JPH10243009A - Switching hub - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the switching hub whose processing is executed at a high speed by selecting a transmission path for uni-cast, multi-cast and broadcast separately and changing dynamically each path. SOLUTION: The hub has a plurality of input ports and output ports and identifies a packet as to whether it is a uni-cast packet, a multi-cast packet or a broadcast packet depending on a destination of the packet received at an input port. In the case of the uni-cast packet, it is sent to an output port through a uni-cast switch 33, and when the packet is a multi-cast packet or a broadcast packet, it is fed to an output port through a repeater selection section 23, a repeat buffer 24 and a port selection section 25. The multi-cast packet or the broadcast packet is sent at a high speed when any output port is idle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching hub capable of dynamically changing a broadcast domain in a LAN (Local Area Network) when constructing the LAN.

[0002]

2. Description of the Related Art Generally, when constructing a network such as a LAN (local area network), wiring is easy and inexpensive, so that 10BASE is used.
The use of a twisted pair as a transmission line, such as -T, has become mainstream. In recent years, network bandwidth has become insufficient due to an increase in traffic due to an increase in the number of terminals and the like, and a switching network using a switching hub has been introduced to solve this kind of problem. The switching network has the advantage that, when the performance is expanded, only the hub of the conventional network is replaced, and no change is required on the terminal side.

In a network using a switching hub of this type, a divided area of the network can be changed only by changing the setting of the switching hub. Therefore, it is possible to set a broadcast domain without changing physical wiring. it can. As described above, a LAN composed of a group of terminals in which a divided area of a network is logically set without depending on physical wiring is referred to as a virtual LAN.
(Hereinafter referred to as VLAN). The VLAN construction method includes a VLAN group (VLAN
), A method of determining a VLAN group using node addresses (MAC addresses, IP addresses), and
There is a method of dividing a LAN group. A port-based VLAN is called a port-based VLAN, an address-based VLAN is called an address-based VLAN, and a protocol-based VLAN is called a protocol-based VLAN.

Here, layer 3 of the OSI basic reference model
Subnet (network layer address (eg, I
Normally, it is necessary to intervene a router for switching between networks having different P addresses). However, if a VLAN group is determined using an IP address or a VLAN group is divided according to a node protocol, it is possible to switch between layer 3 subnets. Can be directly switched by a switching hub without going through a router. Hereinafter, a VLAN that performs direct switching of a layer 3 subnet is referred to as a layer 3 VLAN, and a VLAN that performs layer 2 and lower switching is referred to as a layer 2 VLAN.
Call.

As described above, since the network is logically divided by using the switching technology, the VLAN group is dynamically changed in response to a change in the business structure of a work group or a project of an organization including a company. You can do it. In the layer 2 VLAN, switching between ports is performed using a port unit or a MAC address, and unicast or multicast transmission is performed. That is, the VLAN group is identified by the packet address of the received packet, and if multicast is designated by a predetermined flag or the like included in the frame, the same V-register registered (learned) in advance is used.
Received packets are distributed to all ports belonging to the LAN group.
Transfer the received packet to the port whose address is registered (learned). In the layer 2 VLAN, since subnets using the same routing protocol constitute a VLAN group, when transferring a packet to another VLAN group, the packet is routed through a router. Here, OSPF (Open Shore) defined by RFC1247
By employing the bit-by-bit subnet method of rtest Path First (shortest path priority routing) and VLSM (variable length subnet mask), the entire network can be divided into small VLAN groups.

On the other hand, in a layer 3 VLAN, switching between ports is performed using a network address. Packets of the same VLAN group identified by a layer 3 VLAN group ID (subnet ID) are transmitted to the network in advance. Forward the address to the registered (learned) port. In the switching hub described above, in order to enable multicast transmission, packets are temporarily stored in a buffer and prioritized for transfer. Multicast transmission is used in videoconferencing and the like. Since data is transmitted between terminals in a 1: N (N is an integer of 1 or more), a large amount of data is transmitted. Performing efficiently has a large effect on performance such as delay time.

