JP2001237891A - Packet transfer unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packet transfer unit where a transfer processing delay and a transfer processing load can be reduced in the case of transferring a packet whose header is compressed so as to transfer the packet whose header is compressed at high-speed. SOLUTION: The packet transfer unit is provided with a CRTP transfer table that includes relative data between a flow identifier CID in a header compression system CRTP and an output link, and input interface section that receives a packet transferred from an external packet transfer unit and transmits it to a packet transfer processing section, a packet transfer processing section that receives a packet sent from the input interface, reads a CID from its header, retrieves the CRTP transfer table to specify the output link and transmits the packet to an output interface section, and an output interface section to transfer the packet received from the packet transfer processing section to the external packet transfer unit via the output link.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet transfer device capable of realizing high-speed transfer when transferring a packet with a compressed header.

[0002]

2. Description of the Related Art A packet transfer apparatus for transferring a packet whose header has been compressed by a header compression method CRTP defined in REC2508 of IETF includes an input interface unit, a header restoration unit, an IP path control unit, a header compression unit, It consists of an output interface.

[0003] The input interface unit receives a packet transferred from an external packet transfer device and transmits the packet to the header restoration unit. The header restoration unit restores the header of the packet received from the input interface unit, and transmits the packet with the restored header to the IP path control unit. The IP route control unit has an IP forwarding table composed of correspondence data between the IP and the output link, extracts header information from the packet received from the header restoring unit, and outputs the header information by referring to the IP forwarding table from the header information. The link is determined, and the packet is transmitted to the header compression unit. The header compression unit compresses the header of the packet received from the IP route control unit, and transmits the header-compressed packet to the output interface unit. The output interface unit transfers the packet received from the header compression unit from the output link to an external packet transfer device.

Conventionally, in a device for transferring a packet with a compressed header, as described above, when performing the IP routing, the compressed header is restored to the IP packet form, and then the IP routing is performed. And then re-compress the header again before performing the transfer process. However, this method has a problem that processing load and processing delay for header restoration and recompression at the time of packet transfer are large.

Further, in an apparatus for transferring a packet in which a header is compressed and converted into a cell, conventionally, the packet is assembled and then subjected to IP transfer processing, and the packet is divided into cells and transmitted. In this method, the IP transfer process cannot be performed until all cells constituting the packet have arrived, and there is a problem that a packet assembling delay is large. There is also a problem that a processing load and a processing delay for the packet assembling process and the packet disassembling process occur.

Further, in an apparatus for encapsulating a packet in which a header is compressed and formed into a cell into a connectionless transfer protocol and transferring the packet, conventionally, the packet is assembled and then (de) encapsulated to perform (de) encapsulation. The transmitted packet was decomposed into cells and then transmitted. In this method, the (de) encapsulation process cannot be performed until all cells constituting the packet have arrived, and there is a problem that a packet assembling delay is large. There is also a problem that a processing load and a processing delay for the packet assembling process and the packet disassembling process occur.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the transfer processing delay and transfer processing load when transferring a packet with a compressed header, and to transfer the packet with a compressed header at a high speed. It is an object of the present invention to provide a packet transfer device capable of performing the above.

[0008]

According to the present invention, there is provided a packet transfer apparatus comprising:
A CRTP transfer table including data corresponding to a flow identifier CID and an output link in RTP, an input interface unit for receiving a packet transferred from an external packet transfer device and transmitting the packet to a packet transfer processing unit, and a transmission from the input interface unit A packet transfer processing unit for reading a CID from a header of the received packet, searching the CRTP transfer table to specify an output link, and transmitting the packet to an output interface unit; and a packet transfer processing unit. And an output interface unit for transferring a packet received from the device from the output link to an external packet transfer device.

According to such a packet transfer apparatus of the present invention, when transferring a packet whose header is compressed, the correspondence data between the CID and the output link is determined from the information of the flow identifier CID in the compressed header. Including CR
By specifying the output link with reference to the TP transfer table, it is possible to transfer the packet without restoring the compressed header. Therefore, header restoration and recompression processing can be omitted, and processing delay and processing load can be reduced.

Further, in the case where an IP transfer table including correspondence data between the destination IP address and the output link is provided,
When performing the transfer processing of the head packet of the flow, the C is referred to by referring to the IP transfer table from the header information of the head packet.
By generating an entry in the RTP transfer table, it is possible to dynamically set the correspondence data between the CID and the output link for each flow for each flow, so that it is not necessary to set the entry for each flow.

Further, the apparatus of the present invention for dividing a header-compressed packet into cells of a fixed length and transferring the divided cells has a destination IP using a connection identifier VPI and / or VCI.
I including the correspondence data between the address and the output VPI / VCI
P transfer table, CRTP transfer table including correspondence data between flow identifier CID and output VPI / VCI in header compression method CRTP, cell exchange table including correspondence data between input VPI / VCI and output VPI / VCI, external packet transfer An input interface unit for receiving a cellized packet transferred from the device and transmitting it to the cell transfer processing unit, a cell transmitted from the input interface unit, an IP transfer table, a CRTP
By setting and / or referring to the transfer table and the cell exchange table, the output VPI / VCI of the cell is specified, and the cell transfer processing unit for transmitting the cell to the output interface unit, and from the cell transfer processing unit An output interface unit for receiving the transmitted cell and transferring the received cell to an external packet transfer device is provided.

According to such a packet transfer apparatus of the present invention, an IP transfer table, a CRTP transfer table, and a cell exchange table are provided, and each table can be linked. In particular, when the head packet head cell, head packet succeeding cell, succeeding packet head cell, and succeeding packet succeeding cell are identified, individual transfer processing can be performed for each of them.

That is, by generating entries of the CRTP transfer table and the cell exchange table by referring to the IP transfer table from the header information of the first cell of the first packet, the CRTP path control of the subsequent packet and the cell exchange of each cell of the first packet are performed. Processing becomes possible. Also, by generating an entry of the cell exchange table by referring to the CRTP transfer table from the header information of the head cell of the subsequent packet, the cell exchange processing of each cell of the subsequent packet becomes possible.

For this reason, the header decompression and recompression processing are omitted, and the dynamic CRTP path control for each flow and the transfer processing for each cell can be performed. As a result, the processing delay and processing load for header restoration and recompression processing can be reduced, furthermore, the packet assembling and disassembling processing can be omitted, and the packet assembling delay can be reduced. Processing delay and processing load can be reduced.

