JP2004201032A - Highly reliable transmission method using a plurality of routes and system thereof, and router for highly reliable transmission - Google Patents

Highly reliable transmission method using a plurality of routes and system thereof, and router for highly reliable transmission Download PDF

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Publication number
JP2004201032A
JP2004201032A JP2002367202A JP2002367202A JP2004201032A JP 2004201032 A JP2004201032 A JP 2004201032A JP 2002367202 A JP2002367202 A JP 2002367202A JP 2002367202 A JP2002367202 A JP 2002367202A JP 2004201032 A JP2004201032 A JP 2004201032A
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Prior art keywords
packet
label
plurality
routes
sequence number
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JP2002367202A
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JP4079359B2 (en
Inventor
Fuyuki Fujikawa
冬樹 藤川
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Central Res Inst Of Electric Power Ind
財団法人電力中央研究所
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Abstract

An object of the present invention is to perform highly reliable data transmission by a plurality of routes without providing a transmitting / receiving terminal with a special function and without using a plurality of IP addresses.
A transmitting edge router duplicates a packet received from a transmitting terminal and adds a sequence number and a different label to a plurality of identical packets obtained as a result of transmission. The core routers 103a to 103d transmit the same packet to the receiving edge router 102b via a plurality of routes based on the label designation by the label. The receiving-side edge router 102b checks the sequence number added to the packet, discards the late-arrival packet, and removes the label and sequence number and transmits the packet to the receiving terminal 101b having the destination IP address.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data transmission method, a data transmission system, and a data transmission router. More specifically, the present invention relates to a method, a system, and a router for improving reliability by transmitting the same data through a plurality of routes in a label switching network that transmits packets using labels.
[0002]
[Prior art]
Conventionally, a method of transmitting the same data using a plurality of routes has been proposed in order to ensure high reliability by using an ATM (Asynchronous Transfer Mode) technology (see Non-Patent Document 1). In this method, the same packet is transmitted a plurality of times by the transmitting device, and the later arriving packet of the same packet is discarded by the receiving device.
[0003]
[Non-patent document 1]
FUJITSU DENSO REVIEW Vol.10 No.1 “Power supply information transmission device for Chubu Electric Power Co., Inc.” Internet <URL: http://www.access.fujitsu.com/review/16/hmx.pdf>
[0004]
[Problems to be solved by the invention]
In recent years, in IP (Internet Protocol) networks, MPLS (Multi Protocol Label Switching) technology has attracted attention as a backbone network technology. In MPLS, it is possible to specify a route explicitly using a label, similarly to ATM. Therefore, when the highly reliable transmission using a plurality of routes proposed in the ATM technology is realized in the MPLS technology, the following method can be considered (see FIG. 11).
[0005]
That is, the receiving terminal 408 has two IP addresses “IP1” and “IP2”. The transmitting terminal 401 transmits two packets PK101 and PK102 having the same user data portion and destination IP addresses “IP1” and “IP2”. The transmitting edge router 402 assigns the label “A1” to the packet PK101 having the destination IP address “IP1” among the packets received from the transmitting terminal 401 based on the label table TB101 (the packet after the label is attached). Is indicated by PK103 in the figure), a label “A2” is assigned to the packet PK102 having the destination IP address “IP2” (the packet after the label is indicated by PK104 in the figure), and transmitted to the first core router 403, respectively. To do. The first core router 403 replaces the labels “A1” → “B1” and “A2” → “B2” based on the label table TB102, and transmits the packet with the label “B1” to the second core router 404. The packet of the label “B2” is transmitted to the third core router 405. The second core router 404 replaces the label “B1” → “C1” based on the label table TB103, and transmits the packet PK105 after the label replacement to the fourth core router 406. The third core router 405 replaces the label “B2” → “C2” based on the label table TB104, and transmits the packet PK106 after the label replacement to the fourth core router 406. The fourth core router 406 replaces the labels “C1” → “D1” and “C2” → “D2” based on the label table TB105, and transmits the packets after the label replacement to the receiving edge router 407, respectively. To do. The receiving edge router 407 deletes the labels “D1” and “D2” based on the label table TB106, and transmits the deleted packets PK107 and PK108 to the receiving terminal 408. The receiving terminal 408 discards a later-arriving packet (hereinafter referred to as a “same-arrival same packet”) among the packets PK107 and PK108 having the same user data portion.
[0006]
With the above configuration, for a packet having the same user data portion, the first route following the first core router 403 → the second core router 404 → the fourth core router 406, and the first core router 403 → the third core router 405 → the fourth core router A two-route transmission with the second route following 406 is realized. Even if a failure occurs in one of the first route and the second route, communication between the transmitting terminal 401 and the receiving terminal 408 is not hindered, and communication reliability is improved.
[0007]
However, in the above-described method, it is necessary to prepare a plurality of IP addresses according to the number of redundant routes to be set. Further, the transmitting terminal 401 needs to have a function of transmitting a packet having the same user data a plurality of times. Further, the receiving terminal 408 needs to have a plurality of IP addresses corresponding to the number of redundant routes to be set, and also needs to have a function of discarding the same late-arriving packet. For this reason, in the above method, reliable data transmission by a plurality of routes can be realized only between the transmitting and receiving terminals 401 and 408 having such special functions.
