JPH04286439A - Communication processing unit - Google Patents

Abstract

PURPOSE:To attain miniaturization/high reliability of an interconnection device by eliminating the need for collection of relay cells and recomposition of them into a PDU in the case of interconnecting plural fixed length packet (cell) networks via a fixed length packet network (interconnection network) whose exchange protocol differs from that of the plural networks. CONSTITUTION:Invalid information is inserted between a service data unit (SDU) and protocol control information (PCI) to make the length of protocol control information (PCI) transferred prior to the SDU to be an integral number of multiple of a cell information length. A PCI cell generating section 2-6 generates a cell including only the PCI of the connection network and a cell selection transmission section 2-9 transfers the generated cell prior to the relay of the reception cell.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a communication processing device in a communication network using fixed-length packets.
The present invention relates to a processing method and processing device suitable for interconnection between networks having mutually different protocol control information (PCI) formats.

0002

[Prior Art] Conventionally, as an example of a first conventional communication network using fixed-length packets, ATM
:Asynchronous Transfer Mo
de) DQDQ (DQ) which transmits and receives cells.
DB: Distributed Queue Dual
The communication processing method and PDU format are based on the Draft of Propose IEE Standard DQDB Subnetwork of Metropolitan Area Network (Draft of Propose Bus).
d IEEE Standard DQDBSubnet
work of a metropolitan ar
ea Network P802.6/D13 Jnu
e 22, 1990).

[0003] As an example of a second conventional communication network, ATM
The communication processing method and PDU format of MBLAN, which is a ring-type backbone that transmits and receives cells, is
Computer Society (IEEE Compu
ter Society)'s Fifteenth Conference on Local Computer Networks (15th.Conference onL
ocal Computer Networks), pp. 399-403 of the proceedings.

0004

SUMMARY OF THE INVENTION The first conventional communication network was devised with one of its main purposes being to divide LAN frames into ATM cells and transfer them. That is, L.A.
N's LLC (Logical Link Control
) message as an SDU, and add a 24-byte PC to this
After adding I, the cell information is divided into 44 bytes of cell information. Each communication processing device within the communication network performs transmission and reception within the network using the PCI and a header added before the cell information.

On the other hand, the second conventional communication network also has the function of dividing LAN frames into ATM cells and transferring them, but in this network, the LAN MAC (Media Access
A method is adopted in which a 4-byte PCI is assigned to a sControl) frame as an SDU and then divided into 44-byte cell information. Each communication processing device within the communication network performs transmission and reception within the network using a header added before cell information.

[0006] Here, in a system that interconnects a first conventional communication network and a second conventional communication network, when cells are relayed from the second conventional communication network to the first conventional communication network, the communication processing device The interconnection processing device, which is one of the two, collects the cell information of the second conventional communication network, reassembles the MAC frame, extracts the LLC message, adds a 24-byte PCI to it, and then re-assembles the 44-byte MAC frame. There is a method of dividing into cell information. Also, on the reassembled MAC frame, 2
It is also possible to divide the information into 44-byte cell information again after assigning 4-byte PCI.

[0007] Normally, the first conventional communication network is often used as a relatively wide-area network covering the entire city, and the second conventional communication network is often used as a limited network spread within the same campus. , a configuration in which a plurality of second conventional networks are interconnected via a first conventional communication network can be considered as a general interconnection system. in this case,
In the second conventional communication network to be interconnected, M
Since cells obtained by dividing the AC frame are used, the above-described method of adding PCI to the MAC frame is a good idea considering the amount of processing.

[0008] Generally, in a fixed-length packet network, multiple PDs
Since cells generated from U arrive at the same time, PD
Reassembling U requires a huge amount of memory. The PCI of the first conventional communication network can be expanded to 44 bytes, which is equal to the cell information length, but without expansion, the PCI length is less than 44 bytes. In this case, due to the difference in PCI length between the two, there was a problem in that when reattaching the PCI, a means for reassembling it into a PDU was required.

[0009]

[Means for Solving the Problems] The above conventional problem is that by inserting invalid information between the PCI and SDU of the first conventional communication network, the PCI length is made to be apparently equal to the cell information length (generally is an integer multiple), and in the communication processing device that performs interconnection, when relaying cells from the second conventional communication network to the first conventional communication network, the PCI of the first conventional communication network is one (or more) whose cell information contains only
Solved by sending PCI cells.

0010

[Operation] In the first conventional communication network, even if invalid information is inserted between the PCI and the SDU, the valid information of the PCI can be recognized by the area in the PCI indicating the number of extended bytes of the PCI. Furthermore, each communication processing device in the first conventional communication network is
Since transmission and reception within the network is performed using the header added before the CI and cell information, there is no problem even if invalidation information is inserted following the PCI.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a network system to which the present invention is applied, in which ring LANs 12, 13, and 14 are connected via ring LAN nodes 5, 6, ring LAN nodes 7, and ring LAN nodes 8, 9, respectively. F
DDI (Fiber Distributed Da
lower LAN 22, such as
23, 25, or LAN terminals 21, 24 having an FDDI interface. On the other hand, ring LANs 12, 13, and 14 are connected to wide area network nodes 2 and 3.
, 4 as accelerator points via a wide area network (connection network) 1.