The packet transfer apparatus for transferring a packet from a user network to a packet transfer network according to the present invention comprises: an IP transfer table including correspondence data between a destination IP address and a destination packet transfer apparatus; a flow identifier CID and a destination packet. CRTP transfer table including correspondence data with transfer device, connectionless transfer protocol transfer table including correspondence data between destination packet transfer device and output VPI / VCI, input VPI / VCI
Exchange table containing correspondence data between the network and the output VPI / VCI, a user network input interface unit for receiving a cellized packet transferred from the user network and transmitting it to the encapsulation transfer processing unit, a user network input interface Receiving the cellized packet transmitted from the unit, and setting and / or referring to the IP transfer table, the CRTP transfer table, the connectionless transfer protocol transfer table and the cell exchange table, to the connectionless transfer protocol of the packet. For specifying the output VPI / VCI of the cell into which the packet has been divided, and transmitting the packetized connectionless transfer protocol packet to the packet transfer network output interface unit. And a packet transfer network output interface unit for receiving the packetized connectionless transfer protocol packet transmitted from the encapsulated transfer processing unit and transferring the packet to the packet relay device. And

According to such a packet transfer device of the present invention, each of the tables can be associated with an IP transfer table, a connectionless transfer protocol transfer table, a CRTP transfer table, and a cell exchange table. In particular, when the head packet head cell, head packet succeeding cell, succeeding packet head cell, and succeeding packet succeeding cell are identified, individual transfer processing can be performed for each of them.

That is, the destination packet transfer device is specified by referring to the IP transfer table and the connectionless transfer protocol transfer table from the header information of the first packet first cell, and the entries of the CRTP transfer table and the cell exchange table are generated. A header including the header of the connectionless transfer protocol is created, and the header cell is added before the head cell to encapsulate the head packet in the connectionless transfer protocol, thereby controlling the CRTP route control and encapsulation of the subsequent packet. The cell exchange processing of each cell of the first packet is enabled.

Further, the destination packet transfer apparatus is specified by referring to the CRTP transfer table and the connectionless transfer protocol transfer table from the header information of the head cell of the succeeding packet, and an entry of the cell exchange table is generated.
Based on that, a cell containing the header of the connectionless transport protocol is created, and the header cell is added before the head cell to encapsulate the subsequent packet into the connectionless transport protocol, thereby each cell of the encapsulated subsequent packet. Cell exchange processing.

For this reason, the header decompression and recompression processing are omitted, and the dynamic CRTP path control and the encapsulated transfer processing for each flow can be performed for each cell. This makes it possible to reduce processing delay and processing load for header restoration and recompression processing when performing encapsulated transfer,
Furthermore, the packet assembling delay can be reduced, and the processing delay and processing load of packet assembling and disassembly can be reduced.

The packet transfer apparatus for transferring a packet from a packet transfer network to a user network according to the present invention comprises a destination IP address, an output VPI /
IP transfer table including data corresponding to VCI, CRTP transfer table including data corresponding to flow identifier CID and output VPI / VCI, input VPI / VCI and output V
A cell exchange table containing data corresponding to PI / VCI,
A packet transfer network input interface unit for receiving a cellized connectionless transfer protocol packet transferred from the packet relay device and transmitting the packet to the decapsulation transfer processing unit, and a cell transfer transmitted from the packet transfer network input interface unit Received the connectionless transfer protocol packet,
The packet is decapsulated, and an IP transfer table,
By setting and / or referring to the CRTP transfer table and the cell exchange table, the output VPI / VCI of the cell obtained by dividing the decapsulated packet is specified, and the cellized packet is transmitted to the user network output interface unit. And a user network output interface unit for receiving the cellized packet transmitted from the decapsulation transfer processing unit and transferring the packetized packet to a user network.

According to such a packet transfer device of the present invention, the IP transfer table, the CRTP transfer table, and the cell exchange table can be provided, and the respective tables can be linked. In particular, when the head packet head cell, head packet succeeding cell, succeeding packet head cell, and succeeding packet succeeding cell are identified, individual transfer processing can be performed for each of them.

That is, by generating an entry of the CRTP transfer table and the cell exchange table by referring to the IP transfer table from the header information of the first packet first cell, the CRTP path control of the subsequent packet and the cell exchange of each cell of the first packet are performed. Enable processing. Further, an entry of the cell exchange table is generated by referring to the CRTP transfer table from the header information of the head cell of the succeeding packet,
Thereby, the cell exchange processing of each cell of the subsequent packet is enabled.

For this reason, header decompression and recompression processing are omitted, and dynamic CRTP path control and decapsulation transfer processing for each flow can be performed for each cell. This makes it possible to reduce the processing delay and processing load for header decompression and recompression processing when performing decapsulation transfer, further reduce packet assembly delay, and reduce packet assembly and decomposition processing delay and processing. Processing load can be reduced.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a packet transfer apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a packet transfer network to which the packet transfer device of the present invention is applied. Packet transfer network 1
Are the packet transfer devices 31 to 36 and the packet relay device 41,
It is assumed that 42 is connected by a link. The packet transfer devices 31 to 36 are connected to the user networks 11 to 19, 21 to
These accommodate user networks 11-19, 21
To 29 are encapsulated in a connectionless transfer protocol and transferred. The packet relay devices 41 and 42 perform transfer using a connectionless transfer protocol.

FIG. 2 is a diagram showing a configuration example of the packet transfer device of the present invention. The packet transfer device 31 includes an IP transfer table (for encapsulation) 111, a CRTP transfer table (for encapsulation) 112, a connectionless transfer protocol transfer table 113, and a cell exchange table (for encapsulation) 11.
4, user network input interface unit 115,
An encapsulation transfer processing unit 116, a packet transfer network output interface unit 117, an IP transfer table (for decapsulation) 121, a CRTP transfer table (for decapsulation) 122, a cell exchange table (for decapsulation) 123,
Packet transfer network input interface unit 12
4. It has a decapsulation transfer processing unit 125 and a user network output interface unit 126.

IP transfer table (for encapsulation) 111
Contains the correspondence data between the destination IP address and the destination packet transfer device. CRTP transfer table (for encapsulation)
Reference numeral 112 includes correspondence data between the CID and the destination packet transfer device. Connectionless transfer protocol transfer table
Reference numeral 113 includes correspondence data between the destination packet transfer device and the output VPI / VCI. The cell exchange table (for encapsulation) 114 includes an input VPI / VCI and an output VPI / VCI.
And the corresponding data.