[0007]

As described above, in any of the layer 2 VLAN and the layer 3 VLAN, the switching hub connects the ports one-to-one at each time only by switching. ,
When transmitting multicast or broadcast,
The ports are connected sequentially. As a result, an enormous amount of time is required when the number of terminals that distribute packets is large.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a different transmission path for unicast and multicast or broadcast, and to speed up processing by dynamically changing the path. Another object of the present invention is to provide a simplified switching hub.

[0009]

According to a first aspect of the present invention, a plurality of input ports and output ports are connected one-to-one between an input port and an output port, and the input port and the output port are connected according to the destination of a received packet. A unicast switching unit that dynamically changes the connection relationship, and connects the input port and the output port in a one-to-N connection via a repeat buffer and dynamically changes the connection relationship according to the destination of the received packet. And a switching control unit that dynamically switches the received packet so as to appropriately pass through the switching unit and the repeater unit according to the destination of the received packet. According to this configuration, the unicast transmission is performed through the switching unit, and the multicast or broadcast transmission is performed through the repeater unit, so that both are on separate paths, and the switching unit and the repeater unit are switched by the switching control unit. Can be switched dynamically. In particular, in multicast or broadcast transmission, the input port and the output port are connected one-to-N through the repeat buffer, so that the same packet can be transmitted from a plurality of output ports at the same time. The required time is greatly reduced as compared with the case of sequentially transmitting packets. This configuration can support both connection-type communication and connectionless-type communication.

According to a second aspect of the present invention, in the first aspect of the present invention, a big pipe that is faster than the input port and the output port is added, and the big pipe is connected to the input port and the repeater through the switching unit and the repeater unit. It is connected to the output port. According to this configuration, a server or a backbone can be connected to the big pipe, and a hierarchical network can be constructed.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a dedicated service port for connecting a network service server for performing QoS control is added, and the service port and the network service server are connected. Are connected by a dedicated VLAN group channel. According to this configuration, QoS control can be performed by connecting the network service server to an input port, an output port, and a service port provided separately from the big pipe. The QoS control includes priority processing for giving priority according to the destination, a function of notifying congestion, transmission control of multicast, and the like.

According to a fourth aspect of the present invention, there is provided a service port for connecting a network service switch for performing QoS control by interconnecting the switching hubs according to the first or second aspect of the invention. Dedicated VLAN between network and network service switch
They are connected by group channels. According to this configuration, QoS control can be performed by connecting the network service switch to an input port, an output port, or a service port provided separately from the big pipe. QoS
The control is the same as that of the third aspect, and includes priority processing, congestion processing, and multicast transmission processing. In addition, since the network service switch connects the two switching hubs to each other, packet transmission between the switching hubs becomes possible.

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the VLA of a terminal connected to each port is provided.
A VLAN group table in which at least N group IDs are registered is provided. Each port has a VLA for broadcast or multicast depending on whether the type of received packet is broadcast or multicast.
The N group ID is read from the VLAN group table, the destination of the received packet is replaced with the VLAN group ID, and the VLAN group ID of the received packet is replaced.
Is compared with the replaced VLAN group ID, and the VL
The forwarding judgment is performed for each port so that the received packet having the same AN group ID is forwarded. According to this configuration, the VLAN group ID is collated at each port.
The collation processing for confirming the destination of the packet is decentralized, and the speed can be further increased.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) The present invention is characterized in that, as shown in FIG. 1, transmission routes for unicast and multicast or broadcast are made different inside a switching hub.

In this embodiment, four input ports and four output ports are provided. One transmission line is connected to the input port and the output port. Hereinafter, a set of the input port and the output port is referred to as a segment. Further, in the present embodiment, a set of branch line interfaces is configured by the input port and the output port. That is, in this embodiment, each segment becomes a branch line interface.

Each segment includes, on the input port side, a transmission medium dependent unit 11 adapted to physical characteristics such as an electrical specification of a transmission medium, a transmission line decoding unit 12 for extracting data from a received packet, A switch connection control unit 13 for extracting information for identifying a unicast, a multicast or a multicast based on address information (described later) included in the packet thus obtained, and a branch control unit 14 for branching a unicast and a multicast or a broadcast. And Switch connection control unit 13
Then, packet header information (including the MAC address) included in the received packet is sent to the management unit 41. The management unit 41 performs registration, learning, and identification of a VLAN group, and has a filtering function. The management unit 41 stores the VLAN in the VLAN group table 42
The group is registered or learned, and the VLAN group is identified by comparing it with the packet header information of the received packet. By such collation, a unicast switch 33, a repeater selection unit 23, and a port selection unit 2 described later are used.
5 to perform filtering. Also, the branch control unit 14 sends a packet to a multicast reception buffer (MRB) 21 in the case of multicast, and a unicast reception buffer (URB) 3 in the case of unicast.
Send the packet to 1.

