JP2009206978A - Optoelectronic gateway device and optical node device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the concealment caused by not converting a packet into electric signals, and also to make the signal processing time shorter than the time to convert all the packets into the electric signals, with respect to the packet to be transmitted over an optical network. <P>SOLUTION: In an optical node device which is a component of the optical network, only a header portion of the packet is extracted by the optical signals to be transmitted over the optical network for which the predetermined processing is carried out, so that a new packet synthesized with a payload portion is outputted. In the optoelectronic gateway device, the processing in response to the header content is carried out with respect to the payload portion of the packet where the header portion is processed. Not only the concealment caused by not converting the packet into the electric signals is solved by converting into the electric signals only the header portion of the packet to be transmitted over the optical network and by carrying out the processing based on the content of the converted header portion, but also the processing time is made shorter than the time to convert all the packets into the electric signals. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrical / optical gateway device and an optical node device, and more particularly to an electrical / optical gateway device and an optical node device used in a network including an optical network and an electrical network.

  In an optical network, research on multi-wavelength optical packet communication in which optical signals of a plurality of types of wavelengths are transmitted using one optical fiber has been conducted (for example, Non-Patent Document 1). In multi-wavelength optical packet communication, for example, one wavelength is used for the header of layer 2 (hereinafter referred to as L2), one wavelength is used for the header of layer 3 (hereinafter referred to as L3), three wavelengths are used for the payload, and so on. , The header part and the payload part are allocated with different wavelengths for transmission.

  By the way, not only in the case of multi-wavelength optical packet communication, in general, transmission using an optical network enables higher speed transmission than using an electrical network. When processing is performed by converting an optical signal into an electrical signal, a time loss occurs because the conversion takes time. For this reason, it is desirable to transmit as much optical signals as possible without converting large data into electrical signals. For example, a transmission method in which an optical network is adopted for the core network portion and an optical signal is converted into an electrical signal by a device at the end of the core network can be considered.

In Patent Document 1, optical wavelength signals are optically / electrically converted, the converted header information is recognized and processed, new header information is generated, and the new header information is electrically / optically converted. A technique for combining with an optical data frame signal is described.
JP 2004-336785 A Hideaki Imaizumi 8 others "Consideration on hybrid network using multi-wavelength optical packet switching and optical circuit switching", [online], IEICE, [Search February 15, 2008], Internet <URL: http: //www.mlab.tu-tokyo.ac.jp/publications/2006/imaq-PN-2006.pdf>

If all the optical signals are transmitted using the optical network, the contents of the processing performed in the optical node device cannot be recognized from the outside and are concealed. For example, when a failure occurs in the optical network, information such as an error message cannot be added during transmission. In other words, in the optical network, it is difficult to add new information to the data, and there is a problem that information regarding a failure or state in the optical network cannot be transmitted to the end node. In order to add new information in the middle of transmission, it is necessary to convert it into an electrical signal, and in this case, the above-described time loss occurs.
Here, in Patent Document 1, information such as a destination address in a header subjected to optical / electrical conversion is merely read to determine the order in which data frames are output, and the above problem cannot be solved.

  The present invention has been made to solve the above-described problems of the prior art, and its purpose is to convert only the header portion of a packet transmitted through an optical network into an electrical signal, and based on the contents of the converted header portion. An electrical / optical gateway device and an optical node device that solve the concealment due to not being converted into an electrical signal and reduce the processing time compared to converting all of the packets into electrical signals are provided. That is.

  According to a first aspect of the present invention, there is provided an electrical / optical gateway apparatus that performs predetermined processing on a packet from one of an optical network that transmits a packet based on an optical signal and an electrical network that transmits a packet based on an electrical signal. A gateway device that transmits as a packet of a network, and processes the portion other than the header portion of the packet in which the header portion is processed in the optical node device that is a component of the optical network, according to the contents of the header portion Packet processing means is included. By performing processing based on the contents of the header portion of the packet whose header portion has been processed in the optical node device, concealment due to not converting it into an electrical signal can be solved, and the packet can be transmitted to an appropriate node device.

  According to a second aspect of the present invention, the electrical / optical gateway device according to the first aspect of the invention is characterized in that the packet processing means performs a process of changing contents of a part other than the header part of the packet according to the contents of the header part. It is characterized by that. Appropriate processing can be performed by changing the contents of the payload portion.

