JP5648560B2 - Traffic engineering apparatus, traffic engineering method and program - Google Patents

Description

  The present invention relates to a traffic engineering apparatus, a traffic engineering method, and a program, and more particularly to a traffic engineering apparatus, a traffic engineering method, and a program that perform packet transfer across domains.

  The Internet is configured by interconnecting networks managed by a plurality of organizations. The network managed by each organization is called AS (Autonomous System). Between ASs, BGP (Non-Patent Document 1), which is a route control protocol, is used to exchange information (route information) on address blocks held by itself.

  FIG. 18 is a diagram schematically illustrating the Internet configured by connecting ASs. The AS 100d has two external connection links L2 and L4, and is connected to other ASs via these links. In order to determine which link is used to send a packet to the outside, information acquired by BGP is used. When the AS receives prefix information in BGP, the AS assigns its AS number to the prefix information and sends it to another AS. Therefore, even when the same prefix information is received from a plurality of paths, it is possible to select a path with a small number of ASs to be passed through.

  For example, the prefix 192.168.2.0/24 held by the AS 100b is transmitted to the AS 100d via the link L2, and is further transmitted to the AS 100d via the link L4 after passing through the AS 100a and the AS 100c. Since the number of AS through the former path is smaller, the AS 100d sends a packet addressed to 192.168.2.0/24 from itself to the outside using the link L2.

  On the other hand, when viewed from the AS 100d, the number of ASs that pass through until reaching the AS 100a is equal regardless of which of the external connection links L2 and L4 is used. In this case, the link to be used is determined according to the operation policy of the AS 100d, for example, a policy such that the link L4 is used preferentially over the link L2.

  Each AS generally includes a plurality of routers. The route information received from other ASs is notified using BGP in all routers constituting the self AS. Note that BGP used when exchanging information with the router device inside the AS is called iBGP (internal BGP), and BGP used for exchanging information with the external router device is called eBGP (external BGP).

Y. Rekhter, T .; Li and S.L. Hares, “A Border Gateway Protocol 4 (BGP-4),” RFC 4271, Internet Engineering Task Force, 2006.

  The following analysis was made by the present inventors.

  As described above, information on the topology such as the number of ASs that are routed is used for route selection in BGP, but information on the traffic volume such as the usage rate of the external connection link is not used. Therefore, even if the link has a high usage rate, a link that is topologically close is used, and as a result, packet drop may occur. On the other hand, when traffic is distributed to a plurality of links based only on the link usage rate, there is a problem that the number of ASs to be routed becomes long.

  Therefore, it becomes a problem to distribute traffic to a plurality of external links according to a predetermined policy without increasing the number of ASs through which packets pass. An object of the present invention is to provide a traffic engineering apparatus, a traffic engineering method, and a program for solving such a problem.

The traffic engineering device according to the first aspect of the present invention is:
Route information is received from each of a plurality of router devices located at the boundary with other AS (Autonomous System), the destination prefix, the prefix length, and the priority for each router device are calculated, and the destination prefix, prefix length, router device And a route information storage unit for storing in the first database as route distribution information including priority,
Information on the traffic volume output from each of the plurality of router devices to the other AS is received from each of the plurality of router devices, and the total traffic volume is calculated by summing up the traffic volume for each destination prefix, prefix length, and router device. A traffic information totaling unit that stores traffic information including destination prefix, prefix length, router device, and total traffic volume in a second database,
A pair of router devices included in the route distribution information having a relatively small priority difference among the route distribution information stored in the first database is extracted, and the traffic amount in the extracted router device is predetermined. The distribution ratio updating unit updates the packet distribution ratio between the extracted router devices with reference to the traffic information stored in the second database.

The traffic engineering method according to the second aspect of the present invention is:
Route information is received from each of a plurality of router devices located at the boundary with other AS (Autonomous System), the destination prefix, the prefix length, and the priority for each router device are calculated, and the destination prefix, prefix length, router device And storing in the first database as route distribution information including priority,
Information on the traffic volume output from each of the plurality of router devices to the other AS is received from each of the plurality of router devices, and the total traffic volume is calculated by summing up the traffic volume for each destination prefix, prefix length, and router device. And storing in a second database as traffic information including a destination prefix, prefix length, router device and total traffic volume;
Extracting a pair of router devices included in the route distribution information having a relatively small priority difference among the route distribution information stored in the first database;
Updating the packet distribution ratio between the extracted router devices by referring to the traffic information stored in the second database so that the traffic amount in the extracted router devices conforms to a predetermined policy. Including.