[0008]
Therefore, the present invention performs highly reliable data transmission using a plurality of routes without having a special function in the transmitting / receiving terminal and without preparing a plurality of IP addresses corresponding to the number of redundant routes to be set. It is an object to provide a method and system and a router for reliable transmission.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a highly reliable transmission method using a plurality of routes according to claim 1 is configured to include an edge router and a core router, and to transmit a packet using a label given in correspondence with a destination address. In a label switching network that performs transmission, the transmitting edge router determines whether a label table in which a destination address is associated with a label to be used, and any one of address information, a program identifier, and transmission quality information included in a packet. Or a control table that specifies whether to set a plurality of routes based on a combination of some or all of them, and for a packet received from a communication device outside the label switching network, refer to the control table. To determine whether to set multiple routes, and when setting multiple routes, A case where a packet is duplicated and different labels are respectively assigned to a plurality of same packets obtained as a result based on a label table, and a sequence number indicating a packet order is assigned to each of the plurality of same packets, and a plurality of routes are not specified. Assigns a label to the packet based on the label table, transmits the packet to the core router corresponding to the label, and the core router transmits the received packet to another core router or edge router corresponding to the label attached to the packet. If the packet received from the core router has a sequence number, the receiving edge router discards the same packet that arrives later based on the sequence number and, at the same time, applies the label and sequence number assigned to the earlier packet. And send the first packet to the destination address. If the packet is transmitted to a communication device outside the network and a sequence number is not added to the packet received from the core router, the label given to the packet is removed and the packet is switched based on the destination address. The data is transmitted to a communication device outside the network.
[0010]
According to a fourth aspect of the present invention, there is provided a label switching network comprising an edge router and a core router, wherein a packet is transmitted using a label assigned to a destination address. The edge router has a label table in which a destination address and a label to be used are associated with each other, and any one or a combination of some or all of address information, a program identifier, and transmission quality information included in a packet. A control table that specifies whether or not to set a plurality of routes based on a packet received from a communication device outside the label switching network, and determines whether to set the plurality of routes by referring to the control table. Judgment and when setting multiple routes, duplicate the relevant packet and obtain the result. If a different label is assigned to each of the same packets based on the label table, and a sequence number indicating the order of the packets is assigned to each of the same packets, and if a plurality of routes are not specified, the packet is added to the label table. A label based on the label is transmitted, and the packet is transmitted to the core router according to the label.The core router transmits the received packet to another core router or an edge router according to the label allocated to the packet, and receives the edge on the receiving side. If the sequence number is assigned to the packet received from the core router, the router discards the same packet that arrives later based on the sequence number and removes the label and sequence number attached to the earlier packet and removes the earlier packet. Label switching based on destination address If a packet transmitted to a communication device outside the network and a sequence number is not given to a packet received from the core router, the label attached to the packet is removed, and the packet is transmitted outside the label switching network based on the destination address. It is transmitted to the device.
[0011]
Further, in the edge router for use in a label switching network for transmitting a packet using a label assigned according to a destination address, the destination address and the label to be used correspond to each other. It is specified whether or not to set a plurality of routes based on the attached label table, any one of the address information, the program identifier, and the transmission quality information included in the packet, or a combination of some or all of them. A control table, and for a packet received from a communication device outside the label switching network, determine whether or not to set a plurality of routes by referring to the control table. Duplicate and assign different labels to the resulting multiple identical packets. A sequence number indicating the packet order is assigned to each of a plurality of identical packets, and if a plurality of routes are not specified, a label is assigned to the packet based on the label table, and the packet is labeled. It is transmitted to the core router according to.
[0012]
According to a sixth aspect of the present invention, in the edge router for use in a label switching network for transmitting a packet using a label assigned to a destination address, a sequence number is assigned to a received packet. If it is, discard the same late-arriving packet based on the sequence number, remove the label and sequence number given to the first-arrived packet, and send the first-arrived packet to a communication device outside the label switching network based on the destination address. When a sequence number is not given to the transmitted and received packet, the label given to the packet is removed, and the packet is transmitted to a communication device outside the label switching network based on the destination address.
[0013]
Accordingly, a sequence number indicating the packet transmission order is added to the packet at the transmitting edge router. The same packet is transmitted to the receiving-side edge router via a plurality of routes by specifying the route by the label. The receiving edge router examines the sequence number added to the packet, discards the packet that comes later, removes the label and sequence number of the packet that came earlier, and transmits it to the communication device according to the destination address I do. As a result, packets having the same user data and the same destination address are transmitted through a plurality of routes. A terminal for transmitting data and a terminal for receiving data do not need any function for implementing a plurality of routes. That is, the transmitting terminal does not need to transmit the same data a plurality of times. The receiving terminal does not need to have a plurality of IP addresses, and it is not necessary to discard the same data that comes later. Further, there is no need to prepare a plurality of IP addresses corresponding to the number of redundant routes to be set.
[0014]
According to a second aspect of the present invention, in the highly reliable transmission method using a plurality of routes according to the first aspect, the edge router on the transmitting side assigns a plurality of transmission instruction information when setting a plurality of routes, The receiving-side edge router checks the presence / absence of a plurality of pieces of transmission instruction information in the received packet to determine the presence / absence of a sequence number. In this case, it is easy to determine whether there is a sequence number at the receiving edge router, and the processing of the sequence number can be simplified.
