JPH088942A - Multiple ring network device - Google Patents

Abstract

PURPOSE:To minimize a cell abort rate in the case of inter-ring exchange with a relay node with respect to the distributed cell exchange system by an access node in a multiple ring network. CONSTITUTION:Each exchange 1 arranged in plural sections being divisions of a multiple ring exchanges cells between rings (such as #J, #K, #L, #M) connected with an access node 2 decided by each section. For example, a cell is sent to the ring #J in an operating section 3a of a forward transmission line A multiplexing all rings (#1-#N) from a sender access node 2a to a reception destination access node 2c. Then the exchange 1b exchanges the cell to that of th ring #L in the operating section 3b based on cell ring information on one hand and exchanges the cell of the ring #J to that of the ring #L of an operating section 4b of a transmission line B in the reverse direction where the cell passes directly through the exchange 1b and the exchange 1c multiplexes a cell of the specific ring (such as #L, #M or the like) when the load of the exchange 1b or the ring #L is high and the respective cell is received by the reception destination access node 2c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple ring network device for increasing the speed and capacity of a wide band communication network which efficiently stores wide band information.

[0002]

2. Description of the Related Art For example, a document (Mori et al .: A method of constructing a multiple ring network by autonomous distributed switching, a theoretical theory (B-
I), J72-BI, 2, pp. 83-93, 198
9-02), the access node 02 is regularly connected to all ring multiplex transmission lines A03 and B04 as shown in FIG. 9, and cell branching / addition (addition / addition) to each ring is performed.・ Operates the drop function and the relay function. For example, access nodes 02a and 02b, 0
2c and 02d are #J and
Connect only to #L and #M and #M. Forward and reverse all-ring multiplex transmission lines A03 and B04 are all ring # 1.
For example, optical wavelength division multiplexing is performed on #N.

The conventional multi-ring network device described above is a system in which access nodes having a small number of connection points and having a uniform structure are shuffle-connected on a multi-ring type transmission line for distributed cell switching (access node distributed switching system). Take.

For example, as shown in FIG. 10, the access node 02 extracts only a specific wavelength of the connection ring #J from the forward all-ring multiplex transmission line A03 by the demultiplexer 201, and outputs the optical / electronic (O / E) signal. Converter 203 and physical layer termination unit 205 via medium access control (MAC) unit 206
If it is a cell addressed to its own node, it is taken in, if there is a transmission cell, the transmission cell is inserted in an empty slot, and the physical layer terminating unit 205 and the electronic / optical (E / O) converter 202 via the multiplexer 202 forward It is transmitted to the all-ring multiplex transmission path A03.
On the other hand, from the backward all-ring multiplex transmission line B04 to the demultiplexer 20
At 9, for example, only a specific wavelength of the connection ring #M is taken out, and if it is a cell destined for the own node at the O / E converter 210 and the physical layer terminating unit 205, the cell is sent to the fetching line interface (IF) unit 208. .

As shown in FIG. 9, for example, when performing cell transmission from an access node 02a connected to ring #J of the forward multiplex ring transmission line A03 to an access node 02b connected to the same ring #J, access is performed. Operates the cell branch / insert function of the node. On the other hand, the access node 02 which connects the cell on the ring #L of the forward multiplexing ring type transmission line A03 to the ring #M without connecting to the ring #L
When transmitting to d, the cell relay function of the access node operates so that the access node 02c connected to the ring #L and the ring #M converts it, relays it to the ring #M, and receives it at the access node 02d.

[0006]

The conventional multiple ring network device as described above employs a method of decentralized cell exchange at access nodes, and therefore, when cells are exchanged between rings, the cells are discarded under ring load condition. There was a problem that was very likely to happen.

[0007] The problem to be solved by the present invention is to perform cell exchange between rings only by the exchange of the relay node and connect at the access node so as to minimize the cell discard rate at the time of inter-ring exchange in the multiple ring network device. It is to provide a system (relay node distributed switching system) that operates only a cell dropping / inserting function for a ring.

[0008]

The multiple ring network device of the present invention is characterized in that the following means are provided in order to solve the above problems and a relay node distributed switching system is adopted.

