JP2018037974A - Gateway router, communication system, traffic flow control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fairness among users in a gateway router (transfer device) at an aggregation point.SOLUTION: A gateway router for transferring a packet from an edge router including buffers set for each user to a destination includes: a buffer control unit for dynamically setting the buffers from a prescribed relational expression according to the number of accommodation users of the edge router for each edge router; and a distribution unit for distributing a packet received from an edge router to a buffer corresponding to the edge router.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a gateway router, a communication system, a traffic flow control method, and a program, and more particularly, to a gateway router, a communication system, a traffic flow control method, and a program for performing fair control at an aggregation base.

  In order to provide a more efficient service, a method is considered in which service functions that have been conventionally deployed at the edge portion are separated and deployed centrally in a remote DC (data center) or the like.

  FIG. 1 is a schematic diagram showing a method of deploying service functions at an aggregation base. A group of servers for realizing the service function is centrally deployed in the DC, which is the service function aggregation base. The traffic from each user terminal is distributed by ER (edge router), and the traffic that needs to be processed by the service function is transferred to the aggregation base. Traffic that does not require processing by the service function is directly transferred to the Internet.

  The traffic that is forwarded to the central base is only the one that requires processing of a specific service function, and it is assumed that there is not much bandwidth during normal times, but traffic from multiple bases gathers, so traffic from each ER It is desirable to be able to control the bandwidth at the GWR (gateway router) at the central site in preparation for the case where the amount increases all at once.

  There are methods such as IntServ (Integrated Services) and DiffServ (Differentiated Services) as a method for guaranteeing communication quality by securing a band by a network node (see Non-Patent Documents 1 and 2). It has also been studied to perform fair control by combining IntServ and DiffServ (see Non-Patent Document 3).

  In the BE (Best Effort) service of communication carriers, in order to prevent the heavy user from occupying the bandwidth, a buffer is individually allocated to the user accommodated in the router device, and packets are sent in order according to the set bandwidth for each user. This ensures fairness among users.

  FIG. 2 is a schematic diagram showing fair control between users according to the prior art. FIG. 2A shows a case where fair control between users is not performed, and packets of users 1 to 3 are put in the same buffer. At this time, in FIFO (First-In First-Out), since packets occupy buffers in the order of arrival, there is a possibility that packets of users with a small amount of traffic will be discarded. As a result, a heavy user may occupy the band. FIG. 2 (2) shows a case where fair control between users is performed. Buffers are individually assigned to users 1 to 3, and packets are output in order from each buffer by round robin or the like. As a result, a certain bandwidth is guaranteed for each user.

RFC1633, "Integrated Service in the Internet Architecture", July 1994, Internet (URL: https://tools.ietf.org/html/rfc1633), August 4, 2016 search RFC2122, "Specification of Guaranteed Quality of Service", September 1997, Internet (URL: https://tools.ietf.org/html/rfc2212), search on August 4, 2016 Japan Patent Office, "Control when IntServ / RSVP and DiffServ are combined", Internet (URL: https://www.jpo.go.jp/shiryou/s_sonota/hyoujun_gijutsu/bidirectional_video/132_09.htm), August 2016 4-day search

  As can be seen from FIG. 1, traffic is transmitted from the ER deployed throughout the country to the GWR at the central location. GWR needs to perform fair control to ensure fairness of bandwidth among users, but currently, buffer / policer settings for each user are statically set by SO (service operator) (pre-configuration ) However, since edge routers can accommodate thousands to tens of thousands of users per unit, the number of users that are aggregated at the aggregation base becomes enormous, and hardware performance (buffer capacity, lack of policers) For example, it is difficult to set a buffer / policer statically for all users.

  In GWR, it is also possible to prepare a buffer / policer for each ER, not for each user. However, with this method, there is a possibility that fairness may be lost depending on the number of users using ER.

  FIG. 3 is a schematic diagram showing a problem when a buffer / policer is prepared for each ER in the GWR. Here, it is assumed that the users 1 to 3 are accommodated in the edge router ER1, and the user 4 is accommodated in the edge router ER2. In ER1 and ER2, fair control between users as shown in FIG. 2 is performed, and in GWR, fair control between ERs is performed by a buffer / policer prepared for each ER. However, in the fair control between the ERs, a difference occurs in the usable bandwidth according to the user accommodation rate for each ER. The packet of ER1 accommodating users 1 to 3 is more likely to be dropped from the buffer, and the packet of ER2 accommodating only user 4 is less likely to be dropped from the buffer. As a result, a large number of packets from the ER with a small number of accommodated users are output, and fairness is impaired.