The program according to the third aspect of the present invention is:
Route information is received from each of a plurality of router devices located at the boundary with other AS (Autonomous System), the destination prefix, the prefix length, and the priority for each router device are calculated, and the destination prefix, prefix length, router device And processing to store in the first database as route distribution information including priority,
Information on the traffic volume output from each of the plurality of router devices to the other AS is received from each of the plurality of router devices, and the total traffic volume is calculated by summing up the traffic volume for each destination prefix, prefix length, and router device. , And storing in the second database as traffic information including the destination prefix, prefix length, router device, and total traffic volume;
A process of extracting a pair of router devices included in the route distribution information having a relatively small difference in priority among the route distribution information stored in the first database;
A process of updating a packet distribution ratio between the extracted router devices by referring to the traffic information stored in the second database so that the traffic amount in the extracted router devices conforms to a predetermined policy. Let the computer run.

  According to the traffic engineering apparatus, traffic engineering method, and program of the present invention, traffic can be distributed to a plurality of external links according to a predetermined policy without increasing the number of ASs through which packets pass.

It is a figure which shows the traffic engineering apparatus in 1st Embodiment. It is a figure which shows the routing table which a general router apparatus holds. It is a figure which shows the structure of the route distribution information database in 1st Embodiment. It is a figure which shows the structure of the traffic information database in 1st Embodiment. It is an example of the network configuration in AS including the traffic engineering apparatus in 1st Embodiment. It is the figure which showed the structure of the router apparatus in 1st Embodiment. It is the figure which showed the structure of the external connection router apparatus in 1st Embodiment. It is a flowchart which shows the outline of the traffic engineering operation | movement in 1st Embodiment. It is a flowchart which shows the detail of the route distribution information generation procedure in 1st Embodiment. It is a flowchart which shows the detail of the distribution ratio update process of the route distribution information using the traffic information in 1st Embodiment. It is a flowchart which shows the detail of the packet transfer procedure in 1st Embodiment. It is a figure which shows the traffic engineering apparatus in 2nd Embodiment. It is the figure which showed the structure of the edge router apparatus in 2nd Embodiment. It is the figure which showed the structure of the external connection router apparatus in 2nd Embodiment. It is a figure which shows the detailed flowchart of the update process of the distribution ratio in 3rd Embodiment. It is the figure which showed the structure of the router apparatus in 3rd Embodiment. It is a flowchart which shows the update process of the routing table in 3rd Embodiment. It is a figure which shows the example which several AS connects mutually and comprises the internet.

  First, the outline of the present invention will be described. Note that the reference numerals of the drawings attached to this summary are merely examples for facilitating understanding, and are not intended to limit the present invention to the illustrated embodiment.

  Referring to FIGS. 1 and 5, the traffic engineering device (30) includes a plurality of router devices (external connection router devices 80a and 80b) located at the boundary with other AS (Autonomous Systems) (for example, 100b and 100c). Route information is received from each of them, the priority is calculated for each destination prefix, prefix length, and router device, and the first database (route information) as route distribution information including the destination prefix, prefix length, router device, and priority is calculated. The route information storage unit (12) to be stored in the minute information database 13 and FIG. From each of the router devices (80a, 80b) The total traffic volume is obtained by summing the traffic volume for each destination prefix, prefix length, and router device, and obtaining a second database (traffic information database) as traffic information including the destination prefix, prefix length, router device, and total traffic volume. 17, the traffic information totaling unit (16) stored in FIG. 4) and the route distribution information stored in the first database (13) are included in the route distribution information having a relatively small priority difference. And the traffic information stored in the second database (17) with reference to the traffic information stored in the second database (17) so that the traffic amount in the extracted router device conforms to a predetermined policy. A distribution ratio updating unit (18) for updating a packet distribution ratio; It has.

  The route information storage unit (12) may refer to the path attribute included in the route information and calculate the priority so as to be inversely proportional to the number of ASs through which the packet reaches the destination.

  The traffic information totaling unit (16), when the distribution ratio updating unit (18) updates the packet distribution ratio, includes the total traffic included in the traffic information stored in the second database (17). The amount of traffic may be initialized and the amount of traffic may be aggregated again to determine the total amount of traffic.

  In the present invention, the traffic amount for each destination in the external route acquired by the route control protocol is totaled for each external connection link. In order to realize the operation policy based on the aggregation result, it is determined to which destination traffic the transmission destination change process is applied. When deciding the destination to perform destination change processing, by comparing the route information corresponding to the destination acquired from each destination, the destination that has little influence even if the destination is changed is selected as the target of change. To do. Specifically, priority is determined for path information acquired from each destination using path information given in the path information. Furthermore, the priorities of the route information for the same destination are compared, and a destination having a small difference in priority is selected as a change target.

