JP2002044125A - Packet network - Google Patents

Packet network

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Publication number
JP2002044125A
JP2002044125A JP2000218952A JP2000218952A JP2002044125A JP 2002044125 A JP2002044125 A JP 2002044125A JP 2000218952 A JP2000218952 A JP 2000218952A JP 2000218952 A JP2000218952 A JP 2000218952A JP 2002044125 A JP2002044125 A JP 2002044125A
Authority
JP
Japan
Prior art keywords
packet
means
edge router
route
plurality
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2000218952A
Other languages
Japanese (ja)
Inventor
Naoaki Yamanaka
直明 山中
Original Assignee
Nippon Telegr & Teleph Corp <Ntt>
日本電信電話株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Telegr & Teleph Corp <Ntt>, 日本電信電話株式会社 filed Critical Nippon Telegr & Teleph Corp <Ntt>
Priority to JP2000218952A priority Critical patent/JP2002044125A/en
Publication of JP2002044125A publication Critical patent/JP2002044125A/en
Application status is Pending legal-status Critical

Links

Abstract

PROBLEM TO BE SOLVED: To realize an economical packet network with little drop in the throughput that effectively uses network resources where routing reflecting an actual traffic state is performed without the need for any revision to relay routers. SOLUTION: This invention provides the packet network where an incoming edge side router placed at an input side of a network and an outgoing edge side router installed at an output side transmit/receive a test packet with each other or give a time stamp to an IP packet including user information so as to measure an actual round trip delay or propagation delay time in each route. A route for transmitting a packet is selected according to the result of the measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for packet communication. The present invention is suitable for use in a network using a plurality of relay routers.

[0002]

2. Description of the Related Art FIG. 8 shows a configuration of a conventional packet network. In FIG. 8, reference numerals 2-1 to 2-5 are relay routers, reference numeral 1-1 is an ingress edge router installed on the input side of the packet network, and reference numeral 1-2 is an outgoing edge router installed on the output side of the packet network. Is shown.

In this specification, for the sake of simplicity, a case where a packet is transferred in the direction from A to B in the packet network shown in FIG. 8 will be described. -1, and the output side edge router will be described as the outgoing edge router 1-2. However, in practice, packets are transferred bidirectionally to the packet network. A router having both functions of the outgoing edge rule 1-2 in parallel is arranged.

Conventionally, when communication is performed between A and B, SP
Based on the F algorithm (Shortest Path First), communication is performed by preferentially selecting a route having the least number of router hops. In the example of FIG. 8, the route X is the router 2-
1, 2-2 are relayed by two hops. On the other hand, since the route Y relays the routers 2-3, 2-4, and 2-5 three hops, the traffic mainly passes through the route X.

When traffic is distributed to both routes X and Y, distribution is performed according to the number of hops of each route. For example, in the example of FIG. 8, route X is a two-hop relay and route Y is a three-hop relay, so that three-fifths of all traffic is distributed to route X, and two-fifths of all traffic is distributed to route Y. 5 are dispensed.

[0006]

In the conventional route selection according to the number of hops, it is difficult to reflect the actual traffic situation, and in the example of FIG. Even when congestion occurs, a situation may occur in which the route Y is empty.

In order to improve the drawbacks of the conventional route selection, it is conceivable to observe the traffic situation at each relay router. However, it is necessary to modify a plurality of relay routers. It is difficult to realize in terms of man-hours and costs.

The present invention has been made in view of such a background, and provides a packet network capable of performing route selection reflecting actual traffic conditions without making any modification to a relay router. With the goal. SUMMARY OF THE INVENTION It is an object of the present invention to provide an economical packet network that uses network resources effectively and has a small decrease in throughput.

[0009]

According to the present invention, a test packet is transmitted and received between an ingress edge router installed on an input side of a network and an outgoing edge router installed on an output side of a network. By adding a timestamp to an IP packet including the following, the actual round trip delay or propagation delay time in each route is measured, and a route to transmit the packet is selected according to the measurement result.

[0010] According to this, the route selection reflecting the actual traffic situation can be performed without making any modification to the relay router, the network resources are effectively used, and the economical reduction in the throughput is extremely small. A packet network can be realized.

That is, the present invention connects an incoming edge router installed on the input side of the network, an outgoing edge router installed on the output side of the network, and connects the incoming edge router and the outgoing edge router. This is a packet network including a plurality of relay routers installed on a plurality of routes.

Here, the present invention is characterized in that the ingress edge router inserts a test packet into the plurality of routes and extracts the test packet returned from the plurality of routes. Means, the outgoing edge router comprises means for turning back the test packet coming from the plurality of routes to the ingress edge router, and a packet insertion time by the inserting means and a packet extracting by the extracting means. Means for measuring a round trip delay for each of the plurality of routes based on a time difference from time.