  In particular, in a large-scale carrier network, the number of users accommodated in one router can be several thousand to several tens of thousands, and the difference in the number of users between ERs can be several hundred to several thousand. The difference between the bandwidths allocated per hit increases.

  In order to solve such a solution, an object of the present invention is to improve fairness among users in a GWR (transfer device) at an aggregation base.

A gateway router according to an aspect of the present invention is:
A gateway router for forwarding a packet from an edge router having a buffer set for each user to a destination;
For each edge router, a buffer control unit that dynamically sets a buffer from a predetermined relational expression according to the number of accommodated users of the edge router,
A distribution unit that distributes packets received from an edge router to a buffer corresponding to the edge router;
It is characterized by having.

In addition, a communication system according to one aspect of the present invention includes:
A communication system having an edge router having a buffer set for each user and a gateway router for forwarding a packet from the edge router to a destination,
The edge router is
By grouping the accommodated users of the edge router from a predetermined relational expression according to the number of accommodated users of the edge router and setting a tunnel for each group between the edge router and the gateway router, or for each group By assigning an identifier, it has a distribution unit that distributes packets output from the buffer of the edge router,
The gateway router is
A buffer controller that dynamically sets a buffer according to the set tunnel or the assigned identifier;
A distribution unit that distributes a packet received from an edge router to a tunnel through which the packet has passed or a buffer corresponding to an identifier assigned to the packet;
It is characterized by having.

A traffic flow control method according to an aspect of the present invention includes:
A traffic flow control method in a gateway router that forwards a packet from an edge router having a buffer set for each user to a destination,
For each edge router, dynamically setting a buffer from a predetermined relational expression according to the number of users accommodated by the edge router;
Distributing the packet received from the edge router to the buffer corresponding to the edge router;
It is characterized by having.

A traffic flow control method according to an aspect of the present invention includes:
A traffic flow control method in a communication system having an edge router having a buffer set for each user and a gateway router for forwarding a packet from the edge router to a destination,
In the edge router, by grouping the accommodated users of the edge router from a predetermined relational expression according to the number of accommodated users of the edge router, and setting a tunnel for each group between the edge router and the gateway router Or by assigning an identifier for each group to distribute packets output from the buffer of the edge router;
In the gateway router, dynamically setting a buffer according to the set tunnel or the assigned identifier;
In the gateway router, the packet received from the edge router is distributed to a tunnel through which the packet has passed or a buffer corresponding to an identifier assigned to the packet;
It is characterized by having.

A program according to an aspect of the present invention is
A program for causing a computer to function as a gateway router that forwards a packet from an edge router having a buffer set for each user to a destination.
For each edge router, buffer control means for dynamically setting a buffer from a predetermined relational expression according to the number of users accommodated by the edge router, and distribution means for distributing packets received from the edge router to buffers corresponding to the edge router,
It is made to function as.

A program according to an aspect of the present invention is
A program for causing a computer to function as a gateway router that forwards a packet from an edge router having a buffer set for each user to a destination.
By grouping the accommodated users of the edge router from a predetermined relational expression according to the number of accommodated users of the edge router in the edge router, and setting a tunnel for each group between the edge router and the gateway router, or Receiving means for receiving a packet outputted and distributed from the buffer of the edge router by giving an identifier for each group,
Buffer control means for dynamically setting a buffer according to the set tunnel or the assigned identifier, and the packet received from the edge router corresponds to the tunnel passed by the packet or the identifier assigned to the packet Distribution means to distribute to the buffer
It is made to function as.

  According to the present invention, it is possible to improve fairness among users in a GWR (transfer device) at an aggregation base.

Schematic diagram showing the method of deploying service functions at a central location Schematic showing prior art fair control between users Schematic showing issues when preparing buffer / policer for each ER in GWR Schematic of fair control according to an embodiment of the present invention Schematic of fair control according to Embodiment 1 of the present invention 1 is a flowchart showing control of traffic flow according to the first embodiment of the present invention. Schematic of fair control according to Embodiment 2 of the present invention Flowchart showing control of traffic flow according to embodiment 2 of the present invention (part 1) Flowchart showing control of traffic flow according to embodiment 2 of the present invention (part 2) Schematic of fair control according to Embodiment 3 of the present invention Flowchart showing control of traffic flow according to embodiment 3 of the present invention (part 1) Flowchart showing control of traffic flow according to embodiment 3 of the present invention (part 2)

  Embodiments of the present invention will be described below with reference to the drawings.

