but the present invention is not limited to this, and two or more CE3 may be connected to one PE10, 10a.

[0050] Next, the configuration of the PE 10a-1 will be described.

[0051] As shown in Fig. 4, PE 10a-1 includes a selection list creation unit 12a, a selection unit 13, a weight reference value list creation unit 14, and a weight reference value list exchange unit 15. PE 10a-1 shown in Fig. 4 differs from PE 10-1 shown in Fig. 1 in that it adds a weight reference value list creation unit 14 and a weight reference value list exchange unit 15, and that the selection list creation unit 12 is changed to a selection list creation unit 12a.

[0052] The weight reference value list creation unit 14 creates a weight reference value list including the identifiers of PE10-3, 10-4 and the weight reference values ​​of its own device notified from PE10-3, 10-4 based on the identifiers and weight reference values ​​of PE10a-1, 10a-2 constituting the multihoming notified from PE10-3, 10-4. That is, the weight reference value list creation unit 14 creates a weight reference value list including the identifiers of the multiple communication devices (PE10-3, 10-4) not constituting the multihoming and the weight reference values ​​of its own device notified from each of the multiple communication devices (PE10-3, 10-4) not constituting the multihoming based on the identifiers and weight reference values ​​of the multiple communication devices (PE10a-1, 10a-2) constituting the multihoming notified from each of the multiple communication devices (PE10-3, 10-4) not constituting the multihoming.

[0053] The weight reference value list exchange unit 15 exchanges the weight reference value list created by the weight reference value list creation unit 14 with a plurality of communication devices (other PEs 10a) constituting the Multihoming.

[0054] The selection list creation unit 12a creates a selection list based on the weight reference value list created by the weight reference value list creation unit 14 and the weight reference value lists obtained from multiple communication devices that make up the multihoming through exchange by the weight reference value list exchange unit 15.

[0055] Next, the operation of the PEs 10 and 10a shown in Fig. 4 will be described with reference to Fig. 5. In Fig. 5, the same processes as those in Fig. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

[0056] The notification units 11 of the PEs 10-3 and 10-4 notify the PEs 10-1 and 10-2 of the identifiers of the PEs 10a-1 and 10a-2 and the weight reference values ​​of the PEs 10a-1 and 10a-2 held by the respective devices when a link between the respective devices and a CE 3 is added / deleted, when a new CE 3 is connected / removed to the respective devices, when a new EVI is added / changed / deleted to the respective devices, etc. (Step S21). In the following, it is assumed that the notification unit 11 of the PE 10-3 notifies 5 as the weight reference value of the PE 10a-1 and notifies 3 as the weight reference value of the PE 10a-2. It is also assumed that the notification unit 11 of the PE 10-4 notifies 1 as the weight reference value of the PE 10a-1 and notifies 4 as the weight reference value of the PE 10a-2.

[0057] The weight reference value list creating units 14 of the PEs 10a-1 and 10a-2 create a weight reference value list based on the identifiers and weight reference values ​​of the PEs 10a-1 and 10a-2 notified by the PEs 10-3 and 10-4 (step S22).

[0058] FIG. 6 is a diagram showing an example of the weight reference value list created by the weight reference value list creating unit 14. As shown in FIG.

[0059] As shown in Fig. 6, the weight reference value list creation unit 14 creates a weight reference value list in which the identifiers of the PEs 10-3 and 10-4 that are not configuring Multihoming are associated with the weight reference values ​​of the own device notified from the PEs 10-3 and 10-4 for each ES. Note that, in Fig. 6, the weight reference value list is described as an example for each ES, but is not limited to this. The weight reference value list creation unit 14 may create a weight reference value list for each combination of ES and EVI, for each combination of ES and Ethernet tag, for each combination of ES, EVI and Ethernet tag, for each combination of ES, EVI and MAC address, or for each combination of ES, EVI, Ethernet tag and MAC address.

[0060] Referring again to FIG. 5, the weight reference value list exchange units 15 of the PEs 10a-1 and 10a-2 exchange the weight reference value lists created by the weight reference value list creation unit 14 among the multiple PEs 10a constituting the Multihoming (step S23).