  An optical node device according to a third aspect of the present invention is an optical node device which is a component of an optical network, wherein an optical header extraction means for extracting only a header portion of a packet by an optical signal transmitted through the optical network, and the optical node device A header processing unit that performs a predetermined process on the header portion extracted by the header extraction unit, a portion other than the header portion of the packet and a header portion processed by the header processing unit, and a new packet based on the optical signal And a packet synthesizing means for outputting. By converting only the header part of the packet transmitted through the optical network into an electrical signal and performing processing based on the contents of the converted header part, the concealment due to not converting into an electrical signal is solved, and all Processing time can be shortened compared with the case of converting to an electrical signal.

  An optical node device according to a fourth aspect of the present invention is the optical node device according to the third aspect, wherein the header processing means performs processing for adding information indicating that processing is necessary for a portion other than the header portion of the packet to the header portion. It is characterized by that. By so doing, appropriate processing can be performed on the payload portion in another device.

  According to the present invention, only the header portion of a packet transmitted through an optical network is converted into an electric signal, and processing is performed based on the contents of the header portion after conversion, thereby solving concealment due to not converting into an electric signal. In addition, the processing time can be shortened compared to converting all of the packets into electrical signals. As a result, for example, in an environment where optical transmission is used for the core network, processing of data transmitted / received by the electrical / optical network gateway device that is an edge node of the core network is mainly performed, and processing of the optical node is reduced. An environment in which the state in the optical network can be grasped can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing referred to in the following description, the same parts as those in the other drawings are denoted by the same reference numerals.
(System configuration)
FIG. 1 is a block diagram showing a configuration example of an electrical / optical network system 3 employing electrical / optical gateway devices and optical node devices according to an embodiment of the present invention. Referring to the figure, this system 3 includes an electrical / optical network gateway device (hereinafter referred to as an electrical / optical gateway device) GW1 and GW2 that converts electrical signals and optical signals, and an optical network (optical NW). And optical node devices N1 and N2 provided in the network.

One or more optical node devices Nm (m is a natural number) are provided in the optical network. In this example, two optical node devices N1 and N2 are provided in the optical network. These optical node devices N1 and N2 function as relay nodes in the optical network.
One or more electrical / optical gateway devices GWn (n is a natural number) are provided at the end of the optical network. In this example, two electric / optical gateway devices GW1 and GW2 are provided.

(Configuration of electrical / optical gateway device)
FIG. 2 is a block diagram illustrating a functional configuration example of the electrical / optical gateway device in FIG. 1. In the figure, the electrical / optical gateway device GWn (n is a natural number) of this example includes a packet processing unit 21 that reflects the meta information of the header portion in the payload portion, and packet electricalization that converts the packet from an optical signal to an electrical signal. The unit 22 includes an optical port 23 that transmits and receives optical packets to and from other nodes, and an electrical port 24 that transmits and receives electrical packets to and from other nodes.

(Configuration of optical node equipment)
FIG. 3 is a block diagram illustrating a functional configuration example of the optical node device in FIG. In this figure, the optical node device Nm of this example (m is a natural number is an optical port group 11 composed of optical ports P1, P2,..., Pk (k is a natural number) for transmitting and receiving optical packets with other nodes, and a payload portion. A delay line 12 for buffering the optical signal as it is, a header extracting unit 13 for extracting only the header part from the optical packet, a header processing unit 14 for processing the header part, and a combination of the header part and the payload part A packet combining unit 15 and an optical switch unit 16 for selecting and determining an output port.
Note that any method may be adopted for the header extraction by the header extraction unit 13.

(Operation of the entire system)
Next, an operation example of the entire system will be described focusing on the operation of the optical node device and the electrical / optical gateway device. Here, the optical node device Nm of this system receives data as an optical packet, processes the data, transmits the data to the electrical / optical gateway device GWn, and adds the processing to the data by the electrical / optical gateway device. The procedure up to transmission to the transmission destination as an electrical signal will be described.

(Operation example 1)
4 is a flowchart showing an operation example 1 of the present system, FIG. 4A is a flowchart showing the operation of the optical node device Nm, and FIG. 4B is a flowchart showing the operation of the electrical / optical gateway device GWn. is there.
First, with reference to FIG. 4A, the operation after the point in time when the optical port group 11 in the optical node device Nm according to the present embodiment receives a packet (step S000) will be described.
The optical port group 11 receives a packet from another optical node device or electrical / optical gateway device, and passes the received packet to the payload delay line 12 and the optical header extraction unit 13.
The payload delay line 12 receives a packet from the optical port group 11 and delays the packet for a predetermined time. That is, the packet passes through the payload delay line 12 and is then passed to the packet synthesis unit 15.

