JP3435872B2 - Frame multiplexer and packet traffic multistage relay system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to X. 25 mesh or IS
The present invention relates to a packet processing method in a communication network that provides a packet switching service such as a DN network.

[0002]

2. Description of the Related Art A method of multiplexing packet traffic using a frame multiplexing function in a packet switching network is, for example, "Evolution of a Large Packet Switched N".
etwork for the 90's "(Proceedings of the 10th ICCC, 199)
0).

FIG. 1 shows a configuration example of a conventional packet switching network having a frame multiplexing function. In the figure, each packet terminal 5 is connected to a frame multiplexer 1 of a packet switching network by an incoming line 6, and each frame multiplexer 1 is connected by an outgoing line 7 to a corresponding layer 2 termination unit of the packet switching function unit 3. 4 is connected. The packet transmitted from the packet terminal 5 is frame-multiplexed by the frame multiplexer 1 and then transmitted to the layer 2 termination unit 4 which processes the layer 2 protocol.

Although not shown in the figure, the frame multiplexer 1 actually includes a control device and the like in addition to the frame multiplexer 2. Similarly, although not shown in the figure, the packet switching function unit 3 includes a control device for performing a switching control for taking in the packet received by the layer 2 termination unit 4 or a sending control to a trunk line, and another packet. It includes a layer 2 terminating unit for sending a packet to a trunk line connected to the exchange.

The packet switching function unit receives a packet from the frame multiplexer at the layer 2 termination unit, performs a switching process, and then sends the packet from another layer 2 termination unit to the relay line of the switching destination. The packet switching function unit and the frame multiplexer may be installed adjacent to each other or may be remotely controlled in the packet switching network.

The frame multiplexer multiplexes packets received from a plurality of packet terminals to an outgoing line having a higher transmission rate and sends the multiplexed packets. In detail, the frame multiplexer terminates the flag synchronization and the frame check sequence in the layer 2 protocol, and sets the value of the address field in the layer 2 frame to all layer 2 used by a plurality of accommodated terminals. By replacing a link with a new address value that can be uniquely identified and adding a new frame check sequence, packets from a plurality of terminals are frame-multiplexed and transferred to an outgoing line.

[0007]

In such a conventional frame multiplexing method, each frame multiplexer is connected to each layer 2 (corresponding to a line) terminal unit in a one-to-one relationship. That is, the frame multiplexer and the layer 2 terminating unit are always connected one-on-one by the trunk line. Therefore, even if the terminal traffic concentrated by the frame multiplexer is smaller than the processing capacity of the layer 2 termination part, it is necessary to deploy one layer 2 termination part without fail, and effective use of the layer 2 termination part and the trunk line. There was a problem that could not be achieved.

Further, since the frame multiplexer and the layer 2 terminal are fixedly connected, when a failure or congestion occurs in the frame multiplexer or the layer 2 terminal, the frame multiplexer or the layer 2 terminal is generated. There was a problem that all the terminals accommodated in were lost communication.

The object of the present invention is to solve the above problems,
To realize a packet traffic multi-stage relay system capable of flexibly changing the connection with the frame multiplexer and the layer 2 terminal according to the processing capability of the frame multiplexer and the layer 2 terminal and the failure status of each part. It is in.

[0010]

According to the present invention, in order to solve the above problems, in a frame multiplexer, a frame from a line already multiplexed by another frame multiplexer and from a terminal unit are A front stage line switch having a function of multiplexing a frame and capable of arbitrarily setting a correspondence between an incoming line from a terminal or a trunk line and a frame multiplexing unit or an outgoing line, and / or a frame multiplex It is equipped with a rear-stage line switch that allows the correspondence between the department and the outgoing line to be set arbitrarily.

Further, according to the present invention, in a packet traffic multi-stage relay system of a packet switching system including a plurality of frame multiplexers, at least a post-stage line switch is switched to change the outgoing line to a packet switching function unit or another frame multiplexing unit. It is configured so that it can be switched and relayed to any of them.

Further, according to the present invention, in a packet traffic multi-stage relay system of a packet switching system including a plurality of frame multiplexers, by switching a front-stage line switch, an outgoing line is directly connected without going through the frame multiplexer. The configuration is such that the frame is relayed to another frame multiplexer, and is multiplexed by the frame multiplexer of the relay destination.

[0013]

According to the present invention as described above, by operating the line switches provided before and / or after the frame multiplexing unit, appropriate packet multiplexing is performed, and the number of layer 2 termination units is increased. It is possible to easily realize economicization by reducing the number of times and detour transfer at the time of failure or congestion.

