JP2003163702A - Network repeater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To process a tunnel communication in a network repeater at high speed. <P>SOLUTION: In a routing processing part 320 of a network repeater 3, when a tunnel processing part 3203 receives a request of capsule processing or decapsule processing from a packet transfer processing part 3201, an offset value and a segment length contained in a descriptor generated by the packet transfer processing part 3201 are changed. In the case of capsule processing, created header data are stored in a new segment and a descriptor corresponding thereto is generated and linked to an existent descriptor. When the tunnel processing part 3203 finishes processing, a processing end is reported to the packet transfer processing part 3201. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network relay device, and more particularly to a function for efficiently executing tunnel communication by encapsulation, which is used in communication between various networks having different communication protocols in data communication. The present invention relates to a provided network relay device.

[0002]

2. Description of the Related Art In data communication on a network, generally, there is a unit called a packet in which original transmission data is prefixed with data including information of a destination defined by various communication protocols as header data. used.

Further, in data communication, there are cases where communication is performed across a plurality of networks having different systems such as information such as communication protocols and destination addresses due to network configuration and operational convenience. For example, there are cases in which communication is realized between private networks arranged at distant positions, cases in which the communication protocol in the relay path is different from the communication protocol of the host for transmission / reception, and cases in which transmission packets are encrypted. The communication method used in such a case is generally called tunnel communication.

To realize tunnel communication, a technique called encapsulation is used. Encapsulation is to treat a whole packet including header data as one new transmission data when passing between different networks such as communication protocols, and construct a different packet by adding header data to this packet. Is. That is, when it is desired to tunnel a network having a different communication protocol or the like, the original packet may be encapsulated with the header data matched with the communication protocol or the like of the tunnel target network. At the point of exit from the tunnel target network, the header data added at the time of encapsulation is removed and the packet before encapsulation is restored and transferred to the destination. The former process of newly adding header data at the entrance of the tunnel target network is called encapsulation process, and the latter process of removing header data at the tunnel exit and restoring the packet before entering the tunnel is called decapsulation process.

Generally, a network relay device such as a router or a bridge is used to connect a plurality of networks in a network system. These network relay devices check the destination address based on the header data included in the packet received from the connected network to determine the transfer destination of the packet, and determine the transfer destination network relay device or the network to which the host is connected. Forward the packet. Further, when it is necessary to perform the tunnel communication as described above, it has a function of performing encapsulation processing and decapsulation processing. As a method for realizing a network relay device, Japanese Patent Laid-Open No. 5-19
There are methods described in Japanese Patent No. 9230 and Japanese Patent Laid-Open No. 2001-211203.

[0006]

In recent years, the diversity has increased from the computer systems that have been fixedly operated by companies and research institutes up to now to personal computers in companies and homes, as well as personal portable terminals. In order to accommodate many systems, networks are also becoming more diverse by applying technologies that are specialized to the functions and features of each system. From this background, the tunnel communication function is becoming an essential function for network relay devices.

On the other hand, as the performance of the system connected to the network is improved and the absolute number is increased, the traffic flowing through various networks continues to increase, and the processing performance is required to be improved also in the tunnel communication processing.

However, according to the above-described conventional network relay processing device, the header data and the data to be transmitted are distinguished from the packet received for the relay processing, and necessary information such as the destination address is extracted from the header data. Although it is possible to perform processing, there is a problem that it is difficult to realize a tunnel communication function because so-called encapsulation processing and decapsulation processing that add or delete header data cannot be performed. In the case of a network relay processing device composed of software, there is also a method of realizing tunnel communication by adding the functions of capsule processing and decapsulation processing by changing the software, but the relay processing is performed by hardware. It is undeniable that there is a difference in processing performance compared to network relay processing devices, and it is difficult to improve performance.

In view of the above points, the present invention adopts a data structure and a device configuration which have a tunnel communication function and can effectively perform the encapsulation process and the decapsulation process, thereby increasing diversity and traffic. Another object of the present invention is to provide a network relay device capable of flexibly and rapidly processing an ever-increasing number of network connections.