[0015]
According to a third aspect of the present invention, in the highly reliable transmission method using a plurality of routes according to the first or second aspect, the transmitting edge router includes one or both of a sequence number and a plurality of transmission instruction information in an RTP header. Is described. In this case, there is no need to perform a complicated sequence number check process depending on the format of the user packet, and the sequence number process can be simplified. Since the core router ignores the RTP header, the existing core router can be used as it is.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail based on an embodiment shown in the drawings.
[0017]
1 to 6 show one embodiment of a highly reliable transmission method and system using a plurality of routes and a highly reliable transmission router according to the present invention. This highly reliable transmission system includes an edge router 102, a core router 103, and a transmission path connecting these routers 102 and 103, and uses a label assigned in accordance with a destination address to transmit a packet. In the label switching network 1 for transmission, redundant transmission of the same data is performed using a plurality of routes.
[0018]
For example, in the present embodiment, an example in which the present invention is applied to a typical MPLS as the label switching network 1 will be described. However, application of the present invention to other label switching networks is not excluded. Hereinafter, in the present embodiment, the label switching network is referred to as the MPLS network 1. There is no particular limitation on the number of edge routers 102, the number of core routers 103, and which of the routers 102 and 103 are connected by a transmission line, which constitute the MPLS network 1. The medium constituting the transmission path is not particularly limited, and a known or new cable (a communication line such as a coaxial cable for transmitting an electric signal, or an optical fiber for transmitting an optical signal) may be used. Wireless communication may be used. The number of routes for redundant transmission of the same data is not particularly limited. For example, in the present embodiment, for simplicity of description, the MPLS network 1 is configured as shown in FIG. 1 and described below, and redundant transmission is performed by two routes.
[0019]
That is, in the present embodiment, the MPLS network 1 is configured by two edge routers 102a and 102b and four core routers 103a, 103b, 103c and 103d. Then, the edge router 102a and the first core router 103a are connected by the transmission line TR5. The first core router 103a and the second core router 103b, and the first core router 103a and the third core router 103c are connected by transmission lines TR1 and TR3, respectively. The second core router 103b and the fourth core router 103d are connected to each other, and the third core router 103c and the fourth core router 103d are connected to each other by the transmission lines TR2 and TR4. The fourth core router 103d and the edge router 102b are connected by the transmission line TR6.
[0020]
A transmission terminal (for example, an information processing terminal such as a personal computer) 101a as a communication device outside the MPLS network 1 is connected to the edge router 102a via a transmission line TR7. Further, a receiving terminal (for example, an information processing terminal such as a personal computer) 101b as a communication device outside the MPLS network 1 is connected to the edge router 102b via a transmission line TR8. The communication device 101 outside the MPLS network 1 connected to the edge router 102 is not limited to an information processing terminal such as a personal computer, but may be a relay device such as a router configuring the Internet, an intranet or an extranet, or the like. It may be a server or the like. In this embodiment, for convenience of explanation, the edge router 102a will be described as a transmitting side, and the edge router 102b will be described as a receiving side. However, the edge router 102a can be a receiving side, and the edge router 102b can be a transmitting side. It goes without saying that the edge router 102 can be both a transmitting side and a receiving side. In the present embodiment, a route that follows the first core router 103a → the second core router 103b → the fourth core router 103d is referred to as a first route, and a route that follows the first core router 103a → the third core router 103c → the fourth core router 103d is a first route. Called two routes.
[0021]
The edge router (Label Edge Router, also called LER) 102 constitutes the so-called entrance or exit of the MPLS network 1. That is, a label corresponding to the destination IP address is given to a packet coming into the MPLS network 1. The attached label is removed from the packet going out of the MPLS network 1.
[0022]
Then, the transmitting edge router 102a of the present embodiment establishes a plurality of routes based on the label table TB1 in which the destination IP address is associated with the label to be used, and one or both of the address information and the program identifier included in the packet. And a control table in which whether or not to set is designated. The address information is, for example, a destination IP address. However, in some cases, the source IP address may be used as the address information, or a combination of the destination IP address and the source IP address may be used as the address information. The program identifier is information indicating which program uses the packet, and is, for example, a port number for identifying a user application.
[0023]
Then, the transmitting edge router 102a of the present embodiment performs, for example, the processing shown in the flowchart of FIG. That is, when a packet is received from the transmitting terminal 101a as a communication device outside the MPLS network 1 (step 1), one or both of a destination IP address of the received packet and a port number for identifying a user application and the control table 203 are received. (Step 2), it is determined whether or not a plurality of routes are set for the packet (step 3). When a plurality of routes are set (Step 3; Yes), the received packet is copied (Step 4). For example, in this embodiment in which redundant transmission is performed by two routes, one copy of a received packet is created. Next, different labels are assigned to a plurality of (two in the present embodiment) identical packets obtained as a result of the duplication based on the label table TB1 (step 5). Further, a sequence number indicating the order of the packets is assigned to each identical packet (step 6). Here, the sequence number is information indicating the transmission order of a series of original packets transmitted by the transmission terminal 101a. For example, in the present embodiment, a sequence number is assigned to a series of original packets as a sequence number, and a duplicate packet is assigned the same sequence number as the original packet. Then, the original packet and its duplicate packet are transmitted to the first core router 103a according to the label (step 8). On the other hand, when a plurality of routes are not set (Step 3; No), a label is given to the received packet based on the label table TB1 (Step 7). Then, the received packet is transmitted to the first core router 103a corresponding to the label (Step 8).