[0014]

2 to 4 show an embodiment of the present invention. As shown in these figures, the frame multiplexer 1 according to the present invention
Includes a front stage line switch 8 and / or a rear stage line switch 9 before and after the frame multiplexing unit 2. Furthermore, the multiplex relay configuration of the present invention employs a system of relaying in multiple stages via these switches. In these embodiments, the frame multiplexer 2 accommodates, for example, L incoming lines, N (L> N) of which are used to accommodate packet terminals and the remaining lines are frame multiplexed. Used for connection between devices.

The frame multiplexer 2 receives the packet signal from the incoming line 6 and / or the relay line 20 via the front-stage line switch 8 and, after multiplexing the frame format, transmits this frame signal to the rear-stage line switch. 9 is sent. In the figure, the frame multiplexer 2 and the post-stage line switch 9 are connected by one line, but this is an example, and a plurality of lines are used according to the amount of packet signals to be received and the frame signal speed. Good.

Next, a detailed description will be given of the connection configuration of the outgoing line of each post-stage line switch. In the embodiment shown in FIG.
At least one outgoing line 71, 72 ... Of each subsequent stage line switch 91, 92 ... Of each frame multiplexer 11, 12 ...
Is the pre-stage line switch 8 of the first frame multiplexer 1.
Is connected to the entrance side of. Further, at least one rear-stage line switch of each frame multiplexer, that is, the output line 7 of the rear-stage line switch 9 of the first frame multiplexer 1 is the layer 2 terminal unit 4 in the packet switching function unit 3 in FIG. Connected to. In the packet traffic relay system having such a configuration, the following operation is performed.

The packet traffic of the packet terminals 51, 52, ... Is frame-multiplexed by the frame multiplexers 11, 12 ,. Further, the frame multiplexer 11,
When the trunk line traffic of 12 ... Does not reach a predetermined capacity, the frame multiplexers 11, 12 ... Post-stage line switches 91, 92 ... And the pre-stage line switch 8 of the frame multiplexer 1 Depending on the settings, the frame multiplexer 1
The packets are transferred to the frame multiplexer 1 using the trunk lines 1, 12, ... The frame multiplexer 1 multiplexes all the frame-multiplexed packets from the frame multiplexers 11, 12 ... And the packets from the packet terminal line that directly accommodates them, and the packet switching function unit 3 Transfer to.

In this embodiment, the traffic from the packet terminals accommodated in these frame multiplexers is processed by one layer 2 terminal unit in the packet switching function unit by performing multi-stage multiplex relay. The switch control of the front-stage line switch and the rear-stage line switch is performed by a control device (not shown) in the frame multiplexer.
The switch control by this control device can be performed via the control interface used in the conventional frame multiplexing device.

In the embodiment shown in FIG. 3, each of the frame multiplexers 11, 12 ... K subsequent line switches 91, 92 ...
..At least one of the outgoing lines 71, 72 ... Is the pre-stage line switch 8, 81 of the upper frame multiplexer K-1.
..Connected to the entry side of. Further, at least one rear-stage line switch of the frame multiplexers 1, 11, 12, ..., That is, in FIG. 3, the outgoing line 7 of the rear-stage line switch 9 of the first frame multiplexer 1 is the packet switching function unit 3. It is connected to the layer 2 terminal 4 inside. In the packet traffic relay system having such a configuration, the following operation is performed.

In this embodiment, after frame multiplexing is performed by the frame multiplexer 1n, a frame multiplexer
・ ・ 12, 11 and 1 are repeated. Also in this embodiment, the traffic from the packet terminals accommodated in these frame multiplexers is processed by one layer 2 termination unit in the packet switching function unit by performing multi-stage multiplex relay. The switch control of the front-stage line switch and the rear-stage line switch is performed by a control device (not shown) in the frame multiplexer. The switch control by this control device can be performed via the control interface used in the conventional frame multiplexing device.

In the embodiment shown in FIG. 4, at least one outgoing line 10 ... Of the pre-stage line switch 81 ... Of each frame multiplexer 11 ... Is the pre-stage line switch of the frame multiplexer 1. 8 is connected to the entry side. Further, at least one of the specific frame multiplexers, that is, at least one of the post-stage line switches 9 and 91 in FIG.
The outgoing lines 7 and 71 of the book are connected to the layer 2 termination units 4 and 41 in the packet switching function unit 3. In the packet traffic relay system having such a configuration, the following operation is performed.