[0061] The selection list creation unit 12a of PE 10a-1, 10a-2 creates a selection list including identifiers and weight reference values ​​of multiple PEs 10a that make up the Multihoming, in accordance with predetermined conditions, based on the weight reference value list of its own device created by the weight reference value list creation unit 14 and the weight reference value lists of other PEs 10a that make up the Multihoming obtained through exchange by the weight reference value list exchange unit 15 (step S24).

[0062] The selection list creation unit 12a may create the selection list using, for example, a weight reference value in a weight reference value list including the smallest (or largest) weight reference value. The selection list creation unit 12a may also create the selection list using a weight reference value in a weight reference value list that does not include the smallest (or largest) weight reference value. The selection list creation unit 12a may also calculate an average value of the weight reference values ​​for each weight reference value list, and create the selection list using the weight reference value in the weight reference value list in which the calculated average value is smallest (or largest). The selection list creation unit 12a may also calculate a total or average value of the weight reference value for each PE 10a constituting the Multihoming, and create a selection list including the calculated value as the weight reference value. The selection list creation unit 12a may also create the selection list using a value calculated based on a function that uses the weight reference value in the weight reference value list as a variable, as the weight reference value.

[0063] Creation of a selection list by the selection list creation unit 12a will be described using the weight reference value list shown in Fig. 6 as an example. In the following description, it is assumed that the selection list creation unit 12a creates a selection list that includes a weight reference value in a weight reference value list that includes the smallest weight reference value as the weight reference value of the PE 10a.

[0064] As shown in FIG. 7, the selection list creation unit 12a creates a matrix (weight reference value matrix) in which the rows are identifiers of the PEs 10 that have notified the weight reference values ​​and the columns are identifiers of the PEs 10a that make up the multihoming. The selection list creation unit 12a compares the weight reference values ​​included in the weight reference value matrix to identify the smallest weight reference value ("1" in the example shown in FIG. 7). The selection list creation unit 12a creates a selection list using the weight reference value notified by the PE 10-4 that notified the identified smallest weight reference value as is. Therefore, the selection list creation unit 12a creates a selection list using the weight reference value notified by the PE 10-4 as is, as shown in FIG. 8.

[0065] As described above, the selection list creation unit 12a may calculate the sum of the weight reference value for each PE 10a constituting the multihoming, and create a selection list including the calculated value as the weight reference value. In this case, the selection list creation unit 12a may create a selection list including the sum of the weight reference values ​​notified from PEs 10-3 and 10-4 for each of PEs 10a-1 and 10a-2, as shown in FIG.

[0066] After the selection list is created by the selection list creation unit 12a, the selection unit 13 selects DFs and BDFs from the selection list by the same process as in FIG.

[0067] In the communication system 1 shown in Fig. 4, the weight reference value list is exchanged between the multiple PEs 10a that make up the multihoming to create a selection list. Therefore, even if there are multiple PEs 10 that do not make up the multihoming, the multiple PEs 10a that make up the multihoming can create a common selection list for each of the PEs 10a. This makes it possible to prevent discrepancies in the DF and BDF selected between the PEs 10a.

[0068] In the communication system 1 shown in FIGS. 1 and 4, an example has been described in which the identifiers and weight reference values ​​of the PEs 10 and 10a that are part of the Multihoming are notified from one or more PEs 10 that are not part of the Multihoming, but the present disclosure is not limited to this.

[0069] Fig. 10 is a diagram showing yet another configuration example of the communication system 1 according to an embodiment of the present disclosure. In Fig. 10, the same components as those in Fig. 4 are denoted by the same reference numerals, and description thereof will be omitted.

[0070] The communication system 1 shown in Fig. 10 includes a plurality of PEs 10a (10a-1, 10a-2), 10 (10-3, 10-4) connected to a communication network 2, and a control device 20. The communication system 1 shown in Fig. 10 differs from the communication system 1 shown in Fig. 4 in that a control device 20 that manages the communication network 2 is added. Note that the control device 20 may be provided in a communication system 1 including one PE 10 that does not configure multihoming, as shown in Fig. 1.