The exchange accommodates only all the rings of the forward transmission path and the specific ring of the reverse transmission path in one section where the multiplex ring is divided into a plurality of sections, and is arranged either upstream or downstream of the transmission path accommodating the receiving access node. Exchange cells between multiple rings. Alternatively, a separately provided route control unit monitors the load status of the ring with transmission request status information from the access node that is always connected to the transmission line downstream ring during cell exchange, and a separately provided switch control unit provides monitoring information from the route control unit. The necessity of cell exchange is determined according to the transmission waiting state information of the transmission path downstream ring from the cell switch unit. Alternatively, a separately-provided exchange route holding unit stores and holds that cells of a specific connection have been exchanged with a predetermined ring on the upstream and downstream sides of the transmission line at the time of cell exchange, and exchanges cells of the same connection that arrive continuously.

The access node connects only to each specific ring of the forward and reverse transmission lines in one section where the multiplex ring is divided into a plurality of sections, and operates only the cell dropping / inserting function to each ring. Alternatively, it can be connected to all the rings of the forward transmission path over the entire section. Alternatively, a separately provided multiplexing unit multiplexes the specific wavelength cell extracted from the connection ring of the forward transmission line with the specific wavelength cell of the own node address extracted from the connection ring of the reverse transmission line.

The forward and reverse transmission lines respectively multiplex all rings and a specific ring.

A band management unit, which is separately provided, is provided with an exchange that manages transmission line resources between the exchanges, an access node, and an all-ring multiplex transmission line. When setting a connection from a user terminal, on the other hand, a source access node is used. Between the bandwidth management units of the exchanges, the connection information is exchanged by placing it on a path for call setting in advance, and on the other hand, between the bandwidth management units of the exchanges containing the source access node and the destination access nodes. The connection information is exchanged and it is determined whether or not the request connection permission of the user terminal is required. Alternatively, the virtual path identifier (VP) of the cell header part
I) Using a part of the area, the access node assigns an access node address to the data wavelength from the user terminal and converts it to the destination access node address information, and the exchange determines the access node address to determine the self-contained wavelength Convert to.

[0013]

With the above-mentioned means, the multiple ring network device of the present invention is a switch which divides a multiple ring and arranges it in each of a plurality of sections, and performs cell exchange between the rings connected to the access node which is determined for each section. Next, all the rings and the specific ring are multiplexed to form a dual transmission path in the forward direction and the reverse direction, respectively, so that cell exchange between the rings is made efficient.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a multiple ring network device according to one embodiment of the present invention is such that an exchange 1 divides a multiple ring into a plurality of sections and reverses all the rings of forward transmission lines A3a and 3b in one section. Only the specific rings of the directional transmission lines B4a and 4b are accommodated, and cells are exchanged between a plurality of rings either upstream or downstream of the transmission line accommodating the reception access node 2. The access node 2 is connected only to each specific ring of the forward transmission lines A3a and 3b and the backward transmission lines B4a and 4b in the one section, and operates only the cell dropping / inserting function to each ring. The forward all-ring multiplex transmission line A3 performs, for example, optical wavelength division multiplexing on all the rings # 1 to #N. The reverse specific ring multiplex transmission line B4 performs, for example, optical wavelength division multiplexing on specific rings (for example, #J and #K, #L and #M, etc.).

In the multiple ring network device of the above embodiment, a cell exchange between the rings is performed only by the exchanges of the relay nodes, and the access node operates only the cell branching / inserting function with respect to the connecting ring (relay node distribution). Exchange method).

As shown in FIG. 1, for example, when a cell is transmitted from the source access node 2a to the destination access node 2c to ring #J of the use section 3a of the forward all-ring multiplex transmission line A, one side of the exchange 1b is used. Then, it is determined from the cell header information that the cell should be exchanged with the ring #L, and the cell is exchanged with the ring #L of the usage section 3b, and the receiving access node 2
Receive with c. On the other hand, when the load of the exchange 1b or the ring #L is too high to replace the ring #L, the ring #J
For the cell of interest, directly through the exchange 1b, in the exchange 1c, in the use section 4b of the backward specific ring multiplex transmission line B, ring #
It is exchanged for L and is received by the destination access node 2c.