FIG. 2 shows an example of a wide area network constructed using three DQDBs 1-1, 1-2, and 1-3, and FIG. 3 shows the frame structure of each part. The MAC frame 31 is
This is the communication frame structure of N terminals 21, 24, 26, 27, and 28. In other words, it is a frame structure that is communicated within the lower LANs 22, 23, and 24, and includes a 6-byte destination address (DA) 31-1 and a 6-byte source address (SA).
31-2 and another portion 31-3 having a maximum length of approximately 4.5K bytes. The frame 32 is transmitted to the lower LAN or LAN at the ring LAN nodes 5, 6, 7, 8, and 9.
This structure is used when directly accommodating a terminal, and the MAC frame 31 is used as an SDU 32-2, and a 4-byte P
A LAN frame header (LH) 32-1, which is a CI, is attached. In the ring LAN nodes 5, 6, 7, 8, and 9, the LAN frame 32 is converted into 44-byte cell information 34-1.
A cell 34 is generated by adding cell control information (CH) 34-2 and a cell trailer 34-3. The last cell 35 may include an invalid area 35-1.

[0013] The wide area network connection nodes 2, 3, and 4 receive the cell, and determine whether the cell is to be relayed to the wide area network 1 based on the address information included in each cell control information (CH). In the case of relaying, the IMPDU 33-1 is configured in the form of a PDU 33 in which an IMPDU 33-1, which is a PCI in a wide area network that can be expanded to a maximum of 44 bytes, and a trailer (TRL) 33-3 are added to the frame 32. The PCI cell 36 held in the cell information area is transmitted before the cell to be relayed. Note that when IMPDU 33-1 is less than 44 bytes, invalid information 36-1 is inserted so that it is an integral multiple of 44 bytes (44 bytes in this embodiment). In other words, when viewed from the wide area network, SDU33-2 and PCI33-1
This means that the invalid information 36-1 is inserted between the two.

The inter-DQDB connecting devices 1-12 and 1-23 relay cells based on the received information on the PCI cell 36 and cell control information on each cell.

FIG. 4 shows a block diagram of a wide area network connection node which is the center of the present invention. Ring LAN access control unit (
LACC) 2-1 is a ring LAN node 5, 6, 7,
This block is common to 8 and 9, and has an optical transmission/reception function, a serial/parallel conversion function, a cell transmission right control function, a cell transmission/reception function, etc.

In the LACC 2-1, the access control field (ACF) 51, destination address (DA)/source address (SA) 52, and header check information (HC
S) Process the cell header 50 consisting of 53. The details of each are described in the second reference cited above, so they will be omitted here.

LAN cell reception interface (LRIF)
) 2-2 is a block that recognizes the format of the cells 34 and 35 on the data in the signal line bundle 30 received from the ring LAN based on the result of an internal counter that counts according to the leading information of the cells in the signal line bundle 30; In response to this, LAN
Cell transmission interface (LTIF) 2-3 is ring L
This is a block that sends cells to the AN.

The cell format handled by DQDB includes the cell length shown in FIG. 5, a cell header 50, and an adaptation (AD).
P) The lengths of the header 55, cell information 34-1, and cell trailer 34-3 are the same, but the DA/SA
The area 52 is designated as VCI (Virtual Channel
The main difference is that it is used as an Identifier area. For DA and SA, each ring L
While a node address uniquely assigned to the AN node is set, the VCI has the cell information content L
A value indicating that the data is connectionless data such as AN data is assigned. Therefore, conversion of this area is required for interconnection between the ring LAN and the DQDB. This conversion is
Preset conversion information table (VACT) 2-
Using the conversion information in 5, from the ring LAN to the DQDB
In the case of relaying to, the VCI converter (VCIC) 2-4 performs the relay, and in the reverse case, the address converter (ADDC) 2-11 performs the relay.

[0019] The received cells from the ring LAN are FIFO
Once stored in the cell buffer (CBFF) 2-8 having a memory structure, the PCI cell generator (PCIG) 2
-6, the first cell is extracted from the information in the adaptation header 55, and the MAC addresses 31-1, 32-2 given by the terminal in the cell information and the PCI table (PCIT
) Generate a PCI cell from 2-7.

[0020] The cell selection transmitter (CSLT) 2-9 has P
After transmitting the CI cells, the cells in the CBFF 2-8 are sequentially transferred to the DQDB access control unit (DACC) 2-12. At this time, a cell containing the beginning of the PDU included in the adaptation header 55 (first cell), a cell containing the middle of the PDU (intermediate cell), a cell containing the end of the PDU (last cell), and a cell containing the entire PDU ( single cell)
Change the cell location information that indicates the cell location. That is, the first cell is changed to the middle cell, and the single cell is changed to the last cell. The PCI cell deletion unit (PCID) 2-10 deletes the first cell, which is a PCI cell, from the cells received from the DQDB, and changes the cell location information.