The user network input interface unit 115 receives the packetized cells from the user networks 11 to 13 and sends them to the encapsulation transfer processing unit 116. The encapsulation transfer processing unit 116 receives the cellized packet transmitted from the user network input interface unit 115, and stores an IP transfer table (for encapsulation) 111 and a CRTP transfer table (for encapsulation) 1
12, Connectionless transfer protocol transfer table 113
By setting and referring to the cell exchange table (for encapsulation) 114 as necessary, the packet is encapsulated into the connectionless transfer protocol and the output VPI / VCI of the cell into which the packet is divided is specified. ,
Networked output interface for packetized connectionless transfer protocol packets
Send to 117. The packet transfer network output interface unit 117 receives the packetized connectionless transfer protocol packet transmitted from the encapsulation transfer processing unit 116 and transfers the packet to the packet relay device 41.

IP transfer table (for decapsulation) 121
Contains the correspondence data between the destination IP address and the output VPI / VCI. CRTP transfer table (for decapsulation)
Reference numeral 122 includes correspondence data between the CID and the output VPI / VCI. The cell exchange table (for decapsulation) 123 includes correspondence data between input VPI / VCI and output VPI / VCI.

The packet transfer network input interface unit 124 receives the packetized connectionless transfer protocol packet from the packet relay device 41,
It is transmitted to the decapsulation transfer processing unit 125. The decapsulation transfer processing unit 125 receives the packetized connectionless transfer protocol packet transmitted from the packet transfer network input interface unit 124, decapsulates the packet, and performs an IP transfer table (for decapsulation) 121. By setting and referencing the CRTP transfer table (for decapsulation) 122 and the cell exchange table (for decapsulation) 123 as necessary, the output VPI / VCI of the cell obtained by dividing the decapsulated packet is specified. The packetized packet is transmitted to the user network output interface unit 126. The user network output interface unit 126 receives the cellized packet transmitted from the decapsulation transfer processing unit 125, and transfers the packet to the user networks 11 to 13.

FIG. 3 is a diagram showing a configuration example of the encapsulation transfer processing unit in the packet transfer device of the present invention. The encapsulation transfer processing unit 116 includes a cell identification unit 161, a head packet head cell encapsulation transfer processing unit 162, a head packet subsequent cell encapsulation transfer processing unit 163, a subsequent packet head cell encapsulation transfer processing unit 164, and a subsequent packet subsequent cell. An encapsulation transfer processing unit 165 is provided.

The cell identification unit 161 receives the cell transmitted from the user network input interface unit 115, and determines whether the cell is a cell of the first packet of the flow or a cell of a subsequent packet other than the first packet, A cell or a subsequent cell other than the head cell is identified. If the cell is the head cell of the head packet of the flow, the cell is transmitted to the head packet head cell encapsulation transfer processing unit 162, and the cell is the head packet of the flow. If the cell is the succeeding cell, the packet is transmitted to the head packet subsequent cell encapsulation transfer processing unit 163. If the cell is the head cell of the subsequent packet of the flow, the subsequent packet head cell encapsulation transfer processing unit 16 is transmitted.
4, and if the cell is a succeeding cell of the subsequent packet of the flow, the packet is transmitted to the subsequent packet subsequent cell encapsulation transfer processing unit 165.

The head packet head cell encapsulation transfer processing part 162 receives the head cell of the head packet transmitted from the cell identification part 161, performs the head packet head cell path control processing and the encapsulation processing, and outputs the cell. VPI / VC
I is specified, and the cell is transmitted to the packet transfer network output interface unit 117. The head packet succeeding cell encapsulation transfer processing unit 163 receives the succeeding cell of the head packet transmitted from the cell identification unit 161, performs a head packet subsequent cell route control process, and outputs the output VPI / V of the cell.
The CI is specified, and the cell is transmitted to the packet transfer network output interface unit 117. The subsequent packet head cell encapsulation transfer processing unit 164 receives the head cell of the subsequent packet transmitted from the cell identification unit 161, performs the subsequent packet head cell path control processing and the encapsulation processing, and outputs the VPI / VCI of the cell. And transmits the cell to the packet transfer network output interface unit 117. Subsequent packet subsequent cell encapsulation transfer processing unit 165
Receives the succeeding cell of the succeeding packet transmitted from the cell identification unit 161, performs the succeeding packet subsequent cell route control processing, specifies the output VPI / VCI of the cell, and converts the cell to the packet transfer network output interface unit 117. Send to

FIG. 4 is a diagram showing a configuration example of the head packet head cell encapsulation transfer processing unit according to the present invention. The head packet head cell encapsulation transfer processing unit 162 includes a header information extraction unit 1621, an IP route control unit 1622, and an encapsulation unit.
1623 and a cell exchange unit 1624.

The header information extracting section 1621 is provided with the cell identifying section 16
It receives the head cell of the head packet transmitted from 1 and extracts the header information of the cell, transmits the header information to the IP path control unit 1622, and transmits the cell to the encapsulation unit 1623. The IP route control unit 1622 includes the header information extraction unit 16
Receiving the header information transmitted from the header information 21 and referring to the IP transfer table (for encapsulation) 111 and the connectionless transfer protocol transfer table 113 from the header information, specifying the destination packet transfer apparatus and the CRTP transfer table ( Entries for the encapsulation 112 and the cell exchange table 114 are generated. The encapsulation unit 1623 creates a cell including a header of the connectionless transfer protocol based on the obtained destination packet transfer device information, and adds a header cell before the head cell received from the header information extraction unit 1621 to generate the cell. The packet including the head cell is encapsulated in the connectionless transfer protocol, and the cells are transmitted to the cell switching unit 1624. The cell switching unit 1624 specifies the output VPI / VCI of the cell by referring to the cell switching table (for encapsulation) 114 from the input VPI / VCI of the cell received from the encapsulation unit 1623, and transfers the cell to the packet transfer network. The output is transmitted to the output interface unit 117.

FIG. 5 is a diagram showing an example of the configuration of the head packet succeeding cell encapsulation transfer processing unit according to the present invention. The first packet subsequent cell encapsulation transfer processing unit 163 includes a cell switching unit 1631. The cell switching unit 1631 includes a cell identification unit 161.
Then, the output VPI / VCI of the cell is specified by referring to the cell exchange table (for encapsulation) 114 from the input VPI / VCI of the cell received from the server, and the cell is transmitted to the packet transfer network output interface unit 117.