[0010]

According to the present invention, an operation of adding new data to a mechanism for holding an input packet of a network relay device or conversely deleting data of a specific range from an existing packet is performed. It has functions that can be executed efficiently. Moreover, in order to enable such operation,
It has a descriptor and a packet buffer as a mechanism for holding the input packet. The descriptor has a fixed length and holds information for managing the contents held by the packet buffer. On the other hand, the packet buffer holds the received packet, and as a method thereof, divides the content of the received packet into fixed-length areas called one or a plurality of segments and stores them. This is because the packet buffer has a feature of being easily controlled by hardware. The size of the fixed length can be arbitrarily determined at the time of designing in accordance with the hardware configuration, for example, matching the burst size of the memory that supports burst transfer.

Here, the descriptor has a one-to-one correspondence with the segment. As shown in FIG. 1, the contents held by the descriptor are an identifier for identifying the position of the segment with respect to the packet, a segment pointer indicating the position of the segment in the entire packet buffer, an offset indicating the start of effective data within the segment, and an inside of the segment. A segment length indicating the size of the effective data in, a packet is composed of a plurality of segments, and a link pointer indicating the position of the next descriptor when the descriptor is composed of descriptors. Regarding the link pointer,
This is good information in the case of the method of holding the descriptor in the storage mechanism, and the link pointer is not always necessary in the case of the method of simply managing the descriptor by a queue or the like. As long as the correspondence between descriptors and segments is clear, in addition to being automatically generated according to the input packet, it may also be generated by external control and is deleted when the packet is output. Alternatively, it may be deleted by external control.

Further, according to the present invention, in addition to the basic configuration of the network relay device such as the line corresponding unit, the packet switching unit, the packet transfer and route searching unit, the tunnel communication processing function unit for performing the packet encapsulation process and the decapsulation process. Is provided in the network relay device.

Specifically, the tunnel communication processing function unit is
In the case of encapsulation, the header information of the tunnel target network is registered in a new segment, and a descriptor corresponding to it is generated. Next, the generated new segment and descriptor are linked so as to be positioned at the beginning of the segment holding the input packet and the descriptor group corresponding to the segment. Generation of an encapsulated packet is realized by the above operation.

In the case of decapsulation processing, the offset value and segment value in the descriptor corresponding to the segment in which the header data exists is changed by the amount of the header data to be excluded from the input packet, and the header data is apparently obtained. Pretend to have been deleted.
If the header data to be deleted spans a segment, the unnecessary segment is deleted by deleting the header data, and the corresponding descriptor is deleted, and the segment following it is made to correspond to the first segment. Change the descriptor identifier, offset and segment length. The packet encapsulated by the above operation is taken out.

When it is determined that the device itself is at the entrance or exit of the tunnel in the network as a result of the route search, the tunnel communication processing function unit
Upon receiving the determination processing start notification from the path processing unit, when the corresponding capsule processing or decapsulation processing is completed, the fact is notified to the path processing unit. The route search section has this notification,
Next, the route is searched again for the tunnel target network. At this time, if it is determined again that it is at the entrance or exit of another network tunnel, the above procedure is repeated. That is, even if the tunnels are multiplexed, the encapsulation process or the decapsulation process can be performed by repeating the above-described simple operation. This feature also makes it possible to simplify the device configuration by hardware and contributes to the speeding up of processing.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a conceptual diagram of the entire network system to which the network relay device of the present invention is applied. In FIG. 2, a network relay device 3 and a network relay device 7 that transfer a packet according to information described in a header of the packet are connected to a network 5 and a network 9 that comply with the same protocol, respectively. Further, the network relay device 3 and the network relay device 7 are connected to the network 1.
Here, the network 1 follows a protocol different from those of the networks 5 and 9. A server device 6 is connected to the network 5, and a client device 10 is connected to the network 9.

Network 5 and network relay device 3
Since the packet 4 transmitted between the network 8 and the network 8 and the network relay device 7 follow the same protocol, the information such as the destination address may be different. The format will be the same. However, since the network 1 follows a protocol different from that of the networks 5 and 9, the network relay device 3 and the network relay device 7 cannot send the packet having the same format as the packet 4 or the packet 8 to the network 1. Therefore, as shown as packet 2 in FIG. 2, the header data according to the protocol followed by the network 1 is added to the packet 4 transmitted from the network 5 to the network relay device 3, for example, to use the packet. The relay device 3 and the network relay device 7 communicate with each other via the network 1. This is called tunnel communication.

Here, the case where the server device 6 transmits a packet to the client device 10 will be described.