  Therefore, according to the present invention, according to the operation policy (for example, a policy for equalizing the bandwidth used for each link) while maintaining the conventional route selection criteria using information such as the network connection state such as the number of ASs. The bandwidth used for each external connection link can be adjusted.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a traffic engineering apparatus according to the first embodiment. Referring to FIG. 1, the traffic engineering device 30 includes a packet transfer unit 20, network interfaces 31 to 3 n, and a traffic engineering unit 10.

  The traffic engineering unit 10 includes a route information acquisition unit 11, a route information storage unit 12, a route distribution information database 13 and a route distribution information expansion unit 14, a traffic information acquisition unit 15, a traffic information aggregation unit 16, a traffic information database 17, An allocation ratio update unit 18 and a traffic policy management unit 19 are provided. The route information acquisition unit 11 receives the route information sent from the route information transmission unit 63 (described later with reference to FIG. 7) of the external connection router device 80 and sends it to the route information storage unit 12. The route information storage unit 12 calculates the priority for the route information sent from the route information acquisition unit 11 and stores the route information and the priority in the route distribution information database 13. The route distribution information database 13 stores information created by the route information storage unit 12. The route distribution information expansion unit 14 expands the contents stored in the route distribution information database 13 to all router devices (external connection router device, internal router device, edge router device) in the self AS. The traffic information acquisition unit 15 acquires information about output traffic from the external connection router device 80 to the outside using a protocol such as sFlow, and sends the information to the traffic information aggregation unit 16. The traffic information totaling unit 16 receives the traffic notified from the traffic information acquiring unit 15 for each destination prefix obtained by referring to the external connection router device 80 that is the transmission source of the traffic information and the route distribution information database 13. The information is aggregated and stored in the traffic information database 17. The distribution ratio update unit 18 distributes the distribution ratio in the route distribution information database 13 at regular intervals so as to conform to the operation policy set in the traffic policy management unit 19 based on the contents of the traffic information database 17. Update.

  The packet transfer unit 20 includes a routing processing unit 21 and a route table 22. FIG. 2 shows the configuration of the route table 22. Referring to FIG. 2, the route table 22 stores route information in each row. The route information includes a destination, a prefix length, a next transfer destination, and an interface. FIG. 2 shows the case of IPv4 (Internet Protocol version 4). However, in the case of IPv6 (Internet Protocol version 6), the route table 22 is a table having similar entries. The routing processing unit 21 refers to the destination address field included in the header portion of the packet received from each of the network interfaces 31 to 3n, and searches for the next transfer destination address and interface using the routing table 22. The routing processing unit 21 sends the received packet to the router of the next transfer destination address obtained as the search result via the interface obtained as the search result.

  FIG. 3 shows details of the route distribution information database 13. Referring to FIG. 3, the route distribution information database 13 stores route distribution information in each row. The route distribution information includes a destination prefix, a prefix length, an external connection router device, a path attribute, a priority, and a distribution ratio. For example, if the address of 192.168.2.1 is masked with 24 bits, it matches the third entry in the route distribution information database 13 of FIG. That is, a packet addressed to 192.168.2.1 is transmitted from the AS 100d to the outside via the external connection router device 192.168.1.1. In this way, the process of searching for the entry from the destination is the same as the address search process of the longest match search (Longest Prefix Match) in the route table of the Internet protocol. The field of the external connection router device stores the IP address of the external connection router device that is the transmission source of this route information. Further, path attribute information stored in the route information received by BGP is stored in the path attribute column of the route distribution information database 13. The value determined from the path attribute is stored in the priority column. Further, when there are a plurality of entries having the same destination prefix and the same prefix length as in the first and second entries in the route distribution information database 13, it is used to determine which entry is to be used at which ratio. The value is stored in the distribution ratio. In the example shown in FIG. 3, since the distribution ratio is 40:60, for packets corresponding to 192.168.1.0/24, the first and second entries have a ratio of 2: 3. Used in. As the initial value of the distribution ratio, a value representing the priority ratio in percentage is stored. The distribution ratio update unit 18 updates the distribution ratio according to the traffic situation.