FIG. 6 is a diagram showing a configuration example of a subsequent packet head cell encapsulation transfer processing unit according to the present invention. The subsequent packet head cell encapsulation transfer processing unit 164 includes a header information extraction unit 1641, a CRTP route control unit 1642, an encapsulation unit 1643, and a cell exchange unit 1644.

The header information extracting section 1641 is provided with the cell identifying section 16
Receives the first cell of the subsequent packet transmitted from 1 and extracts the header information of the cell, and replaces the header information with the CRT
The cell is transmitted to the P path control unit 1642, and the cell is encapsulated in the encapsulation unit 1643.
Send to The CRTP path control unit 1642 receives the header information transmitted from the header information extraction unit 1641, and uses the header information to generate a CRTP transfer table (for encapsulation).
112 and connectionless transfer protocol transfer table 1
Referring to FIG. 13, the destination packet transfer apparatus is specified, and an entry of the cell exchange table (for encapsulation) 114 is generated. The encapsulation unit 1643 creates a cell including a header of the connectionless transfer protocol based on the obtained destination packet transfer device information, and generates a header information extraction unit 1641.
, A header cell is added before the head cell received from, a packet including the head cell is encapsulated in the connectionless transfer protocol, and the cells are transmitted to the cell switching unit 1644. The cell switching unit 1644 refers to the cell exchange table (for encapsulation) 114 from the input VPI / VCI of the cell received from the encapsulation unit 1643 and outputs the VPI / VCI of the cell.
The VCI is specified, and the cell is transmitted to the packet transfer network output interface unit 117.

FIG. 7 is a diagram showing a configuration example of a subsequent packet subsequent cell encapsulation transfer processing unit according to the present invention. The subsequent packet subsequent cell encapsulation transfer processing unit 165 includes a cell switching unit 1651. The cell switching unit 1651 includes a cell identification unit 161.
Then, the output VPI / VCI of the cell is specified by referring to the cell exchange table (for encapsulation) 114 from the input VPI / VCI of the cell received from the server, and the cell is transmitted to the packet transfer network output interface unit 117.

FIG. 8 is a diagram showing a configuration example of a decapsulation transfer processing unit in the packet transfer device of the present invention. The decapsulation transfer processing unit 125 includes a cell identification unit 251, a head packet head cell decapsulation transfer processing unit 252, a head packet subsequent cell decapsulation transfer processing unit 253, a subsequent packet head cell decapsulation transfer processing unit 254, and a The packet subsequent cell decapsulation transfer processing unit 255 is provided.

The cell identification unit 251 receives the cell transmitted from the packet transfer network input interface unit 124, removes the header cell if the cell includes a connectionless transfer protocol header, and removes the header cell. If not, the cell is identified as a cell of the first packet of the flow or a cell of a succeeding packet other than the first packet, and further, whether the cell is the first cell of the packet or a subsequent cell other than the first cell. If it is the first cell of the packet, it is transmitted to the first packet first cell decapsulation transfer processing unit 252, and if this cell is the cell following the first packet of the flow, it is transmitted to the first packet subsequent cell decapsulation transfer processing unit 253. If the cell is the first cell of the subsequent packet of the flow, the subsequent packet first cell decapsulation transfer process is performed. Transmitted to part 254, if the cell is a subsequent cell of the subsequent packets of the flow is sent to the subsequent packets subsequent cell decapsulation transfer processing unit 255.

The head packet head cell decapsulation transfer processing unit 252 receives the head cell of the head packet transmitted from the cell identification unit 251, performs the head packet head cell path control process, and outputs the VPI / VCI of the cell. Is specified, and the cell is connected to the user network output interface unit 126.
Send to The head packet succeeding cell decapsulation transfer processing unit 253 receives the succeeding cell of the head packet transmitted from the cell identification unit 251 and performs the head packet subsequent cell route control processing to specify the output VPI / VCI of the cell. , The cell to the user network output interface 126
Send to The subsequent packet head cell decapsulation transfer processing unit 254 receives the head cell of the subsequent packet transmitted from the cell identification unit 251 and performs a subsequent packet head cell path control process to specify the output VPI / VCI of the cell. , The cell to the user network output interface 126
Send to Subsequent packet subsequent cell decapsulation transfer processing section 255 receives the subsequent cell of the subsequent packet transmitted from cell identification section 251 and performs subsequent packet subsequent cell path control processing to specify the output VPI / VCI of the cell. , The cell to the user network output interface 126
Send to

FIG. 9 is a diagram showing a configuration example of a head packet head cell decapsulation transfer processing unit according to the present invention. The head packet head cell decapsulation transfer processing unit 252 includes a header information extraction unit 2521, an IP route control unit 2522, and a cell exchange unit 2523.

The header information extraction unit 2521 is provided with a cell identification unit 25
The first cell of the first packet transmitted from 1 is received, the header information of the cell is extracted, the header information is transmitted to the IP path control unit 2522, and the cell is transmitted to the cell switching unit 2523. The IP route control unit 2522 includes a header information extraction unit 2521
From the header information, referring to the IP transfer table (for decapsulation) 121 from the header information, and entering the entries of the CRTP transfer table (for decapsulation) 122 and the cell exchange table (for decapsulation) 123. Generate. The cell switching unit 2523 includes a header information extraction unit
The output VPI / VCI of the cell is specified by referring to the cell exchange table (for decapsulation) 123 from the input VPI / VCI of the cell received from 2521, and the cell is transmitted to the user network output interface unit 126.

FIG. 10 is a diagram showing an example of the configuration of the head packet succeeding cell decapsulation transfer processing unit according to the present invention.
The first packet subsequent cell decapsulation transfer processing unit 253
A cell exchange unit 2531 is provided. The cell switching unit 2531 refers to the cell switching table (for decapsulation) 123 from the input VPI / VCI of the cell received from the cell identification unit 251 and specifies the output VPI / VCI of the cell, and connects the cell to the user network. The data is transmitted to the output interface unit 126.

FIG. 11 is a diagram showing a configuration example of a subsequent packet head cell decapsulation transfer processing unit according to the present invention.
The subsequent packet head cell decapsulation transfer processing unit 254
It comprises a header information extraction unit 2541, a CRTP route control unit 2542, and a cell exchange unit 2543.