The optical header extraction unit 13 receives a packet from the optical port group 11, extracts only the header part from the packet (step S001), and passes the extracted header part to the header processing unit 14.
The header processing unit 14 receives the header part extracted by the optical header extraction unit 13 and processes the header part (step S002). At that time, the header processing unit 14 determines whether or not it is necessary to change the payload part that is paired with the header part (that is, the part other than the header part) (step S003).

  If it is determined that the payload portion needs to be changed, the header processing unit 14 adds header information to the header to add meta information indicating that processing by the electrical / optical gateway device is required (steps S003 → S004). ). In addition, the header processing unit 14 determines an optical port to be used for optical packet transmission from the processing result in the optical port group 11 (step S005), passes the processed header part to the packet combining unit 15, and uses it. The optical port information to be transmitted is passed to the optical switch unit 16.

On the other hand, if it is determined in step S003 that the payload portion need not be changed, the header processing unit 14 determines an optical port to be used for optical packet transmission from the processing result in the optical port group 11 (step S003 → In step S005), the processed header portion is transferred to the packet combining unit 15 and the optical port information to be used is transferred to the optical switch unit 16.
The packet combiner 15 receives the packet from the payload delay line 12 and the header from the header processor 14, combines them to generate one packet (step S 006), and passes the generated packet to the optical switch 16.

The optical switch unit 16 receives the optical port information used from the header processing unit 14, the packet generated from the packet combining unit 15, and passes the generated packet to the designated optical port.
The optical port receives the packet from the optical switch unit 16, and transmits the packet to another optical node device or the electrical / optical gateway device (step S007). That is, a packet obtained by combining the processed header portion and payload portion is transmitted to an appropriate node device or a source node device.

On the other hand, in FIG. 4B, the optical port 23 of the electrical / optical gateway device GWn receives the packet from the optical node device (step S050), and passes the received packet to the packet electrification unit 22.
When receiving the packet from the optical port 23, the packet electrification unit 22 converts the optical signal into an electrical signal (step S051), and passes the converted packet to the packet processing unit 21.

When the packet processing unit 21 receives a packet converted into an electric signal from the packet electrification unit 22, whether or not meta information indicating that processing by the electric / optical gateway device 2 is required is added in the header. Is determined (step S052).
When the meta information is added, the packet processing unit 21 modifies the information of the payload portion based on the meta information in the header (steps S052 → S053), and sends the packet including the modified payload to the electrical port 24. hand over. Thereby, the packet is transmitted (step S054).
On the other hand, if the meta information is not given in step S052, the packet processing unit 21 passes the packet as it is to the electrical port 24, and the packet is transmitted (S052 → step S054).

(Operation example 2)
FIG. 5 is a flowchart showing an operation example 2 of the present system, FIG. 5A is a flowchart showing the operation of the optical node device Nm, and FIG. 5B is a flowchart showing the operation of the electrical / optical gateway device GWn. is there.
In FIG. 5A, the same processing as in FIG. 4A is performed in the optical node device up to step S000.
The optical header extraction unit 13 of the optical node device receives the packet from the optical port group 11, extracts only the L2 header portion from the packet (step S101), and passes the extracted L2 header portion to the header processing unit 14.

  The header processing unit 14 receives the header part extracted from the optical header extraction unit 013, and processes the header part (step S102). It is determined whether or not it is necessary to generate an ICMP message when the information in the L2 header cannot be transmitted to the next node (step S103). ICMP (Internet Control Message Protocol) is described in the standard RFC792.

  When it is necessary to generate an ICMP message in step S103, the header processing unit 14 determines the type of the ICMP message based on a rule determined by RFC or the like (step S103 → S104), and corrects it in the L2 header. And meta information indicating the type of the ICMP message (step S105), the optical port group 11 to be used for optical packet transmission is determined from the processing result (step S005), and the processed header portion is used as the packet combining unit 15. In addition, the optical port information to be used is passed to the optical switch unit 16.

On the other hand, if it is not necessary to generate an ICMP message in step S103, the header processing unit 14 determines the optical port group 11 to be used for optical packet transmission from the processing result (step S103 → S005), and the processed header portion. To the packet combining unit 15 and the optical port information to be used are passed to the optical switch unit 16.
The subsequent processing of the optical node device is the same as the processing after step S006 in FIG. As a result, a packet obtained by combining the processed header portion and payload portion is transmitted to an appropriate node device or a source node device.