  FIG. 4 shows details of the traffic information database 17 of FIG. Referring to FIG. 4, the traffic information database 17 stores traffic information in each row. The traffic information includes a destination prefix, a prefix length, an external connection router device, and a traffic amount. The traffic information is obtained by totaling the amount of traffic transmitted to the outside of the AS via the external connection router device for each destination prefix. For example, consider a case where a packet with a destination of 192.168.1.1 and a size of 1500 bytes is sent to the outside via the external connection router device 10.1.1.1. In this packet, the destination prefix, the prefix length, and the external connection router device correspond to the first entry in FIG. Therefore, the traffic information totaling unit 16 adds 1500 which is the packet size to the value stored in the traffic amount field of the first entry of the traffic information database 17. The field of the total traffic amount is cleared to zero after the distribution ratio update operation performed at regular intervals by the distribution ratio update unit 18 is completed. At this time, in the total traffic amount field, the traffic amount transmitted to the outside via each external connection router device per unit time is stored for each destination prefix. Further, as the total traffic amount, the number of packets may be recorded instead of recording the packet size. Thereby, the processing load of the traffic information totaling unit 16 can be reduced.

  FIG. 5 is a diagram illustrating a network configuration in the AS including the traffic engineering device 30 as an example. The network in the AS 100d includes router devices 80a, 80b, and 50a to 50d. The traffic engineering device 30 is connected to the network via one of these router devices. Of the router devices, router devices connected to external AS (AS 100b, AS 100c) are referred to as external connection router devices 80a, 80b, and a router device accommodating the terminals 201, 202 in the AS 100d is the edge router device 50c. , 50d, and other router devices are called internal router devices 50a, 50b. The externally connected router devices 80a and 80b acquire external route information from the router devices in the AS 100b and AS 100c using eBGP, and transmit the acquired route information to the traffic engineering device 30 using iBGP. Further, the external connection router devices 80a and 80b transmit information related to traffic sent to the AS 100b and AS 100c via the external connection router devices 80a and 80b to the traffic engineering device 30 using a protocol such as sFlow. To do.

  FIG. 6 is a block diagram showing the configuration of the router device 50 in the present embodiment. Referring to FIG. 6, the router device 50 includes a packet transfer unit 45, a route distribution information management unit 40, and network interfaces 51 to 5n.

  The route distribution information management unit 40 includes a route distribution information reception unit 41 and a route distribution information database 42. The route distribution information receiving unit 41 receives the route distribution information sent from the route distribution information expanding unit 14 of the traffic engineering device 30. The route distribution information database 42 stores the route distribution information received by the route distribution information receiving unit 41. The information stored in the route distribution information database 42 is the same as the route distribution information database 13 (FIG. 1) of the traffic engineering device 30, and the detailed configuration is as shown in FIG.

  The packet transfer unit 45 includes a distribution routing processing unit 46 and a route table 47. The route table 47 is equivalent to the route table 22 (FIGS. 1 and 2) in the traffic engineering device 30. The distribution routing processing unit 46 refers to the route distribution information database 42 and determines which external connection router device the packet should be transferred to. Further, by referring to the routing table 47, the address of the next transfer destination router for delivering the packet to the external connection router device is determined, and the packet is sent to the next transfer destination router via any one of the network interfaces 51 to 5n. Is sent out.

  FIG. 7 is a block diagram showing a configuration of the external connection router device 80 in the present embodiment. Referring to FIG. 7, the external connection router device 80 includes a path control unit 60, a packet transfer unit 70, a traffic management unit 65, and network interfaces 81 to 8n.

  The route control unit 60 includes a route information exchange unit 61, a route calculation unit 62, and a route information transmission unit 63. The route information exchange unit 61 exchanges route information with an adjacent router using a route control protocol such as BGP, and sends the collected route information to the route calculation unit 62 and the route information transmission unit 63. The route calculation unit 62 performs route calculation determined for each route control protocol being used, and registers route information in the route table 72. The route information transmission unit 63 notifies the traffic engineering device 30 of the route information received from the route information exchange unit 61.

  The traffic management unit 65 includes a traffic information acquisition unit 66 and a traffic information transmission unit 67. The traffic information acquisition unit 66 acquires header information in the packet transferred by the routing processing unit 71 and sends it to the traffic information transmission unit 67. The traffic information transmission unit 67 transmits the header information transmitted from the traffic information acquisition unit 66 to the traffic engineering device 30 using a protocol such as sFlow. At this time, the header information sent to the traffic engineering device 30 may be for all packets or only for sampled packets. For example, in order to reduce the processing load and the transfer load, one packet per 1000 packets or one packet within a unit time may be extracted and only that packet may be targeted.

  FIG. 8 is a flowchart showing an outline of the traffic engineering operation in the present embodiment. First, route distribution information is generated from the route information acquired by the external connection router device from the external network using BGP (step S1). Next, using sFlow or the like, the traffic volume of the output traffic for each external connection router device and each destination is measured (step S2). Next, the distribution ratio in the route distribution information database is updated based on the traffic volume measured in step S2, and the update information is distributed to each router device in the network (step S3). Each router device transfers the arrived packet to the external connection router device determined based on the route distribution information (step S4).