The server device 6 transmits the packet 4 having the header 202 containing the address of the client device 10 as the destination address to the network 5. The packet relay device 3 receives the packet 4 from the network 5. Since the network relay device 3 relays the packet 4 to the network relay device 7 via the network 1, the packet 2 is generated from the packet 4. That is, the header data 203 having a format according to the protocol followed by the network 1 is added to the packet 4. This process performed by the network relay device 3 is a capsule process. On the other hand, the network relay device 7 extracts the packet 8 from the packet 2. That is, the header data 203, which is unnecessary when communicating via the network 9, is deleted from the packet 2. This process performed by the network relay device 7 is a decapsulation process. Then, the extracted packet 8 is sent to the client device 10 via the network 9.

FIG. 3 shows a block diagram of the overall configuration of the network relay device 3 that performs tunnel processing. In FIG. 3, the network relay device 3 includes a route exchange unit 31 and route search processing units 320 and 321.

The route search processing units 320 and 321 input / output packets to / from the line interfaces 300 and 301, and search the packet transfer destination from the header information of the packets to transfer the packets. Route exchange unit 31
Is connected to the route search processing units 320 and 321 and transfers packets between the route search processing units. As the types of the line interfaces 300 and 301 connected to the route search processing units 320 and 321, a LAN (Local Area Network) such as Ethernet (registered trademark),
WAN (Wide Area Network), AT
M (Asynchronous Transfer Mo
de) etc.

FIG. 4 shows a detailed block diagram of the route search processing unit 320.

In FIG. 4, the packet transfer processing unit 320
1 generates a descriptor from a packet arriving at the line interface interface 3205 or the route switching interface 3204, issues a transfer destination search request to the route search unit 3202, and determines the transfer destination based on the result. The route search processing unit 3202 searches for a packet transfer destination based on the information and request from the packet transfer processing unit 3201. The tunnel processing unit 3203 adds or removes header data when tunnel processing such as encapsulation processing or decapsulation processing is required. The route exchange unit interface 3204 controls an interface with the route exchange unit. The line interface unit 3205 controls an interface with the line interface. The packet buffer 3207 holds the packet. The packet buffer control unit 3206 controls the packet buffer 3207. The descriptor buffer 3209 holds the descriptor. The descriptor buffer control unit 3208 controls the descriptor buffer 3209.

When the packet arrives at the line interface interface 3205 or the route exchange interface 3204, the packet is transferred to the packet transfer processor 3201. The packet transfer processing unit 3201 generates a descriptor from the packet, and the descriptor buffer control unit 3
A write request is issued to the packet 208, and a write request is issued to the packet buffer control unit 3206 for the packet body, and each is held. Then, a transfer destination search request is issued to the route search unit 3202. Upon receiving the search request, the route search unit 3202 searches the packet transfer destination from the packet header data, and the result is searched by the packet transfer processing unit 3202.
Respond by returning to 201. When the result of the search by the route search unit 3202 is a normal packet relay, the packet transfer processing unit 3201 is replied that the packet should be transferred to the line interface unit 3205 or the route switching unit interface 3204 according to the content thereof. . On the other hand, as a result of the search, when it is determined that the device is the entrance or the exit of the tunnel, the packet transfer information indicating that the encapsulation process or the decapsulation process is necessary is transmitted to the tunnel processing unit 3203. It responds to the processing unit 3201. Packet transfer processing unit 3201
Transfers the packet based on the response from the route search unit 3202. When transferring the packet to the tunnel processing unit 3203, the tunnel processing unit 3203 issues a tunnel communication processing request while holding the descriptor and the packet. .

The tunnel processing unit 3203 changes the descriptor generated by the packet transfer processing unit 3201 according to an instruction of the encapsulation process or the decapsulation process,
In some cases, a new descriptor and header data are additionally generated and combined with the original descriptor or packet. When the processing by the tunnel processing unit 3203 is completed, a response of processing completion is returned to the packet transfer processing unit 3201.

Performing the encapsulation process or the decapsulation process means that the header data is replaced, and from the viewpoint of the route process, it means that the packet is different from the packet before the process.
Therefore, in the packet transfer processing unit 3201, the reception of the processing end response from the tunnel processing unit 3203 is treated with the same meaning as the packet arrival notification from the line interface 3205 or the route switching unit interface 3204. However, since the descriptor and the packet of the packet already exist, the descriptor generation and holding and the packet holding request are not performed, and the transfer destination search request is issued again to the route search unit 3202. Then, the packet transfer process is performed again based on the result.