Each segment performs, on the output port side, a priority control unit 15 for controlling a schedule for sending data from the multicast transmission buffer (MTB) 22 to the unicast transmission buffer (UTB) 32 and a medium access control (MAC). A switch connection control unit 16,
A transmission path encoding unit 17 for assembling a packet to be transmitted;
And a transmission medium dependent unit 18 adapted to physical characteristics such as electrical specifications of the transmission medium.

If the data received at the input port is unicast, the data passed through URB 31 is input to unicast switch 33. Unicast switch 33
Is a one-to-one connection between each input port and each output port. The management unit 41 compares the packet header information from the switch connection control unit 13 with the VLAN group table 42, and And Therefore, the unicast data received at each input port is transmitted from a required output port according to the packet header information. As described above, the switching unit is configured by the unicast switch 33, the management unit 41, and the VLAN group table 42.

On the other hand, if the data received at the input port is a multicast, the data passed through the MRB 21 is input to one of the three repeat buffers 24 through the repeater selector 23. That is, each repeater selection unit 23
Are connected to all the repeat buffers 24, respectively.
The data of one MRB 21 can be associated with one to N (N is an integer of 1 ≦ N ≦ 3) repeat buffers 24. On the other hand, each repeat buffer 24 is connected to the MTB 22 via the port selector 25. The port selection units 25 are provided in the same number as the MTBs 22. Each port selection unit 25 has a one-to-N
It is possible to associate with. The association between each MRB 21 or each MTB 22 and each repeat buffer 24 is performed by the dynamic bus connection control unit 43 controlling the repeater selection unit 23 and the port selection unit 25. The dynamic bus connection control unit 43 dynamically associates an input port with an output port by collating the packet header information received from the branch control unit 14 by the management unit 41 with a VLAN group table. in this way,
In multicast transmission, an input port and an output port can be dynamically associated with each other. Repeat buffer 2
If the number 4 is provided for the number of VLAN groups, data for each VLAN group can be stored in each repeat buffer 24. That is, a repeater unit is configured by the repeater selection unit 23, the repeat buffer 24, the port selection unit 25, the VLAN group table 42, and the dynamic bus connection control unit 43. As described above, by simultaneously reading data from the repeater unit to a plurality of ports performing multicast transmission, one-to-N in the VLAN group can be read.
Data transmission is realized.

Further, the branch control unit 14, MRB21, M
The switching control unit is configured by the TB22, the URB31, the MTB32, and the management unit 41. Incidentally, the format of the MAC / LLC frame is as shown in FIG. In the illustrated example, the preamble and the delimiter are omitted. Level 2 V
The LAN transmits this frame. Then, MA
The C frame basically has a MAC address (destination MAC address, source MAC address) as shown in FIG.
It comprises LLC information, information, and a frame check sequence.

As shown in FIG. 2B, the destination MAC address and the source MAC address each have a 1-bit I / G identifying an individual or a group, and a 1-bit U / L identifying a local or a local. And 46-bit address data. I / G = 0 indicates an individual (that is, unicast), and I / G = 1 indicates a group address. Also, U / L = 0 indicates that the address is global management without including the address in the LAN, and U / L = 1 indicates that the address is L
Indicates that the management is local to the AN. Therefore, if I / G = 1 and U / L = 1, it indicates broadcast. This portion is packet header information used for control of the branch control unit 14, and can be identified as unicast, multicast, or broadcast.