  FIG. 9 is a flowchart showing details of the route distribution information generation procedure (step S1 in FIG. 8). First, the external connection router device Re transfers the external route re received from the router device of the external network to the traffic engineering device 30 (step S11). Next, the traffic engineering device 30 acquires an address ai in the internal network in the external connection router device Re that is the transmission source of the received route information re (step S12). The destination prefix de, prefix length le, and path attribute pa are extracted from the route information re (step S13). It is checked whether information having a combination of the same destination prefix de and prefix length le is already registered in the route distribution information database 13 (step S14).

  If route distribution information having the same destination prefix de and prefix length le is not registered (NO in step S14), the four items de, re, ai, and pa are stored in the route distribution information database 13 that the device has. The set is registered with a priority of 100 and a distribution ratio of 100 (step S15), and all the processes are terminated.

  On the other hand, when route distribution information having the same destination prefix de and prefix length le is already registered (YES in step S14), the registered information is compared with the path attribute, and the priority of each information Then, the distribution ratio is determined (step S16). In general, in BGP, when there are a plurality of routes having the same destination prefix and the same prefix length, the best route to be used is determined by referring to the respective path attributes. The priority in the present embodiment reflects these selection criteria, and the one that is highly likely to be selected as the best route is set to a higher priority.

  For example, two entries whose destination prefix and prefix length are 192.168.1.0/24 in FIG. 3 have different AS_PATH attributes in their respective path attributes. The AS_PATH attribute refers to an attribute that is notified of an AS number that passes through to a destination. In the case shown in FIG. 3, when the first entry is used, the packet passes through three ASs, and when the second entry is used, the packet passes through two ASs. In BGP, entries with fewer ASs are used. In order to reflect such selection criteria in BGP, in the example shown in FIG. 3, a value obtained by dividing a predetermined value (here, 12) by the number of ASs in AS_PATH is registered as a priority. At this time, the priorities of the two entries are 4 (= 12 ÷ 3) and 6 (= 12 ÷ 2), respectively. Further, the distribution ratios of the two entries are obtained according to these ratios, and 40 and 60 are used as the percentages, respectively.

  Next, the priority and the distribution ratio of the information having the combination of de and le registered in the route distribution information database 13 owned by itself are updated to the determined values (step S17). In the route distribution information database 13 that the user owns, the determinant and distribution ratios of the four groups de, re, ai, and pa are registered (step S18).

  FIG. 10 is a flowchart showing details of the process of updating the distribution ratio in the route distribution information using the traffic information (step S3 in FIG. 8). In order to realize the policy, the external connection router device connected to the link to be distributed and the traffic amount are determined. The distribution source external connection router device is set to r1, the distribution destination external connection router device is set to r2, and the traffic volume to be distributed is set to t (step S31).

  For example, consider a policy case in which there are three router devices connected to the outside and these are used equally. Further, the traffic amounts transferred to the outside via these router devices are 50, 40 and 60, respectively. At this time, the third router device is r1, the second router device is r2, and the traffic amount t to be distributed is 10.

  Next, among the route distribution information that has not been processed, route distribution information m1 and m2 having a small priority difference between the externally connected router devices r1 and r2 are found (step S32). Based on the destination prefix included in the route distribution information m1, the traffic information database 17 is referred to and the traffic amounts t1 and t2 passing through the externally connected router devices r1 and r2 are checked (step S33).

  Next, t1 and t are compared (step S34). If t1 is smaller than t (YES in step S34), the distribution ratio of the route distribution information m1 is updated to 0, and the distribution ratio of the route distribution information m2 Is updated to 1 (step S35). Further, the value of t−t1 is calculated, and the value is substituted into t (step S36), and the processes after step S32 are repeated.

  On the other hand, if t1 is greater than or equal to t (NO in step S34), values of (t1−t) / (t1 + t2) and (t2 + t) / (t1 + t2) are obtained and set as a1 and a2 respectively (step S37). ). The distribution ratio included in the route distribution information m1 is updated to a1, and the distribution ratio included in the route distribution information m2 is updated to a2 (step S38). Next, the field of the total traffic volume in all entries of the traffic information database 17 is cleared to zero (step S39), and the process ends.