It is preferable that the ingress edge router includes means for selecting a route having the smallest round trip delay as a packet transmission route according to the measurement result of the measuring means.

The inserting means includes means for periodically inserting the test packet into the plurality of routes, and the measuring means calculates a value obtained by smoothing a plurality of measurement results within a predetermined period. The means for selecting as the transmission route may include means for selecting the route having the smallest smoothed value as the packet transmission route.

According to this, the influence of the instantaneous change in the delay time due to disturbance or the like can be eliminated, so that inappropriate route selection can be avoided.

Alternatively, the ingress edge router is provided with a means for adding a time stamp to a part of a header of an IP packet including user information transmitted to the plurality of routes, and the egress edge router is provided with Means for removing the time stamp from the header of the IP packet containing the user information to be deleted is provided, and for each of the plurality of routes, a time difference between the time stamp adding time by the adding means and the time stamp removing time by the removing means is provided. Means for measuring the propagation delay time may be provided.

According to this, the band for transmitting the IP packet including the user information can be effectively used so that the test packet is not used for measuring the propagation delay time.

Preferably, the ingress edge node includes means for selecting a route having the shortest propagation delay time as a packet transmission route according to the measurement result of the measuring means.

The means for giving a time stamp includes means for periodically giving a time stamp to a part of a header of an IP packet including user information sent to the plurality of routes, and the means for measuring comprises: A means for calculating a value obtained by smoothing a plurality of measurement results within a certain period; and a means for selecting the transmission route as means for selecting a route having the smallest smoothed value as a packet transmission route. It can also be.

According to this, since the influence of the instantaneous delay time fluctuation due to disturbance or the like can be removed, inappropriate route selection can be avoided.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a packet network according to an embodiment of the present invention will be described with reference to FIGS. 1, 2, 3 and 7. FIG. FIG. 1 is a block diagram of a main part of an incoming edge router and an outgoing edge router according to a first embodiment of the present invention. FIG. 2 is a block diagram of a main part of an input line unit of the incoming edge router. FIG. 3 is a diagram for explaining the route distribution operation. FIG. 7 is a block diagram of a main part of an incoming edge router and an outgoing edge router according to the second embodiment of the present invention.

According to the present invention, as shown in FIG. 8, an ingress edge router 1-1 installed on the input side of a network and an outgoing edge router 1-1 installed on the output side of this network.
2 and a plurality of relay routers 2-1 to 2-5 installed on routes X and Y connecting the ingress edge router 1-1 and the egress edge router 1-2.

As shown in FIG. 2, the ingress edge router 1-1
The input line unit 3 analyzes the IP address of the arriving packet by the IP address analysis unit 4, and refers to the route control table 5 according to the analysis result to recognize the output route corresponding to the IP address. The tag is assigned to the packet by the tag assigning unit 6 according to the recognition result. As shown in FIG. 3, the switch unit 7
The route can be sorted by tag. Control unit 14
By setting the correspondence between the IP address and the outgoing route in the route control table 5, a route corresponding to the tag in the switch unit 7 can be set. Note that the configurations and operations of the output line unit of the ingress edge router 1-1 and the input line unit and the output line unit of the egress edge router 1-2 are not directly related to the present invention, and will not be described.

Here, the feature of the present invention is that, as shown in FIG.
Packet insertion unit 1 for inserting a test packet into Y and Y
0, and a packet drop unit 11 for extracting the test packet returned from the routes X and Y. The output edge router 1-2 receives the test packet coming from the routes X and Y in the input edge router 1. A measuring unit 13 for measuring a round trip delay for each of the routes X and Y based on a time difference between a packet insertion time by the packet insertion unit 10 and a packet extraction time by the packet drop unit 11; And where it is.

The incoming edge router 1-1 includes a control unit 14 for selecting a route having the smallest round trip delay as a packet transmission route according to the measurement result of the measurement unit 13.

The packet insertion unit 10 includes routes X and Y
The test packet is periodically inserted into the
Calculates a value obtained by smoothing a plurality of measurement results within a certain period, and the control unit 14 can select a route having the smallest smoothed value as a packet transmission route.

Alternatively, as shown in FIG. 7, the ingress edge router 1-1 has a time stamp adding unit for adding a time stamp to a part of a header of an IP packet including user information transmitted to routes X and Y. The outgoing edge router 1-2 is provided with an I
A time stamp removing unit 16 for removing the time stamp from the header of the P packet is provided, and a time difference between the time stamp adding time by the time stamp adding unit 15 and the time stamp removing time by the time stamp removing unit 16 is used for the routes X and Y. A configuration including a propagation delay time measuring unit 17 that measures the propagation delay time for each of them may be adopted.

In this case, the control unit 14 of the incoming edge node 1-1 selects the route having the shortest propagation delay time as the packet transmission route according to the measurement result of the propagation delay time measuring unit 17.

