JPH05292092A - Local area network system - Google Patents

Abstract

PURPOSE:To efficiently provide service by selecting a subsequently corresponded reception and an access processing function based on the decision result of an identification bit at the time of the reception from a transmission line. CONSTITUTION:In an access processing reception selection part 35, the identification bit of the third byte bit of a cell is recognized based on the head information 33 of the cell, and reception data 38 is transferred to a connection less access processing part 36 or an ATM cell access processing part 37 in accordance with the decision result of the identification bit. The selection of both access processings 36 and 37 is performed by using selection signals 39 and 40. The selected connection processing part 36 or the ATM cell processing part 37 transfers the cell to an FDDI connection part 41 or an ATM terminal connection part 42, respectively, when the cell is the reception cell addressed to a self-node from the information within the control area and the transfer route area of a cell header. In the case of the cell addressed to other nodes, the parts 36 and 37 repeats the cell and performs the release acquisition processing of a transmission right and a self-node transmission processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local area network (LAN) system, and more particularly, to a terminal or a communication network connected via a communication node device (hereinafter simply referred to as a node) via a transmission line to transmit transmission data. The present invention relates to a LAN system for transmitting packet data in packets, and particularly to a LAN system for transmitting packet data of different types in a single LAN and a node used for the LAN system.

[0002]

2. Description of the Related Art As a data transmission format of a LAN system, a terminal accommodated in a node or a communication network performs connectionless service in which direct data transfer is possible without setting a connection as packet transfer route information, and connection After setting, there are some that provide connection-oriented services. ANSI (American National Standard Institute "American Nat" is a typical example of a network that provides connectionless services.
Ional Standards Institute
e)) Standard transmission rate of 100 Mbps FDI DI (FDDI: Fiber Distributed Data Interface “Fiber Dis”)
tiributed Data Interfac
e ″) is well known.

The FDDI network is a type of LAN that transfers data. A unique MAC (MAC) address is assigned in advance to a node used for FDDI that constitutes a LAN. In the header of the packet used in FDDI, transfer path information composed of a pair of a 6-byte-long destination node MAC address and a 6-byte-long source node MAC address is used. In this case, MAC
Since the data is transferred using the address, connection setting, connection between the terminals accommodated in the LAN or the communication network,
That is, a call is placed before the communication process, and a connectionless service that does not require a process for determining transfer route information is performed.

On the other hand, as a network switching method suitable for the integration of multimedia such as voice and image information, the CMT standard CCM (ATM: Asynchronous Transfer Mode) is used. "Asynchronous Transf
er Mode ") ATM exchange method is an exchange method that uses a 53-byte fixed-length packet called a cell, but the connection number is used for each communication as transfer route information in the cell header of the packet. With this connection number, the process of setting the connection number is executed between the terminal and the switch prior to the data transfer, that is, the ATM switching system provides the connection-oriented service to the connected terminal.

In order to support such multimedia, a LAN adopting ATM as a transfer method is used as a LAN for Globecom '90 900.2 A.T.M.R .: Architecture for Broadband Networks " ATMR: Rin
g Architecture for Broadba
nd Networks "(abbreviated as the first ATM LAN) and The Fifteens Conference on Local Computer Networks" The
15TH Conference on Local
High-speed multimedia backbone LAN architecture based on Computer Networks "Based-on ATM technology" High
-Speed Multimedia Backbon
e LAN Architectre Based o
n ATM Technology "(second ATM
Abbreviated as LAN) has been reported.

In the first ATM LAN, in order to attach importance to the connection with the ATM switching network requesting the connection-oriented service, the transfer route information area in the packet header is set in the connection setting procedure as in the CCITT standard. It is set on the assumption that it will be done in. on the other hand,
The second ATM LAN uses the transfer path information area in the cell header as a MAC address area in the same manner as FDDI in order to efficiently accommodate a LAN that requests a connectionless service such as FDDI.

Further, as a similar method, an ATM switching method is used to connect between LANs, and a unique connection number given in advance for connectionless service is used (abbreviated as a third ATM LAN). There is. This method is IEE 80
2.6 In the method standardized internationally by the committee,
EE Standard 802.6 "Local and Metropolitan Area Networks (IE
EE Standard 802.6 "Local a
nd Metropolitan Area Netw
orks ") 1990.