  FIG. 11 is a flowchart showing details of the packet transfer procedure (step S4 in FIG. 8). First, the route distribution information database 42 is searched based on the destination of the packet, and the corresponding entry is determined (step S41). When there are a plurality of entries having the same destination prefix and the same prefix length as the first and second entries in FIG. 3, all of them are extracted. Next, a 5 tuple hash value included in the received packet is calculated (step S42). “5tuple” refers to a set of five pieces of information including a destination address, a source address, a protocol number, a destination port number, and a source port number included in the packet header. Packet groups having the same 5 tuple value are recognized as one flow. Next, in order to transfer this flow, which entry among the plurality of entries found in step S41 is used is determined based on the hash value calculated in step S42 (step S43).

  The first and second entries in FIG. 3 each have a distribution ratio of 40:60. For example, when a hash function that can take values from 0 to 99 is used, the first entry is used if the hash value is 0 to 39, and the second entry is used if the hash value is 40 to 99. Thereby, it is possible to select an entry based on the distribution ratio.

  Next, the routing table 47 is searched using the address of the externally connected router of the entry determined in step S43 as a destination, and the next transfer destination is determined (step S44). The packet is sent to the next transfer destination determined in step S44 (step S45), and the packet transfer process is terminated.

(Embodiment 2)
In the first embodiment, it is necessary to develop the route distribution information created by the traffic engineering device 30 in each router device in the network. Therefore, a second embodiment that does not require these unfolding operations will be described.

  In this embodiment, the edge routers 50c and 50d in FIG. 5 encapsulate the packets received from the terminals 201 and 202, and transmit them to one of the externally connected router devices 80a and 80b. The external connection router devices 80a and 80b decapsulate the transmitted packets and transmit them to the external AS. In the present embodiment, the internal router device only needs to set a route to the external connection router device. Therefore, there is no need to deploy the route distribution information to the internal router device. Further, the edge router devices 50c and 50d inquire the traffic engineering device 30 about the route distribution information necessary when receiving the packet. As a result, the operation of expanding the route distribution information from the traffic engineering device 30 to the edge router devices 50c and 50d becomes unnecessary.

  FIG. 12 is a block diagram illustrating a configuration of the traffic engineering apparatus 130 in the present embodiment. Compared with the traffic engineering device 30 in the first embodiment shown in FIG. 1, the traffic engineering device 130 of this embodiment includes a mapping information response unit 114 instead of the route distribution information expansion unit 14. In response to the inquiry from the edge router device, the mapping information response unit 114 searches the route distribution information database 113 and returns a response. During the inquiry from the edge router device, header information of the packet received by the edge router device is included. A corresponding entry in the route distribution information database 113 is found using the destination address in the header information. Information contained in the entry found by the search is returned to the edge router. When a plurality of entries having the same destination prefix and prefix length are found by the search, the mapping information response unit 114 includes all of these entries in the response message.

  The configuration of the edge router apparatus will be described with reference to the drawings. FIG. 13 is a block diagram illustrating a configuration of the edge router device 150. Referring to FIG. 13, the edge router device 150 includes a route distribution information management unit 140, a packet transfer unit 145, a tunnel processing unit 149, and network interfaces 151 to 15n.

  Except for the tunnel processing unit 149 and the route distribution information management unit 140, the operation of each unit of the edge router device 150 is the same as the operation of the router device 50 of the first embodiment shown in FIG. Further, the distribution routing processing unit 46 in the first embodiment refers to the route distribution information database 42, but the distribution routing processing unit 146 in the present embodiment refers to the route distribution information cache 142.

  The route distribution information management unit 140 includes a route distribution information inquiry unit 141 and a route distribution information cache 142. When the distribution routing processing unit 146 refers to the route distribution information cache 142 and there is no corresponding entry, the route distribution information inquiry unit 141 inquires the traffic engineering device 30 about the route distribution information. The route distribution information cache 142 stores the result of the route distribution information inquiry unit 141 inquiring the traffic engineering device 30 so that it can be reused. That is, the configuration of the route distribution information cache 142 is basically the same as the configuration of the route distribution information database 13 in FIG.

  The tunnel processing unit 149 encapsulates the packet addressed to the address of the designated external connection router device, and passes it to the packet transfer unit 145.

  FIG. 14 is a block diagram showing a configuration of the external connection router device 180 in the present embodiment. Referring to FIG. 14, the external connection router device 180 includes a route control unit 160, a packet transfer unit 170, a tunnel termination unit 174, a traffic management unit 165, and network interfaces 181 to 18n.

  Except for the tunnel termination unit 174, the operation of each part of the external connection router device 180 is the same as the operation of each part of the external connection router device 80 of the first embodiment shown in FIG. When the destination of the packet is the address of the external connection router device, the tunnel termination unit 174 releases the packet encapsulation and sends the packet to the packet transfer unit 170.