In the above embodiment, the access node 2 is described as being connected to only the specific rings of the forward transmission lines A3a and 3b in one section. However, as shown in FIG. 2, the access nodes 2 of the forward transmission lines A3a and 3b are connected in all sections. It may be connectable to all rings.
The load status can be distributed throughout the ring. As shown in FIG. 2, for example, when a cell is transmitted from the source access node 2a to the destination access node 2c to the ring #E of the use section 3a of the forward all-ring multiplex transmission path A, the exchange 1b, on the other hand, uses the cell header information. From this, it is determined that the cell should be exchanged to ring #H, and is converted to ring #H. On the other hand, when the exchange 1b or the ring #H cannot be exchanged to the ring #H due to a heavy load, the cell of the ring #E is directly passed through the exchange 1b and the exchange 1c directly connects the ring # of the reverse specific ring multiplex transmission line B. It is exchanged for L and is received by the destination access node 2c.

In the above embodiment, for example, the switch 1b for cell exchange from the ring # 1 to the ring # 4 is provided with a switch control unit 101 and a route control unit 102 as shown in FIG. Connect to ring # 4 of 3b. For example, the transmission request state (R
EQ) Receiving a cell, monitoring the ring load state, the switch control unit 101 determines whether or not to perform cell exchange according to the monitoring information from the route control unit 102 and the ring # 4 transmission waiting state information from the cell switch unit 100. You may do it. Since it is determined which of the transmission path upstream and downstream switches that accommodates the receiving access node is to be used for cell exchange in each load state of the upstream and downstream paths accommodated in the exchange 1b, 2
The load condition can be distributed by a single switch.

Further, in the above embodiment, for example, the exchange 1b at the time of cell exchange from the ring # 1 to the ring # 4 is provided with the exchange route holding unit 106 to establish a specific network connection (connection) upstream and downstream of the transmission line. The fact that the cell has been exchanged with the predetermined ring may be stored and retained, and the cells of the same connection that arrive successively may be exchanged. The paths for cell exchange from the ring # 1 to the ring # 4 are as follows: when the upstream switch exchanges the ring # 1 to the ring # 4 of the forward transmission line A3a, and when the downstream switch exchanges the ring # 1 to the reverse transmission line B4. In some cases, the cell of the same connection may be exchanged, and the cell of the same connection needs to continuously pass through the selected route. Therefore, when a cell of a new connection comes, the relevant connection value and the decided route are held and the next comes. The load condition can be adjusted by controlling so that they are on the same route.

In the above embodiment, the access node 2 is shown in FIG.
As described above, the multiplexing unit 211 is provided, and the demultiplexer 201 is connected from, for example, the connection ring #M of the backward specific ring multiplex transmission line B4.
In the O / E converter 210 and the physical layer terminating unit 205 via multiplex unit 211, if the node is the own node address cell, the specific wavelength cell is extracted from the connection ring of the forward all-ring multiplex transmission line A3. Alternatively, the signals may be multiplexed and sent to the line interface unit 208 via the demultiplexing unit 207. Since the node configuration is such that the specific wavelength cell from the forward all-ring multiplex transmission line A3 is received and transmitted, and only the reverse specific ring multiplex transmission line B4 is received, the reception load state of the nodes can be dispersed.

In the above embodiment, the access node 2 has the same configuration as that of FIG. 10 of the above conventional example, performs cell transmission only to the forward all-ring multiplex transmission line A3, and the reverse specific ring multiplex transmission line B4. The reception process may be performed by taking in only the specific wavelength cell of the own node address.
Cell access control can be easily performed at the time of transmission and unnecessary at the time of reception.

In place of the above embodiment, the multiple ring network device is, as shown in FIG. 6, an exchange 11 including a bandwidth management unit 110 for managing transmission line resources between the exchanges, an access node 22, an all ring multiplex transmission line. 33, for example, when setting a connection from the user terminal 55a, on the other hand, the source access node 22a and the exchange 11a.
Of the bandwidth management unit 110a, the call setting path is set in advance, the connection information is exchanged on the path, and the bandwidth management unit 110a of the exchange 11a and the exchange 11b accommodating the destination access node 22b. The connection information may be exchanged between the bandwidth management units 110b to determine whether to permit the requested connection of the user terminal 55a. Since the access node managed by each exchange 11 is specified in one of the groups between the exchanges and the bandwidth management units 110 of each exchange 11 communicate with each other to hierarchically determine the bandwidth management of the system, the processing configuration is simple. You can

Further, in the above embodiment, a part of the virtual path identifier (VPI) area of the cell header part is used as shown in FIG. 7, and as shown in FIG. 8, for example, at the access node 22a, with respect to the data wavelength from the user terminal 55a, Access node (AN)
An address may be assigned and converted into reception destination AN address information, and the exchange 11a may determine from the AN address whether the cell is a self-contained wavelength cell and convert the self-contained wavelength. Since the AN address is sequentially assigned for each optical wavelength and the VPI area of the cell header is used, the interface with the outside of the system can be easily realized.