  In the embodiment of the present invention, a communication system having an ER (edge router) and a GWR (gateway router) will be described. The ER is a device that accommodates a user, and is a router device that forwards a packet from the user to an appropriate destination. The GWR is a router device that is arranged at a service function aggregation base or the like and forwards packets transferred from the ER to a destination service function providing server or the like. In order to achieve fair control among users in such a communication system, fair control between users is performed by setting a buffer for each user in the ER, and further, when a packet from the ER is transferred to the destination in the GWR. In addition, fair control is implemented by setting a buffer / policer according to the number of ER accommodation users for each ER. The GWR temporarily stores the received packet in the buffer, but because the buffer capacity is limited, the policer discards the packet that cannot be stored in the buffer. In the following description, a combination of a buffer and a policer is described as a buffer / policer.

  FIG. 4 is a schematic diagram of fair control according to the embodiment of the present invention. In this example, the order of packets by fair control in the first stage (ER) is utilized, and even if traffic is distributed roughly in the second stage (GWR), the fairness among users is (somewhat) reduced. Pay attention to what can be secured.

  ER implements fair control among users. Since traffic arriving at the GWR is fair controlled by the ER, variation in the number of packets of each user of the same ER received per unit time is reduced. Therefore, even if users are grouped for each same ER and a buffer is assigned to each group, it is considered that the number of packets of users entering the buffer is almost equal.

  In order to realize such fair control, the GWR manages the number of users communicating and the buffers / policers assigned to each user, and controls the number of users assigned to each buffer so that there is no bias. Group and control distribution to buffer / policer. Note that user grouping may be performed in the ER, and the GWR may control the distribution to the buffer / policer based on the grouping in the ER. When the number of users that can be accommodated in the buffer / policer has reached the upper limit, the GWR dynamically creates and configures the buffer / policer.

  The upper limit value x of the number of users assigned to one buffer / policer is a numerical value equal to or smaller than the number of users of the ERs connected to the GWR at the aggregation base but having the smallest number of accommodated users, and satisfies the following condition. The number of buffers / policers set in GWR is y, and the maximum number is ymax. When the number of accommodated users of each ER (ER1, ER2,...) Is a1, a2,..., The number of buffers / policers required to store all users of each ER is b1, b2,. (Example: When x = 90 and a1 = 200, b1 = 3). At this time, the following expression is satisfied.

すなわち、xはGWRに接続するERの収容ユーザ数の最小値以下の数値とし、当該数値で各ERの収容ユーザ数a1、a2・・・を除した数の和が、GWRに設定可能なバッファ数ymaxを超えないように設定される。なお、xは小さい方が公平性は向上するため、上記の式を満たす範囲内で、xで各ERの収容ユーザ数a1、a2・・・を除した数の和をできるだけ大きい値とすることが好ましい。

That is, x is a numerical value equal to or smaller than the minimum number of ER accommodation users connected to the GWR, and the sum of the number obtained by dividing the number of accommodation users a1, a2,. It is set not to exceed the number ymax. Since the fairness improves when x is smaller, the sum of the number obtained by dividing the number of accommodated users a1, a2,. Is preferred.

  In this way, for each ER, a plurality of buffers are dynamically set in the GWR according to the number of ER accommodating users. Here, the larger the number of accommodated users, the larger the number of buffers set. And the fairness between users is ensured (to some extent) by distributing each user's packet received from ER to an appropriate buffer.

  The following embodiments will be described in detail as means for distributing each user's packet to an appropriate buffer.

  (Example 1) The identification information of the user who is performing communication, such as 5-tuple and VLAN (Virtual Local Area Network) information, is recorded by GWR. When a packet is received, it is determined whether the user identification information has already been registered. If registration is necessary, the user is recognized as a new user. GWR dynamically allocates buffers for new users.

  (Embodiment 2) Buffers / policers possessed by ER are grouped, and a tunnel between ER and GWR is created for each group. GWR prepares a buffer / policer for each tunnel, and distributes each tunnel.

  (Embodiment 3) Buffers / policers possessed by ER are grouped, a different identifier for each group is assigned to a packet and transferred to GWR. The GWR refers to the identifier and performs distribution to the buffer / policer.

<Example 1>
In the first embodiment, a specific example in which the GWR is assigned alone will be described. In the first embodiment, in the GWR, a buffer is set for each ER, and a traffic flow from the ER is assigned to a buffer / policer set for each ER. That is, traffic flows from different ERs do not enter the same buffer / policer.