  In FIG. 5B, the processing up to step S051 of the operation of the electrical / optical gateway device is the same as the processing of the corresponding step in FIG. Whether the packet processing unit 21 of the electrical / optical gateway apparatus receives the converted packet from the packet electricalizing unit 22 and is meta information indicating that processing in the electrical / optical gateway apparatus is required in the L2 header? It is determined whether or not (step S152).

When the meta information is given, the packet processing unit 21 modifies the information in the L3 header part and the payload part based on the meta information in the L2 header and the ICMP rules defined in the RFC (steps S152 → S153). ). Then, the ICMP packet including the modified payload portion is transferred to the electrical port 24, and the packet is transmitted (step S054).
On the other hand, when the meta information is not given in step S152, the packet processing unit 21 passes the packet as it is to the electrical port 24, and the packet is transmitted (step S152 → S054).
The subsequent processing of the electrical / optical gateway device is the same as the processing after step S054 in FIG.

(Operation example 3)
6 is a flowchart showing an operation example 3 of the present system. FIG. 6A is a flowchart showing the operation of the optical node device Nm, and FIG. 6B is a flowchart showing the operation of the electrical / optical gateway device GWn. is there.
In FIG. 4A, the same processing as in FIG. 4A is performed in the optical node device until step S000.
The optical header extraction unit 13 of the optical node device receives the packet from the optical port group 11, extracts only the L2 header and L3 header portions from the packet (step S201), and extracts the extracted L2 header and L3 header portions as a header processing unit. 14

The header processing unit 14 receives the L2 header and L3 header portions from the optical header extraction unit 13, and performs processing on the header portions (step S202). Specifically, processing such as reducing the TTL (Time To Live) value of the IP header included in the header portion is performed.
In addition, the header processing unit 14 determines whether or not it is necessary to generate an ICMP message according to the state of the IP header based on a rule defined in RFC or the like (step S103).

If there is no need to generate an ICMP message, the header processing unit 14 determines the optical port group 11 to be used for optical packet transmission from the processing result (step S103 → S005), and the processed header portion is sent to the packet combining unit 15. The optical port information to be used is passed to the optical switch unit 16.
On the other hand, when it is necessary to generate an ICMP message in step S103, the header processing unit 14 determines the type of the ICMP message based on a rule determined by RFC or the like (step S103 → S104), and in the L2 header. Is added with meta information indicating the necessity of correction and the type of ICMP message (step S105). Further, it is determined whether the old IP header is required according to the determined ICMP message (step S206).

In the case of an ICMP message that requires an old IP header, a new IP header is inserted before the old IP header (steps S206 → S207), and the generated new header part is passed to the packet combining unit 15.
On the other hand, in the case of an ICMP message that does not require the old IP header in step S206, a new IP header is inserted instead of the old IP header (steps S206 → S208), and the generated new header part is passed to the packet combining unit 15. .

The header processing unit 14 determines the optical port group 11 to be used for optical packet transmission from the processing result (step S005), passes the processed header part to the packet combining unit 15, and uses the optical port information to be used as an optical switch. Pass to part 16.
The subsequent processing of the optical node device is the same as the processing after step S006 in FIG. As a result, a packet obtained by combining the processed header portion and payload portion is transmitted to an appropriate node device or a source node device.

In FIG. 6B, the processing up to step S051 of the operation of the electrical / optical gateway device is the same as the processing of the corresponding step in FIG. 4B. Whether the packet processing unit 21 of the electrical / optical gateway apparatus receives the converted packet from the packet electricalizing unit 22 and is meta information indicating that processing in the electrical / optical gateway apparatus is required in the L2 header? It is determined whether or not (step S152).
When the meta information is given, the packet processing unit 21 inserts an ICMP header after the new IP header based on the meta information (step S251).
Subsequently, it is determined whether the ICMP message needs to change the payload portion (step S252).

In step S252, when it is necessary to change the payload part, the packet processing part 21 modifies and changes the information in the IP payload part based on the meta information in the L2 header and the ICMP rule defined in the RFC. Then, the ICMP packet including the changed payload is transferred to the electrical port 24 (steps S252 → S253).
If it is not necessary to change the payload part in step S252, the packet processing unit 21 passes the packet as it is to the electrical port 24, and the packet is transmitted (step S252 → S054).
The subsequent processing of the electrical / optical gateway device is the same as the processing after step S054 in FIG.