[0024]
FIG. 2 shows an example of a functional block diagram of the transmitting edge router 102a. The transmitting-side edge router 102a includes a terminal input unit 201 that executes the processing of Step 1 in FIG. 4, a header analysis unit 202 that executes the processing of Steps 2 and 3, and a multi-route control that executes the processing of Steps 4 to 6. It mainly comprises a unit 204, a label control unit 205 for executing the processing of Step 7, a CR output unit 206 for executing the processing of Step 8, a control table 203, and a label table TB1.
[0025]
The control table 203 and the label table TB1 are created in advance by a network administrator or the like. As an example of the configuration of the control table 203, (1) list IP addresses specifying a plurality of routes (in this case, port numbers are not limited), and (2) list port numbers specifying a plurality of routes (in this case, (3) List IP address and port number pairs that specify a plurality of routes (in this case, consider the combination of IP addresses and port numbers). (4) IP that does not specify a plurality of routes. Enumerate addresses, (5) Enumerate port numbers that do not specify multiple routes, (6) Enumerate pairs of IP addresses and port numbers that do not specify multiple routes, (7) Enumerate IP addresses or port numbers or IP addresses A form of listing combinations of port numbers and information (for example, flags) indicating the necessity of specifying a plurality of routes is conceivable. . In addition, as a form of listing the pair of the IP address and the port number, a wildcard symbol (*) may be used when the IP address or the port number is not particularly limited. The point is that the control table 203 only needs to be configured so that the computer can determine whether or not to designate a plurality of routes based on one or both of the IP address and the port number of the received packet. Further, when three or more redundant routes can be set, the number of routes to be set may be specified in the control table 203. For example, in the control table 203 of the present embodiment, a set of information indicating whether or not it is necessary to specify a plurality of routes is described.
[0026]
In the label table TB1, a set of an IP address and a label used for the IP address is listed. Here, for example, in the label table TB1 of the present embodiment, an IP address for which a plurality of routes are not set has a one-to-one relationship with a label used for the IP address. The IP addresses are described redundantly (for example, two in the present embodiment), and are paired with different labels.
[0027]
The terminal input unit 201 receives a packet from the transmitting terminal 101a as a communication device outside the MPLS network 1. The header analysis unit 202 searches the control table 203 for the destination IP address of the packet received by the terminal input unit 201, and sets a plurality of routes based on information indicating whether or not a plurality of routes corresponding to the IP address need to be specified. It is determined whether or not. If a plurality of routes are to be set, the subsequent process is requested to the plurality of routes control unit 204. On the other hand, if a plurality of routes are not set, the subsequent process is requested to the label control unit 205.
[0028]
The label control unit 205 searches the label table TB1 for a destination IP address of the packet received by the terminal input unit 201, and assigns a label associated with the searched IP address to the received packet.
[0029]
The multiple route control unit 204 creates a copy of the received packet for redundant transmission. Further, the destination IP address of the received packet is searched from the label table TB1. As a result, a plurality of (two in this embodiment) labels used for the IP address are searched. The multiple route control unit 204 assigns the searched two different labels to the original received packet and its duplicate packet. Also, the multiple route control unit 204 assigns the same sequence number to two identical packets.
[0030]
When the sequence number is stored in the user data portion of the IP packet, the format of the sequence number depends on the user packet, and the receiving edge router 102b recognizes the format of each user packet and processes the sequence number. Must be performed, which is very complicated. Therefore, in the present embodiment, the sequence number is described in the RTP (Real Time Protocol, Real-time Transport Protocol) header. RTP is a standardized header format of the Internet used for transmitting real-time traffic, and is also used for VoIP (Voice over IP) for transmitting voice over IP. FIG. 6 shows an RTP packet format used in the case of VoIP. In the RTP header, a field of a sequence number indicating a packet transmission order is prepared.
[0031]
Further, in the present embodiment, in order to simplify the processing of the sequence number in the receiving edge router 102b, a plurality of transmission instruction information is added to a packet that performs redundant transmission. For example, the multiple route control unit 204 in the present embodiment adds an RTP header to a packet, and describes a sequence number and multiple transmission instruction information in the RTP header. The sequence number is described in the sequence number field of the RTP header. The multiple transmission instruction information is described in, for example, a field called a payload type of the RTP header.
[0032]
The packet processed by the label control unit 205 or the multiple route control unit 204 as described above is transmitted from the CR output unit 206 to the first core router 103a according to the label attached to the packet.
[0033]
The core router 103 of the present embodiment is a router having an MPLS function (also called a Label Switch Router, LSR), and has a function of performing packet transfer based on a label attached to a packet. The core routers 103a to 103d perform label replacement (label swapping) according to a predetermined label table TB2, TB3, TB4, TB5. As the core router 103, for example, an existing LSR may be used.
[0034]
The receiving edge router 102b of the present embodiment performs, for example, the processing shown in the flowchart of FIG. That is, when a packet is received from the fourth core router 103d (step 9), it is determined whether or not a sequence number is given to the received packet (step 10). If a sequence number is given (step 10; Yes) , Based on the sequence number, it is determined whether or not the same packet arrives later, that is, whether the same packet arrives first (step 11). If the same packet arrives later (step 11; Yes), the packet is discarded (step 12). On the other hand, if the packet is a first-arrival packet (step 11; No), the sequence number assigned to the first-arrival packet is removed (step 13), and the label assigned to the first-arrival packet is removed (step 14). Then, the first packet is transmitted to the receiving terminal 101b as a communication device outside the MPLS network 1 based on the destination IP address (step 15). On the other hand, if the sequence number is not given to the received packet (Step 10; No), the label given to the received packet is removed (Step 14), and the received packet is sent to the MPLS network 1 based on the destination IP address. (Step 15).