  FIG. 5 is a schematic diagram of fair control according to the first embodiment of the present invention. The GWR according to the embodiment of the present invention includes a distribution function unit 101, a distribution management unit 103, and a buffer / policer control unit 105.

  The distribution function unit 101 distributes the packet received from the ER to a buffer corresponding to the ER. Specifically, the distribution function unit 101 groups packets received from the ER based on a transmission source user, and distributes buffers for each group. In response to an inquiry from the distribution function unit 101, the distribution management unit 103 instructs a distribution destination buffer. Further, the distribution management unit 103 instructs the buffer / policer control unit 105 to create a buffer / policer as necessary. The buffer / policer control unit 105 dynamically sets the buffer / policer from the above relational expression (Formula 1) according to the number of ER accommodated users. FIG. 5 shows an example of a functional configuration in the GWR. For example, the distribution function unit 101 and the distribution management unit 103 may be realized as one functional unit.

  Next, referring to FIGS. 5 and 6, a traffic flow control procedure according to the first embodiment will be described. FIG. 6 is a flowchart showing traffic flow control according to the first embodiment of the present invention.

  The GWR stores user identification information such as 5-tuple and VLAN information, and transmission source ER information of the traffic flow. When the packet is received, it is determined whether the user identification information has already been registered. If there is no registration, it is recognized as a new user (STEP 151 in FIG. 6 and STEP 101 in FIG. 5). If it has already been registered, the distribution function unit 101 distributes the traffic flow to the already distributed buffer / policer (STEP 163 in FIG. 6).

  The GWR identifies a traffic flow by the distribution function unit 101, and when receiving a new communication, the GWR inquires which buffer to distribute to the distribution management unit 103 (STEP153 in FIG. 6 and STEP103 in FIG. 5). The distribution management unit 103 determines whether any of the buffers / policers to be distributed (assigned to the transmission source ER) has not reached the upper limit (STEP 155 in FIG. 6). If there is a buffer / policer that has not reached the upper limit, one of the buffers (for example, the vacant buffer) is selected, and the distribution function unit 101 is instructed as a distribution destination buffer (STEP 161 in FIG. 6).

  When all the buffers / policers to be distributed (assigned to the transmission source ER) have reached the allowable number of users, the distribution management unit 103 generates a buffer / policer to the buffer / policer control unit 105. When instructed (STEP 157 in FIG. 6 and STEP 105 in FIG. 5), the buffer / policer control unit 105 generates and sets a buffer / policer (STEP 159 in FIG. 6 and STEP 107 in FIG. 5). The distribution management unit 103 instructs the newly generated buffer / policer as a distribution destination (STEP 161 in FIG. 6).

  The distribution function unit 101 distributes the user's traffic flow to an appropriate buffer (STEP163 in FIG. 6 and STEP109 in FIG. 5).

  Next, a specific example of buffer allocation when the user 7 starts communication in FIG. 5 will be described.

  The numbers of users a1 and a2 accommodated in ER1 and ER2 are set statically, and a1 = 4 and a2 = 3. Four users are communicating in ER1, and two users are communicating among three users in ER2.

  If the maximum number of users x stored in the buffer is 2, the number of buffers b1 and b2 prepared in ER1 and ER2 is 2 (b1 = 4/2 = 2, b2 = 3 / 2≈2), respectively.

  Buffer 1 and buffer 2 are set in ER1, user 1 and user 2 are assigned to buffer 1, and user 3 and user 4 are assigned to buffer 2. Similarly, buffer 3 and buffer n are set in ER2, and user 5 and user 6 are assigned to buffer 3. When only two users are communicating in ER2, the buffer n is not used and resources are reserved.

  When the user 7 starts communication, the buffer 3 is already assigned with the maximum number of users x (= 2), so the buffer n is newly created and set, and the user 7 is assigned to the buffer n. .

  In this way, the buffer / policer control unit 105 dynamically sets one or more buffers in the GWR from a predetermined relational expression for each ER according to the number of ER accommodation users. Here, the larger the number of accommodated users, the larger the number of buffers set. Then, by distributing each user's packet received from the ER to an appropriate buffer, fairness among users can be ensured (to some extent).

  Assuming that the number y of buffers set in the GWR satisfies the above-described predetermined relational expression (Formula 1), the closer the value is to ymax, the smaller the variation in the number of users accommodated between buffers, and the higher the fairness. In addition, when a necessary number of buffers are set in advance and a new user's communication is recognized, the buffer with the smallest number of accommodated users at that time is selected, and the number of users between the buffers is selected by assigning the new user to that buffer. Can be suppressed.

