JP4069106B2 - Packet transfer device - Google Patents

Description

  The present invention relates to a configuration method of a packet transfer device such as a router in an information communication network.

  The IP network that uses IP packets as a transfer unit can use various applications such as e-mail, WWW (World Wide Web), VoIP (Voice over IP), video distribution, etc. Compared with the conventional telephone-based switching method In recent years, traffic has increased explosively due to advantages such as low device costs.

  In addition, various applications can be used, and in the use of a specific application, a function corresponding to the QoS (Quality of Service) problem of how to guarantee the required communication service quality is also required. It is getting to be. As a function for dealing with such QoS, there is a function of priority control (hereinafter simply referred to as “priority control”) according to QoS. For example, in order to execute a communication application that handles CD (Compact Disk) quality sound, it is necessary to secure a bandwidth sufficient for the application and to forward packets preferentially. In order to cope with such a request, it is necessary to determine a priority class and a necessary bandwidth in accordance with an application, and control to preferentially transfer a packet having a high priority class. Such packet congestion control is called priority control and is indispensable for current IP (Internet Protocol) communication.

  The router arranged at each node of the IP network determines the output line of the packet based on the IP header of the received packet. Conventional routers are mainly software routers that determine the output line of a packet by means of a CPU (Central Processing Unit) that is bus-coupled to the input / output line support unit. However, in order to cope with the explosive increase in traffic, Therefore, hardware routers that speed up packet transfer by performing header analysis of IP packets with hardware and connecting the input / output line corresponding parts with high-speed switches are in the spotlight.

  The hardware router does not perform packet processing by the CPU, but performs packet processing using hardware dedicated to network processing. An example of such hardware dedicated to network processing is a network processor (NP). Depending on the hardware, the network processor reads information about the output line in the header of the packet, maintains routing information storage means, changes the header information, and determines the output line of the packet This function can be set.

  An example in which a router is configured using a network processor is shown in FIG. 4 (see Non-Patent Document 1). FIG. 4 shows a configuration example using a network processor in a normal router. In the configuration of FIG. 4, the input line corresponding unit 2B and the output line corresponding unit 3B before and after the switch unit 6B are implemented as hardware, aiming at high-speed switching processing.

In the conventional packet switching apparatus (see FIG. 4), the output line corresponding part of the packet is determined by referring to the routing information storage means based on the IP header information (not shown) of the packet in the input line corresponding part 2B. It is transmitted to the switch unit 6B together with the information of the output line corresponding unit. The switch unit 6B exchanges packets received from a plurality of input line corresponding units according to the information of the output line corresponding unit, and transmits the packets to the output line corresponding unit (corresponding to one of the codes 3B) to be transmitted. In the switch unit 6B, a packet from a plurality of input line corresponding units 2B is given to the packet in order to cope with packet congestion caused by biasing to a specific output line corresponding unit (corresponding to one of the reference numerals 3B). Priority control execution means (not shown) for exchanging packets according to the priority class. Here, in order to avoid having a high-function priority control execution means (not shown) in the switch unit 6B that accommodates the plurality of input line corresponding units 2B and the plurality of output line corresponding units 3B, the switch unit 6B and the input A protocol is defined between the line corresponding units 2B, and the input line corresponding unit 2B shares priority control in cooperation with the switch unit 6B. Further, the output line corresponding unit 3B is configured to have priority control execution means (not shown) in order to perform transmission according to the output line 5.
Aoki, Kurimoto, Kakishima, Urushidani, “A Consideration on the Construction Method of Economical Routers”, Proceedings of the 2004 IEICE General Conference, B6-87, B-II Volume, p. 87

  In the prior art, the priority control function in packet transfer is distributed and arranged in the input line corresponding unit, the switch unit, and the output line corresponding unit. Therefore, in order to perform priority control, it is necessary to exchange information between the respective priority control functions. Therefore, the relationship between the input line corresponding unit, the switch unit, and the output line corresponding unit cannot be made sparse. It was closely related. As a result, for example, if the design of the input line corresponding part is to be changed, the design of the output line corresponding part needs to be changed. For example, if the input line corresponding part is updated to a new one, the output line corresponding part is updated. The relationship between the input line corresponding part and the output line corresponding part could not be made sparse.