[0071] The control device 20 is connected to the PEs 10a-1 and 10a-2 that make up the Multihoming. The control device 20 may be directly connected to the PEs 10a-1 and 10a-2, or may be connected via the communication network 2. In addition, in FIG. 10, the control device 20 is connected to the PEs 10a-1 and 10a-2, but this is not limited thereto, and the control device 20 may be connected to only one of the PEs 10a-1 and 10a-2. In addition, in FIG. 10, the control device 20 is connected to two PEs 10a that make up the Multihoming, but this is not limited thereto, and the control device 20 may be connected to three or more PEs 10a.

[0072] The control device 20 holds weight reference values ​​of the PEs 10a-1 and 10a-2 constituting the Multihoming, and notifies at least one of the PEs 10a-1 and 10a-2. The control device 20 acquires the weight reference values ​​of the PEs 10a-1 and 10a-2 based on, for example, network information between the CEs 3-3 and 3-1 measured by the CEs 3-3, network information temporarily set by a telecommunications carrier for the maintenance of the PEs 10 and 10a, or network information acquired by the control device 20 from the PEs 10-3 and 10-4 for the purpose of centralized management of the communication network 2.

[0073] Next, the operation of the PE 10a will be described.

[0074] The weight reference value list creation unit 14 adds to the weight reference value list the identifier of the control device 20 and the weight reference value of its own device notified by the control device 20. When the weight reference value list creation unit 14 adds the identifier and weight reference value notified by the control device 20 to the weight reference value list, it may add to the weight reference value list an identifier indicating that the pair of the identifier and weight reference value was notified by the control device 20.

[0075] The weight reference value list exchange unit 15 exchanges the weight reference value list created by the weight reference value list creation unit 14 with the other PEs 10a constituting the Multihoming.

[0076] The selection list creation unit 12a creates a selection list based on the weight reference value list created by the weight reference value list creation unit 14 and the weight reference value lists of the other PEs 10a obtained by exchange by the weight reference value list exchange unit 15.

[0077] The selection unit 13 selects a DB and a BDF from the selection list created by the selection list creation unit 12. Here, when the selection list includes a weight reference value notified by the control device 20, the selection unit 13 may select a DF and a BDF based on the weight reference value.

[0078] As shown in FIG. 10, the control device 20 notifies the identifier and weight reference value of the PE 10a that constitutes the Multihoming, so that network information outside the communication network 2 can be reflected in the selection of the DF and BDF, or the DF and BDF can be temporarily changed when a communication carrier performs maintenance on the communication network 2.

[0079] Next, another configuration of the PE 10a that is part of the Multihoming and the PEs 10 (PEs 10-3 and 10-4) that are not part of the Multihoming will be described.

[0080] First, another configuration of the PE 10a-1 constituting the Multihoming will be described with reference to Fig. 11. In Fig. 11, the configuration of the PE 10a-1 will be described as an example, but the PE 10a-2 may have a similar configuration.

[0081] As shown in Fig. 11, the PE 10a-1 includes a selection list creation unit 12a, a selection unit 13, a weight reference value list creation unit 14a, a weight reference value list exchange unit 15, and a first measurement unit 16. The PE 10a-1 shown in Fig. 11 differs from the PE 10a-1 shown in Figs. 4 and 10 in that the first measurement unit 16 is added and that the weight reference value list creation unit 14 is changed to a weight reference value list creation unit 14a.

[0082] The first measurement unit 16 measures network information between the own device and the CE3 (CE3-1) connected thereto.

[0083] The weight reference value list creation unit 14a corrects the weight reference value of the own device notified from PE 10-3, 10-4 based on the weight reference value corresponding to the network information measured by the first measurement unit 16, and creates a weight reference value list including the corrected weight reference value. The weight reference value list creation unit 14a corrects the notified weight reference value by adding or subtracting the weight reference value corresponding to the network information measured by the first measurement unit 16 to the notified weight reference value of the own device.

[0084] By measuring network information between the device itself and the CE3 connected to it, and correcting the weight reference value notified from other devices based on the weight reference value corresponding to the measured network information, it is possible to flexibly track changes in end-to-end network information and select DF and BDF.

[0085] Next, another configuration of PE 10 (PE 10-3, PE 10-4) that is not configured in Multihoming will be described with reference to Fig. 12. In Fig. 12, the configuration of PE 10-3 will be described as an example, but PE 10-4 may have a similar configuration.