The time stamp adding section 15 periodically adds a time stamp to a part of a header of an IP packet including user information transmitted to the route X or Y,
The propagation delay time measurement unit 17 calculates a value obtained by smoothing a plurality of measurement results within a certain period, and the control unit 14 can select a route having the smallest smoothed value as a packet transmission route. Hereinafter, embodiments of the present invention will be described in more detail.

(First Embodiment) The first embodiment of the present invention is shown in FIGS.
This will be described with reference to FIG. FIG. 4 is a diagram showing a round trip table according to the first embodiment of the present invention. The packet insertion unit 10 shown in FIG. 1 inserts a test packet for measuring a traffic situation. Here, a test packet is periodically inserted into all routes X and Y to the outgoing edge router 1-2 facing the incoming edge router 1-1.

The test packet return section 12 of the outgoing edge router 1-2 simply returns the test packet.
The returned test packet is sent to the ingress edge router 1-1.
Is extracted by the packet drop unit 11. Measuring unit 1
In 3, the round trip delay of the routes X and Y is measured from the difference between the insertion time and the extraction time of the test packet.

The control unit 14 selects a route according to the result of the measurement, and
Set the departure route corresponding to the address. Control unit 1
In 4, the route can be selected using the measurement result as it is, but in order to remove the influence of the instantaneous delay time fluctuation due to disturbance or the like, a plurality of measurement results within a certain period are reduced using a low-pass filter. By smoothing, past round trip delays can also be considered.

The collected round trip delay is generated by the control unit 14 as a round trip table as shown in FIG. As a result, the round trip delays of the routes X and Y are known, and the route with the smaller round trip is used as the route to the outgoing edge router 1-2. Generally, when a route encounters congestion, the round trip for congestion becomes infinite, and the congested route is automatically excluded from the route and rerouted to another route, for example, route Y in this example. Become.

In this way, since the route having the shortest round trip is assigned to the connection between the edge routers of the transit network, the end-to-end
In addition, there is no influence on the terminal supporting the conventional TCP-IP, and a relay router can be realized by the conventional product.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a diagram showing a state of adding and removing a time stamp according to the second embodiment of the present invention. FIG. 6 is a diagram schematically showing the structure of an IP packet used in the second embodiment of the present invention. As shown in FIG. 5, in the ingress edge node 1-1, the IP containing the input user information
At the same time as routing the packet, the time of transmission into the packet network is added to the packet as a time stamp. At the outgoing edge node 1-2, the time stamp is removed, and at the same time,
The propagation delay time of the route is measured.

That is, the time stamp is given to the IP packet by the time stamp giving unit 15 shown in FIG. 7, as shown in FIG. The time stamp added to the IP packet is removed by the time stamp removing unit 16 of the outgoing edge router 1-2. The propagation delay time measuring unit 17 measures the propagation delay time of the IP packet based on the difference between the time when the time stamp was added and the time when the time stamp was removed. Also, in this IP packet,
As described in the first embodiment, the tag is provided,
The pass route is also determined by this tag. The information on the propagation delay time and the passing route is transmitted to the control unit 14.

The control unit 14 selects a route having the shortest propagation delay time as a packet transmission route, and sets an outgoing route corresponding to the IP address in the route control table 5. Further, the control unit 14 can also create a propagation delay time table in the same manner as the round trip table shown in FIG.

The measured propagation delay times of the routes X and Y are notified to the ingress edge router 1-1 using any of the following methods. (1) Actually, since bidirectional communication is performed, a part of the header of the packet flowing in the reverse direction on the routes X and Y is used to notify the incoming edge router 1-1. (2) Notify the ingress edge router 1-1 using a special packet. (3) Notify via OPS (Operation System).

The ingress router 1-1, which has obtained the delay times of the routes X and Y by any of the above methods, preferentially uses the route with the short delay time as the route as in the first embodiment.

[0040]

As described above, according to the present invention,
By measuring the delay time or round-trip delay of each of multiple routes and selecting a sub-optimal route based on the measured values, network resources can be used effectively and "hot points" A route that automatically avoids the point of congestion that has occurred in a packet network, which is called a packet network, can be used, and an economical and simple network can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of an incoming edge router and an outgoing edge router according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a main part of an input line unit of an incoming edge router.

FIG. 3 is a diagram for explaining a route distribution operation.

FIG. 4 is a diagram showing a round trip table according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a state of adding and removing a time stamp according to a second embodiment of the present invention.

FIG. 6 is a diagram schematically showing a configuration of an IP packet used in a second embodiment of the present invention.

FIG. 7 is a block diagram of a main part of an incoming edge router and an outgoing edge router according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a packet network.