  The object of the present invention is to solve these problems of the prior art and adopt a configuration in which the input line corresponding unit and the output line corresponding unit are in a sparse relationship even when priority control is performed, and each part can be improved in independence. That is.

In order to solve the above-mentioned problems, the present invention accommodates at least one input line, accommodates at least one input line corresponding to an input line corresponding unit for transferring a packet from the input line, and outputs at least one output line. A plurality of output line corresponding units that transfer packets to the output line, and a transfer path for packets transferred from the input line corresponding unit to the output line corresponding unit. In the packet transfer apparatus for transferring a packet so as to be output from a predetermined output line, the input line corresponding unit includes a header reading means for reading the header information of the packet, a routing information storage means for storing the routing information, and a header of the packet A packet from the plurality of output line corresponding units with reference to the routing information storage means based on the information; An output line corresponding unit determining unit for determining a predetermined output line corresponding unit to be transferred; and a packet sending unit for transmitting a packet to be transferred through the transfer path to the determined output line corresponding unit; A packet receiving means for receiving a packet sent through the transfer path; a header reading means for reading header information of the packet; and a priority control executing means for performing priority control of a packet according to a priority class assigned to the packet, It said input line corresponding unit volume inputted by the input line to all of the output line corresponding unit (hereafter, "capacity" is to refer to the maximum amount of communication transferred by line is allowed. ) comprising an arrangement for transferring packets from said input line corresponding unit to the output line corresponding unit in the above capacity, the output times Corresponding section, Ru includes a receivable said packet receiving means packets simultaneously from all of the input line corresponding unit through the transfer path.

  According to this configuration, the input line corresponding unit determines the predetermined output line corresponding unit by referring to the routing table for the packet input from the input line based on the packet header information, and the output determined through the transfer path. The packet is transferred to the line corresponding unit without causing congestion. As a result, the output line accommodated in the output line corresponding unit outputs the transferred packet. In this configuration, when a priority class is set for the packet, priority control according to the priority class is executed by the priority control execution means provided in the output line corresponding unit.

  Further, the present invention is characterized in that the transfer path is configured by a mesh type network.

  According to this configuration, a packet can be transferred from an arbitrary input line corresponding unit to an arbitrary output line corresponding unit.

  According to the present invention, even when priority control is performed, the input line corresponding unit and the output line corresponding unit are in a sparse relationship, and the independence of each part can be enhanced.

Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a packet transfer apparatus according to an embodiment of the present invention. In FIG. 1, the packet transfer apparatus 1 includes an output line corresponding unit from a plurality of input line corresponding units 2 (2X, 2Y), a plurality of output line corresponding units 3 (3X, 3Y), and an input line corresponding unit 2 (2X, 2Y). 3 (3X, 3Y) including a mesh type network 7 as a transfer path for packets transferred to 3 (3X, 3Y).

[Input line support section]
Each input line corresponding unit 2 accommodates at least one or more input lines 4, and includes header reading means 21, output line corresponding part determining means 22, all output line corresponding parts 3X, It comprises interfaces (packet sending means) 23a and 23b that are directly connected to 3Y and routing information storage means 24. The header reading unit 21 reads the header information of the packet input from the input line 4. The output line corresponding unit determining means 22 determines the output line corresponding unit 3 to which the packet is to be sent by referring to the routing information storage means 24 based on the header information. By the way, the interface 23a of the input line corresponding unit 2X is connected to the interface 31a of the output line corresponding unit 3X, and the interface 23b of the input line corresponding unit 2X is connected to the interface 31c of the output line corresponding unit 3Y via the mesh type network 7. Yes. Since the interfaces 23c and 23d are the same as the interfaces 23a and 23b, description thereof is omitted. In addition, the input line corresponding unit 2Y has the same configuration as the input line corresponding unit 2X, and the description thereof will be omitted.

  The packet input from the input line 4 is output by the output line corresponding unit determining means 22 to be transmitted by the header information of the packet and the entry of the routing table included in the routing information storage means 24. (3X, 3Y) Is transmitted to the interface 23 (23a, 23c) connected to the interface 31 (31a, 31b) of the determined output line corresponding unit 3. At this time, since the packet transfer capacity of the interface 23 is greater than or equal to the capacity of the input line 4, there is no quality degradation such as delay, and the packet is transferred to the interface 31 of the determined output line corresponding unit 3.