By the way, LLC information is LLC (Logical
Link Control) A PDU (Protocol Data Unit), which is defined in IEEE802.2 and shown in FIG.
Like DSAP (Destination Service Access Point)
t) Address, SSAP (Source Service Access Point)
) Has an address. The DSAP has a 1-bit I / G for identifying an individual or a group as shown in FIG. 2 (d), and the SSAP has a 1-bit C / D indicating a command or a response as shown in FIG. 2 (e). I / G having R = 0 indicates an individual, and I / G = 1 indicates a group. Also, C / R = 0 indicates a command, and C / R = 1 indicates a response. LLC P
It is also possible to use a header specified in IEEE802.10 as an option instead of the DU. This header includes a clear header and a protected header as shown in FIG. As shown in FIG. 2 (g), the clear header is an 802.110 LASP (Logical Service Access).
Point) and SAID (Security Association Identif)
ier) and an MDF (Manegemnt Defined Field), and the protected header comprises a source address. The VLAN ID is put in the SAID. That is, as shown in FIG. 2 (h), three octets of SNAP (SubNetwo
rk Attachment Point) and OUI (Organizationally)
Unique Identifier) and VType are used.

The information of the MAC frame includes LLC PD
Following U, a destination network address and a source network address are placed, and further, after a destination application address and a source application address are placed, data is placed. The frame check sequence includes a checksum (ICV = Integrity Check Valu
e) is used.

By the way, the ATM Forum MPOA
Is also called router emulation, the routing function is loaded on top of LAN emulation, and NHRP
(NextHop Resolution Protocol), and implements a virtual router function that separates the routing protocol engine and the forwarding engine. In MPOA, routing is performed on a subnet basis of a subgroup IASG (Internet Address Sub Group) of the internetwork layer. Information between functional groups is defined by LLC / SNA defined in RFC1483.
It is transferred using a P encapsulation header. LLC / SN
An LLC frame in AP encapsulation includes a DSAP address, an SSAP address, LLC control, and LLC data. However, when the LLC header is AA-AA-03, the LLC data includes OUI and PID (Protocol
Identifier) and SNAP data. If the header is FE-FE-03, there is no OUI and PID, and the ISO PDU is transmitted as a packet. OUI and PID
Depends on the protocol, and has the relationship shown in Table 1.

[0025]

[Table 1]

In the VLAN of level 3, a packet header as shown in FIG. 3 is added. FIG. 3A shows a packet header for adding an IP address. FIG. 3A shows an IPv4 packet header currently used. However, since the number of addresses that can be set is becoming insufficient, FIG. ) Is extended with the IPv6 packet header. In IPv6, Hop-by-Hop option, routing, fragment, authentication,
There is an End-to-End option. In IPv6, addresses are hierarchized, and an NSAP address, an IPX address (NetWare of Novell), a unicast address for a provider, a geographic address, a local address, a multicast address (or a broadcast address), or the like can be used.

The VLAN group table 42
Basically, [destination client address, output port ID, source client address, input port I
D, protocol type, VLAN group ID, priority, QoS parameter, and forwarding port], and the VLAN group ID is separately set for unicast, multicast, and broadcast. Is set. Here, the forwarding port is represented by VPI (virtual path identifier) and VCI (virtual channel identifier) in association with the header of the ATM cell.

Here, when the transmission is close to the real time as in the case of the multicast transmission and the video data is required, the transmission takes precedence over the unicast transmission at a predetermined cycle according to the QoS parameter set to guarantee the delay time. Transmitted. In other words, in multicast transmission, data is sent to a plurality of output ports all at once, so there is a high probability that the data will compete with unicast transmission. In such a case, however, the delay time of high-priority data can be determined using the QoS parameter. By managing and controlling the priority control unit 15, a delay of a predetermined time or more does not occur for data with high priority.

The switching hub shown in FIG. 1 includes a CSMA / CD control unit 44 with priority processing.
The CSMA / CD control unit 44 monitors the state of the output port, and when an output port to be multicast is vacant, reads out the packets stored in the repeat buffer 24 at the output port and gives priority control to the multicast traffic. I do. Here, reading of the packet to the output port is performed simultaneously while synchronizing with each output port. The CSMA / CD control unit 44 is an IEEE80
Rather than waiting for transmission when there is a carrier of a pulse signal as defined in 2.3, whether or not transmission is possible from the output port according to the state of the priority control unit 15 according to the priority control scheduling Is to judge.