[0035]
FIG. 3 shows an example of a functional block diagram of the receiving edge router 102b. The receiving edge router 102b includes a CR input unit 301 for executing the process of step 9 in FIG. 5, a header control unit 302 for executing the process of step 10, and a late arrival discard for executing the processes of steps 11, 12, and 13. It mainly comprises a unit 303 and a terminal output unit 304 for executing the processing of steps 14 and 15.
[0036]
The CR input unit 301 receives a packet transmitted from the fourth core router 103d. Then, for example, the header control unit 302 of the present embodiment determines whether a sequence number is given to a received packet as follows. That is, the header control unit 302 checks whether or not a plurality of transmission instruction information is described in the payload type in the RTP header of the packet received by the CR input unit 301. If the plurality of transmission instruction information is described, the received packet is checked. It is determined that a sequence number is assigned to the received packet, and if a plurality of transmission instruction information is not described, it is determined that no sequence number is assigned to the received packet.
[0037]
In addition, for example, the last-arrival discarding unit 303 of the present embodiment determines whether or not the received packet is the same as the second-arrival packet as follows. That is, the last-arrival discard unit 303 has a log file 305 that records the sequence number of the first-arrival packet, reads the sequence number in the RTP header of the packet received by the CR input unit 301, and stores the sequence number in the log file 305. Check if it exists. If the received packet does not exist in the log file 305, it is determined that the received packet is a first-arrival packet that has not been received in the past, and the sequence number is written in the log file 305. Thus, when the same packet is received next time, it can be confirmed from the log file 305 that the packet is the second-arrival. On the other hand, if the sequence number of the received packet already exists in the log file 305, it is determined that the packet is the same as the packet received in the past. Further, in the last-arrival discard unit 303 of the present embodiment, the sequence number and the multiple transmission instruction information are removed from the packet transmitted to the receiving terminal 101b by deleting the RTP header.
[0038]
An example of the operation of the transmission-side and reception-side edge routers 102a and 102b configured as described above and the operation of the highly reliable transmission system including the edge routers 102a and 102b will be described with reference to FIG. In the example of FIG. 1, it is assumed that a packet (indicated by PK1 to PK6 in the figure) transmitted from the transmitting terminal 101a to the receiving terminal 101b is a UDP (User Datagram Protocol) packet. Therefore, it is assumed that these packets PK1 to PK6 also include the UDP header. Note that, for simplicity of explanation, the IP address of the receiving terminal 101b is “IP1”. In the control table 203, when the destination IP address is “IP1”, the two-route transmission designation is “present”, and when the destination IP address is “IP2”, the two-route transmission designation is “none”. I do. In the label table TB1 of the transmitting edge router 102a, it is assumed that two different labels “A1” and “A2” are specified for the IP address “IP1”. In the label table TB2 of the first core router 103a, it is assumed that label replacement of “A1” → “B1” and “A2” → “B2” is specified. In the label table TB3 of the second core router 103b, it is assumed that the replacement of the label “B1” → “C1” is specified. In the label table TB4 of the third core router 103c, it is assumed that the replacement of the label “B2” → “C2” is specified. In the label table TB5 of the fourth core router 103d, it is assumed that label replacement of “C1” → “D1” and “C2” → “D2” is specified. It is also assumed that the label table TB6 of the receiving edge router 102b has designated the deletion of the labels "D1" and "D2".
[0039]
Therefore, when a packet (indicated by PK1 in FIG. 1) is transmitted from the transmitting terminal 101a to the receiving terminal 101b, the transmitting edge router 102a first receives the packet PK1. The transmitting edge router 102a searches the control table 203 for the destination IP address “IP1” of the received packet PK1. As a result, in the control table 203, when the destination IP address is “IP1”, the two-route transmission designation is “Yes”, and therefore, at the transmitting edge router 102a, the received packet PK1 is a packet to be transmitted by a plurality of routes. Is determined. Therefore, the transmitting edge router 102a duplicates the packet PK1 and obtains two transmission packets (indicated by PK2 and PK3 in FIG. 1). Then, the label “A1” is assigned to one packet PK2 and the label “A2” is assigned to the other packet PK3 of the two transmission packets. In addition, an RTP header is added to each of the two transmission packets PK2 and PK3, and a sequence number and a plurality of transmission instruction information are described in the RTP header. Then, these two transmission packets PK2 and PK3 are transmitted to the first core router 103a.
[0040]
In the first core router 103a, for the packet PK2 to which the label "A1" is added, the label is changed to "B1", transmitted to the second core router 103b, and for the packet PK3 to which the label "A2" is added, The label is changed to “B2” and transmitted to the third core router 103c. The second core router 103b changes the label of the packet with the label “B1” to “C1” and transmits the packet after the label replacement (indicated by PK4 in FIG. 1) to the fourth core router 103d. . The third core router 103c changes the label of the packet with the label “B2” to “C2”, and transmits the packet after the label replacement (indicated by PK5 in FIG. 1) to the fourth core router 103d. . In the fourth core router 103d, the packet PK4 to which the label "C1" is assigned is re-labeled to "D1", transmitted to the receiving edge router 102b, and the packet PK5 to which the label "C2" is attached is transmitted. , The label is changed to “D2” and transmitted to the receiving edge router 102b.