[0024]

In the multiple ring network device of the present invention as described above, cells are exchanged between the rings only by the exchanges of the relay nodes, and the access nodes operate only the cell dropping / inserting function with respect to the connecting ring. Therefore, compared to the conventional method of decentralized cell switching at the access node, there is a route that is exchanged at either the switch located upstream or downstream of the transmission line and received at the access node, and the cell is discarded when congestion occurs. Has the effect of keeping the value low.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a multiple ring network device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of another embodiment showing the present invention.

FIG. 3 is a diagram for explaining the function of another embodiment of the exchange shown in FIGS. 1 and 2.

FIG. 4 is a diagram for explaining the function of another embodiment of the exchange shown in FIGS. 1 and 2.

FIG. 5 is a diagram for explaining functions of another embodiment of the access node shown in FIGS. 1 and 2.

FIG. 6 is a configuration diagram of another embodiment showing the present invention.

FIG. 7 is a diagram showing a configuration of a cell header section.

FIG. 8 is a diagram showing allocation of access node addresses to respective optical wavelengths.

FIG. 9 is a configuration diagram of a conventional multiple ring network device.

10 is a diagram for explaining the function of the access node shown in FIG.

[Explanation of symbols]

1, 11 Switch, 2, 22 Access node, 3 Forward all-ring multiplex transmission line A, 4 Reverse specific ring multiplex transmission line B, 33 All-ring multiplex transmission line, 55 User terminal. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (8)

[Claims] 1. A multi-ring is divided into a plurality of sections, which accommodates only all rings of a forward transmission path and a specific ring of a reverse transmission path in one section, and has a plurality of transmission paths that accommodate receiving access nodes, either upstream or downstream. An exchange that exchanges cells between the rings; and an access node that connects only to each specific ring of the forward and reverse transmission lines in the one section and that only operates a cell branching / inserting function to each ring, A multi-ring network device comprising the forward transmission path for multiplexing all rings and the reverse transmission path for multiplexing a specific ring. 2. The multiple ring network device according to claim 1, wherein the access node is connectable to all the rings of the forward transmission path over the entire section. 3. A route control unit that monitors the load state of the ring by transmission request state information from an access node that is always connected to a transmission line downstream ring when a cell is exchanged in an exchange, and monitoring information from the route control unit and a cell. 3. The multiple ring network device according to claim 1, further comprising: a switch control unit that determines whether or not cell exchange is necessary according to the transmission waiting state information of the transmission line downstream ring from the switch unit. 4. An exchange for storing and retaining that a cell of a specific network connection (connection) has been exchanged with a predetermined ring on the upstream and downstream sides of a transmission line at the time of cell exchange by an exchange, and for exchanging cells of the same connection that arrive continuously. 4. The multi-ring network device according to claim 1, further comprising a route holding unit. 5. The access node is provided with a multiplexer for multiplexing the specific wavelength cell taken out from the connection ring of the forward transmission line with the specific wavelength cell of the own node address taken out from the connection ring of the reverse transmission line. The multi-ring network device according to claim 1, 2, 3, or 4. 6. The access node transmits cells only to the forward transmission line and fetches only the specific wavelength cell of the own node address from the reverse transmission line for reception processing. , 4 or 5 multiple ring network device. 7. A multiple ring network device comprising an exchange including a band management unit for managing transmission line resources between respective exchanges, an access node, and an all-ring multiplex transmission line,
When setting the connection from the user terminal, on the one hand, the connection information is exchanged between the source access node and the bandwidth management unit of the exchange by placing it on the path for call setting in advance, and on the other hand, the source access node A multi-ring network device, characterized in that the connection information is exchanged between each of the bandwidth management units of the exchange that accommodates the destination access node and the exchange that accommodates the destination access node, and whether or not the request connection permission of the user terminal is required. . 8. A virtual path identifier (VP) in a cell header part
I) Using a part of the area, the access node assigns an access node address to the data wavelength from the user terminal and converts it to the destination access node address information, and the exchange determines the access node address to determine the self-contained wavelength 8. The multiple ring network device according to claim 7, wherein the multiple ring network device is converted into