<Example 2>
In the second embodiment, a specific example in which the ER and the GWR perform cooperation in cooperation will be described. In the second embodiment, in the ER, the accommodation users are grouped from a predetermined relational expression (Equation 1) according to the number of accommodation users, and a tunnel between the ER and the GWR is created for each group. In GWR, a buffer is set for each tunnel, and a traffic flow from the ER is assigned to a buffer / policer set for each tunnel.

  FIG. 7 is a schematic diagram of fair control according to the second embodiment of the present invention. The ER according to the embodiment of the present invention includes a tunnel distribution unit 201. The GWR also includes a distribution function unit 101, a distribution management unit 103, and a buffer / policer control unit 105.

  The tunnel distribution unit 201 sets an appropriate number of one or more tunnels between ER and GWR from the above relational expression (Expression 1) according to the number of ER accommodation users, and is output from the ER buffer. The packet is distributed to one of the tunnels. The distribution function unit 101 distributes the packet received from the ER through the tunnel to the buffer corresponding to the tunnel through which the packet has passed. In response to an inquiry from the distribution function unit 101, the distribution management unit 103 instructs a distribution destination buffer. Further, the distribution management unit 103 instructs the buffer / policer control unit 105 to create a buffer / policer as necessary. The buffer / policer control unit 105 dynamically sets a buffer / policer according to the set tunnel. FIG. 7 shows an example of a functional configuration in the ER and GWR. For example, the distribution function unit 101 and the distribution management unit 103 may be realized as one functional unit.

  Next, a traffic flow control procedure according to the second embodiment will be described with reference to FIGS. 8 and 9 are flowcharts showing control of traffic flow according to the second embodiment of the present invention. Although FIG. 8 shows an example in which a tunnel is dynamically generated, a tunnel may be set between the ER and the GWR in advance according to the number of accommodated users.

  The ER stores identification information of a user performing communication such as 5-tuple and VLAN information. When the packet is received, it is determined whether the user identification information has already been grouped. If grouping is necessary, the user identification information is recognized as a new user (STEP 231 in FIG. 8 and STEP 201 in FIG. 7). When the grouping has already been performed, the tunnel distribution unit 201 distributes the traffic flow to the already distributed tunnel (STEP 241 in FIG. 8 and STEP 203 in FIG. 7).

  The ER identifies the traffic flow in the tunnel allocating unit 201, and when a new communication is received, the ER determines whether there is a group for which the allowable number of users has not reached the upper limit (see FIG. If there is a group that has not reached the upper limit, one of the groups (for example, the vacant group) is selected (STEP 239 in FIG. 8).

  When all the groups to be distributed have reached the allowable number of users, the tunnel distribution unit 201 creates a new group, sets a user for new communication to the group (STEP 235 in FIG. 8), A new tunnel is constructed (STEP237 in FIG. 8).

  The tunnel distribution unit 201 distributes the user's traffic flow to an appropriate tunnel (STEP 241 in FIG. 8 and STEP 203 in FIG. 7).

  In this way, the ER has a separate buffer / policer for each user, and these buffers / policers are grouped into a certain number, and the traffic flow of each user is forwarded to the GWR through a separate tunnel for each group.

  In the distribution function unit 101, the GWR discriminates the tunnel based on the reception port, tunnel ID, and the like, and recognizes the traffic flow that has not been distributed as a new tunnel (STEP 251 in FIG. 9). If it has already been distributed, the distribution function unit 101 distributes the traffic flow to the buffer / policer that has already been distributed (STE 261 in FIG. 9 and STEP 205 in FIG. 7).

  When the distribution function unit 101 determines that the tunnel is a new tunnel, the distribution management unit 103 is inquired of which buffer to distribute to (step 253 in FIG. 9). When a buffer / policer is not generated for the new tunnel, the distribution management unit 103 instructs the buffer / policer control unit 105 to generate a buffer / policer (STEP 255 in FIG. 9), and the buffer / policer control unit 105 A buffer / policer is generated and set (STEP 259 in FIG. 9 and STEP 207 in FIG. 7). The distribution management unit 103 instructs the newly generated buffer / policer as a distribution destination (STEP 259 in FIG. 9).

  The distribution function unit 101 distributes the traffic flow received via the tunnel to an appropriate buffer (STEP 261 in FIG. 9 and STEP 205 in FIG. 7).

  Next, a specific example of buffer allocation when the user 7 starts communication in FIG. 7 will be described.