[0008]

In a backbone LAN supporting multimedia, a LAN terminal requesting a connectionless service or a communication network which is a LAN itself such as FDDI, and an ATM terminal or an ATM requesting a connection oriented service. It is necessary to connect both the exchange and the like.

In the above first ATM LAN, a connection is set even when the LAN is accommodated as a communication network accommodated in the node. Therefore, when the LAN is connected, the connection number setting procedure becomes an overhead and the transfer throughput is increased. descend. Since the second ATM LAN does not have a communication procedure for setting a connection, the connection oriented service cannot be provided to the connecting terminal device. In the above third ATM LAN,
Since the cell header does not include the route information, the higher address is referred to for each relay node in order to know the relay destination. Therefore, the high-speed switchability which is a feature of the ATM switching system cannot be utilized, and the relay delay amount is increased when viewed from the connection terminal, as compared with the case where the LAN is a connectionless network.

As described above, in the conventional LAN, there is a connectionless service using a destination and a source node address, and an access processing method called a connection-oriented service that performs a processing of determining a connection number as a preprocessing of information transmission. There has been a problem that both services that use transfer route identification information differently cannot be performed by one network without degrading the connectionless service performance. The object of the present invention is 1
One LAN that efficiently performs both connectionless service and connection-oriented service
It is to realize the system and the nodes used for it.

[0011]

In order to achieve the above object, the present invention provides a packet in a local area network system in which terminals or communication networks are connected by transmission lines via nodes and transmission data is transmitted in packets. An identification bit indicating a packet type is provided at a specific position, and a node is provided with a plurality of types of access processing means and a connection means with a terminal corresponding to the packet type, and the identification bit of the packet received by the receiving unit. And a discrimination means for discriminating between the plurality of types of access processing means and a means for processing the packet received from the connection means with the terminal,
A means for adding a packet identification bit to the packet to be transmitted is provided in the transmitter.

In a preferred embodiment, since the type of the packet is a connectionless service, a packet in which a node address is fixedly assigned as a transfer route information in a header area in the packet and a connection-oriented service are performed, It is typical to use a packet in which a connection number is dynamically allocated as a transfer path information in a header area in a packet as a pre-process of information transmission. The position of the header area of the identification bit may be any position, but a transfer route information area having a destination address and a source address is preferable. When set in the header area (control area) excluding the transfer route information area, the identifier area can be used efficiently, but it is difficult to set each bit in the control area freely for each network system because it is generally necessary to follow the standard method. There is a case.

[0013]

In the LAN system of the present invention, the packet signal processing unit in the node is divided into a signal processing unit that requires a connectionless service and a signal processing unit that requires a connection-oriented service, and is provided in a slot. Since the processing unit for the signal of the slot is selected by a few identification bits, both the connectionless service and the connection-oriented service can be efficiently performed by one LAN without degrading the connectionless service performance.

If the identification bit is provided in the transfer route information area having the destination address and the source address, the number of connections that can be set at the same time is halved as compared with the case where the identification bit is not provided. However, since the transfer path information area is provided with 24 bits, there is practically no problem considering that the number of devices connected to the network is generally several thousands to tens of thousands. On the other hand, the maximum number of connected terminals determined from the address area varies depending on the allocation position in the transfer route information area.
When set in the AC address area, the destination node MA
If the identification bit is set at a position in the C address area where there is originally no information corresponding to the display bit digit of the broadcast communication and the individual communication, the address can be efficiently allocated.

[0015]

1 is a block diagram showing the configuration of an embodiment of a LAN system according to the present invention. A plurality of nodes 1-1, 1
-2, 1-3, and 1-4 are connected in a loop by a transmission line to form a backbone LAN 2. A unique 11-bit MAC address is assigned to each node. LAN for connectionless communication to these nodes
The terminals 3-1 and 3-2 are connected via the FDDI nodes 5-1 and 5-2 forming the FDDIs 4-1 and 4-2, and at the same time, the AT performs connection-oriented communication.
M terminals 6-1 and 6-2 are also connected. That is, the backbone LAN 2 provides connectionless service for communication between the LAN terminal 3-1 and the LAN terminal 3-2, and the ATM terminal 6-1.
Connection oriented service is provided for communication between the ATM terminal 6-2 and the ATM terminal 6-2.