[0086] As shown in Fig. 12, PE10-3 includes a notification unit 11 and a second measurement unit 17. PE10-3 shown in Fig. 12 differs from PE10-3 shown in Figs. 1 and 4 in that it further includes a second measurement unit 17. In the following, a description will be given taking the communication system 1 shown in Fig. 4 as an example.

[0087] The second measurement unit 17 measures network information between each of the PEs 10a-1 and 10a-2 constituting the Multihoming and connected via the communication network 2. When measuring delay as the network information, the second measurement unit 17 measures the delay using Ping, Twanp, Ether-OAM (DM), etc. When measuring bandwidth as the network information, the second measurement unit 17 measures the bandwidth using an interface counter of the own device, etc.

[0088] The notification unit 11 determines weight reference values ​​for the PEs 10a-1 and 10a-2 based on the network information between the PEs 10a-1 and 10a-2, respectively, measured by the second measurement unit 17, and notifies the PEs 10a-1 and 10a-2 of the determined weight reference values.

[0089] By measuring network information between each of PEs 10a-1 and 10a-2 and determining weight reference values ​​for each of PEs 10a-1 and 10a-2 based on the measured network information, it is possible to select DF and BDF in a manner that flexibly follows changes in the network information of communication network 2.

[0090] Note that PE10-3 and PE10-4 that are not part of Multihoming may include the first measurement unit 16. For example, PE10-3 shown in FIG. 12 may further include the first measurement unit 16. In this case, the notification unit 11 may notify PE10 that is part of Multihoming of a weight reference value based on network information measured by the second measurement unit 17 and a weight reference value based on network information between PE10-3 and CE3-3 measured by the first measurement unit 16.

[0091] In this embodiment, the configurations of the PEs 10 and 10a that configure Multihoming and the PE 10 that does not configure Multihoming have been described separately, but the PEs 10 and 10a may or may not configure Multihoming. Therefore, one PE 10 may have a configuration for configuring Multihoming and a configuration for not configuring Multihoming.

[0092] Next, the hardware configuration of the PE10 according to the present disclosure will be described. In the following, the PE10 will be described as an example, but the same applies to the PE10A. As described above, the configuration of the PE10 may be any of a configuration in which Multihoming is configured, a configuration in which Multihoming is not configured, and a configuration in which Multihoming is configured and a configuration in which Multihoming is not configured.

[0093] Fig. 13 is a diagram showing an example of a hardware configuration of a PE 10 according to an embodiment of the present disclosure. Fig. 13 shows an example of a hardware configuration of a PE 10 in a case where the PE 10 is configured by a computer capable of executing program instructions. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal computer), an electronic notepad, etc. The program instructions may be program code, code segments, etc. for performing necessary tasks.

[0094] 13, the PE 10 has a processor 110, a read only memory (ROM) 120, a random access memory (RAM) 130, a storage 140, an input unit 150, a display unit 160, and a communication interface (I / F) 170. Each component is connected to each other so as to be able to communicate with each other via a bus 190. The processor 110 is specifically a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), a digital signal processor (DSP), a system on a chip (SoC), or the like, and may be composed of multiple processors of the same type or different types.

[0095] The processor 110 is a controller that controls each component and executes various arithmetic processing. That is, the processor 110 reads a program from the ROM 120 or the storage 140, and executes the program using the RAM 130 as a working area. The processor 110 controls each component of the PE 10 described above and executes various arithmetic processing according to the program stored in the ROM 120 or the storage 140. In this embodiment, the ROM 120 or the storage 140 stores a program for causing a computer to function as the PE 10 according to the present disclosure. The program is read and executed by the processor 110, thereby realizing each component of the PE 10, 10a, that is, the notification unit 11, the selection list creation unit 12, the selection unit 13, the weight reference value list creation unit 14, the weight reference value list exchange unit 15, the first measurement unit 16, and the second measurement unit 17.

[0096] The program may be provided in a form stored in a non-transitory storage medium such as a CD-ROM (Compact Disk Read Only Memory), a DVD-ROM (Digital Versatile Disk Read Only Memory), a USB (Universal Serial Bus) memory, etc. The program may also be provided in a form downloaded from an external device via a network.