Now, the priority control unit 15 determines that all the output ports corresponding to the multicast data stored in the upper repeat buffer 24 among the three repeat buffers 24 shown in FIG. 1 can transmit. It is assumed that the state indicates. At this time, the dynamic bus connection control unit 43 sets the port selection unit 25 in the upper-stage repeat buffer 24 according to a command from the CSMA / CD control unit 44. Therefore, the packet in the upper-stage repeat buffer 24 is output from the M of the output port to be multicast.
The packet is written in the TB 22 and transmitted simultaneously with the output port through the priority control unit 15 in response to a command from the CSMA / CD control unit 44. The priority of the packet is determined according to the type of the packet and the type of the VLAN, and is registered in the VLAN group table 42 by the management unit 41.

On the other hand, at the time of unicast transmission, if the destination is known, forwarding is performed only to the output port corresponding to the destination. In the management unit 41, the VL
Referring to all data in the AN group table 42,
If the output port of the destination is not known but the segment of the VLAN group is known, multicast transmission is performed for that segment, and if neither the output port nor the segment of the destination is known, broadcast transmission is performed.

As described above, multicast transmission is performed through the repeater unit having the repeat buffer 24, and data stored in the repeat buffer 24 is simultaneously read out while synchronizing with the output port, thereby realizing a 1: N repeater communication mode. be able to. In addition, since a switching unit having a unicast switch 33 is used for unicast transmission, and a repeater unit and a switching unit are provided, when output ports are different between unicast and multicast transmissions, store and The forward switch function and the repeater function are executed in parallel, and the switching between the switch function and the repeater function is dynamically performed.

(Embodiment 2) In this embodiment, as shown in FIG. 4, one of the four input ports and one output port in Embodiment 1 is replaced with a big pipe. . The big pipe is a port connected to a server or a backbone, and is faster than other input ports and output ports. For example, if a normal input port or output port is 10BASE-T, it is 100BA.
SE-T, 110VG-Any-LAN, FDDI, A
TM or the like is used. The big pipe is, like a normal input port or output port, a transmission medium dependent unit 11a, 1
8a, transmission path decoding unit 12a, switch connection control unit 13
a, 16a, branch control unit 14a, URB 21a, MRB
31a, a repeater selector 23a, a port selector 25a,
It includes a UTB 22a, an MTB 32a, a priority control unit 15a, and a transmission path coding unit 17a. However, a dedicated backbone dynamic bus connection control unit 45 is used for controlling the switch connection control unit 13a, the repeater selection unit 23a, and the port selection unit 25a on the input port side.

In the big pipe, the repeat buffer 24
And the unicast switch 33 is shared with other input ports and output ports, and the backbone dynamic bus connection control unit 45 selects the repeat buffer 24, selects the output port, performs filtering, and converts the speed between ports by buffering. Perform Although only one big pipe is provided in the illustrated example, if a plurality of big pipes are provided, each big pipe is provided with a backbone dynamic bus connection control unit 45 so that each big pipe is connected to the repeat buffer 24.
Can be connected to

In this embodiment, the broadcast proxy server 46 is used because a hierarchical structure can be provided by providing a big pipe, and a large-scale network can be constructed. The switching hub (or a network service server or the like connected to the outside of the switching hub) collectively manages the results of the inquiry and the broadcast of the IPX and the like without performing the request individually from the client. Is provided to directly respond to the switching hub. Other configurations and operations are the same as those of the first embodiment.

Embodiment 3 In this embodiment, as shown in FIG. 5, a service port 4 dedicated to a network service is provided.
Is provided. The branch line interface 1 in FIG. 5 means a set of segments including an input port and an output port, as described in the first embodiment. In short, the branch line interface 1 is as shown in FIG.
, The transmission medium dependent units 11 and 18, the transmission path decoding unit 12, the switch connection control units 13 and 16, and the branch control unit 1
4, URB21, MRB31, UTB22, MTB3
2, including a priority control unit 15 and a transmission line coding unit 17. The switch core 2 includes a repeat buffer 24, a unicast switch 33, a management unit 41, a dynamic bus connection control unit 43, and a CSMA / CD control unit 44. The repeater selecting unit 23 and the port selecting unit 25 are included in the branch line interface 1 here.