[0041]
The receiving edge router 102b confirms that a plurality of transmission instruction information is described in the RTP header of the packet received from the fourth core router 103d, and recognizes that the received packet has a sequence number. Then, based on the sequence number in the RTP header of the received packet, it is determined whether or not the received packet is the same packet received later. As a result, the receiving-side edge router 102b discards the late-arrival packet among the packet with the label “D1” and the packet with the label “D2”. On the other hand, among the packets with the label “D1” and the packets with the label “D2”, the RTP header and the label are removed (indicated by PK6 in FIG. 1), and the packet is transmitted to the receiving terminal 101b. Transmit.
[0042]
As described above, packets having the same user data and the same destination IP address can be transmitted by two routes. Therefore, even if a failure occurs in one of the first route and the second route, communication between the transmitting terminal 101a and the receiving terminal 101b is not hindered, and communication reliability is improved.
[0043]
Moreover, the transmitting terminal 101a and the receiving terminal 101b do not need any function for implementing a plurality of routes. That is, the transmitting terminal 101a does not need to transmit the same data a plurality of times. The receiving terminal 101b does not need to have a plurality of IP addresses, and need not discard the same data that comes later. Further, there is no need to prepare a plurality of IP addresses corresponding to the number of redundant routes to be set. According to the present invention, a transmission path using a plurality of routes can be easily provided between any existing or new information processing apparatuses having an IP address.
[0044]
For example, the user of the transmitting terminal 101a or the receiving terminal 101b notifies a network administrator or the like of whether or not to perform transmission by a plurality of routes, and the network administrator or the like notifies the control table 203 and the label table TB1 of the transmitting edge router 102a. , It is possible to very easily secure a highly reliable transmission path using a plurality of routes.
[0045]
Further, since the edge router 102 is provided with a multiple route setting function, the existing core router 103 can be used as it is. Further, since a sequence number and a plurality of transmission instruction information are described in the RTP header, there is no need to perform a complicated sequence number check process depending on the format of the user packet, and the sequence number process can be simplified. Further, since the core router 103 ignores the RTP header, there is no need to change the settings of the existing core router 103. Further, by providing the control table 203, it is possible to control whether or not to perform data transmission by a plurality of routes in fine units such as an IP address and a port number. As a result, fine traffic control can be realized in consideration of various factors such as the importance of data, the nature of an application to be used, and the degree of network congestion.
[0046]
【Example】
Hereinafter, results of verification of the above-described method and system of the present invention by simulation will be described as examples. FIG. 7 shows an evaluation model used for the simulation. The line speed was 1.5 Mbps. Note that the terminal 101c was used to generate background traffic. The simulation model was created using communication model simulation software OPNET (manufactured by OPNET). Measurement traffic was transmitted from the transmitting terminal 101a at a constant interval of 1000 packets per second. On the other hand, background traffic is generated from the terminal 101c at 556 packets per second (1000 bits in length), and the interval is random. The simulation time was 4 seconds.
[0047]
8A and 8B show packet transmission characteristics when only data transmission on the first route is performed without performing two-route transmission. FIG. 8A shows the number of packet discards on the first route, and FIG. Indicates the number of packets. When two-route transmission is not performed, the transmitting terminal 101a transmits 1000 packets per second to the first route, but as shown in FIG. 8A, the total number of traffic packets exceeds the capacity of the used bandwidth. Therefore, a congestion state occurs and packet discarding occurs. Note that the number of discarded packets shown in FIG. 8A is the total number of the measured traffic and the background traffic. In this case, as shown in FIG. 8B, the background traffic stays in the buffer of the core router 103 and then overflows from the buffer, so that packet discarding occurs and the number of received packets at the receiving terminal 101b decreases. I understand.
[0048]
On the other hand, FIG. 9 shows packet transmission characteristics when two-route transmission is performed, (A) shows the number of packet discards in the first route, and (B) shows the number of received packets in the receiving terminal 101b. When two-route transmission is performed, as shown in FIG. 9A, packet discard occurs on the first route as in FIG. The reason why the number of discarded packets is increased as compared with the case where two-route transmission is not performed is that the used bandwidth is slightly increased by adding the RTP header. However, even if packet discarding occurs on the first route, the packet from the second route can be received. Therefore, as shown in FIG. 9B, it is confirmed that the receiving terminal 101b is receiving normally. it can.
[0049]
10A and 10B show the packet reception characteristics for each route when two-route transmission is performed. FIG. 10A shows the number of packet discards in the first route, and FIG. 10B shows the number of packets received by the receiving terminal 101b via the first route. (C) shows the number of packets received by the receiving terminal 101b via the second route. As shown in FIGS. 10A and 10B, the receiving terminal 101b receives a packet via the first route until a delay or packet discard occurs on the first route due to the influence of the background traffic. I understand. When the delay increases in the first route and packet discarding occurs thereafter, it can be confirmed that the packet is received via the second route as shown in FIG.
[0050]
The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, the control table specifies whether to set a plurality of routes based on one or a combination of some or all of address information, a program identifier, and transmission quality information included in a packet. May be. As the transmission quality information, for example, a value of a field for specifying priority control called ToS (Type of Service) in the IP header corresponds. For example, when the ToS value = 0, the multi-route transmission designation may be “present”, and when the ToS value = 1, the multi-route transmission designation may be “absent”.