[0097] The ROM 120 stores various programs and various data. The RAM 130 temporarily stores programs or data as a working area. The storage 140 is configured with a hard disk drive (HDD) or a solid state drive (SSD), and stores various programs including an operating system and various data.

[0098] The input unit 150 includes a pointing device such as a mouse and a keyboard, and is used to perform various input operations.

[0099] The display unit 160 is, for example, a liquid crystal display, and displays various information. The display unit 160 may function as the input unit 150 by adopting a touch panel system.

[0100] The communication interface 170 is an interface for communicating with other devices (other PEs 10, 10a or the control device 20) and uses standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark).

[0101] A computer can be suitably used to function as each of the above-mentioned PEs 10 and 10a. Such a computer can be realized by storing a program describing the processing contents for realizing the functions of each of the PEs 10 and 10a in a storage unit of the computer, and reading and executing the program by the processor 110 of the computer. That is, the program can cause the computer to function as the above-mentioned PEs 10 and 10a. The program can also be recorded on a non-transitory recording medium. The program can also be provided via a network.

[0102] The following supplementary notes are further disclosed regarding the above embodiment.

[0103] (Additional note 1) A communication device that is connected to a communication network and that configures a multihoming configuration in which a plurality of communication devices are connected to one customer network device, comprising: A controller is provided. The controller creates a selection list including identifiers and weight reference values ​​of each of the communication devices constituting the multihoming, based on identifiers of each of the communication devices constituting the multihoming notified from another device and weight reference values ​​according to communication states of each of the communication devices constituting the multihoming; A communications device that selects, from the created selection list, a DF (Designated Forwarder) that will forward traffic to the customer network device, and a BDF (Backup DF) that will become the new DF when a failure occurs in the DF, based on predetermined conditions based on the weight reference value.

[0104] (Additional note 2) In the communication device according to claim 1, The other device is a communication device that is connected to a customer network device other than the one customer network device and does not constitute the multihoming with the one customer network device, or a control device that manages the communication network.

[0105] (Additional note 3) In the communication device according to claim 1, the other devices are a plurality of communication devices that are connected to a customer network device other than the one customer network device and do not constitute the multihoming with the one customer network device; the controller creates a weight reference value list including the identifiers of the communication devices not forming the multihoming and the weight reference value of the own device notified by each of the communication devices not forming the multihoming, based on the identifiers of the communication devices not forming the multihoming and the weight reference value notified by each of the communication devices not forming the multihoming; The created Weight reference value list is exchanged with the plurality of communication devices constituting the Multihoming. A communication device that creates the selection list based on the created weight reference value list and weight reference value lists acquired from the multiple communication devices that make up the Multihoming through the exchange.

[0106] (Additional note 4) In the communication device according to claim 3, The controller measures a communication state between the controller itself and a customer network device connected thereto; a communication device that creates the weight reference value list including weight reference values ​​obtained by correcting the weight reference values ​​notified from the other devices in accordance with the results of the measurement;

[0107] (Additional note 5) A communication device that is not part of the multihoming and is connected to a plurality of communication devices that are part of a multihoming with one customer network device via a communication network, comprising: A controller is provided. The controller notifies each of the communication devices constituting the multihoming of an identifier of each of the communication devices constituting the multihoming and a weight reference value corresponding to the communication state of each of the communication devices constituting the multihoming.

[0108] (Additional note 6) In the communication device according to claim 5, The controller measures a communication state between each of the communication devices constituting the multihoming, A communication device that determines the weight reference value based on a result of the measurement.

[0109] (Additional note 7) A communication method by a communication device connected to a communication network, which configures a multihoming in which a plurality of communication devices are connected to one customer network device, comprising the steps of: Based on the identifiers of the communication devices constituting the multihoming notified from other devices and the weight reference values ​​corresponding to the communication states of the communication devices constituting the multihoming, a selection list including the identifiers and weight reference values ​​of the communication devices constituting the multihoming is created; A communication method in which a DF (Designated Forwarder) that forwards traffic to the customer network device and a BDF (Backup DF) that becomes a new DF when a failure occurs in the DF are selected from the created selection list based on predetermined conditions based on the weight reference value.

[0110] (Additional note 8) A non-transitory storage medium storing a program executable by a computer, the non-transitory storage medium storing the program causing the computer to function as the communication device described in appended claim 1.

