KR100565943B1 - Optical packet label switching system based on the wavelength band path - Google Patents

Abstract

The present invention relates to an optical packet label switching device based on a wavelength band path.

In the present invention, each of the N + 1 + N / L input and output terminals having L optical wavelength switch configured in parallel, the N / L output terminal and the input terminal of each optical wavelength switch to N / L optical fiber line An optical fiber packet retarder formed by connection, N input line cards connected through N optical fiber lines to N input terminals of each optical wavelength switch, and optical fiber lines connected to one input terminal of each optical wavelength switch. A wavelength demultiplexer, N output line cards connected to N output terminals of each optical wavelength switch by N optical fiber lines, and a wavelength multiplexer connected to an output terminal of each optical wavelength switch by optical fiber lines .

According to an embodiment of the present invention, the packet loss rate can be minimized while using a small number of optical fiber delay lines. In addition, the total packet delay time between the input and output nodes in the transport network is very small, which is advantageous in accommodating not only IP traffic but also TDM data requiring real time service.

Switching, Labels, Delays, Demultiplexers, Multiplexers, Optical Packets

Description

Optical packet label switching system based on the wavelength band path}

1 is a structural diagram of an optical packet label switching device according to an embodiment of the present invention.

2 is a schematic diagram of an optical wavelength switch module having an optical fiber packet retarder.

3 is a diagram illustrating a structure of an input line card according to an exemplary embodiment of the present invention.

4 is an exemplary structure diagram of an output line card according to an exemplary embodiment of the present invention.

The present invention relates to a communication data traffic switching device, and more particularly, to an optical packet label switching device based on a wavelength band path.

At present, a high speed optical packet switching system using optical technology is provided to effectively accommodate various types of data traffic. Among these, an optical packet switching system including an optical fiber splitter for cores having a low-speed routing function in wavelength units and an optical packet switch for high speed edges that efficiently receive and handle packet traffic by connecting to an IP domain is located at an edge. Packet traffic processing using a wavelength path on a wavelength division multiplexing (WDM) optical transport network is performed.

The conventional optical packet switching system using the wavelength unit optical path as described above is effective for accommodating high-speed packet traffic with granularity below the wavelength level, and utilizes network resources when integrated with an optical line splitter. It can be increased, and the dimension of the optical line splitter is also reduced.

However, the conventional optical packet switching system requires a high speed variable wavelength converter in addition to the optical fiber delay line in order to implement a relatively large optical packet buffer, and it is difficult to control switching and buffering as the system dimension increases. have.

The optical packet switching system developed to solve the shortcomings of the conventional optical packet switching system is composed of one WDM-based optical interconnect fabric and several unit packet switches, thereby achieving granularity of bandwidth utilization. It is possible to switch below wavelength, and it is advantageous to implement a large-capacity optical packet switch, but it requires a high speed variable wavelength receiver that is difficult to implement in front of the unit switch, and due to all / optical conversion and electronic packet buffer End-to-end packet delay has the disadvantage of accommodating high speed real-time data service.

In order to overcome the complexity of the optical buffer control, a pure wavelength / space mixed optical packet switch using a plurality of wavelength channels instead of an optical buffer in a WDM optical transport network utilizes a wavelength technology for packet collision resolution and efficiently uses bandwidth. Although there is an advantage to increase the flexibility of the, there is a disadvantage that requires a large number of optical gate array (array) and a variable wavelength converter.

Therefore, the technical problem to be achieved by the present invention is to solve the conventional problems, in a multi-service based provisioning edge switching system that accommodates various communication equipment such as IP routers, Ethernet switches, ATM switches, TDM devices, etc. In addition, the present invention provides a wavelength band path-based optical packet label switching device having excellent packet loss and delay characteristics with a minimum amount of optical buffers that are difficult to implement with current optical device technologies.