  The numbers of users a1 and a2 accommodated in ER1 and ER2 are set statically, and a1 = 4 and a2 = 3. Four users are communicating in ER1, and two users are communicating among three users in ER2.

  If the maximum number of users x stored in the buffer is 2, the number of buffers b1 and b2 prepared in ER1 and ER2 is 2 (b1 = 4/2 = 2, b2 = 3 / 2≈2), respectively.

  Buffer A and buffer B are set in ER1, and buffer C and buffer D are set in ER2. In each ER, users are grouped for each buffer to be allocated, and traffic is forwarded to the GWR through a separate tunnel for each group. The number of users accommodated in one group is less than or equal to x. In this embodiment, user 1 and user 2 are in buffer A, user 3 and user 4 are in buffer B, user 5 and user 7 are in buffer C, and user Group 6 into buffer D. GWR distributes traffic to the corresponding buffer in tunnel units. When a new tunnel is established, a new buffer is added in the GWR.

  Thus, the tunnel distribution unit 201 sets one or more tunnels from a predetermined relational expression according to the number of ER accommodation users. Here, the greater the number of accommodated users, the greater the number of tunnels that are set. And in GWR, the fairness between users can be ensured (to some extent) by distributing each user's packet received through the tunnel to an appropriate buffer. In the second embodiment, the tunnel management load increases because the control is performed in units of tunnels, but the scaleability is higher than that in the first embodiment.

  The number of tunnels to be set, that is, the number of buffers y set in the GWR is based on the assumption that the above-mentioned predetermined relational expression (Equation 1) is satisfied. Increases nature. In addition, when a necessary number of buffers are set in advance and a new tunnel is recognized, a buffer with the smallest number of accommodated users at that time is selected, and a new tunnel is assigned to the buffer. Can be suppressed. As shown in FIG. 8, it is also possible to dynamically group users who are communicating, but in this case, the number of users assigned to a newly created group is reduced, so that fairness may be impaired. There is sex.

<Example 3>
In the third embodiment, a specific example in which the ER and the GWR perform cooperation in cooperation will be described. In the third embodiment, in the ER, accommodated users are grouped from a predetermined relational expression (Equation 1) according to the number of accommodated users, and a different identifier for each group is assigned to the packet and transferred to the GWR. In GWR, a buffer is set for each identifier, and a traffic flow from the ER is assigned to a buffer / policer set for each identifier.

  FIG. 10 is a schematic diagram of fair control according to the third embodiment of the present invention. The ER according to the embodiment of the present invention includes an identifier assigning unit 251. The GWR also includes a distribution function unit 101, a distribution management unit 103, and a buffer / policer control unit 105.

  The identifier assigning unit 251 assigns an identifier to the packet output from the ER buffer based on the relational expression (Expression 1) according to the number of ER accommodating users. The distribution function unit 101 distributes the packet received from the ER to a buffer corresponding to the identifier assigned to the packet. In response to an inquiry from the distribution function unit 101, the distribution management unit 103 instructs a distribution destination buffer. Further, the distribution management unit 103 instructs the buffer / policer control unit 105 to create a buffer / policer as necessary. The buffer / policer control unit 105 dynamically sets the buffer / policer according to the assigned identifier. FIG. 10 illustrates an example of a functional configuration in the ER and the GWR. For example, the distribution function unit 101 and the distribution management unit 103 may be realized as one function unit.

  Next, a traffic flow control procedure according to the third embodiment will be described with reference to FIGS. 11 and 12 are flowcharts illustrating traffic flow control according to the third embodiment of the present invention. Although FIG. 11 shows an example of dynamically assigning identifiers, identifiers may be set in advance according to the number of accommodated users.

  The ER stores identification information of a user performing communication such as 5-tuple and VLAN information. When the packet is received, it is determined whether the user identification information has already been grouped. If grouping is necessary, the user identification information is recognized as a new user (STEP 331 in FIG. 11 and STEP 301 in FIG. 10). If grouping has already been performed, the identifier assigning unit 251 assigns the already assigned identifier to the packet (STEP 341 in FIG. 11 and STEP 303 in FIG. 10).

  The ER identifies the traffic flow by the identifier assigning unit 251 and, when a new communication is received, determines whether there is a group whose distribution target has not reached the upper limit (see FIG. 11). STEP 333) If there is a group that has not reached the upper limit, one of the groups (for example, the vacant group) is selected (STEP 339 in FIG. 11).