In this embodiment, the line of the packet terminal 51 accommodated in the frame multiplexer 11 is relayed to the frame multiplexer 1 by the pre-stage line switch 81 in the frame multiplexer 11. The frame multiplexer 1 multiplexes the frame from the relay line together with the frame from the packet terminal 5 which is directly accommodated, and the layer 2 termination unit 4
Transfer to. The layer 2 termination unit 4 is a frame multiplexer 11
Layer 2 different from the layer 2 termination section 41 in which
It is the terminal part.

Also in this embodiment, the switch control of the front-stage line switch and the rear-stage line switch is performed by the control device in the frame multiplexing device (not shown). The switch control by this control device can be performed via the control interface used in the conventional frame multiplexing device.

In the embodiment of the present invention described above,
As a method of setting the switch states of the front stage line switch and the rear stage line switch by the control device of each frame multiplexing device, for example, a method of setting by a command from the central maintenance station to the control device by a known remote maintenance method, Various methods such as a method of inputting and setting a maintenance command from the maintenance device of the frame multiplexer can be used.

[0025]

According to the present invention, the following effects can be obtained. (1) Even if the packet traffic from the packet service user accommodated in each frame multiplexer is small,
The packet relay line between the packet terminal and the packet switching device and the layer 2 line termination function in the packet switching device can be efficiently operated. (2) When the frame multiplexer is congested or malfunctions, the congestion is caused by transferring the new packet call to another frame multiplexer by circuit switching without passing through the frame multiplexer of the frame multiplexer. Alternatively, it is possible to avoid packet loss or frame discard that may occur due to a failure.

(3) In the case where a specific layer 2 terminal part has a failure,
By transferring the multiplexed line to another frame multiplexer by circuit switching, it is possible to avoid packet call loss that may occur due to a failure. (4) By changing the subscriber line and the relay line through a line switch, the total packet traffic volume accommodated in each layer 2 termination unit is increased or decreased, or congestion or failure in the frame multiplexer or layer 2 termination unit It is possible to dynamically adapt to changes in the operating state such as occurrence or cancellation of.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a conventional packet switching network having a frame multiplexing function.

FIG. 2 is a diagram showing a configuration of a packet switching network having a frame multiplexing function according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a packet switching network having a frame multiplexing function according to another embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a packet switching network having a frame multiplexing function according to still another embodiment of the present invention.

[Explanation of symbols]

1, 11, 12 frame multiplexer 2,21 frame multiplexer 3 Packet switching function 4, 41 Layer 2 termination 5, 51, 52 Packet terminal 5 Lines with 6, 61, 62 7, 71, 72 outgoing lines 8,81 Pre-stage line switch 9, 91, 92 Rear line switch 10 Front stage line switch Out line 20 trunk lines

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsunori Dobashi 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, Fujitsu Limited (56) References JP-A-7-336358 (JP, A) JP-A-2-161841 (JP, A) JP 4-239230 (JP, A) JP 3-32297 (JP, A) JP 60-177756 (JP, A) JP 64-57852 (JP, A) 58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/56

Claims (5)

(57) [Claims] 1. A frame multiplexer for multiplexing frames input to a packet switch, wherein a frame from a line and a frame from a terminal which have already been multiplexed by another frame multiplexer are multiplexed. It has a function, and the correspondence between the incoming line from the terminal or the trunk line and the frame multiplexing unit or the outgoing line can be set arbitrarily. A frame multiplexing device comprising one or both of rear-stage line switches that can be arbitrarily set. 2. A packet traffic multi-stage relay system of a packet switching system including a plurality of frame multiplexers according to claim 1, wherein at least a post-stage line switch is switched to set a packet switching function unit or another frame multiplexing function for an outgoing line. A multistage packet traffic relay system characterized by being configured so that it can be relayed by switching to any of the conversion units. 3. A packet traffic multi-stage relay system of a packet switching system including a plurality of frame multiplexers according to claim 1, wherein by switching a pre-stage line switch, an outgoing line is output without going through the frame multiplexing unit. The packet traffic multi-stage relay system is characterized in that the packet traffic is directly relayed to another frame multiplexer, and the frame multiplexer of the relay destination performs multiplexing. 4. At least one of the post-stage line switches of the one or more frame multiplexers excluding the specific frame multiplexer connected to the packet switching function unit is the front-stage line switch of the particular frame multiplexer. The multi-stage packet traffic relay system according to claim 2, wherein the multi-stage packet traffic relay system is connected to an incoming line. 5. The multistage packet traffic multi-stage according to claim 2, wherein at least one of the post-stage line switches of the frame multiplexer is connected to the incoming line of the pre-stage line switch of the upper frame multiplexer. Relay system.