The backbone interface 3 corresponds to the input / output of the big pipe in the second embodiment, and as shown in FIG.
8a, transmission path decoding unit 12a, switch connection control unit 13
a, 16a, branch control unit 14a, URB 21a, MRB
31a, a repeater selector 23a, a port selector 25a,
It comprises a UTB 22a, an MTB 32a, a priority control unit 15a, a transmission line coding unit 17a, and a backbone dynamic bus connection control unit 45.

In this embodiment, the provision of the service port 4 on the switching hub A allows the network service server B to be directly connected to each service port 4 of the plurality of switching hubs A. That is, the service port 4 and the network service server B
Is connected by a dedicated VLAN group channel, and the dedicated service port 4 is connected without going through the backbone.
Therefore, QoS control such as priority processing, congestion control, and multicast control can be reliably added.

The service port 4 may have the same configuration as the branch line interface 1. Further, since the network service server B is connected to a plurality of switching hubs A, it has a plurality of service ports 5a, and the service ports 5a are 100 BA.
When a service port 4 faster than the branch line interface 1 is required, as in the case of being supported by the repeater connection of the SE-T, a configuration similar to that of the backbone interface 3 may be adopted.

Incidentally, the network service server B in the present embodiment is a protocol or a server OS.
And a broadcast relay service unit 5b for processing a broadcast that depends on. Therefore, in each switching hub A, when the management unit 41 collates the corresponding packet, it connects to the channel of the specific VLAN group passing through the service port 4 and transfers the data to the broadcast relay service unit 5b.

When the switching hub A according to the present embodiment is used for constructing a network such as a disaster prevention system or a building management system, a common service or a common facility for providing high-priority services such as a building facility service is provided. The service unit 5c is a network service server B
Is provided. Also in this case, each switching hub A does not pass through the backbone but through the dedicated service port 4.
Can be connected to a channel of a VLAN group dedicated to network services.

The network service server B is also provided with a backbone interface 5d, which is connected to the backbone via the trunk switch 6 together with the backbone interface 3 of each switching hub A. Other configurations and operations are the same as those of the second embodiment. (Embodiment 4) In the present embodiment, as shown in FIG.
Is replaced with a network service switch C. The network service switch C connects the service ports 4 of the plurality of switching hubs A to each other, and is connected by a channel of a dedicated VLAN group. Further, similarly to the network service server B, QoS control such as priority processing, congestion control, and multicast control is added.

The switch core 7 is provided in the network service switch C, and the switch core 7 is, like each switching hub A, a repeat buffer 24c, a unicast switch 33c, a management unit 41c, a dynamic bus connection control unit 43c, a CSMA / C It includes a CD control unit 44c. Further, the switch core 7 includes a service unit 7a having a service function of relaying multicast transmission between the switch hubs A, a peer-to-peer communication function, and a function of avoiding a failure due to redundancy.

A VLAN dedicated to a network service for multicasting between switching hubs A
A group is set, and when the management unit 41 of each switching hub A collates the corresponding packet, a specific V
Connect to LAN group channel. Further, since the service ports 4 of the plurality of switching hubs A are connected to each other, a peer-to-peer VL dedicated to network services is used.
An AN group channel can be provided. Therefore, when the management unit 41 of each switching hub A collates the packet of the peer-to-peer communication, the peer-to-peer communication is performed using the channel of the specific VLAN group for the network service. This will start the traffic of the peer-to-peer communication flowing to the backbone.

Further, when a failure occurs in the backbone due to the redundancy, the packet sent to the backbone is diverted from the service port 4 to the network service switch C. As a result, even when a failure occurs, packets can be transmitted through the detour. As described above, since the network service switch C shares the VLAN group table between the switching hubs A, the switching hub A performs connectionless communication for each switching hub A without passing through a broadcast server or a route server. Broadcasting of N to N multicast can be performed dynamically. Other configurations and operations are the same as those of the third embodiment.

(Embodiment 5) The present embodiment is characterized in that, as shown in FIG. 8, management sections 41 'and 41a' are provided for each input port in the configuration of Embodiment 2. That is, the management units 41 'and 41a' are provided at the normal input port and the input port of the big pipe, respectively. The management units 41 ′ and 41 a ′ process the packets according to the priority using the priority registered and managed by the priority setting unit 47. The VLAN group table 42 is shared by the management units 41 'and 41a'.