[Output line support section]
The output line corresponding unit 3 (3X, 3Y) has an interface (packet receiving unit) 31 (31a, 31b) that directly connects to all the input line corresponding units 2 (2X, 2Y), a header reading unit 32, and execution of priority control. It is constituted by means 33 and is connected to at least one output line 5. The priority control execution means 33 determines the physical line capacity of the output line 5 and the path capacity of layer 2 or higher such as LSP (Label Switched Path) on the output line, and performs packet transfer according to the priority class assigned to the transfer packet. . Note that the interfaces 31c and 31d are the same as the interfaces 31a and 31b, and a description thereof will be omitted.

  In the output line corresponding unit 3, packets arrive at the corresponding interfaces 31 (31a, 31b) from all the input line corresponding units 2 (2X, 2Y). Packets arriving at the corresponding interface 31 from a plurality of input line corresponding units 2 are controlled by the priority control execution means 33 according to the path capacity of layer 2 or higher in which each packet is accommodated, and sent to the output line 5. Note that any priority control method can be used for the priority control means 33, and the priority control method is not limited to the priority control method in the present embodiment.

[Mesh type network]
FIG. 2 is a diagram showing a configuration of the mesh type network shown in FIG. Next, the configuration of the mesh type network 7 will be described with reference to FIG.

  In FIG. 1, the input line corresponding unit 2 is described by two indicated by reference numerals 2X and 2Y, and the output line corresponding unit 3 is also indicated by two indicated by reference numerals 3X and 3Y. However, as shown in FIG. There may be any number of corresponding units 2 and output line corresponding units 3. The required number of interfaces 23 and 31 may be prepared according to the number of input lines 4 and the number of output lines 5, respectively. Then, as shown in FIG. 2, if each input line corresponding unit 2A and all output line corresponding units 3A are directly connected one by one, the configured line network becomes a mesh type line network.

  In FIG. 2, the line network is represented as a mesh-type line network 7. As described above, each line and interface is configured with a capacity larger than that of the input line, so that any input line 4 from which the packet enters will pass through this mesh-type line network 7 and the output line corresponding unit. Congestion does not occur until 3A is reached.

  Compared with the configuration shown in FIG. 4, in the configuration of FIG. 4, even if the capacity of the line from the input line corresponding unit 2 </ b> B to the switch unit 6 </ b> B is larger than the input line capacity, there is a possibility that congestion occurs in the switch unit 6 </ b> B. Thus, the switch unit 6B alone cannot sufficiently cope with this congestion. Therefore, in the configuration of FIG. 4, the input line corresponding unit 2B also requires priority control execution means (not shown) that closely cooperates with the switch unit 6B.

  On the other hand, in the present embodiment shown in FIG. 2, no congestion occurs in the mesh type network 7 corresponding to the switch unit 6B, and no congestion occurs until the output line corresponding unit 3A is reached. The line corresponding unit 2A can be configured to have no priority control execution means.

[Operation of packet transfer device]
Next, the operation of the packet transfer apparatus having the above-described configuration will be described with reference to FIGS. 1 and 2 and FIG. FIG. 3 is a sequence diagram showing the operation of the packet transfer apparatus.

  For example, when the input line corresponding unit 2X of the packet switching apparatus 1 inputs a packet from the input line 4 accommodated therein (S21), the header reading unit 21 first reads the header of the input packet (S22). . Then, the input line corresponding unit 2X uses this information to determine the transfer destination output line corresponding unit 3 by the output line corresponding unit determining unit 22 with reference to the routing information storage unit 24 (S23). Here, it is assumed that the packet transfer destination is the output line corresponding unit 3Y.

  The input line corresponding unit 2X transfers the packet from the interface 23b to the interface 31c of the destination output line corresponding unit 3Y through the mesh type network 7. The output line corresponding unit 3Y receives the transferred packet via the interface 31c. The output line corresponding unit 3Y that has received the packet reads the priority class information of the header of the packet by the header reading unit 32 (S31).

