JP2000349776A - Route bypass method during in-switch congestion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a route bypass method at the time of in-switch congestion in an IP VPN using an ATM switch. SOLUTION: This method is fitted to switch in a repeater on an ATM network 14 together with information included in data. Communications between computers use an IP Packet. A converter 12 has a function for converting the IP Packet into an ATM Cell. The ATM network has a function for outputting an inputted ATM Cell to an appropriate port. The switch has in its inside a function which once assemble the IP Packet, reads necessary information and converts it again into the ATM Cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the switching of routes in an ATM switch, and more particularly, to an ATM switch which has routing information in an IP layer in order to avoid congestion in an ATM switch and which uses the information to avoid congestion. IP VP used
N in the case of intra-switch congestion.

[0002]

2. Description of the Related Art An example of a conventional apparatus and method using a detour route for distributing a load in order to avoid congestion is described in JP-A-8-191306.
The congestion control method and the apparatus described in this publication, when a specific line is congested in an ATM network, detects the congestion state, and detects all the logics assigned to the detected line. Select a free logical channel from the channels and switch dynamically. The line switching timing is set at a packet break. In order to prevent the cell from reversing, the output of the destination line is stopped for a certain period of time. Thus, in a system in which a terminal is connected to an ATM switch through a plurality of lines, it is possible to avoid congestion due to uneven traffic.

[0003]

A method for avoiding congestion in the ATM layer of an ATM network is disclosed in Japanese Patent Application Laid-Open No. Hei 8-1913.
No. 06, there is a method of controlling congestion by switching the routes of an ATM switch and a method of avoiding it at the ATM layer as shown in the apparatus.

[0004] IP realized by ATM Switch
VPN (Virtual Private Network)
In the (ork) function, communication of the Traffic may be hindered by various network causes.

[0005] For example, ATM Switch-ATM
Link failure between switches and ATM Switch
h. Traffic congestion within h. Regarding the above-mentioned link failure, the problem can be solved by duplicating the link. However, Trafi in ATM Switch
Regarding c congestion, no consideration is given to failure.

An object of the present invention is to perform a detour by an IP protocol and a detour by hardware.
It is an object of the present invention to provide a route detour method at the time of congestion in a switch in an IP VPN using an ATM switch that distributes a biased load on an ATM switch and guarantees traffic from an end user.

[0007]

According to the present invention, there is provided a method for bypassing a route in the event of congestion in a switch, comprising: a computer which is a terminal device of an ATM network;
A conversion device for performing P / ATM or ATM / IP conversion, and an ATM network that is connected to a plurality of the computers and performs an ATM communication between the computers;
In the communication sent from the computer, the layer 2 and lower layers are the ATM layer, are mounted on the ATM switch having the IP processing function, and include the routing information in the IP address,
It is characterized in that routing is limited to static routing.

[0008] Further, the ATM network includes an output A
Means for detecting congestion on the TM line is implemented,
At the ATM level, congestion at the ATM line output side is detected, and the route registered in the static routing is switched from a normal route to a sub route for communication.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 shows the IP / ATM of the present invention.
It is a figure showing the whole flow. FIG. 2 is a first diagram illustrating an ATM network according to the present invention. FIG. 3 is a diagram showing a routine table of the present invention. FIG. 4 is a diagram showing a routing table according to the present invention. FIG. 5 is a second diagram illustrating the ATM network of the present invention.

According to the present invention, ATM is used for layer 2 and
It is implemented in an ATM switch having a P processing function. Routing is limited to static routing. Static routes have a regular route (primary:
Primary and sub route (Secondary: Seco)
ndary). Means for detecting congestion on the outgoing ATM line is implemented. That is, congestion at the ATM line output side is detected at the ATM level, and the statically registered route is switched from the normal route to the sub route for communication.

As shown in FIG. 1, a route detour method in the case of congestion in a switch according to the present invention comprises a computer 10 which is a terminal device of an ATM network, and a conversion device connected to the computer 10 for performing IP / ATM or ATM / IP conversion. And an ATM network 14, which is a network for connecting to a plurality of computers 10 and performing ATM communication between the computers.

The present invention is implemented in a switch in a relay device on the ATM network 14 together with information included in data. Communication between computers is IP
Use Packet. The conversion device 12 is an IPP
It has a function to convert the packet into an ATM cell.
The ATM network has a function of outputting an input ATM cell to an appropriate port, but has a function of once assembling an IP packet into the switch, reading necessary information, and converting the information to an ATM cell again.