[0051]
【The invention's effect】
As is apparent from the above description, a highly reliable transmission method using a plurality of routes according to claim 1, a highly reliable transmission system according to claim 4, and a highly reliable transmission router according to claims 5 and 6 are described. According to this, packets having the same user data and the same destination IP address can be transmitted through a plurality of routes, and the reliability of communication can be improved. Moreover, the transmitting terminal and the receiving terminal do not need any special function for realizing a plurality of routes. That is, the transmitting terminal does not need to transmit the same data a plurality of times. The receiving terminal does not need to have a plurality of IP addresses, and it is not necessary to discard the same data that comes later. Further, there is no need to prepare a plurality of IP addresses corresponding to the number of redundant routes to be set. According to the present invention, a transmission path using a plurality of routes can be easily provided between any existing or new information processing apparatuses having an IP address. For example, a user of a transmitting terminal or a receiving terminal notifies a network administrator or the like whether or not to perform transmission by a plurality of routes, and the network administrator or the like sets a control table and a label table of a transmitting edge router, thereby A highly reliable transmission path using a plurality of routes can be realized very easily. Further, by providing the control table, it is possible to control whether or not to perform data transmission by a plurality of routes in fine units such as an IP address and a port number. As a result, fine traffic control can be realized in consideration of various factors such as the importance of data, the nature of an application to be used, and the degree of network congestion.
[0052]
Further, according to the highly reliable transmission method using a plurality of routes according to the second aspect, it is easy to determine the presence / absence of a sequence number at the receiving edge router, and the processing of the sequence number can be simplified.
[0053]
Further, according to the highly reliable transmission method using a plurality of routes according to the third aspect, the transmitting edge router describes one or both of the sequence number and the plurality of transmission instruction information in the RTP header. In addition, there is no need to perform a complicated sequence number check process depending on the format of the user packet, and the sequence number process can be simplified. Since the core router ignores the RTP header, the existing core router can be used as it is.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing one embodiment of a highly reliable transmission method and system using a plurality of routes according to the present invention.
FIG. 2 is a schematic functional block diagram showing an embodiment of a highly reliable transmission router (transmission side) of the present invention.
FIG. 3 is a schematic functional block diagram showing an embodiment of a highly reliable transmission router (receiving side) of the present invention.
FIG. 4 is a schematic flowchart showing an example of processing of a highly reliable transmission router (transmission side) according to the present invention.
FIG. 5 is a schematic flowchart showing an example of processing of a highly reliable transmission router (receiving side) according to the present invention.
FIG. 6 is a diagram illustrating an example of an RTP packet format.
FIG. 7 is a schematic configuration diagram showing one embodiment of a highly reliable transmission method and system using a plurality of routes according to the present invention.
8A and 8B show packet transmission characteristics when data transmission is performed by a single route. FIG. 8A shows the relationship between the number of discarded packets and time lapse, and FIG. Show the relationship.
9A and 9B show packet transmission characteristics when data transmission is performed in two routes, FIG. 9A shows the relationship between the number of packet discards in the first route and elapsed time, and FIG. And the relationship between time and time.
10A and 10B show the packet reception characteristics for each route when data transmission is performed by two routes, FIG. 10A shows the relationship between the number of discarded packets in the first route and elapsed time, and FIG. (C) shows the relationship between the number of packets received by the receiving terminal via the second route and the elapsed time, and (C) shows the relationship between the number of packets received by the receiving terminal via the second route and the elapsed time.
FIG. 11 is a schematic configuration diagram showing a conventional data transmission method and system using a plurality of routes.
[Explanation of symbols]
1 MPLS network (label switching network)
101a Transmission terminal (communication device)
101b Receiving terminal (communication device)
102 Edge Router
103 core router

Claims (6)

  1. In a label switching network configured to include an edge router and a core router and transmitting a packet using a label assigned in accordance with a destination address, the edge router on the transmission side has a destination address and a label to be used. It is specified whether or not to set a plurality of routes based on the associated label table, any one of the address information, the program identifier, and the transmission quality information included in the packet, or a combination of some or all of them. Having a control table, for a packet received from a communication device outside the label switching network, determine whether to set a plurality of routes by referring to the control table, when setting a plurality of routes, Duplicate the packet and add the resulting multiple identical packets A different label is assigned based on the label table, and a sequence number indicating a packet order is assigned to each of the plurality of identical packets. If a plurality of routes are not specified, a label based on the label table is assigned to the packet. Attached, and transmits the packet to the core router according to the label, the core router transmits the received packet to another core router or the edge router according to the label attached to the packet, and When the sequence number is given to the packet received from the core router, the edge router discards the same packet that arrives later based on the sequence number, and replaces the label and the sequence number given to the earlier packet based on the sequence number. Remove the first-arrival packet based on the destination address When transmitted to a communication device outside the label switching network and the sequence number is not added to the packet received from the core router, the label attached to the packet is removed, and the packet is removed based on the destination address. A highly reliable transmission method using a plurality of routes, wherein the transmission is performed to a communication device outside a label switching network.
  2. The edge router on the transmitting side, when setting a plurality of routes, gives a plurality of transmission instruction information, and the edge router on the receiving side confirms the presence or absence of the plurality of transmission instruction information for a received packet, 2. The highly reliable transmission method using a plurality of routes according to claim 1, wherein the presence or absence of a sequence number is determined.
  3. 3. The highly reliable transmission method using a plurality of routes according to claim 1, wherein the edge router on the transmission side describes one or both of the sequence number and the plurality of transmission instruction information in an RTP header.