(Operation example 4)
FIG. 7 is a flowchart showing an operation example 4 of the present system, FIG. 7A is a flowchart showing the operation of the optical node device Nm, and FIG. 7B is a flowchart showing the operation of the electrical / optical gateway device GWn. is there.
In FIG. 4A, the same processing as in FIG. 4A is performed in the optical node device until step S002.
During the process of step S002, the header processing unit 14 of the optical node device checks whether or not the number of packets being processed indicating the congestion of the optical node device is equal to or greater than a threshold (step S303).
If the number of packets being processed is equal to or greater than the threshold, the header information is changed by adding meta information indicating that processing for ECN (Explicit Congestion Notification) is required in the header by the electrical / optical gateway device (step S304). . If the number of packets being processed is less than the threshold value, the process of step S304 is not performed. ECN is described in the standard RFC3162.

The header processing unit 14 determines the optical port group 11 to be used for optical packet transmission from the processing result (step S005), passes the processed header part to the packet combining unit 15, and uses the optical port information to be used as an optical switch. Pass to part 16.
The subsequent processing of the optical node device is the same as the processing after step S006 in FIG. As a result, a packet obtained by combining the processed header portion and payload portion is transmitted to an appropriate node device or a source node device.

In FIG. 7B, the processing up to step S051 of the operation of the electrical / optical gateway device is the same as the processing of the corresponding step in FIG. The packet processing unit 21 of the electrical / optical gateway device receives the converted packet from the packet electricalization unit 22, and is given meta information in the header indicating that processing for ECN is required in the electrical / optical gateway device. It is determined whether or not (step S352).
When the meta information is not given, the packet processing unit 21 passes the packet as it is to the electrical port 24 (step S352 → S054).

On the other hand, when meta information is given in step S352, the packet processing unit 21 determines whether the packet is a TCP segment (steps S352 → S353).
If it is not a TCP segment, the packet processing unit 21 passes the packet to the electrical port 24 (step S353 → S054).
On the other hand, if it is a TCP segment in step S353, the packet processing unit 21 modifies and changes the TOS (Type Of Service) field in the IP header to perform ECN processing (step S353 → S354). The packet is transferred to the electrical port 24 (step S054).

(Example of header change)
Examples of processing contents such as the header processing unit in the operation examples 1 to 4 described above will be described with reference to FIGS.
(In case of ATM)
FIG. 8 is a diagram for explaining the processing contents of the header processing unit when the received packet is an ATM packet. This figure shows the data structure of the header portion of the packet according to the ATM standard.
As shown in the figure, the ATM header includes GFC (Generic Flow Control), VPI (Virtual Path Identifier), VCI (Virtual Channel Identifier), PT (Payload Type), CLP (Cell Loss Priority), HEC (header error checksum). ) And each field. The PT field includes network congestion information. Note that ATM (Asynchronous Transfer Mode) is described in URL: http://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode.
Based on the ATM standard, in step S304 of the operation example 4 described above, a flag is set in this PT field at the time of congestion, and in step S352 of the operation example 4, it is determined whether or not there is congestion by looking at this PT field. Note that the ATM packet in FIG. 8 cannot be applied to Operation Example 2 and Operation Example 3.

(For MPLS)
FIG. 9 is a diagram for explaining the processing contents of the header processing unit when MPLS (Multi-Protocol Label Switching) is used. This figure shows a data structure of an MPLS header (Shim header) inserted between a layer 2 header (Layer 2 Header) and a layer 3 header (Layer 3 Header). The Shim header includes a Level field, an EXP (Experimental Use) field, an S (Bottom of Stack) field, and a TTL (Time to Live) field. Note that MPLS is described in URL: http://en.wikipedia.org/wiki/Multi-Protocol_Label_Switching.

Here, the EXP field is used. That is, in step S304 of the operation example 4, during congestion, for example, “111” is set in the EXP field, and ECN processing is performed by the electrical / optical gateway device.
Further, in the case of the MPLS TTL Time Out in Step S105 of the operation example 2 and the operation example 3, for example, “110” is set in the EXP field, and the process of ICMP Time Exceeded for Datagram is performed in the electrical / optical gateway device. Do.