[0111] Although the above-mentioned embodiment has been described as a representative example, it is obvious to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present disclosure. Therefore, the present invention should not be interpreted as being limited by the above-mentioned embodiment, and various modifications or changes can be made without departing from the scope of the claims. For example, it is possible to combine multiple building blocks shown in the configuration diagram of the embodiment into one, or to divide one building block. [Explanation of symbols]

[0112] 1. Communication Systems 2. Communication Network 3 CE (Customer Network Equipment) 10,10a PE (communication equipment) 11 Notification Department 12,12a Selection List Creation Department 13 Selection Department 14 Weight Reference Value List Creation Section 15 Weight Reference Value List Exchange Section 16 1st measurement section 17 Second measuring section 20 Control device 110 Processor 120 ROM 130 RAM 140 Storage 150 Input section 160 Output section 170 Communication I / F 190 Pass

Claims

1. A communication device that is connected to a communication network and that configures a multihoming configuration in which a plurality of communication devices are connected to one customer network device, comprising: a selection list creation unit that creates a selection list including identifiers and weight reference values ​​of each of the communication devices constituting the multihoming, based on identifiers of each of the communication devices constituting the multihoming notified from other devices that are not constituting the multihoming and weight reference values ​​according to communication states of each of the communication devices constituting the multihoming; A communication device comprising: a selection unit that selects a DF (Designated Forwarder) that forwards traffic to the customer network device and a BDF (Backup DF) that becomes a new DF when a failure occurs in the DF from the created selection list based on predetermined conditions based on the weight reference value.

2. 2. The communication device according to claim 1, The other device is a communication device that is connected to a customer network device other than the one customer network device and does not constitute the multihoming with the one customer network device, or a control device that manages the communication network.

3. 2. The communication device according to claim 1, the other devices are a plurality of communication devices that are connected to a customer network device other than the one customer network device and do not constitute the multihoming with the one customer network device; a weight reference value list creation unit that creates a weight reference value list including identifiers of each of the communication devices not forming the multihoming and a weight reference value of the own device notified by each of the communication devices not forming the multihoming, based on identifiers of each of the communication devices forming the multihoming and the weight reference value notified by each of the communication devices not forming the multihoming; a weight reference value list exchange unit that exchanges the weight reference value list created by the weight reference value list creation unit with a plurality of communication devices that constitute the multihoming; A communication device in which the selection list creation unit creates the selection list based on the weight reference value list created by the weight reference value list creation unit and the weight reference value lists obtained from multiple communication devices that constitute the Multihoming through exchange by the weight reference value list exchange unit.

4. 4. The communication device according to claim 3, The method further includes a first measurement unit that measures a communication state between the device itself and a customer network device connected thereto, The weight reference value list creation unit creates the weight reference value list including weight reference values ​​obtained by correcting the weight reference values ​​notified from the other devices in accordance with the results of measurement by the first measurement unit.

5. A communication device that is not part of the multihoming and is connected to a plurality of communication devices that are part of a multihoming with one customer network device via a communication network, comprising: A communication device comprising a notification unit that notifies each of a plurality of communication devices constituting the multihoming of an identifier of each of the plurality of communication devices constituting the multihoming and a weight reference value according to the communication state of each of the plurality of communication devices constituting the multihoming.

6. 6. The communication device according to claim 5, A second measurement unit that measures a communication state between each of the communication devices constituting the multihoming is further provided, The notification unit determines the weight reference value based on a result of the measurement by the second measurement unit.

7. A communication method by a communication device connected to a communication network, in which a multihoming is configured in which a plurality of communication devices are connected to one customer network device, comprising the steps of: creating a selection list including the identifiers and weight reference values ​​of each of the communication devices constituting the multihoming, based on the identifiers of each of the communication devices constituting the multihoming notified by other devices not constituting the multihoming and a weight reference value according to a communication state of each of the communication devices constituting the multihoming; A communication method in which a DF (Designated Forwarder) that forwards traffic to the customer network device and a BDF (Backup DF) that becomes a new DF when a failure occurs in the DF are selected from the created selection list based on predetermined conditions based on the weight reference value.

8. A program causing a computer to function as the communication device according to any one of claims 1 to 6.

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