  The priority control execution means 33 performs priority control according to the priority class according to this information, and transmits a packet to the line 5 accommodated in the output line corresponding unit 3Y (S33, S34, S35). As priority control, description will be given by taking, as an example, priority control of three classes of the highest priority class, the bandwidth reservation class, and the best effort class.

  The packet of the highest priority class determined as the highest priority class from the priority class information (S32) waits for packets of other classes, and the lines accommodated by the output line corresponding unit 3Y in the order of arrival between the highest priority class packets. 5 (S33). The bandwidth reservation class packet determined to be the bandwidth reservation class from the priority class information (S32), when there is no packet of the highest priority class waiting for transmission, the output line corresponding unit within the bandwidth allocated to the bandwidth reservation class It is transmitted to the line 5 accommodated by 3Y (S34). The best effort class packet determined as the best effort class from the priority class information (S32) is a bandwidth reservation for transmission within the bandwidth allocated to the bandwidth reservation class when there is no packet of the highest priority class waiting for transmission. When there is no class packet (in FIG. 3, the highest priority class and the bandwidth reservation class are expressed as higher classes), the packet is transmitted to the line 5 accommodated in the output line corresponding unit 3Y (S35). The best-effort class packet is accumulated in the buffer if there is no opportunity to be transmitted to the line 5 accommodated by the corresponding unit 3Y, and is discarded due to a buffer overflow. Only the packet transmitted from the priority control execution means 33 to the line 5 accommodated in the output line corresponding unit 3Y is output from the output line (S36).

  As described above, in the present embodiment, as shown in FIG. 1, since the packet transfer priority control is performed only by the output line corresponding unit 3, at least the priority control is performed with the input line corresponding unit 2. As a result, the input line corresponding unit 2 and the output line corresponding unit 3 can be configured to some extent independently. This not only facilitates the design of the input line corresponding part and the output line corresponding part, but when higher performance hardware appears for each part, it is updated to the aforementioned high performance hardware. This makes it possible to provide a highly flexible packet transfer apparatus that can easily perform this. In the above-described embodiment, the transfer path is described as a mesh type. However, the transfer path is not limited to this, and other transfer paths, for example, a mode involving establishment of a large-capacity optical pass-through in Non-Patent Document 1. It may be like a transfer path.

It is a block diagram which shows the packet transfer apparatus which concerns on embodiment of this invention. It is a figure which shows the specific example of the mesh type | mold network shown in FIG. It is a sequence diagram which shows operation | movement of the packet transfer apparatus of FIG. It is a figure which shows the structural example of the conventional packet transfer apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Packet transfer apparatus 2 Input line corresponding part 3 Output line corresponding part 4 Input line 5 Output line 7 Mesh type | mold network (forwarding path)
21 Header Reading Unit 22 Output Line Corresponding Portion Determining Unit 23 Interface (Packet Sending Unit)
24 routing information storage means 31 interface (packet receiving means)
32 Header reading means 33 Priority control execution means

Claims (2)

An input line corresponding unit for accommodating at least one input line and transferring a packet from the input line, and an output line corresponding unit for accommodating at least one output line and transferring a packet to the output line And a transfer path for packets transferred from the input line corresponding unit to the output line corresponding unit, so that packets input from the input line are output from a predetermined output line. In the packet transfer device to transfer,
The input line corresponding unit includes a header reading unit that reads packet header information, a routing information storage unit that stores routing information, and the routing information storage unit that refers to the plurality of output lines based on packet header information. An output line corresponding unit determining unit for determining a predetermined output line corresponding unit for transferring a packet from the corresponding unit, and a packet sending unit for transmitting a packet to be transferred through the transfer path to the determined output line corresponding unit,
The output line corresponding unit performs packet priority control in accordance with a packet receiving means for receiving a packet sent through the transfer path, a header reading means for reading header information of the packet, and a priority class assigned to the packet. With priority control execution means,
The input line corresponding unit comprises a configuration for transferring packets from the input line corresponding unit to the output line corresponding unit with a capacity equal to or greater than the capacity input by the input line to all the output line corresponding units ,
The packet transfer apparatus, wherein the output line corresponding unit includes the packet receiving unit capable of simultaneously receiving packets from all the input line corresponding units through the transfer path . The packet transfer apparatus according to claim 1, wherein the transfer path is configured by a mesh type network.

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