An embodiment of an interconnection device for a connection network and a communication network has been described above. However, the present device is also effective in the case where the connecting network directly accommodates the terminal, ie, in the interconnection between peer communication networks.

[0022]

As is clear from the above description, according to the present invention, in interconnection between communication networks in which PDUs having different PCI formats, which are one of the constituent elements, are divided into fixed lengths and transferred, When changing the PCI to the relay destination communication network format, the fixed length division positions do not change, so reassembly can be made unnecessary. Furthermore, information that depends on the connection network protocol is separated at the cell level (PCI
cell), interface section and conversion table (PCIT)
You can easily realize an interconnection device with any network by simply replacing the .

[Brief explanation of the drawing]

FIG. 1 is an example of an overall configuration diagram of a network system to which the present invention is applied.

FIG. 2 shows a specific example of a network system to which the present invention is applied.

FIG. 3 is a frame structure diagram of each part in FIG. 2;

FIG. 4 is a block diagram of a wide area connection node showing an embodiment of the present invention.

FIG. 5 is a diagram of the cell format within the ring LAN of this embodiment.

[Explanation of symbols]

2... Wide area connection node, 2-1... Ring LAN access control unit, 2-2... LAN cell reception interface, 2-3
...LAN cell transmission interface, 2-4...VCI converter, 2-5...conversion information table, 2-6...PCI cell generator, 2-7...PCI table, 2-8...cell buffer, 2-9 ...Cell selection transmission section, 2-10...PCI cell deletion section, 2-11...Address translation section, 2-12...DQDB access control section, 36...PCI cell, 36-1...Invalidity information.

Claims (5)

[Claims] [Claim 1] Protocol control information (hereinafter referred to as PCI)
A protocol data unit (hereinafter referred to as PDU) consists of a following service data unit (hereinafter referred to as SDU).
This is a processing method of a communication processing device that divides a cell into fixed lengths and sends/receives cells in which a header containing information indicating the division position of the PDU is added to the division information.
) are interconnected via a connection network (C), and the communication network (A) and the connection network (C) use different types of PCI.
), when relaying cells from the communication network (A) to the connection network (C), the connection network (
The cell containing the PCI of C) is sent to the connection network (C), and the division position information of subsequent cells generated from the same PDU is changed, while the cell is sent from the connection network (C) to the communication network (A). When relaying, delete the first cell and use the same P
An inter-network connection system characterized by changing division position information of subsequent cells generated from a DU. [Claim 2] PD consisting of PCI and following SDU
A communication processing device that divides U into fixed lengths and transmits and receives cells in which a header containing information indicating the division position of the PDU is added to the division information, and connects a plurality of communication networks (A) to a connecting network (C).
PCs of different formats when interconnected via
In a communication processing device that interconnects a communication network (A) and a connection network (C) using I, a reception processing means analyzes the header of a cell received from the communication network (A), and address information contained in the header,
Alternatively, a PCI cell generation means for generating a cell containing only the PCI of the transfer destination communication network from address information included in the head information of the protocol data unit, a buffer means for temporarily storing the received cell, and an output of the PCI cell generation means. a means for selecting an output cell of a cell and a buffer means, and a connection network (after changing division position information of the selected cell);
C); a means for deleting the first cell from the division position information received from the connection network (C); and a means for changing the division position information of subsequent cells. Processing equipment. [Claim 3] PD consisting of PCI and following SDU
A processing method of a communication processing device that divides U into fixed lengths and sends/receives cells with headers added to them, and is an interconnection method between communication networks that use different formats of PCI. When relaying a cell to the communication network (B), prior to the transfer, a cell including the PCI of the communication network (B) is transmitted to the communication network (B), and further the division position of subsequent cells generated from the same PDU is determined. An inter-network connection method characterized by changing information. [Claim 4] PD consisting of PCI and following SDU
A communication processing device that divides U into fixed lengths and transmits and receives cells with headers added to the cells, and which processes P in different formats.
In a communication processing device that interconnects communication networks using CI, a reception processing means analyzes the header of a received cell, and address information included in the header extracted by the reception processing means or head information of a protocol data unit. PC of the destination communication network from the address information included in
PCI cell generation means for generating a cell containing only I, buffer means for temporarily storing received cells, means for selecting an output cell of the PCI cell generation means and an output cell of the buffer means, and the selected cell 1. A communication processing device comprising cell transmitting means that transmits a cell after changing division position information of the cell. [Claim 5] PD consisting of PCI and following SDU
In a communication processing device that transmits and receives cells with headers added to cell information obtained by dividing U into fixed lengths,
PCI and S so that the PCI length is an integral multiple of the cell information length.
A communication processing device comprising means for inserting invalidation information between DIs.