With the above operation, tunnel communication becomes possible. Even when performing tunnel communication in which tunnels are multiplexed, according to the network relay device of the present embodiment, as described above, the packet transfer processing unit 3201 issues a search processing request to the route search unit 3202, and By simply repeating the tunnel processing request from the packet transfer processing unit 3201 to the tunnel processing unit 3203, the processing required for tunnel communication can be realized without requiring any other complicated procedure.

FIG. 5 specifically shows the data structure of the descriptor and the relationship with the segment. Segment 51
The descriptor 501 corresponding to 1 is an identifier 5011 indicating the attribute of the corresponding segment 511, a segment pointer 5012 indicating the position of the segment in the packet buffer memory, and an offset indicating the start position of the effective data (packet) stored in the segment. 5013, a segment length 5014 indicating the length of effective data (packet) stored in the segment, and a position in the descriptor buffer of the descriptor 502 following the descriptor 501 when one packet is composed of a plurality of descriptors and segments It includes a link pointer 5015.

FIG. 6 shows a list of segment types represented by the identifier 5011. The first and last segments indicated by the identifier “1” are, for example, the segment 7 shown in FIG.
A segment in the case where the entire packet including the header data is contained in a single segment like 02 is shown. The beginning and continuous segment indicated by the identifier "0" means
For example, like the segment 811 shown in FIG. 8, when a packet does not fit in a single segment, the first segment of the segment group in which the packet is stored is shown. The non-leading and final segment indicated by the identifier “3” is, for example, the segment 8 shown in FIG.
13 shows the last segment of the segment group in which the packet is stored when the packet does not fit in a single segment. The non-leading and continuous segment indicated by the identifier “2” is a segment in which the packet is stored when the packet does not fit in a single segment, for example, the segment 812 shown in FIG. The middle segment of the group is shown.

A method of managing packets using the descriptor will be described below.

FIG. 7 shows a state in which a normal packet that is not tunnel-communicated and whose total size is smaller than the total size of one segment is stored in the segment and the structure of the descriptor corresponding to the segment. Show.

The segment 702 stores the entire packet composed of header data and data body. In this case, the packet transfer processing unit 3201 uses, as the descriptor 701, an identifier 7011 of “1” indicating the first and last segment, a segment pointer 7012 of the value of the first address where the segment 702 is located, and an offset of 7.
A descriptor in which 013 is the value “0” and the segment length 7014 is the octet length of the packet is generated. In this case, the value of the link pointer 7015 is ignored.

Further, FIG. 8 shows a state in which a normal packet that is not tunnel-communicated and whose packet size is larger than the size of two segments is stored in the segment group, and the structure of the descriptor corresponding to each segment. Indicates.

In FIG. 8, segments 811, 81
Packets are divided and stored in 2, 813. In the segment 811, the head portion of the packet, that is, the header data and the head portion of the data body are stored. The segment 812 stores the intermediate portion of the packet, that is, the intermediate portion of the data body. Further, the segment 813 stores the rest of the packet, that is, the rest of the data body. In this case, the packet transfer processing unit 3201 generates the descriptor 801 corresponding to the segment 811, the descriptor 802 corresponding to the segment 812, and the descriptor 803 corresponding to the segment 813, respectively. The descriptor 801 includes “0” as the identifier 8011 indicating the beginning and continuation segment existence, the start address value of the segment 811 as the segment pointer 8012, the value “0” as the offset 8013, the size of the entire segment 811 as the segment length 8014, and the link. Pointer 80
15 includes the start address value of the descriptor 802 following the descriptor 801. The descriptor 802 has “2” indicating a non-leading and continuing segment as an identifier 8021, a leading address value where the segment 812 is present as a segment pointer 8022, a value “0” as an offset 8023, and a segment length 8024.
As the total size of the segment 812, and as the link pointer 8025, the start address value of the descriptor 803 following the descriptor 802 is included. The descriptor 803 has a segment pointer 8032, which is “3” indicating a non-leading and final segment as an identifier 8031.
Is the start address value of the segment 813, the offset 8033 is the value "0", and the segment length 803
4 includes the size of the portion of the packet stored in the segment 813. In the case of the descriptor 803, nothing is done about the link pointer 8035, and this information is ignored in the transfer process.

As described above, the packet transfer processing unit 3201
One packet is managed by the descriptors 801 to 803 generated by.