The header information extraction unit 2541
Receives the first cell of the subsequent packet transmitted from 1 and extracts the header information of the cell, and replaces the header information with the CRT
The cell is transmitted to P path control section 2542, and the cell is transmitted to cell switching section 2543. The CRTP path control unit 2542 receives the header information transmitted from the header information extraction unit 2541, and uses the header information to generate a CRTP transfer table (for decapsulation).
Refer to 122, cell exchange table (for decapsulation) 1
Generate 23 entries. The cell switching unit 2543 receives the input VPI / V of the cell received from the header information extraction unit 2541.
The output VPI / VCI of the cell is specified by referring to the cell exchange table (for decapsulation) 123 from the CI, and the cell is transmitted to the user network output interface unit 126.

FIG. 12 is a diagram showing a configuration example of a subsequent packet subsequent cell decapsulation transfer processing unit according to the present invention.
The subsequent packet subsequent cell decapsulation transfer processing unit 255
The cell switching unit 2551 is provided. The cell switching unit 2551 specifies the output VPI / VCI of the cell by referring to the cell switching table (for decapsulation) 123 from the input VPI / VCI of the cell received from the cell identification unit 251 and identifies the cell as a user network. The data is transmitted to the output interface unit 126.

Next, the operation will be described based on the configuration example of the packet transfer apparatus of the present invention shown in FIGS.
In the following, the packet transfer device 31 (FIG. 1) will be described as an example.

It is assumed that the user network input interface unit 115 of the packet transfer apparatus 31 receives a packet flow whose header has been compressed from the user network 11. First, the user network input interface unit 115 receives the head cell of the head packet of the flow. The user network input interface unit 115 transmits the cell to the encapsulation transfer processing unit 116. The cell identification unit 161 of the encapsulation transfer processing unit 116 receives the cell transmitted from the user network input interface unit 115, identifies that the cell is the first cell of the first packet of the flow, and Packet head cell encapsulation transfer processing unit 16
Send to 2.

The header information extraction unit 1621 of the head packet head cell encapsulation transfer processing unit 162 receives the head packet head cell transmitted from the cell identification unit 161, extracts the header information of the cell, and extracts the header information. The packet is transmitted to the IP route control unit 1622, and the cell is transmitted to the encapsulation unit 1623. The IP route control unit 1622 receives the header information transmitted from the header information extraction unit 1621, refers to the IP transfer table (for encapsulation) 111 and the connectionless transfer protocol transfer table 113 from the header information, and The transfer device is specified, and the entries of the CRTP transfer table (for encapsulation) 112 and the cell exchange table (for encapsulation) 114 are performed.

The encapsulation unit 1623 creates a cell including a connectionless transfer protocol header based on the obtained destination packet transfer device information, and
A header cell is added before the head cell received from 21 to encapsulate a packet including the head cell in a connectionless transfer protocol, and those cells are encapsulated in a cell switching unit 1624.
Send to The cell switching unit 1624 refers to the cell switching table (for encapsulation) 114 from the input VPI / VCI of the cell received from the encapsulation unit 1623 and outputs the VPI of the cell.
/ VCI is specified, and the cell is transmitted to the packet transfer network output interface unit 117. The packet transfer network output interface section 117 receives the packetized connectionless transfer protocol packet transmitted from the cell exchange section 1624 of the head packet head cell encapsulation transfer processing section 162 of the encapsulation transfer processing section 116, The data is transferred to the relay device 41 (FIG. 1).

Next, the user network input interface unit 115 receives the succeeding cell of the head packet of the flow. The user network input interface unit 115 transmits the cell to the encapsulation transfer processing unit 116. Cell identification section 161 of encapsulation transfer processing section 116
Is the user network input interface 11
The cell transmitted from step 5 is received, the cell is identified as a cell subsequent to the head packet of the flow, and the cell is transmitted to the head packet subsequent cell encapsulation transfer processing unit 163. First packet subsequent cell encapsulation transfer processing unit 163
Of the cell received from the cell identification unit 161, specifies the output VPI / VCI of the cell by referring to the cell exchange table (for encapsulation) 114 from the input VPI / VCI of the cell, and transfers the cell to the packet. It is transmitted to the network output interface unit 117. The packet transfer network output interface unit 117 includes the encapsulation transfer processing unit 1
It receives the packetized connectionless transfer protocol packet transmitted from the cell switching unit 1631 of the 16 first packet subsequent cell encapsulation transfer processing unit 163 and transfers it to the packet relay device 41 (FIG. 1). The same applies hereinafter.

[0053]

As described above, according to the packet transfer apparatus of the present invention, when a packet with a compressed header is transferred, the packet can be transferred without restoring the header. When a packet is transferred as a cell, the packet can be transferred to the cell-by-cell without assembling the cell-packeted packet. Further, when the header is compressed and the cell-packet is encapsulated and transferred, the packet is assembled. (De) encapsulation and transfer can be performed in a cell-by-cell without the need. As a result, a packet with a compressed header can be transferred at a high speed. Furthermore, short packets having a large header to payload ratio (eg, Voice over
When transferring (IP packets) and the like, it is possible to improve the band use efficiency and at the same time realize high-speed transfer, thereby making it possible to increase the bandwidth of the packet transfer network. As a result, the cost performance of the packet transfer network is improved, and reduction in user cost can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a packet transfer network to which a packet transfer device of the present invention is applied.

FIG. 2 is a diagram illustrating a configuration example of a packet transfer device of the present invention.

FIG. 3 is a diagram illustrating a configuration example of an encapsulated transfer processing unit in the packet transfer device of the present invention.

FIG. 4 is a diagram showing a configuration example of a head packet head cell encapsulation transfer processing unit according to the present invention.

FIG. 5 is a diagram illustrating a configuration example of a head packet subsequent cell encapsulation transfer processing unit according to the present invention.

FIG. 6 is a diagram illustrating a configuration example of a subsequent packet head cell encapsulation transfer processing unit according to the present invention.

FIG. 7 is a diagram illustrating a configuration example of a subsequent packet subsequent cell encapsulation transfer processing unit according to the present invention.

FIG. 8 is a diagram illustrating a configuration example of a decapsulation transfer processing unit in the packet transfer device of the present invention.

FIG. 9 is a diagram showing a configuration example of a head packet head cell decapsulation transfer processing unit according to the present invention.

FIG. 10 is a diagram showing a configuration example of a head packet succeeding cell decapsulation transfer processing unit according to the present invention.