  When all the groups to be distributed have reached the allowable number of users, the identifier assigning unit 251 creates a new group, sets a user for new communication to the group (STEP 335 in FIG. 11), and creates a new group. An identifier is assigned to (STEP337 in FIG. 11).

  The identifier assigning unit 251 assigns an appropriate identifier to the user packet (STEP 341 in FIG. 11 and STEP 303 in FIG. 10).

  In this way, the ER has individual buffers / policers for each user, and these buffers / policers are grouped into a certain number, and each user's packet is given a different identifier for each group and transferred to the GWR.

  The GWR discriminates the identifier assigned in the ER in the distribution function unit 101, and recognizes it as a new identifier if it is a traffic flow that has not yet been distributed (STEP 351 in FIG. 12). If it has already been distributed, the distribution function unit 101 distributes the traffic flow to the buffer / policer that has already been distributed (STE 361 in FIG. 12, STEP 305 in FIG. 10).

  If the distribution function unit 101 determines that the identifier is a new identifier, the distribution management unit 103 is inquired about which buffer to distribute to (step 353 in FIG. 12). When a buffer / policer is not generated for the new identifier, the distribution management unit 103 instructs the buffer / policer control unit 105 to generate a buffer / policer (STEP 355 in FIG. 12), and the buffer / policer control unit 105 A buffer / policer is generated and set (STEP359 in FIG. 12 and STEP307 in FIG. 10). The distribution management unit 103 instructs the newly generated buffer / policer as a distribution destination (STEP359 in FIG. 12).

  The distribution function unit 101 distributes the packet to which the identifier is assigned to an appropriate buffer (STEP 361 in FIG. 12 and STEP 305 in FIG. 10). Here, the identifier given in the ER is removed.

  Next, a specific example of buffer allocation when the user 7 starts communication in FIG. 10 will be described.

  The numbers of users a1 and a2 accommodated in ER1 and ER2 are set statically, and a1 = 4 and a2 = 3. Four users are communicating in ER1, and two users are communicating among three users in ER2.

  If the maximum number of users x stored in the buffer is 2, the number of buffers b1 and b2 prepared in ER1 and ER2 is 2 (b1 = 4/2 = 2, b2 = 3 / 2≈2), respectively.

  Buffer A and buffer B are set in ER1, and buffer C and buffer D are set in ER2. Each ER groups users for each buffer to be allocated, assigns a different identifier to each group, and forwards traffic to the GWR. The number of users accommodated in one group is less than or equal to x. In this embodiment, user 1 and user 2 are in buffer A, user 3 and user 4 are in buffer B, user 5 and user 7 are in buffer C, and user Group 6 into buffer D. The GWR reads the identifier and distributes traffic to the corresponding buffer. When traffic having a new identifier is received, a new buffer is added in the GWR.

  Thus, the identifier assigning unit 251 assigns one or more identifiers from a predetermined relational expression according to the number of ER accommodation users. Here, the greater the number of accommodated users, the greater the number of identifiers that are set. In the GWR, the fairness among users can be ensured (to some extent) by allocating each user's packet received by reading the identifier to an appropriate buffer. In the third embodiment, a mechanism for assigning an identifier is required for the ER because control is performed in units of identifiers. A mechanism for reading the identifier and distributing traffic and a mechanism for removing the identifier are necessary for the GWR. And scale is high.

  The number of identifiers to be set, that is, the number of buffers y set in the GWR is based on the assumption that the above-mentioned predetermined relational expression (Formula 1) is satisfied. Increases nature. In addition, when a necessary number of buffers are set in advance and a new identifier is recognized, a buffer with the smallest number of accommodated users at that time is selected, and a new identifier is assigned to that buffer. Can be suppressed. As shown in FIG. 11, it is possible to dynamically group communicating users, but in this case, since the number of users assigned to a newly created group is reduced, fairness may be impaired. There is sex.

<Effect of the embodiment of the present invention>
As described above, according to the embodiment of the present invention, the fairness among users can be improved without excessively adding hardware resources such as buffers and policers in the GWR of the aggregation base that accommodates a huge number of users. It becomes possible to make it. Also, the buffer / policer resource usage efficiency can be improved by dynamically generating, setting, and allocating a buffer / policer according to the number of users connected simultaneously.

  Also, by allocating flows evenly to buffers / policers according to the number of users, the difference in the number of users accommodated per GWR buffer / policer can be suppressed. In addition, although one policer is shared by a plurality of people in the GWR, since the first stage of fair control is performed by the ER, fairness is not impaired if users are in the same ER. As a result, the bandwidth difference that can be used by each user in the GWR can be reduced, and the fairness among users can be improved.