According to an aspect of the present invention, there is provided an optical packet label switching device comprising: L optical wavelength switches each having N + 1 + N / L input / output terminals and configured in parallel; It is formed of N / L optical fiber lines connecting N / L output terminals and input terminals of each optical wavelength switch, and delays an optical packet having a predetermined wavelength output from the optical wavelength switch and inputs the optical wavelength switch. Optical fiber packet delayer; Connected to the N input terminals of each of the optical wavelength switch, and processing the received IP data to generate an optical packet having a predetermined wavelength according to the destination address to transmit to one optical wavelength switch of the L optical wavelength switching N input line cards; A wavelength demultiplexer connected to one input terminal of each optical wavelength switch and demultiplexing an input optical packet and transmitting the demultiplexed optical packets to each optical wavelength switch; N output line cards connected to the N output terminals of the optical wavelength switches, respectively, for receiving optical packets having a predetermined wavelength output from the optical wavelength switches; And a wavelength multiplexer connected to one output terminal of each optical wavelength switch, the multiplexer outputting multiplexed optical packets outputted from the optical wavelength switches, wherein each optical wavelength switch is an optical signal received from the input line card. The packet is transmitted to the output line card or wavelength multiplexer corresponding to the destination address according to the wavelength.

When each input line card simultaneously transmits a plurality of optical packets to one destination address through the one optical wavelength switch, each input line card exchanges arbitration request / license signals with other input line cards to different optical wavelengths. The switch allows multiple optical packets to be sent to one destination address. In particular, the fiber optic packet delayer delays the optical packet for one time slot time.

On the other hand, each optical wavelength switch includes a first variable wavelength converter connected to the output terminal of the wavelength demultiplexer by an optical fiber line; A second variable wavelength converter connected to an output terminal of the optical fiber packet delay unit; An optical coupler connected to the input line card and the output terminals of the first and second variable wavelength converters, respectively, by an optical fiber line, for coupling the input optical packets and outputting them through one output terminal; And a wavelength demultiplexer connected to an output terminal of the optical coupler to output wavelength demultiplexed to the output line card, the wavelength multiplier, and the optical fiber packet retarder according to the wavelength of the optical packets. have.

In addition, each input line card includes a frame receiving and processing unit for receiving input IP data, processing a frame level header, and outputting the payload data together with the payload data; A forwarding lookup table storing labels for each destination address; A packet generation and storage unit for determining a destination address with reference to the forwarding lookup table based on the header information, and generating and storing a packet by attaching a label according to the destination address; A packet collision controller for exchanging a re-request / permit signal with another input line card and outputting wavelength information and output switching information corresponding to a destination address, respectively; A wavelength tunable optical packet transmitter for receiving a packet from the packet generation and storage unit, and modulating and outputting the packet according to the wavelength information; And a photogate array unit configured to transmit an optical packet modulated to one optical wavelength switch among the L optical wavelength switches according to the output switching information.

The output line card may further include: an optical packet receiving array unit for receiving the optical packets from the L optical wavelength switches and then performing photoelectric conversion and outputting them as electrical signals; A packet assembly and storage unit for restoring IP data according to the electrical signal and outputting the data in an input order; And a frame processing and transmitting unit configured to totally convert the IP data and output the converted IP data.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a structural diagram of an optical packet label switching device according to an embodiment of the present invention. As shown in FIG. 1, an optical packet label switching device according to an embodiment of the present invention includes an optical fiber packet delay formed by connecting L optical wavelength switches 1 and an input / output terminal of the optical wavelength switch 1. Group 2, N input line cards 3, wavelength demultiplexer 4, N output line cards 5, and wavelength multiplexer 6. Where L is the number of optical wavelength switches and N is the number of input / output line cards. And L and N are one or more natural numbers.

Each of the L optical wavelength switches 1 has N + 1 input terminals, N + 1 output terminals, and input / output terminals for N / L optical fiber packet delay units 2, and the N + 1 input terminals N input line cards 3 and one wavelength demultiplexer 4 are connected.

At this time, the connection between the optical wavelength switch 1, the input line card 3 and the wavelength demultiplexer 4 is made by N + 1 optical fiber lines. That is, one optical fiber line is connected to one of the input terminals of the optical wavelength switch 1 and to one of the N input line cards (or the wavelength demultiplexer). The N + 1 output terminals of the optical wavelength switch 1 are connected to N output line cards 5 and one wavelength multiplexer 6, and each connection is also made by N + 1 optical fiber lines.