Similarly, if delivery to the destination is not possible in step S105 of operation example 2 and operation example 3, for example, a value of “001” to “100” is set in the EXP field, and the ICMP Destination Unreachable is set in the electrical / optical gateway device. Perform the process.
In Step S105 of the operation example 3, when the destination address of the layer 2 header / layer 3 header is own and the Protocol field of the IP header is ICMP, for example, a value of “101” is set. An ICMP Echo Reply process is performed in the optical gateway device.

(For ECN)
FIG. 10 is a diagram for explaining the processing contents of the header processing unit when the received packet is an ECN packet. FIG. 4A shows the data structure of an IPv4 or IPv6 IP packet, and FIG. 4B shows the TOS field in FIG. 2A, that is, the ECN field in the DS (Differentiated Services) field (bold frame). It is a figure which shows the position of CE bit in. FIG. 4C shows the data structure of the TCP packet, and FIG. 4D shows the position of the ECN-Echo flag in the reserved field (bold frame) in FIG. FIG.

  In the operation example 4 described above, when receiving the ECN packet, the electrical / optical gateway apparatus looks at the information in the PT field in the case of an ATM packet, and when there is congestion, the CE bit in the IP header and the ECN-Echo in the TCP header. Make a bit. Similarly, in the case of MPLS, the information in the EXP field is viewed, and the CE bit in the IP header and the ECN-Echo bit in the TCP header are set during congestion.

(In the case of ICPM)
FIGS. 11 to 13 are diagrams for explaining processing examples by the header processing unit and the packet processing unit when the received packet is an ICMP packet.
FIG. 11A shows a packet including an L2 header (L2 Hdr), an IP header (IP Hdr), and a payload. In step S101 of the operation example 2 described above, only the portion 41 of the L2 header in FIG. 9A is electrified by the header processing unit, and the other portions are not electrified. Similarly, in the process of step S153 of the operation example 2, the packet processing unit looks at the EXP field of MPLS, and a new IP header and an ICMP header are inserted before the old IP header. The state where these headers 42 are inserted is shown in FIG. In FIG. 6B, in the case of step S153 in the operation example 2, the total of the old IP header and the payload is cut at 64 bits, and the remaining part is discarded (the broken line part in FIG. 5B). .

FIG. 12 shows a processing example in the case of Destination Unreachable or Time Exceeded for Datagram of ICMP. FIG. 2A shows a packet including an L2 header (L2 Hdr), an IP header (IP Hdr), and a payload.
In step S201 of the operation example 3 described above, only the L2 header (L2 Hdr) and the IP header (IP Hdr) portion 43 are electrified by the header processing unit, and the other portions are not electrified. .
FIG. 5B shows a state after the process in step S207 of the above-described operation example 3. That is, the header processing unit performs processing for generating and inserting a new IP header. Then, three header portions 44, a new L2 header (new L2 Hdr), a new IP header (new IP Hdr), and an old IP header (new IP Hdr), are passed to the packet combining unit 15.

  FIG. 7C shows a state after the process in step S253 of the operation example 3 described above. That is, the packet processing unit looks at the MPLS EXP field and inserts the ICMP header 45 in front of the old IP header. In FIG. 6C, in the case of step S253 of the operation example 3, the total of the old IP header and the payload is cut at 64 bits, and the remaining part is discarded (the broken line part in FIG. 5C). .

FIG. 13 shows a processing example in the case of Echo Request / Reply of ICMP. FIG. 2A shows a packet including an L2 header (L2 Hdr), an IP header (IP Hdr), an ICMP header (ICMP Hdr), and a payload.
In step S201 of the operation example 3 described above, only the L2 header (L2 Hdr) and the IP header (IP Hdr) part 46 are electrified by the header processing unit, and the other parts are not electrified. .

FIG. 5B shows a state after the process in step S208 of the above-described operation example 3. That is, the header processing unit performs processing for generating and replacing a new IP header. Then, two header portions 47, a new L2 header (new L2 Hdr) and a new IP header (new IP Hdr), are passed to the packet combining unit 15.
FIG. 5C shows a state after the process in step S252 of the above-described operation example 3. That is, the packet processing unit looks at the MPLS EXP field and generates and adds an ICMP header 48. In FIG. 9C, in the case of step S252 of the operation example 3, Payload is in a state as it is.

(Summary)
In this system, the processing at the optical node is minimized by using the electrical / optical gateway device that exists between the optical network and the optical network to centrally perform processing that reflects the information related to the optical network in the data to be transmitted and received. The state in the core network can be grasped at the end host while limiting to the limit. Therefore, it is possible to solve the problem in the prior art that the state in the optical network is concealed from the end host.