FIG. 2 shows a 53-byte cell (having a fixed packet length) having the first structure used for connectionless communication of the backbone LAN 2, and FIG. 3 shows
5 shows a 53-byte long cell having a second structure used for connection-oriented communication. The cell having the first structure shown in FIG. 2 has a cell structure for the slotted ring access method, and the first byte 11 consists of the access control bit group. The structure of the access control bit group is the same as that conventionally known, and the details thereof are described in The 15th Conference on Local Computer Network (The 15TH Conf.
rence on Local Computer Ne
"high speed multimedia backbone LAN architecture based on"
ATM technology (High-speed Mu
ltimemedia BackboneLAN Arch
itector Based on ATMTechn
3.3) of FIG. 3.3) and is not directly related to the description of the present invention, and the description thereof is omitted.

The area 14 of bit 0 of the second byte is a display bit for broadcast communication, and when this bit is "0",
Indicates that the cell is for individual node communication,
Area 12 from bit 1 of byte to bit 3 of third byte
If the 11-bit MAC address of the destination node is set in the area 14 and the area 14 is "1", it indicates that the communication is broadcast, and the group including all broadcasts in which all 11 bits are "1" is included. The address is set in the area 12. The 11-bit MAC address of the source node is set in the area 13 of bit 5 of the third byte to bit 7 of the fourth byte.

The area 15 of bit 4 of the third byte indicates whether the transfer path information area of the cell header is the MAC address used for connectionless service (FIG. 2) or the connection number used for connection-oriented services (FIG. 3). Which is an identification bit indicating
In the case of the C address (FIG. 2), it is set to “1”, and in the case of the connection number (FIG. 3), it is set to “0”.
The identification bit 15 can be placed at an arbitrary position in the header, but in the present embodiment, it is set in the transfer route information area by matching both cell structures.

The error detection code from the first byte to the fourth byte is set in the area 16 of the fifth byte. The area 17 from the 6th byte to the 53rd byte is an information area,
For example, in an FDDI frame divided into 44 bytes,
48-byte information to which position information and the like for the original FDDI frame of the divided information is added is placed. In the cell structure of FIG. 2, the format is the same as that of a conventionally known cell except for the identification bit 15.

FIG. 3 shows a second structure 53 used for connection-oriented communication of the backbone LAN 2.
Indicates a byte-length cell (fixed packet length). The cell of the second structure shown in FIG. 3 is an ATM except for the identification bit placed in the area 22 of bit 4 of the third byte.
A replacement user interface structure that has substantially the same format as an ATM cell (for example, see C
CITT B-ISDN Recommendation I. 413). The transfer path information area of this cell is a VPI (Virtual Path Identifier "Virtual".
l PathIdentifier ”), VCI (Virtual Channel Identifier“ Vir ”
tual Channel Identifier ”)
Is an area 21 from bit 4 of the first byte to bit 3 of the fourth byte.

In the communication procedure in the ATM switch, the connection control procedure and the data transfer procedure are separated.
Prior to the data transfer, the connection is set by negotiating the VPI and VCI used for the data transfer between the nodes by the control procedure. That is, the ATM cell uses the connection number, and the communication procedure is different from the communication procedure performed using the cell of FIG. 2 defined as the node address, and the cell header structure is inevitably changed.
The recognition as an ATM cell is based on that the identification bit placed in the area 22 of the bit 4 of the third byte corresponding to the area 15 of FIG. 2 is set to "0".

FIG. 4 is a block diagram showing the configuration of an embodiment of a node according to the present invention. Reception processing unit 32 of the receiving unit
Performs reproduction and timing extraction of the digital signal received from the transmission path 31, performs serial-parallel conversion, recognizes the cell from the transmission code rule, and performs access processing on the cell head information 33 and the reception data (packet) 34. The data is transferred to the reception selection unit (identification bit determination unit) 35. The access processing reception selection unit 35 recognizes the identification bit (area 15 in FIG. 2 and area 22 in FIG. 3) of bit 4 of the third byte of the cell based on the cell head information 33, and the determination result of the identification bit According to
The received data 38 is transferred to the connectionless access processing unit 36.
Alternatively, it is transferred to the ATM cell access processing unit 37. Selection of both access processing units 36 or 37 is performed using selection signals 39 and 40.