The optical fiber packet delay unit 2 is made by interconnecting N / L input / output terminals among the input / output terminals of the optical wavelength switch 1 with N / L optical fibers, respectively. Input line card 3 and wavelength demultiplexer 4 have L output terminals, output line card 5 and wavelength multiplexer 6 have L input lines, wavelength demultiplexer 4 and wavelength. The multiplexer 6 is connected to the input / output terminals of the L optical wavelength switches 1 and L optical fiber lines, respectively.

FIG. 2 shows an optical wavelength switch for switching an optical packet transmitted from an input line card 3 or a wavelength demultiplexer 4 to the corresponding output line card 5 or a wavelength multiplexer 6 without pre / optical conversion. Detailed structural diagram of 1).

As shown in FIG. 2, the optical wavelength switch 1 includes N / L + 1 variable wavelength converters 10 and 11, an optical coupler 12, and a wavelength demultiplexer 13. The optical coupler 12 has N + 1 + N / L optical inputs and one optical output, and the wavelength demultiplexer 13 has one optical input and N + 1 + N / L optical outputs.

The optical coupler 12 has light having wavelengths such as λ1, λ2, ... λN, λN + 1, λN + 2, ... λN + 1 + N / L, etc. input from the N input line cards 3. Packets are combined and output, and the wavelength demultiplexer 13 outputs the combined optical packets to an output line card 5, a wavelength multiplexer 6, and an optical fiber delay line 14 (functioning as an optical fiber packet delayer) according to each wavelength. Switch. The optical packet via the optical fiber delay line 14 is input to the variable wavelength converter 11.

The N / L variable wavelength converters 11 output the wavelengths inputted according to the forwarding information in the N / L input line cards 3 corresponding to 1: 1 and output line card 5 or the wavelength multiplexer 6. A wavelength corresponding to?) Is converted into wavelengths? 1,? 2, ...? N,? N + 1 and the optical packets are switched via the optical coupler 12 and the wavelength demultiplexer 13.

The variable wavelength converter 10 converts an optical packet input from the wavelength demultiplexer 4 into wavelengths of λ1, λ2, ... λN, λN + 1 according to a forwarding lookup table, and outputs them to the optical coupler 12, Switch to output line card 5 or wavelength multiplexer 6.

On the other hand, the input line card (3) for receiving the IP traffic to determine the destination address according to the lookup table, generate the optical packet, and then transmit the optical packet to the corresponding optical wavelength switch (1) according to the routing information to be implemented as follows. Can be.

3 is a diagram illustrating an implementation example of an input line card according to an exemplary embodiment of the present invention. As shown in FIG. 3, the input line card 3 includes a frame receiving and processing unit 20, a packet generating and storing unit 21, a forwarding lookup table 22, a wavelength variable optical packet transmitter 23, and a packet collision. The control unit 24 and the photogate array unit 25 may be configured.

The frame receiving and processing unit 20 receives the input IP data, processes the frame level header, and delivers the packet to the packet generation and storage unit 21 together with the payload data. The packet generation and storage unit 21 accesses the forwarding lookup table 22 by using the frame header (or input port) information to determine the destination address of the corresponding frame, attach the label, and generate the packet to the internal memory. Save it.

The packet collision control unit 24 receives routing information corresponding to the packet to be forwarded from the forwarding lookup table 22 and exchanges the arbitration request / permit signal with the other input line cards 3, and then the wavelength variable optical packet transmitter Waveform information corresponding to the destination address and output switch information corresponding to the output terminal of the photogate array unit 25 are transmitted to the 23 and the photogate array unit 25, respectively.

The wavelength tunable optical packet transmitter 23 receives the packet from the packet generation and storage unit 21, modulates the packet data with the wavelength information received from the packet collision control unit 24, and outputs the packet data to the optical gate array unit 25. .

The photogate array unit 25 selects a corresponding output port according to the output switch information received from the packet collision control unit 24 and transmits the optical packet input to one optical wavelength switch 1 among the L optical wavelength switches 1. do.

In addition, the output line card 5 which receives and assembles the optical packets simultaneously input from the L optical wavelength switches 1 and outputs the IP data may be implemented as follows.

4 is a diagram illustrating an implementation example of an output line card according to an exemplary embodiment of the present invention. As shown in FIG. 4, the output line card 5 may include an optical packet receiving array unit 33, a packet assembling and storing unit 32, and a frame processing and transmitting unit 31.