FIG. 11 is a diagram illustrating a configuration example of a subsequent packet head cell decapsulation transfer processing unit according to the present invention.

FIG. 12 is a diagram illustrating a configuration example of a subsequent packet subsequent cell decapsulation transfer processing unit according to the present invention.

[Explanation of symbols]

Reference Signs List 1 packet transfer network 31-36 packet transfer device 41, 42 packet relay device 11-19, 21-29 user network 111 IP transfer table (for encapsulation) 112 CRTP transfer table (for encapsulation) 113 connectionless transfer protocol transfer table 114 Cell exchange table (for encapsulation) 115 User network input interface unit 116 Encapsulation transfer processing unit 117 Packet transfer network output interface unit 121 IP transfer table (for decapsulation) 122 CRTP transfer table (for decapsulation) 123 Cell exchange table (For decapsulation) 124 Packet transfer network input interface unit 125 Decapsulation transfer processing unit 126 User network output Interface section 161, 251 Cell identification section 162 First packet first cell encapsulation transfer processing section 163 First packet subsequent cell encapsulation transfer processing section 164 Subsequent packet first cell encapsulation transfer processing section 165 Subsequent packet subsequent cell encapsulation transfer processing section 252 First Packet head cell decapsulation transfer processing unit 253 Head packet subsequent cell decapsulation transfer processing unit 254 Subsequent packet head cell decapsulation transfer processing unit 255 Subsequent packet subsequent cell decapsulation transfer processing unit 1621, 1641, 2521, 2541 Header Information extraction units 1622, 2522 IP route control units 1623, 1643 Encapsulation units 1624, 1631, 1644, 1651, 2523,
2531, 2543, 2551 Cell switching unit 1642, 2542 CRTP route control unit

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyuki Hara 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term (reference) in Nippon Telegraph and Telephone Corporation 5K030 GA02 HA08 HA10 HB14 HB29 HD07 JA05 KA05 5K033 AA02 CC01 DA05 DB18

Claims (20)