(Embodiment 3)
In general, in IP routing, a transfer operation is performed with reference to only a destination. In the first and second embodiments, packets having the same destination are sent to the outside via different external connection routers depending on the case, and an extension to a general transfer function is required. In the present embodiment, an embodiment that does not involve extension of the transfer function for IP routing will be described. In the present embodiment, the value stored in the distribution ratio of the route distribution information database 13 shown in FIG. Further, of the entries having the same destination prefix and the same prefix length, there is one entry having a distribution ratio of 100.

  To change the distribution ratio as described above, first, when determining the distribution ratio in step S16 of FIG. 9, only the entry having the highest priority among the entries having the same destination prefix and the same prefix length is used. Is assigned as the distribution ratio 100, and the other entries are registered as the distribution ratio 0.

  FIG. 15 is a flowchart illustrating details of the distribution ratio update process according to this embodiment. In this embodiment, there is no processing corresponding to steps S37 and S38 (FIG. 10) of the first embodiment for determining the distribution ratio so as to divide traffic for the same destination prefix. Referring to FIG. 15, if t1 is equal to or greater than t (NO in step S55), step S52 is used to search for other route distribution information without using the route distribution information selected in step S52. Return to. Due to these changes, it may be necessary to use route distribution information having a large difference in priority in order to distribute the target traffic volume. Therefore, the upper limit of the priority difference is set in advance, and if only route distribution information exceeding the upper limit is found in step S52 (YES in step S53), the process is terminated.

  FIG. 16 is a block diagram showing a configuration of the router device 250 in the present embodiment. The router device 250 includes a routing processing unit 246 instead of the distribution routing processing unit 46 in the first embodiment shown in FIG. Further, instead of the route distribution information database 42, the router device 250 includes a route information update unit 242.

  The routing processing unit 246 determines the next transfer destination router device and the output interface for the packet destination with reference to the route table 247, and sends the packet to the determined next transfer destination router device. The route information updating unit 242 updates the route table 247 while matching the route distribution information received by the route distribution information receiving unit 241 with the information in the route table 247.

  FIG. 17 is a flowchart showing the update process of the route table 247 by the route information update unit 242. First, the destination prefix tp, the prefix length tl, the address le of the external connection router device, and the distribution ratio lr are extracted from the route distribution information received from the route distribution information receiving unit 241 (step S61). Next, it is confirmed whether or not the distribution ratio lr is 100 (step S62). If the distribution ratio is not 100 (NO in step S62), the process ends. On the other hand, if the distribution ratio is 100 (YES in step S62), the route having le as the destination is searched from the route table, and the next transfer destination nh and interface if for the address le are determined (step S63). An entry having a set of destination prefix tp, prefix length tl, next transfer destination nh, and interface if is registered in the route table 247 (step S64).

  Each disclosure of the prior art documents such as the above non-patent documents is incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiment can be changed and adjusted based on the basic technical concept. Various combinations and selections of various disclosed elements are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

  As an example, the present invention can be applied to a network of a service provider that connects to the Internet.

10, 110 Traffic engineering unit 11, 111 Route information acquisition unit 12, 112 Route information storage unit 13, 42, 113 Route distribution information database (route distribution information DB)
14 Route distribution information expansion unit 15, 66, 115, 166 Traffic information acquisition unit 16, 116 Traffic information totaling unit 17, 117 Traffic information database (traffic information DB)
18, 118 Distribution ratio update unit 19, 119 Traffic policy management unit 20, 45, 70, 120, 145, 170, 245 Packet transfer unit 21, 71, 121, 171, 246 Routing processing unit 22, 47, 72, 122 147, 172, 247 Route table 30, 130 Traffic engineering devices 31 to 3n, 51 to 5n, 81 to 8n Network interfaces 131 to 13n, 151 to 15n, 181 to 18n Network interfaces 251 to 25n Network interfaces 40, 140, and 240 Route distribution information management unit 41, 241 Route distribution information reception unit 46, 146 Distribution routing processing unit 50, 250 Router device 50a, 50b Internal router device 50c, 50d Edge router device 60, 160 Route control unit 61, 161 Route information exchange unit 62, 162 Route calculation unit 63, 163 Route information transmission unit 65, 165 Traffic management unit 67, 167 Traffic information transmission unit 80, 180, 80a, 80b External connection router devices 100a to 100d AS (Autonomous System)
114 Mapping information response unit 141 Route distribution information inquiry unit 142 Route distribution information cache 149 Tunnel processing unit 150 Edge router device 174 Tunnel termination unit 201, 202 Terminal 242 Route information update unit L1 to L4 Link