The optical packet receiving array unit 33 receives the optical packets from the L optical wavelength switches 1 and transmits the optical packets to the packet assembly and storage unit 32 after photoelectric conversion. The received optical packet is restored to the IP data in the packet assembly and storage unit 32 and stored in the memory in order to prevent temporary loss and then transferred to the frame processing and transmission unit 31 in the input order. The frame processing and transmitter 31 outputs the IP data after the frame header processing and the optical conversion.

Next, an optical packet label switching process according to an embodiment of the present invention for IP traffic input based on the above-described structure will be described.

When each IP data arrives at the input line card 3, each input line card 3 interprets the destination address of the received IP data with reference to the stored forwarding look-up table. After labeling, create an optical packet.

Here, each of the N input line cards 3 forwards the optical packet to the N output line cards 5 and one wavelength multiplexer 6, so that the N output line cards 5 and one wavelength In order to correspond to the multiplexer 6, specific wavelengths such as λ1, λ2, ..., λn, λn + 1, which are different from each other, are designated and transmitted to the optical wavelength switch 1. That is, optical packets having respective specific wavelengths are transmitted to each of the N output line cards 5 and one wavelength multiplexer 6.

On the other hand, when the input line card 3 forwards one or more optical packets simultaneously by using one optical wavelength switch 1 to the output line card 5 or the wavelength multiplexer 6, the corresponding optical wavelength switch At the output end of (1), a collision by the same wavelength occurs. Therefore, the N input line cards (3) are each output line card (5) or wavelength through multiple optical wavelength switches (1) connected to the second to Lth output stages after exchanging arbitration request / permit signals. The optical packet is transmitted to the medium period 6. Accordingly, each output line card 5 or wavelength multiplexer 6 can simultaneously receive up to L optical packets from the input line card 3 or the wavelength demultiplexer 4 without packet delay.

In case N or more packets are forwarded simultaneously to the same output line card (5) or wavelength multiplexer (6), N input line cards (3) are classified into L groups in total by N / L in order. For each input line card 3, a group number is assigned 1: 1 to the corresponding L wavelength switch 1 and is assigned as 1st to N / Lth. Input cards 3 corresponding to each group correspond to optical packets with fixed wavelengths such as λ N + 1 + 1, λ N + 1 + 2, λ N + 1 + N / L, etc., so as to correspond to the group number. By transmitting to the optical wavelength switch 1, the optical fiber packet delay unit 2 is stored only for one time slot time and then switched to the output line card 5 or the wavelength multiplexer 6.

In the above-described structure, the optical wavelength switch 1 and the optical fiber packet retarder 2 store packets only for one time slot time and then switch packets so that the output line card 5 or the wavelength at the input line card 3 is switched. The number of packets that can be switched to the multiplexer 6 is up to 2L. If more packets arrive, the remaining packets are lost.

The optical packets forwarded from the input line card 3 to the wavelength multiplexer 6 via the optical wavelength switch 1 are traffic routed to the other edge nodes, where the switched optical packets are routed at the wavelength multiplexer 6. After conversion multiplexing to the wavelength of interest, there is no packet delay or loss to the other edge node through the wavelength band path of the optical network (label switching based path consisting of several wavelength channels such as 1, 2, ... L, etc.). It is transmitted transparently.

The optical packets inputted through the wavelength band path composed of L channels from the optical transmission network are classified according to the wavelengths in the wavelength demultiplexer 4, and then in each optical wavelength switch 1 according to the forwarding table λ1, λ2, ... wavelength converted into λ N, λ N + 1, etc., and switched to the output line card 5 or the wavelength multiplexer 6.

According to the present invention, after the IP packet traffic input from the input line card 3 is labeled according to the forwarding lookup information and the optical packet is generated, λ1, λ2,... According to the destination address so that packet collision does not occur. ... converts into a specific wavelength such as λN, λN + 1, λN + 2, ... λN + 1 + N / L, transmits the optical packet to the appropriate wavelength switch 1 of L, and transmits the optical packet. ) Switches the input optical packet directly to the output line card 5 and the wavelength multiplexer 6 after one time slot via the optical fiber packet delayer 2 or the optical packet delayer 2 so that the input optical packets are switched once before loss. There is more opportunity, so that a low packet loss rate can be obtained even with a small number (i.e., L value) of the wavelength switch 1.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only and not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

As described above, according to the present invention, since the input optical packets have one more switching opportunity before the loss, it is possible to reduce the packet loss rate even using a small number of optical wavelength switches.