As shown in FIG. 2, the ATM network 14 has a port 16 which is an entrance of the ATM network,
It has a node 18 which is a relay point of the ATM network and can be switched to a target port 16 by being switched by communication data on the network, and a transmission line 20 which connects the plurality of ports 16 and the nodes 18 and is a path for communication data.

The node 18 has the ATM / IP switch of the present invention. The ATM / IP switch is implemented as an ATM switch, but is not an ATM switch that handles only the ATM layer purely, but a switch that can handle up to the IP layer.

As shown in FIG. 3, on the network, A
From the header information of the TM Cell, it is possible to recognize which VP / VC in the switch is used. In the node, an ATM cell is assembled into an IP packet. The IP address in the header of the IP packet can be recognized. When recognizing the IP address, the switch refers to a routing table that statically holds the switch and checks the number. Primary / secondary and VP / VC numbers are set in the routing table.

The routine table shown in FIG. 4 indicates that when congestion occurs when a port to be used in the primary is simultaneously used in another communication, etc., when the detection by hardware operation is performed at the ATM level, You can give up the use of and automatically select the route set on the secondary. The operation is performed at the ATM level.
This will be performed with the P address in mind.

As shown in FIG. 1, there is an ATM network. This network shall support IPVPN. In the IP VPN, the setting is made such that each user is attached to each ATM VCI unit, and the users are grouped. Further, only the set user can access the VCI. VP
The VCI used for each N, before reaching the destination,
There is a possibility that the route may pass through a common route with a VCI used in another VPN. If the number of the VCIs increases, communication may not be performed. In such a case, by setting a detour route in the switch in advance, it is possible to automatically select a vacant route by a hardware mechanism, thereby avoiding communication delay or interruption. AT as in Figure 2
When there is an M network, communication flows as shown in FIG.

Next, the operation of the embodiment of the present invention will be described. FIG. 6 is a diagram showing the operation inside the switch of the present invention. For the setting by the network maintainer, the route used for this service is set in advance as primary and secondary on the switch. As shown in FIG. 6, the switch automatically switches to the always-set Pri
Attempt to perform communication on the Mary route. Communication was attempted, but due to congestion, the incoming line P
When a back pressure is applied to the ort buffer, the communication is automatically switched to the secondary route and communication is performed.

[0019]

The route detour method according to the present invention at the time of congestion in a switch can always provide a stable communication quality for an end user. For operators,
Many subscribers can be accommodated in a limited facility.

In the route detour method, when congestion occurs, switching to a secondary designated in advance prevents congestion and enables smooth communication.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flow of an entire IP / ATM according to the present invention.

FIG. 2 is a first diagram illustrating an ATM network according to the present invention;

FIG. 3 is a diagram showing a routine table of the present invention.

FIG. 4 is a diagram showing a routing table of the present invention.

FIG. 5 is a second diagram illustrating the ATM network according to the present invention;

FIG. 6 is a diagram showing an operation in the switch of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Computer 12 Converter 14 ATM network 16 Port 18 Node 20 Transmission line

Claims (6)

[Claims] 1. A computer as a terminal device of an ATM network, and an IP / ATM or ATM connected to the computer.
And a conversion device for performing / IP conversion, and an ATM network that is connected to a plurality of the computers and performs an ATM communication between the computers. A communication transmitted from the computer in the communication of the ATM network. Indicates that the layer 2 and below are ATM layers and I
A route detour method at the time of congestion in a switch, which is implemented in an ATM switch having a P processing function, includes routing information in an IP address, and limits routing to static routing. 2. The ATM network according to claim 1, wherein said ATM network is an outgoing ATM.
Means for detecting congestion on the line is implemented,
2. A route detour at the time of congestion in a switch according to claim 1, wherein congestion at an ATM line output side is detected at an M level, and a route registered in said static routing is switched from a normal route to a sub route for communication. Method. 3. The static routing has a primary which is a normal route and a secondary which is a sub-route, and refers to the secondary when congestion occurs in the ATM network to avoid congestion. 3. The route detour method according to claim 2, wherein the switch is congested. 4. The communication network according to claim 1, wherein the communication A
4. The route bypass method in the case of congestion in a switch according to claim 3, wherein which VP / VC in the switch is used can be recognized from the header information of the TM Cell. 5. The method according to claim 4, wherein the ATM switch for switching communication in a node of the ATM network is a switch that can handle up to an IP layer. 6. The routing information includes a primary /
6. The route bypass method according to claim 5, further comprising a routing table in which a secondary and a VP / VC number are set, wherein the number is checked by referring to the routing table.