[Explanation of symbols]

 1-1 Ingress edge router 1-2 Egress edge router 2-1 to 2-5 Relay router 3 Input line unit 4 IP address analysis unit 5 Route control table 6 Tag assignment unit 7 Switch unit 10 Packet insertion unit 11 Packet drop unit 12 Test packet return section 13 Measurement section 14 Control section 15 Time stamp addition section 16 Time stamp removal section 17 Propagation delay time measurement section

Claims (6)

[Claims]
1. An ingress edge router installed on an input side of a network, an outgoing edge router installed on an output side of the network, and a plurality of routes connecting the ingress edge router and the outgoing edge router. A packet network comprising a plurality of relay routers installed in the ingress edge router, means for inserting a test packet into the plurality of routes, and extracting the test packet returned from the plurality of routes. The outgoing edge router includes means for returning the test packet coming from the plurality of routes to the ingress edge router, and a packet insertion time by the inserting means and a packet by the extracting means. The round trip delay is measured for each of the plurality of routes based on the time difference from the extraction time. A packet network comprising:
2. The packet network according to claim 1, wherein said ingress edge router includes means for selecting a route having the smallest round trip delay as a packet transmission route according to a measurement result of said measuring means.
3. The means for inserting includes means for periodically inserting the test packet into the plurality of routes, wherein the measuring means calculates a value obtained by smoothing a plurality of measurement results within a predetermined period. 3. The packet network according to claim 1, further comprising: means for calculating, and wherein the means for selecting as the transmission route includes means for selecting a route having the smallest smoothed value as a packet transmission route.
4. An ingress edge router installed on an input side of a network, an outgoing edge router installed on an output side of the network, and a plurality of routes connecting the ingress edge router and the outgoing edge router. In the packet network comprising a plurality of relay routers installed in the inbound edge router, the ingress edge router includes means for giving a time stamp to a part of a header of an IP packet including user information transmitted to the plurality of routes. The outgoing edge router is provided with I
Means for removing the time stamp from the header of the P packet is provided, and a propagation delay time is measured for each of the plurality of routes by a time difference between a time stamp adding time by the adding means and a time stamp removing time by the removing means. A packet network, comprising:
5. The packet network according to claim 4, wherein said ingress edge node includes means for selecting a route having the shortest propagation delay time as a packet transmission route according to a measurement result of said measuring means.
6. The means for giving a time stamp,
A means for periodically adding a time stamp to a part of a header of an IP packet including user information transmitted to the plurality of routes, wherein the measuring means smoothes a plurality of measurement results within a certain period. 6. The packet network according to claim 4, further comprising: means for calculating a value; and wherein the means for selecting as the transmission route includes means for selecting a route having the smallest smoothed value as a packet transmission route.
JP2000218952A 2000-07-19 2000-07-19 Packet network Pending JP2002044125A (en)

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Application Number Priority Date Filing Date Title
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006001105A1 (en) * 2004-06-29 2006-01-05 Matsushita Electric Industrial Co., Ltd. Radio base station device, radio control system, and operation control method
JP2006005942A (en) * 2004-06-18 2006-01-05 Avaya Technology Corp Rapid fault detection and recovery for internet protocol telephony
US7200330B2 (en) 2001-11-02 2007-04-03 Nippon Telegraph And Telephone Corporation Optical dynamic burst switch
US7706292B2 (en) 2006-11-20 2010-04-27 Fujitsu Limited Network system, network apparatus, route change method, and program storage medium storing program thereof
JP2011176479A (en) * 2010-02-23 2011-09-08 Fujitsu Ltd Information communication system and latency calculation method
JP2016082373A (en) * 2014-10-16 2016-05-16 Necプラットフォームズ株式会社 Repeating device, communication device, communication path selection method and program

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7200330B2 (en) 2001-11-02 2007-04-03 Nippon Telegraph And Telephone Corporation Optical dynamic burst switch
JP2006005942A (en) * 2004-06-18 2006-01-05 Avaya Technology Corp Rapid fault detection and recovery for internet protocol telephony
US7782787B2 (en) 2004-06-18 2010-08-24 Avaya Inc. Rapid fault detection and recovery for internet protocol telephony
JP4625377B2 (en) * 2004-06-18 2011-02-02 アバイア インコーポレーテッド Fast failure detection and recovery for Internet protocol phones
WO2006001105A1 (en) * 2004-06-29 2006-01-05 Matsushita Electric Industrial Co., Ltd. Radio base station device, radio control system, and operation control method
US7706292B2 (en) 2006-11-20 2010-04-27 Fujitsu Limited Network system, network apparatus, route change method, and program storage medium storing program thereof
JP2011176479A (en) * 2010-02-23 2011-09-08 Fujitsu Ltd Information communication system and latency calculation method
JP2016082373A (en) * 2014-10-16 2016-05-16 Necプラットフォームズ株式会社 Repeating device, communication device, communication path selection method and program

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