  4. In a label switching network configured to include an edge router and a core router and transmitting a packet using a label assigned in accordance with a destination address, the edge router on the transmission side has a destination address and a label to be used. It is specified whether or not to set a plurality of routes based on the associated label table, any one of the address information, the program identifier, and the transmission quality information included in the packet, or a combination of some or all of them. Having a control table, for a packet received from a communication device outside the label switching network, determine whether to set a plurality of routes by referring to the control table, when setting a plurality of routes, Duplicate the packet and add the resulting multiple identical packets A different label is assigned based on the label table, and a sequence number indicating a packet order is assigned to each of the plurality of identical packets. If a plurality of routes are not specified, a label based on the label table is assigned to the packet. Attached, and transmits the packet to the core router according to the label, the core router transmits the received packet to another core router or the edge router according to the label attached to the packet, and When the sequence number is given to the packet received from the core router, the edge router discards the same packet that arrives later based on the sequence number, and replaces the label and the sequence number given to the earlier packet based on the sequence number. Remove the first-arrival packet based on the destination address When transmitted to a communication device outside the label switching network and the sequence number is not added to the packet received from the core router, the label attached to the packet is removed, and the packet is removed based on the destination address. A highly reliable transmission system using a plurality of routes, wherein the transmission is performed to a communication device outside a label switching network.
  5. In an edge router used in a label switching network for transmitting a packet using a label assigned according to a destination address, a label table in which a destination address is associated with a label to be used, address information included in the packet, and a program A control table that specifies whether to set a plurality of routes based on any one of the identifier and the transmission quality information or a combination of some or all of them; and a communication outside the label switching network. For the packet received from the device, it is determined whether or not to set a plurality of routes by referring to the control table. In the case of setting a plurality of routes, the packet is duplicated and each of a plurality of identical Different labels are added based on the above label table. When a plurality of routes are not specified, a sequence number indicating the order of one packet is assigned to each of the plurality of identical packets. A highly reliable transmission router characterized by transmitting data to a network.
  6. In an edge router used in a label switching network that transmits a packet using a label assigned according to a destination address, if a sequence number is assigned to a received packet, the same packet received later based on the sequence number And discarding the label and the sequence number given to the first packet and transmitting the first packet to a communication device outside the label switching network based on the destination address, and adding the sequence number to the received packet. If not, a highly reliable transmission router that removes the label attached to the packet and transmits the packet to a communication device outside the label switching network based on the destination address.
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WO2006090789A1 (en) * 2005-02-25 2006-08-31 Softbank Bb Corp. Data communication system and data communication method
JP2007013510A (en) * 2005-06-30 2007-01-18 Oki Telecommunication Systems Co Ltd Packet communication system and packet communication apparatus
JP2008141614A (en) * 2006-12-04 2008-06-19 Fujitsu Ltd Packet transfer apparatus and network system
US7787451B2 (en) 2006-07-13 2010-08-31 Nec Corporation Packet transmission method and packet transmission system
WO2011155064A1 (en) * 2010-06-11 2011-12-15 株式会社日立製作所 Relay communication device and multi-stage relay communication system
JP2013197784A (en) * 2012-03-19 2013-09-30 Hitachi Ltd Network relay device and network system
KR101509496B1 (en) * 2014-05-09 2015-04-08 한국전자통신연구원 System for one-way data transmission and reception
KR101610715B1 (en) * 2014-06-11 2016-04-08 한국전자통신연구원 One-way data transmission and reception system, and one-way data transmission and reception method
JP2016523497A (en) * 2013-06-27 2016-08-08 徐 正 煥SEO, Jeong Hoan Multiple connection system and method for service using Internet protocol

Cited By (12)

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WO2006090789A1 (en) * 2005-02-25 2006-08-31 Softbank Bb Corp. Data communication system and data communication method
JP2007013510A (en) * 2005-06-30 2007-01-18 Oki Telecommunication Systems Co Ltd Packet communication system and packet communication apparatus
US7787451B2 (en) 2006-07-13 2010-08-31 Nec Corporation Packet transmission method and packet transmission system
JP2008141614A (en) * 2006-12-04 2008-06-19 Fujitsu Ltd Packet transfer apparatus and network system
WO2011155064A1 (en) * 2010-06-11 2011-12-15 株式会社日立製作所 Relay communication device and multi-stage relay communication system
JP5485389B2 (en) * 2010-06-11 2014-05-07 株式会社日立製作所 Relay communication device and multistage relay communication system
US8971318B2 (en) 2010-06-11 2015-03-03 Hitachi, Ltd. Relay communication apparatus and multistage relay communication system
JP2013197784A (en) * 2012-03-19 2013-09-30 Hitachi Ltd Network relay device and network system
JP2016523497A (en) * 2013-06-27 2016-08-08 徐 正 煥SEO, Jeong Hoan Multiple connection system and method for service using Internet protocol
KR101509496B1 (en) * 2014-05-09 2015-04-08 한국전자통신연구원 System for one-way data transmission and reception
KR101610715B1 (en) * 2014-06-11 2016-04-08 한국전자통신연구원 One-way data transmission and reception system, and one-way data transmission and reception method
US9565162B2 (en) 2014-06-11 2017-02-07 Electronics And Telecommunications Research Institute One-way transmission and reception with delayed TCP ACK message and monitoring for UDP and TCP frames

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