The connection processing unit 36 or the ATM cell processing unit 37 selected by the selection signals 39 and 40 are
From the information in the control area and the transfer route area of the cell header, when the cell is a receiving cell addressed to the own node, the cell is transferred to the FDDI connection unit 41 or the ATM terminal connection unit 42, and when the cell is addressed to another node, relayed, On the other hand, the transmission right release acquisition process and the own node transmission process are performed.

The interface between the processing units 36 and 37 and the corresponding connection units 41 and 42 is carried out on a cell-by-cell basis.
It is shown that 3 is addressed to the node. On the other hand, at the time of transmission, the transmission permission signal 45 indicates that the transmission cell can be transferred, and the FDDI connection unit 41 responds to this by enabling the transmission valid signal 47 to transfer the transmission cell 46. Also in the ATM cell processing unit 37 and the ATM terminal connection unit 42, signals 43 ', 44', 45 ', 46' and 47 'similar to the signals 43, 44, 45, 46 and 47, respectively.
have. The access processing transmission selection unit 48 receives the transmission cell data 49 and 50 from the processing units 36 and 37 together with the transmission selection signals 51 and 52, multiplexes cells according to the instruction, and sends the cells to the transmission processing unit 53. In the transmission processing unit 53, the function corresponding to the reception processing unit 32 is executed,
The cell signal is transmitted to the transmission line 54.

The connection processing unit 36 and the FDD
The configuration and operation of the I connection unit 41 is the same as that of the node of the connectionless LAN which is well known in the related art except that it is selected by the selection signal 39 and that an identification bit is added when a transmission cell is sent from the terminal. The configuration and operation are exactly the same (see, for example, the above-mentioned document “The Fifteens Conference on Local Computer Networks” The 15TH Config-rance).
on Local Computer Network
s ”of Anne Dee Dee Bridge
For the High Speed Multimedia Backbone LAN “An FDDIbridge fo
r the High-speed Multimed
iaBackbone LAN "as described in detail),

The configuration and operation of the ATM cell processing unit 37 and the ATM terminal connection unit 42 are the points except that they are selected by the selection signal 40 and that an identification bit is added when sending a transmission cell from the ATM terminal. The configuration and operation of a connection-oriented service type LAN node which is well known in the related art are completely the same (for example, 900. of the above-mentioned GLOVECOM '90.
2 AT M: Architecture
Four Broadband Networks "ATMR:
Ring Arch-structure for Br
(Details are the same as those described in detail in “adbandNetworks”), and thus detailed description is omitted.

FIG. 5 is a timing chart of representative signals for explaining the operation of the node shown in FIG. The first signal is the cell head information 33 that becomes 1 in the first byte of the packet.
The second signal is the received data 34 after serial-parallel. The third and fourth signals are the connectionless processing unit 36 and the AT, respectively.
Selection signals 39 and 40 addressed to the M cell processing unit 37. Received data 38 corresponding to these selection signals 39 and 40
The timing is shown in the fifth signal. From the address analysis results of the third signal and the fifth signal, the sixth signal indicates that the first packet of the received data is addressed to the own node. Similarly, the seventh signal indicates that the third packet of the received data was addressed to the ATM terminal connection unit of the node. 8th
The signal is the reception data 43 corresponding to the reception valid signal 44. The ninth signal indicates that the second cell area of the reception data is an empty cell area for connectionless, and accordingly, the cell transmitted by the FDDI connection unit 41 is shown in the tenth signal. The eleventh signal indicates the transmission data 55 cell-multiplexed by the access processing transmission selection unit 48.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. In the LAN of the above embodiment, a case where a plurality of nodes are connected in a loop by a transmission line is shown, but the present invention is also applicable to a case where they are connected in a ring or a mesh. Also, the packet types are shown as two types of connectionless service type and connection oriented service type, but it can be applied to the case of adding another type of packet, in which case the number of identification bits is Further increasing, the position of the identification bit in the packet can also be changed.