In the case of normal packet relay, the packet transfer processing unit 3201 manages the packet using the descriptor and segment data generated as described above, and transfers the packet to the route switching unit interface 3204 and the line interface unit 3205. Perform processing. But,
When encapsulation processing and decapsulation processing are required for tunnel communication, the tunnel processing unit 3203 needs to add or change the combination of these descriptors and segments as follows.

FIG. 9 shows the tunnel processing unit 32 when the tunnel processing unit 3203 executes capsule processing.
03 shows a structure of new header data added by 03 and a descriptor corresponding thereto.

As shown in FIG. 7, a descriptor 901 is generated by the packet transfer processing unit 3201 for a packet arriving at the packet transfer processing unit 3201.
The packet is held in the segment 911.
Here, when the tunnel processing unit 3203 receives the encapsulation processing request, a new segment 912 is secured in the packet buffer 3207 and new header data for tunnel communication is created. Also, the descriptor 902 corresponding to the segment 912 is generated. Descriptor 902
Is “0” indicating the beginning and continuation segment existence as the identifier 9021, the start address value indicating the location of the segment 912 as the segment pointer 9022, and the offset 9
023 includes the value “0”, the segment length 9024 includes the data length of the new header data, and the link pointer 9025 includes the address value of the descriptor 901. Then, the tunnel processing unit 3203 checks the descriptor 9 stored in the descriptor buffer 3209.
The identifier 9011 of 01 is rewritten from “1” indicating the first and last segment to “3” indicating the non-first and last segment. The capsule processing unit 3203 performs the above processing to create a packet subjected to the capsule processing, and the tunnel processing unit 3203 notifies the packet transfer processing unit 3201 of the processing end.

The example shown in FIG. 9 assumes the case where the packet size before encapsulation is less than or equal to the size of one segment, but also when the packet size is larger than the size of one segment as shown in FIG. The tunnel processing unit 3203 only performs the same operation as described with reference to FIG. 9 for the first segment of the segment group storing the packet and the descriptor corresponding thereto. The identifier of the tunnel processing unit 3203 is “0”.
Recognize a descriptor that is "1" or "1" as a descriptor to be changed, and add it to the intermediate segment and the last segment whose identifier is "2" or "3",
Do not make any changes.

FIG. 10 shows how the descriptor is changed by the tunnel processing unit 3203 when the decapsulation process is executed by the tunnel processing unit 3203.

First, the descriptor 1001 is generated for the capsule-processed packet arriving at the packet transfer processing unit 3201, and the packet is segment 1
It is held at 011.

In this state, the tunnel processing section 320
3 receives the decapsulation processing request, the tunnel processing unit 3203 causes the offset 100 of the descriptor 1001 stored in the descriptor buffer 3209 to be 100.
13 is changed to a value obtained by adding the size of the header data to be removed to the value held so far. Further, the value of the segment length 10014 is changed to a value obtained by subtracting the value of the header data size to be removed from the value held so far. The descriptor 1001 is changed to the descriptor 1002 by the tunnel processing unit 3203 performing such a changing process. Descriptor 1002
At offset 10023 is segment 1011
Indicates the start position of the original header data of the encapsulated packet stored in
Reference numeral 24 indicates the length of the packet (before being encapsulated) in which the header data added by the encapsulation is removed from the encapsulated packets stored in the segment 1011. Therefore, as shown in FIG. 10, the packet managed by the modified descriptor 1002 is not the entire encapsulated packet stored in the segment 1011 but is apparently shown as the segment 1012, It becomes a packet (before being encapsulated) excluding the header data added by encapsulation.

As a result, the decapsulation processing by the tunnel processing unit 3203 is completed.

When the decapsulation process continues due to the process for the multiple tunnel communication, the header data before the decapsulation process straddles the segment, and the original header data desired to be obtained after the decapsulation process is not the first segment,
It may be present in the intermediate segment that follows.

FIG. 11 shows the structure of the segment and descriptor in such a case.

A segment 1111 at the beginning stores a part of the header data added by the encapsulation process, and a segment 1112 stores the remaining portion of the header data added by the encapsulation process and the original packet (original packet). Header data and data body) are stored.

In this state, the tunnel processing section 320
When 3 receives the decapsulation processing request, the values of the offset 11013 and the segment length 11014 of the descriptor 1101 corresponding to the first segment 1111 are changed, as described above.