In addition, when input IP traffic is transparently routed to other optical packet edge systems through wavelength band paths (i.e., 1, 2, ... L) on the optical network, the packet delay at the I / O node is less than one time slot and therefore burst. It is also advantageous for accommodating real-time TDM data and ATM services as well as IP traffic.

In addition, by using a variable wavelength converter and an optical fiber packet delayer instead of an expensive large-capacity electronic memory for optical packet buffering, it is possible to implement packet label switching at a lower price than a large optical packet transmission network.

Claims (7)

An optical packet label switching device based on a wavelength band path, L optical wavelength switches each having N + 1 + N / L input / output terminals and configured in parallel; N / L output terminals and N / L optical fiber lines connecting the input terminals of the respective optical wavelength switches, the optical packets of a predetermined wavelength output from the optical wavelength switch is delayed and output to the optical wavelength switch. Optical fiber packet delayer; Connected to the N input terminals of each of the optical wavelength switch, and processing the received IP data to generate an optical packet having a predetermined wavelength according to the destination address to transmit to one optical wavelength switch of the L optical wavelength switching N input line cards; A wavelength demultiplexer connected to one input terminal of each optical wavelength switch and demultiplexing an input optical packet and transmitting the demultiplexed optical packets to each optical wavelength switch; N output line cards connected to the N output terminals of the optical wavelength switches, respectively, for receiving optical packets having a predetermined wavelength output from the optical wavelength switches; And A wavelength multiplexer connected to one output terminal of each optical wavelength switch and outputting multiplexed optical packets outputted from the optical wavelength switches Including; Each optical wavelength switch transmits an optical packet received from the input line card to the output line card or wavelength multiplexer corresponding to the destination address according to the wavelength, wherein L and N are one or more natural numbers. Device. The method of claim 1 Each input line card transmits the generated optical packet to a wavelength band path corresponding to a destination address, wherein the wavelength band path is different for each destination address. The method of claim 1 When each input line card simultaneously transmits a plurality of optical packets to one destination address through the one optical wavelength switch, the different optical wavelengths are exchanged by exchanging arbitration request / permit signals with other input line cards. An optical packet label switching device for transmitting a plurality of optical packets to a destination address through a switch. The method of claim 1 And the optical fiber packet delay device delays the optical packet for one time slot time. The method of claim 1 Each optical wavelength switch is A first variable wavelength converter connected to an output terminal of the wavelength demultiplexer by an optical fiber line; A second variable wavelength converter connected to an output terminal of the optical fiber packet delay unit; An optical coupler connected to the input line card and the output terminals of the first and second variable wavelength converters, respectively, by an optical fiber line, for coupling the input optical packets and outputting them through one output terminal; And A wavelength demultiplexer connected to an output terminal of the optical coupler to demultiplex wavelengths to be applied to one of the output line card, a wavelength multiplexer, and the optical fiber packet delayer according to the wavelength of the optical packets. Optical packet label switching device comprising a. The method of claim 1  Each input line card A frame receiving and processing unit for receiving input IP data, processing a frame level header, and outputting the payload data together with the payload data; A forwarding lookup table storing labels for each destination address; A packet generation and storage unit for determining a destination address with reference to the forwarding lookup table based on the header information, and generating and storing a packet by labeling the destination address; A packet collision controller for exchanging a re-request / permit signal with another input line card and outputting wavelength information and output switching information corresponding to a destination address, respectively; A wavelength tunable optical packet transmitter for receiving a packet from the packet generation and storage unit, and modulating and outputting the packet according to the wavelength information; And A photogate array unit configured to transmit an optical packet modulated to one optical wavelength switch among the L optical wavelength switches according to the output switching information Optical packet label switching device comprising a. The method of claim 1 Each output line card, An optical packet receiving array unit which receives the optical packets from the L optical wavelength switches and then converts the photo packets into an electrical signal; A packet assembly and storage unit for restoring IP data according to the electrical signal and outputting the data in an input order; And Frame processing and transmission unit for converting the optical data by the optical conversion Optical packet label switching device comprising a.

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