[Claims] 1. An apparatus for transferring a packet whose header is compressed by a header compression method CRTP specified in REC2508 of IETF, comprising: a flow identifier CID in the header compression method CRTP.
A CRTP transfer table containing data corresponding to the data and the output link, an input interface for receiving a packet transferred from an external packet transfer device and transmitting it to the packet transfer processing unit, and receiving a packet transmitted from the input interface And read the CID from the header,
A packet transfer processing unit for searching a transfer table to specify an output link and transmitting the packet to an output interface unit, and transferring a packet received from the packet transfer processing unit from the output link to an external packet transfer device A packet transfer device comprising an output interface unit for performing the operation. 2. The apparatus further comprises an IP transfer table including correspondence data between a destination IP address and an output link, wherein the packet transfer processing unit receives a packet transmitted from the input interface unit, and transmits the packet to the REC 2508. Identify whether the packet is the first packet or the next packet of the flow of the specified header compression method CRTP, and if the packet is the first packet of the flow, send it to the first packet transfer processing unit, and the packet is the next packet of the flow In the case, the packet identification unit to be transmitted to the subsequent packet transfer processing unit, the first packet transmitted from the packet identification unit is received,
A leading packet transfer processing unit for specifying an output link by referring to the IP transfer table from the header information of the packet, generating an entry of the CRTP transfer table, and transmitting the packet to the output interface unit, and a packet identification unit Receive subsequent packets sent from
2. The packet according to claim 1, further comprising a subsequent packet transfer processing unit for specifying an output link by referring to a CRTP transfer table from header information of the packet and transmitting the packet to an output interface unit. Transfer device. 3. An apparatus for dividing a packet, whose header has been compressed by a header compression method CRTP defined in IETF REC2508, into fixed-length cells and transferring the divided cells, comprising: an ITU-T Recommendation I.T. An IP transfer table including correspondence data between a destination IP address using the connection identifier VPI and / or VCI defined in 150 and output VPI / VCI, a flow identifier CID in the header compression method CRTP
CRTP transfer table containing correspondence data between input and output VPI / VCI, cell exchange table containing correspondence data between input VPI / VCI and output VPI / VCI, receive cellized packets transferred from external packet transfer device The input interface unit for transmitting to the cell transfer processing unit; receiving the cell transmitted from the input interface unit;
A cell transfer processing unit for specifying an output VPI / VCI of the cell by setting and / or referring to the IP transfer table, the CRTP transfer table, and the cell exchange table, and transmitting the cell to the output interface unit; A packet transfer device comprising an output interface unit for receiving cells transmitted from a cell transfer processing unit and transferring the cells to an external packet transfer device. 4. The cell transfer processing unit receives a cell transmitted from an input interface unit,
Identify whether the cell is the cell of the first packet of the flow or the cell of the succeeding packet, and whether the cell is the first cell of the packet or the following cell. If the cell is the first cell of the first packet of the flow, the first cell of the first packet Send to the transfer processing unit, if the cell is the succeeding cell of the head packet of the flow, send to the head packet succeeding cell transfer processing unit, if the cell is the head cell of the subsequent packet of the flow, the head cell of the subsequent packet A cell identification unit for transmitting to the transfer processing unit, and when the cell is a succeeding cell of a subsequent packet of the flow, a cell identification unit for transmitting to the subsequent cell subsequent cell transfer processing unit; and a leading cell of the first packet transmitted from the cell identification unit. Receiving, performing the head packet head cell path control processing to specify the output VPI / VCI of the cell, and transmitting the cell to the output interface unit The first packet first cell transfer processing unit receives the subsequent cell of the first packet transmitted from the cell identification unit, performs the first packet subsequent cell route control process, specifies the output VPI / VCI of the cell, and outputs the cell. A head packet subsequent cell transfer processing unit for transmission to the interface unit, receives a head cell of a subsequent packet transmitted from the cell identification unit, performs a subsequent packet head cell route control process, and specifies an output VPI / VCI of the cell. Then, a subsequent packet head cell transfer processing unit for transmitting the cell to the output interface unit, and a subsequent cell of the subsequent packet transmitted from the cell identification unit are received, and a subsequent packet subsequent cell path control process is performed to perform the following process. Subsequent packet subsequent cell transfer processing for specifying the output VPI / VCI of the cell and transmitting the cell to the output interface unit The packet transfer apparatus according to claim 3, characterized in that it comprises a part. 5. The head packet head cell transfer processing unit receives a head packet head cell transmitted from a cell identification unit, extracts header information of the cell, and transmits the header information to an IP path control unit. , A header information extracting unit for transmitting the cell to the cell switching unit, receiving the header information transmitted from the header information extracting unit,
An IP route control unit for generating entries of the RTP transfer table and the cell exchange table; and a cell input VPI / V received from the header information extraction unit
From CI, referring to the cell exchange table, output V of the cell
5. The packet transfer device according to claim 4, further comprising a cell switching unit for specifying a PI / VCI and transmitting the cell to an output interface unit. 6. The head packet succeeding cell transfer processing unit refers to a cell exchange table from an input VPI / VCI of a cell received from a cell identification unit and outputs a VPI / VCI of the cell.
The packet transfer device according to claim 4, further comprising a cell switching unit for specifying a VCI and transmitting the cell to an output interface unit. 7. The subsequent packet head cell transfer processing unit receives the subsequent packet head cell transmitted from the cell identification unit, extracts header information of the cell, and transmits the header information to a CRTP path control unit. A header information extracting unit for transmitting the cell to the cell switching unit, receiving the header information transmitted from the header information extracting unit, and generating a cell exchange table entry by referring to the CRTP transfer table from the header information. CR for
Input VPI / V of cell received from TP path control unit and header information extraction unit
From CI, referring to the cell exchange table, output V of the cell
5. The packet transfer device according to claim 4, further comprising a cell switching unit for specifying a PI / VCI and transmitting the cell to an output interface unit. 8. The subsequent packet transfer processing unit of the subsequent packet refers to a cell exchange table from an input VPI / VCI of the cell received from the cell identification unit and outputs a VPI / VCI of the cell.
The packet transfer device according to claim 4, further comprising a cell switching unit for specifying a VCI and transmitting the cell to an output interface unit. 9. A connectionless transfer protocol for accommodating a user network, specifying a path of a packet whose header is compressed and cellized by a header compression system CRTP and transferred from the user network by an IP path control function, A packet transfer device that performs transfer by encapsulating the packet into a packet, and a packet relay device that performs transfer using the connectionless transfer protocol.
An apparatus for transferring packets from a user network to a packet transfer network in a packet transfer network connected like a network by a communication link, comprising: an IP transfer table including correspondence data between a destination IP address and a destination packet transfer apparatus; CRTP transfer table including correspondence data between identifier CID and destination packet transfer device; connectionless transfer protocol transfer table including correspondence data between destination packet transfer device and output VPI / VCI; and input VPI / VCI and output VPI / VCI. A cell exchange table containing corresponding data, a user network input interface section for receiving a cellized packet transferred from the user network and transmitting it to the encapsulation transfer processing section, Receives the packet cell assembling sent from over the face portion, IP forwarding table, CRTP forwarding table, set the connectionless transport protocol forwarding table and cell exchange table and /
Alternatively, by referring to the packet, the packet is encapsulated in the connectionless transfer protocol and the output VPI / VCI of the cell obtained by dividing the packet is specified, and the packetized connectionless transfer protocol packet is output to the packet transfer network output interface. And a packet transfer network output interface for receiving the packetized connectionless transfer protocol packet transmitted from the encapsulated transfer processing unit and transferring the packet to the packet relay device. A packet transfer device comprising: 10. The encapsulated transfer processing unit receives a cell transmitted from a user network input interface unit, and determines whether the cell is a cell of a leading packet or a subsequent packet of a flow, and a leading cell of the packet. Or the subsequent cell, and if the cell is the first cell of the first packet of the flow, transmit to the first packet first cell encapsulation transfer processing unit.If the cell is the next cell of the first packet of the flow, The first packet is transmitted to the subsequent cell encapsulation transfer processing unit. If the cell is the first cell of the subsequent packet of the flow, the subsequent packet is transmitted to the first cell encapsulation transfer processing unit, and the cell is the subsequent cell of the subsequent packet of the flow. If it is, the subsequent packet is transmitted from the cell identification unit for transmission to the subsequent cell encapsulation transfer processing unit. The head packet of the head packet is received, the head packet head cell path control and the encapsulation process are performed to specify the output VPI / VCI of the cell, and the head packet head for transmitting the cell to the packet transfer network output interface unit. A