At this time, the segment length 1101 of the descriptor 1101 corresponding to the first segment 1111
When the calculated value when changing the value of 4 becomes a negative value, or when the calculated value when changing the offset 11013 becomes equal to or larger than the size of the entire segment 1111, the tunnel processing unit 3203 may have the above-described case. Detect that it has occurred. Therefore, the tunnel processing unit 3203 deletes the segment 1111 and the descriptor 1101 corresponding to it, which are the head before the decapsulation process. Then, the tunnel processing unit 3203 uses the descriptor 110.
If the identifier 11021 of the descriptor 1102 subsequent to 1 is “2” indicating a non-leading and continuous segment, that identifier is set to “0” indicating the leading and continuing segment, and “3” indicating a non-leading and final segment. If it is "," it is changed to "1" indicating the first and last segment. Further, the value of the offset 11023 is changed to a value obtained by subtracting the size of the entire segment 1112 from the value calculated when the offset 11013 is changed, and the value of the segment length 11024 is changed from the original value to the offset 110.
Change to the value obtained by subtracting the value of 23. Tunnel processing unit 320
By performing the above processing by the packet No. 3, the decapsulated packet is created, and the tunnel processing unit 3203 notifies the packet transfer processing unit 3201 of the processing end.

The example shown in FIG. 10 assumes a case where the size of the packet to be decapsulated is less than or equal to the size of one segment. However, as shown in FIG. 8, the packet size before decapsulation is the size of one segment. Even in the case of a larger value, the tunnel processing unit 3203 only performs the same operation as described with reference to FIG. 10 on the first segment of the segment group storing the packet and the descriptor corresponding thereto.

[0051]

According to the present invention, the processing for tunnel communication in the network relay device can be realized at high speed and efficiently by hardware.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure of descriptors and segments.

FIG. 2 is a conceptual diagram of an entire network system to which a network relay device is applied.

FIG. 3 is a block diagram showing the configuration of a network relay device.

FIG. 4 is a detailed block diagram of a route search processing unit of the network relay device.

FIG. 5 is a diagram showing the structure of descriptors and segments.

FIG. 6 is a diagram showing a segment type represented by an identifier.

FIG. 7 is a diagram showing the configuration of descriptors and segments when the packet size is one segment size or less.

FIG. 8 is a diagram showing a configuration of descriptors and segments when the packet size is one segment size or more.

FIG. 9 is a diagram showing the configuration of descriptors and segments when capsule processing is executed.

FIG. 10 is a diagram showing the configuration of descriptors and segments when decapsulation processing is executed.

FIG. 11 is a diagram showing a configuration of a descriptor and a segment when header data to be removed by the decapsulation process straddles the segment.

[Explanation of symbols]

1, 5, 9 ... Network 2, 4, 8 ... Packet 3, 7 ... Network relay device 6 ... Server device 10 ... Client device 31 ... Route exchange unit 320, 321 ... Route search processing unit 3201 ... Packet transfer processing unit 3201 3202 ... Route search unit 3203 ... Tunnel processing unit 3204 ... Route exchange interface 3205 ... Line interface interface 3206 ... Packet buffer control unit 3207 ... Packet buffer 3208 ... Descriptor buffer control unit 3209 ... Descriptor buffer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yohei Kondo             Stock at 456 Sakai, Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture             Ceremony Hitachi Information Technology             -In F-term (reference) 5K030 GA02 GA03 HA08 HD03 KA05                       LB15 LE09

Claims (5)

[Claims] 1. A network relay device for determining a relay destination of a received packet according to header information of a packet received from any network and relaying the received packet to any network, the interface being connected to the network. And a packet buffer for holding the packet received by the interface in an area of a predetermined size, a packet transfer processing unit for generating management information of an area for holding the received packet in the packet buffer, and transfer of the received packet A network relay characterized by having a route search unit for determining a destination according to header information and instructing the transfer destination to the packet transfer processing unit, and a tunnel processing unit for executing encapsulation processing or decapsulation processing for a received packet. apparatus. 2. The network relay device according to claim 1, further comprising a management information buffer holding the management information. 3. The network device according to claim 1, wherein the encapsulation process or the decapsulation process executed by the tunnel processing unit includes a process of changing the content of the management information. 4. The network device according to claim 3, wherein the capsule processing executed by the tunnel processing unit is:
The network relay device further includes a process of creating new header data and holding it in another region of the packet buffer, and a process of generating management information of the holding region of the new header data. 5. The network device according to claim 3, wherein the decapsulation process executed by the tunnel processing unit further includes one management information out of two or more management information generated by the packet transfer processing unit. A network relay device including a process of deleting.