<Supplement>
For convenience of explanation, the ER and GWR according to the embodiment of the present invention are described using functional block diagrams. However, the ER and GWR according to the embodiment of the present invention may be hardware, software, or a combination thereof. It may be realized. For example, each functional unit of the ER and GWR may be realized by a CPU (Central Processing Unit) executing data and programs stored in a storage device or a memory device. Further, the embodiment of the present invention includes a program for causing a computer to realize the functions of the ER and GWR according to the embodiment of the present invention, a program for causing a computer to execute each procedure of the method according to the embodiment of the present invention, etc. May be realized. Furthermore, the functional units may be used in combination as necessary. In addition, the method according to the embodiment of the present invention may be performed in an order different from the order shown in the embodiment.

  As mentioned above, although the method for improving the fairness between users in the GWR (transfer device) at the aggregation base has been described, the present invention is not limited to the above-described embodiments, Can be changed and applied.

101 Distribution Function Unit 103 Distribution Management Unit 105 Buffer / Policer Control Unit 201 Tunnel Distribution Unit 251 Identifier Assignment Unit

Claims (8)

A gateway router for forwarding a packet from an edge router having a buffer set for each user to a destination;
For each edge router, a buffer control unit that dynamically sets a buffer from a predetermined relational expression according to the number of accommodated users of the edge router,
A distribution unit that distributes packets received from an edge router to a buffer corresponding to the edge router;
Gateway router with   The upper limit value of the number of users per buffer according to the predetermined relational expression is set to a value equal to or less than the minimum number of accommodated users of the edge router connected to the gateway router, and the number of accommodated users of each edge router is divided by this value. The gateway router according to claim 1, wherein the sum of the numbers is set so as not to exceed a number of buffers that can be set in the gateway router.   The gateway router according to claim 1, wherein the buffer control unit sets a buffer for a communicating user. A communication system having an edge router having a buffer set for each user and a gateway router for forwarding a packet from the edge router to a destination,
The edge router is
By grouping the accommodated users of the edge router from a predetermined relational expression according to the number of accommodated users of the edge router and setting a tunnel for each group between the edge router and the gateway router, or for each group By assigning an identifier, it has a distribution unit that distributes packets output from the buffer of the edge router,
The gateway router is
A buffer controller that dynamically sets a buffer according to the set tunnel or the assigned identifier;
A distribution unit that distributes a packet received from an edge router to a tunnel through which the packet has passed or a buffer corresponding to an identifier assigned to the packet;
A communication system. A traffic flow control method in a gateway router that forwards a packet from an edge router having a buffer set for each user to a destination,
For each edge router, dynamically setting a buffer from a predetermined relational expression according to the number of users accommodated by the edge router;
Distributing the packet received from the edge router to the buffer corresponding to the edge router;
A traffic flow control method comprising: A traffic flow control method in a communication system having an edge router having a buffer set for each user and a gateway router for forwarding a packet from the edge router to a destination,
In the edge router, by grouping the accommodated users of the edge router from a predetermined relational expression according to the number of accommodated users of the edge router, and setting a tunnel for each group between the edge router and the gateway router Or by assigning an identifier for each group to distribute packets output from the buffer of the edge router;
In the gateway router, dynamically setting a buffer according to the set tunnel or the assigned identifier;
In the gateway router, the packet received from the edge router is distributed to a tunnel through which the packet has passed or a buffer corresponding to an identifier assigned to the packet;
A traffic flow control method comprising: A program for causing a computer to function as a gateway router that forwards a packet from an edge router having a buffer set for each user to a destination.
For each edge router, buffer control means for dynamically setting a buffer from a predetermined relational expression according to the number of users accommodated by the edge router, and distribution means for distributing packets received from the edge router to buffers corresponding to the edge router,
Program to function as. A program for causing a computer to function as a gateway router that forwards a packet from an edge router having a buffer set for each user to a destination.
By grouping the accommodated users of the edge router from a predetermined relational expression according to the number of accommodated users of the edge router in the edge router, and setting a tunnel for each group between the edge router and the gateway router, or Receiving means for receiving a packet outputted and distributed from the buffer of the edge router by giving an identifier for each group,
Buffer control means for dynamically setting a buffer according to the set tunnel or the assigned identifier, and the packet received from the edge router corresponds to the tunnel passed by the packet or the identifier assigned to the packet Distribution means to distribute to the buffer
Program to function as.

Images