  By the way, the present invention can be applied to all upper protocols operating on an optical network such as an IP network and a virtual network. According to the prior art, as described above, there is a problem that the state of the optical network as a lower layer cannot be grasped regardless of whether it is an IP network or a virtual network. On the other hand, according to the present invention, the present invention can be applied to an IP network or a virtual network that is an upper layer of an optical network, and information in the optical network can be listed as an upper protocol with as little overhead as possible.

A virtual network forms a virtual network on a real network (physical network). This virtual network uses a technique for constructing a virtually partitioned network on a network in which hardware such as physical routers, cables, and servers are integrated. The virtual network is, for example, a network based on voice communication circuit switching or a network based on data communication packet switching. The virtual network is described in STANFORD UNIVERSITY “Clean Slate Design for Internet”, Internet <URL: http://cleanslate.stanford.edu/index.php>.
Note that the present system can be suitably used even when a header of a specific wavelength in multi-wavelength optical packet communication is taken out.

  The present invention can be applied to a network including an optical network and an electrical network.

1 is a block diagram illustrating a configuration example of an electrical / optical network system employing an electrical / optical gateway device and an optical node device according to an embodiment of the present invention. FIG. It is a block diagram which shows the function structural example of the electrical / optical gateway apparatus in FIG. It is a block diagram which shows the function structural example of the optical node apparatus in FIG. 2 is a flowchart showing an operation example 1 of the system of FIG. 1, (a) is a flowchart showing the operation of the optical node device, and (b) is a flowchart showing the operation of the electrical / optical gateway device. 3 is a flowchart showing an operation example 2 of the system of FIG. 1, (a) is a flowchart showing the operation of the optical node device, and (b) is a flowchart showing the operation of the electrical / optical gateway device. 4 is a flowchart showing an operation example 3 of the system of FIG. 1, (a) is a flowchart showing the operation of the optical node device, and (b) is a flowchart showing the operation of the electrical / optical gateway device. 5 is a flowchart showing an operation example 4 of the system of FIG. 1, (a) is a flowchart showing the operation of the optical node device, and (b) is a flowchart showing the operation of the electrical / optical gateway device. It is a figure for demonstrating the example of a process of a header process part when the packet received is an ATM packet. It is a figure for demonstrating the example of a process of the header process part at the time of using MPLS. It is a figure for demonstrating the example of a process of a header process part when the received packet is a packet of ECN. It is a figure for demonstrating the example of a process by a header process part and a packet process part in case the received packet is a packet of ECN. It is a figure for demonstrating the example of a process by a header process part and a packet process part in case the received packet is a packet of ECN. It is a figure for demonstrating the example of a process by a header process part and a packet process part in case the received packet is a packet of ECN.

Explanation of symbols

3 Electrical / Optical Network System 11 Optical Port Group 12 Payload Delay Line 13 Optical Header Extraction Unit 14 Header Processing Unit 15 Packet Synthesis Unit 16 Optical Switch Unit 21 Packet Processing Unit 22 Packet Electricalization Unit 23 Optical Port 24 Electrical Ports GW1 to GWn Electricity・ Optical network gateway devices N1 to Nm Optical node devices P1 to Pk Optical ports

Claims (4)

  A gateway device that performs predetermined processing on a packet from one of an optical network that transmits a packet based on an optical signal and an electrical network that transmits a packet based on an electrical signal, and sends the packet as a packet on the other network, An electrical / optical gateway comprising packet processing means for processing a portion other than the header portion of a packet whose header portion has been processed in an optical node device which is a component of a network, according to the contents of the header portion apparatus.   2. The electric / optical gateway device according to claim 1, wherein the packet processing unit performs a process of changing contents of a part other than the header part of the packet according to contents of the header part.   An optical node device that is a component of an optical network, wherein an optical header extraction means for extracting only a header portion of a packet by an optical signal transmitted through the optical network, and a header portion extracted by the optical header extraction means Header processing means for performing processing, and packet combining means for combining a portion other than the header portion of the packet and a header portion processed by the header processing means to output a new packet based on an optical signal. An optical node device.   4. The optical node device according to claim 3, wherein the header processing unit performs processing for adding information indicating that processing is necessary for a portion other than the header portion of the packet to the header portion.

Images