Claims (10)

Route information is received from each of a plurality of router devices located at the boundary with other AS (Autonomous System), the destination prefix, the prefix length, and the priority for each router device are calculated, and the destination prefix, prefix length, router device And a route information storage unit for storing in the first database as route distribution information including priority,
Information on the traffic volume output from each of the plurality of router devices to the other AS is received from each of the plurality of router devices, and the total traffic volume is calculated by summing up the traffic volume for each destination prefix, prefix length, and router device. A traffic information totaling unit that stores traffic information including destination prefix, prefix length, router device, and total traffic volume in a second database,
A pair of router devices included in the route distribution information having a relatively small priority difference among the route distribution information stored in the first database is extracted, and the traffic amount in the extracted router device is predetermined. A distribution ratio updating unit that updates the distribution ratio of packets between the extracted router devices by referring to the traffic information stored in the second database. Features traffic engineering equipment.   The path information storage unit refers to a path attribute included in the path information, and calculates the priority so as to be inversely proportional to the number of ASs through which a packet reaches a destination. Item 4. The traffic engineering device according to Item 1.   The traffic information aggregation unit initializes the total traffic amount included in the traffic information stored in the second database when the distribution ratio update unit updates the packet distribution ratio, and again The traffic engineering apparatus according to claim 1, wherein the traffic amount is totaled to obtain a total traffic amount.   The distribution ratio updating unit transfers from the first router device included in the first route distribution information stored in the first database to the second router device included in the second route distribution information. When distributing a predetermined traffic volume, if the traffic volume passing through the first router device is smaller than the predetermined traffic volume, the distribution ratio included in the first route distribution information is updated to zero. The traffic engineering apparatus according to claim 1, wherein the distribution ratio included in the second route distribution information is updated to 1. 5.   The distribution ratio updating unit transfers from the first router device included in the first route distribution information stored in the first database to the second router device included in the second route distribution information. When the predetermined traffic amount t is distributed, if the traffic amount t1 passing through the first router device is equal to or greater than the predetermined traffic amount t, the distribution ratio included in the first route distribution information 2 to (t1-t) / (t1 + t2), and the distribution ratio included in the second route distribution information is updated to (t2 + t) / (t1 + t2). 5. The traffic engineering device according to any one of 4 above. Route information is received from each of a plurality of router devices located at the boundary with other AS (Autonomous System), the destination prefix, the prefix length, and the priority for each router device are calculated, and the destination prefix, prefix length, router device And storing in the first database as route distribution information including priority,
Information on the traffic volume output from each of the plurality of router devices to the other AS is received from each of the plurality of router devices, and the total traffic volume is calculated by summing up the traffic volume for each destination prefix, prefix length, and router device. And storing in a second database as traffic information including a destination prefix, prefix length, router device and total traffic volume;
Extracting a pair of router devices included in the route distribution information having a relatively small priority difference among the route distribution information stored in the first database;
Updating the packet distribution ratio between the extracted router devices by referring to the traffic information stored in the second database so that the traffic amount in the extracted router devices conforms to a predetermined policy. A traffic engineering method characterized by comprising.   The method according to claim 6, further comprising: calculating the priority based on a path attribute included in the route information so as to be inversely proportional to the number of ASs through which the packet reaches the destination. Traffic engineering methods.   Including a step of initializing the total traffic amount included in the traffic information stored in the second database and calculating the total traffic amount by again counting the traffic amount when the packet distribution ratio is updated The traffic engineering method according to claim 6 or 7, wherein Route information is received from each of a plurality of router devices located at the boundary with other AS (Autonomous System), the destination prefix, the prefix length, and the priority for each router device are calculated, and the destination prefix, prefix length, router device And processing to store in the first database as route distribution information including priority,
Information on the traffic volume output from each of the plurality of router devices to the other AS is received from each of the plurality of router devices, and the total traffic volume is calculated by summing up the traffic volume for each destination prefix, prefix length, and router device. , And storing in the second database as traffic information including the destination prefix, prefix length, router device, and total traffic volume;
A process of extracting a pair of router devices included in the route distribution information having a relatively small difference in priority among the route distribution information stored in the first database;
A process of updating a packet distribution ratio between the extracted router devices by referring to the traffic information stored in the second database so that the traffic amount in the extracted router devices conforms to a predetermined policy. A program characterized by being executed by a computer.   The computer is configured to cause the computer to execute a process of calculating the priority based on a path attribute included in the route information so as to be inversely proportional to the number of ASs through which the packet reaches the destination. Item 10. The program according to Item 9.

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