[0029]

According to the present invention, an identification bit indicating whether the transfer route information is the address type identifier or the connection number type identifier is provided at a specific position in the packet, and the determination result of the identification bit is obtained when receiving from the transmission line. Based on this, the subsequent corresponding reception and access processing functions can be selected, so that one network can efficiently provide both connectionless service and connection-oriented service.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a LAN system according to the present invention.

FIG. 2 is a format diagram of a first cell used in one embodiment of the LAN system of the present invention.

FIG. 3 is a format diagram of a second cell used in one embodiment of the LAN system of the present invention.

FIG. 4 is a configuration block diagram of an embodiment of a node according to the present invention.

5 is a timing chart for explaining an operation of the node of FIG.

[Explanation of symbols]

15 ... Identification bit, 35 ... Access processing reception selection section, 36 ... Connectionless access processing section, 37 ... ATM cell access processing section, 48 ... Access processing transmission selection section.

Claims (7)

[Claims] 1. In a local area network system in which terminals or communication networks are connected by a transmission line via a communication node device to transmit transmission data in packets, an identification bit indicating a packet type is provided at a specific position of the packet. Provided, the communication node device discriminates a plurality of types of access processing means and a connection means with a terminal corresponding to the type of the packet, and the identification bit of the packet received by the receiving unit to access the plurality of types of access processing. Means and a means for processing a packet received from the connection means with the terminal, and a means for adding a packet identification bit to the packet to be transmitted to the transmitting unit. .. 2. In a local area network system in which terminals or communication networks are connected by a transmission line via a communication node device and transmit transmission data in packets, the packet is transmitted to a packet generator of the communication node device. An identification bit is added to the header area to determine whether the transfer path identification information in the header area is the transfer path identification information fixedly assigned to the node or the transfer path identification information dynamically assigned to the node. Means for discriminating the packet received by the discrimination bit in the receiving unit for the packet from the transmission line, and the fixedly assigned transfer path discrimination information selected by the signal of the discrimination means. And a circuit for processing a packet having the dynamically assigned transfer path identification information. A local area network system characterized by the following. 3. The local area network system according to claim 2, wherein the fixedly assigned transfer route identification information and a part of the area assigned to the dynamically assigned transfer route identification information are identified. A communication node device characterized by being used as a bit. 4. The local area network system according to claim 2 or 3, wherein the fixed transfer path identification information is a pair of a destination communication node device address and a source communication node device address. A local area network system characterized by being. 5. The local area network system according to claim 3 or 4, wherein 1 bit of the destination communication node device address is used as a display bit for broadcast communication and individual communication, and corresponds to a digit of the display bit. A local area network system, wherein 1 bit of a source communication node device address area is used as the identification bit. 6. A communication node device of a local area network system, receiving means for receiving a packet from a transmission line and determining the type of the packet, and packet type for a packet to be transmitted to the transmission line. And a plurality of packet access processing means corresponding to the packet type, and a plurality of packet access based on the packet type determined by the receiving means. A communication node device comprising: selecting means for selecting a packet access processing means for processing a received packet from the processing means. 7. A connection unit for connecting to a terminal or a communication network, a reception processing unit for receiving packet format data from a transmission line, and a transmission processing unit for transmitting packet format data to be transmitted to the transmission line. A packet from the reception processing unit is added to the connection unit or transferred to the transmission processing unit,
In the communication node device having an access processing unit that selectively converts the information to be transmitted from the terminal or the communication network via the connection unit into packet format data and sends the packet data to the transmission processing unit, The unit has a first connection unit connected to a terminal or a communication network for which a connectionless service is provided, and a second connection unit connected to a terminal or a communication network for which a connection-oriented service is provided, and the access processing The unit has a first signal processing unit for exchanging data with the first connection unit, and a second signal processing unit for exchanging data with the second connection unit,
The reception processing unit has means for selecting the first signal processing unit or the second signal processing unit based on the identification bit included in the received packet, and should be transmitted to the connection unit or the transmission processing unit. A communication node device comprising means for adding an identification bit for identifying whether the connectionless service or the connection-oriented service is performed in a specific area of the packet. ..