cell encapsulation / transfer processing unit that receives a succeeding cell of the head packet transmitted from the cell identification unit, performs a head packet subsequent cell route control process, specifies an output VPI / VCI of the cell, and transfers the cell to a packet transfer network. A first packet for subsequent transmission to the output interface unit, a subsequent cell encapsulation transfer processing unit, which receives the first cell of the subsequent packet transmitted from the cell identification unit, performs subsequent packet first cell path control and encapsulation processing, and performs Identify the output VPI / VCI and transfer the cell to the packet transfer network output Receiving the subsequent cell of the subsequent packet sent from the cell identification unit, and performing the subsequent packet subsequent cell route control processing to output the cell. The packet transfer apparatus according to claim 9, further comprising a subsequent packet subsequent cell encapsulation transfer processing unit for specifying a VPI / VCI and transmitting the cell to the packet transfer network output interface unit. 11. The head packet head cell encapsulation transfer processing unit receives a head packet head cell transmitted from a cell identification unit, extracts header information of the cell, and sends the header information to an IP path control unit. A header information extracting unit for transmitting the cell to the encapsulating unit, receiving the header information transmitted from the header information extracting unit, and referring to the IP transfer table and the connectionless transfer protocol transfer table from the header information. An IP route control unit for identifying a destination packet transfer device and generating entries of a CRTP transfer table and a cell exchange table; and a cell including a connectionless transfer protocol header based on the obtained destination packet transfer device information. Create and add a header cell before the first cell received from the header information extraction unit. By encapsulating the packet including the head cell into the connectionless transfer protocol, transmitting the cells to the cell switching unit, and the input VPI / VCI of the cell received from the encapsulation unit. , Referring to the cell exchange table, the output VPI /
The packet transfer device according to claim 10, further comprising a cell switching unit for specifying a VCI and transmitting the cell to a packet transfer network output interface unit. 12. The head packet succeeding cell encapsulation transfer processing unit refers to a cell exchange table from an input VPI / VCI of a cell received from a cell identification unit and outputs an output VPI / VCI of the cell.
The packet transfer device according to claim 10, further comprising a cell switching unit for specifying a VCI and transmitting the cell to a packet transfer network output interface unit. 13. The subsequent packet head cell encapsulation transfer processing unit receives the subsequent packet head cell transmitted from the cell identification unit, extracts the header information of the cell, and sends the header information to the CRTP path control unit. A header information extracting unit for transmitting the cell to the encapsulating unit, receiving the header information transmitted from the header information extracting unit, and referring to the CRTP transfer table and the connectionless transfer protocol transfer table from the header information. hand,
A CRTP route control unit for specifying a destination packet transfer device and generating an entry in the cell exchange table, creating a cell including a connectionless transfer protocol header based on the obtained destination packet transfer device information, and extracting the header information By adding a header cell before the head cell received from the unit, a packet including the head cell is encapsulated in the connectionless transfer protocol, and an encapsulation unit for transmitting those cells to the cell switching unit, and From the input VPI / VCI of the cell received from the encapsulation unit, the output VPI / VCI /
The packet transfer device according to claim 10, further comprising a cell switching unit for specifying a VCI and transmitting the cell to a packet transfer network output interface unit. 14. The subsequent packet encapsulation / transfer processing unit refers to a cell exchange table from an input VPI / VCI of a cell received from a cell identification unit and outputs a VPI / VCI of the cell.
The packet transfer device according to claim 10, further comprising a cell switching unit for specifying a VCI and transmitting the cell to a packet transfer network output interface unit. 15. A connectionless transfer protocol for accommodating a user network, specifying a path of a packet in which a header is compressed by a header compression method CRTP and converted into a cell and transferred from the user network by an IP path control function. A packet transfer network that connects a packet transfer device that performs transfer by encapsulating the packet in a network and a packet relay device that performs transfer using the connectionless transfer protocol from a packet transfer network to a user network through a communication link. An apparatus for transferring a packet, an IP transfer table containing correspondence data between a destination IP address and an output VPI / VCI, a CRTP transfer table containing correspondence data between a flow identifier CID and an output VPI / VCI, an input VP A cell exchange table including correspondence data between the I / VCI and the output VPI / VCI, a packet for receiving a packetized connectionless transfer protocol packet transferred from the packet relay device and transmitting the packet to the decapsulation transfer processing unit A transfer network input interface unit, receives a packetized connectionless transfer protocol packet transmitted from the packet transfer network input interface unit, decapsulates the packet, and converts an IP transfer table, a CRTP transfer table, and a cell exchange table. By setting and / or referencing, the output VPI of the cell obtained by dividing the decapsulated packet
/ VCI, and a decapsulation transfer processing unit for transmitting the cellized packet to the user network output interface unit; and receiving the cellized packet transmitted from the decapsulation transfer processing unit, A packet transfer device comprising a user network output interface unit for transferring to a network. 16. The decapsulation transfer processing unit receives a cell transmitted from a packet transfer network input interface unit, and removes the header cell if the cell is a header cell including a connectionless transfer protocol header. , If not a header cell,
Identify whether the cell is the cell of the head packet or the succeeding packet of the flow, and whether the cell is the head cell or the succeeding cell of the packet. Transmit to the encapsulation transfer processing unit, if the cell is the succeeding cell of the head packet of the flow, transmit the head packet to the subsequent cell decapsulation transfer processing unit, and if the cell is the head cell of the subsequent packet of the flow Is transmitted to the subsequent packet head cell decapsulation transfer processing unit, and if the cell is a subsequent cell of the subsequent packet of the flow, a cell identification unit for transmission to the subsequent packet subsequent cell decapsulation transfer processing unit; Receiving the first cell of the first packet transmitted from the section, performs the first packet first cell path control process, specifies the output VPI / VCI of the cell, A head packet head cell decapsulation transfer processing unit for transmitting the cell to the user network output interface unit, receiving a succeeding cell of the head packet transmitted from the cell identification unit, and performing a head packet subsequent cell route control process. A head packet for specifying the output VPI / VCI of the cell, a head packet for transmitting the cell to the user network output interface unit, a subsequent cell decapsulation transfer processing unit, and a head cell of a subsequent packet transmitted from the cell identification unit is received. , A subsequent packet head cell decapsulation transfer processing unit for specifying the output VPI / VCI of the cell by performing a subsequent packet head cell path control process, and transmitting the cell to the user network output interface unit; Receive the subsequent cell of the subsequent packet transmitted from the A subsequent packet subsequent cell decapsulation transfer processing unit for performing a subsequent cell path control process to specify an output VPI / VCI of the cell and transmitting the cell to a user network output interface unit. The packet transfer device according to claim 15, wherein: 17. The head packet head cell decapsulation transfer processing unit receives a head packet head cell transmitted from a cell identification unit, extracts header information of the cell, and converts the header information to an IP route control unit. The header information extracting unit for transmitting the cell to the cell switching unit, receiving the header information transmitted from the header information extracting unit, and referring to the IP transfer table from the header information,
An IP route control unit for generating entries of the CRTP transfer table and the cell exchange table, and an input VPI / V of the cell received from the header information extraction unit
From CI, referring to the cell exchange table, output V of the cell
17. The packet transfer device according to claim 16, further comprising a cell switching unit for specifying a PI / VCI and transmitting the cell to a user network output interface unit. 18. The head packet succeeding cell decapsulation transfer processing unit refers to a cell exchange table from an input VPI / VCI of a cell received from a cell identification unit and outputs a VPI / VCI of the cell.
17. The packet transfer device according to claim 16, further comprising a cell switching unit for specifying a VCI and transmitting the cell to a user network output interface unit. 19. The subsequent packet head cell decapsulation transfer processing unit receives the subsequent packet head cell transmitted from the cell identification unit, extracts header information of the cell, and converts the header information into a CRTP path control unit. The header information extracting unit for transmitting the cell to the cell switching unit, receiving the header information transmitted from the header information extracting unit, referring to the CRTP transfer table from the header information, and C to create entry
Input VPI / V of cell received from RTP path control unit and header information extraction unit
From CI, referring to the cell exchange table, output V of the cell
17. The packet transfer device according to claim 16, further comprising a cell switching unit for specifying a PI / VCI and transmitting the cell to a user network output interface unit. 20. The succeeding packet subsequent cell decapsulation transfer processing unit refers to a cell exchange table from an input VPI / VCI of a cell received from a cell identification unit and outputs the VPI / VCI of the cell.
17. The packet transfer device according to claim 16, further comprising a cell switching unit for specifying a VCI and transmitting the cell to a user network output interface unit.