The management units 41 ′ and 41 a ′ provided for each input port are connected to the VLAN group table 42.
The VLAN group client address and V
The LAN group ID is registered. After that, if the destination addresses detected by the switch connection control units 13 and 13a are broadcast or multicast,
The destination address is changed to a broadcast or multicast VLAN group ID with reference to the VLAN group table 42. At each input port, the changed VLAN group ID and buffer (MRB
21, the URB 31) is compared with the original VLAN group ID, and the dynamic bus connection control unit 43 selects the repeat buffer 24 and the output port so as to forward a packet having the same VLAN group ID or unicast destination address. It makes autonomous forwarding decisions for each port.

Here, the buffer (MRB) on the input port side
21, URB 31), a buffer included in the repeat buffer 24 or the unicast switch 33, and a buffer on the output port side (MTB 22, UTB 32). Although two types of buffers, a repeater section and a switching section, are provided, the capacity of the input port side buffer and the output port side buffer is reduced by controlling with a pointer.

The management units 41 'and 41a' define a VLAN group for performing multicast transmission inside the switching hub, a routing protocol, synchronization and priority processing of multicast transmission inside the switching hub, broadcast and multicast of external VLAN. And the like in the switching hub. Other configurations and operations are the same as those of the second embodiment.

Embodiment 6 As shown in FIG. 9, this embodiment is an example in which a network constructed by using the switching hub A shown in Embodiment 3 is used for a building management system. Basically, a switching hub A to which a function for load monitoring and control is added is used as a local node X, and the local node X is connected to a center node Y via a backbone. The system is constructed by directly connecting the port 4 to the distributed network service server Z.

The local node X has the same basic configuration as the switching hub A shown in the third embodiment. However, in addition to the branch line interface 1, a branch line equipment control unit 8a is provided for load control, and an operation input is provided. A monitoring unit 8b for receiving is provided. The monitoring unit 8b requests the switch core 2 to control the port via the local management agent 8c. That is, the console 51 having an operation unit is connected to the monitoring unit 8b, and when operation information of the console 51 is input to the switch core 2 through the monitoring unit 8b and the management agent 8c,
The information is transmitted to the business department 52 and the information department 53 through the required branch line interface 1, and the loads (the lighting load 54, the sanitary equipment 55, and the air conditioning load 56) are controlled through the branch line control unit 8a. On the other hand, the center node Y includes a trunk line concentrating unit 60 for connecting the backbone, and the trunk line concentrating unit 60 functions in the same manner as a switching hub. In other words, switching between backbones and VLA
It performs learning, identification, and filtering of N groups, and also performs intranet routing. The trunk line concentrating unit 60 is connected to a dedicated line or a public network via a WAN connection unit 61 having a firewall function and a routing function, and constructs a WAN or the Internet. The monitoring for each local node X is
The monitoring unit 62 monitors the state of the load and the traffic. The monitoring unit 62 is also provided with a network management function, a building automation function, and a disaster prevention or security management function, thus enabling integrated building management.

Also, the distributed network service server Z
Is connected to the local node via a service channel 4 of the local node X via a dedicated channel, and includes a facility control unit 63 having a facility controller for controlling facilities as various loads; A service unit 7a for providing various services such as a communication service, a local building facility service, and a common network service. By using such a distributed network service server Z, a network
QoS control such as priority processing, congestion control, and multicast control can be added to the service. This embodiment shows an example of a system configuration, and it goes without saying that various systems can be constructed. Other configurations and operations are the same as those of the third embodiment.

[0053]

According to the first aspect of the present invention, a plurality of input ports and output ports are connected one-to-one between the input ports and the output ports, and the connection relationship is operated according to the destination of the received packet. A unicast switching unit for changing the connection, and a repeater unit for connecting the input port and the output port in a one-to-N relationship via a repeat buffer and dynamically changing the connection relationship according to the destination of the received packet. A switching control unit that dynamically switches a received packet through a switching unit and a repeater unit as appropriate according to the destination of the received packet, and performs unicast transmission through the switching unit, and performs multicast or broadcast. Is transmitted via the repeater unit, and both are on separate paths. The units are dynamically switched by the switching control unit. In particular, in multicast or broadcast transmission, the input port and the output port are connected one to N through a repeat buffer, so that the same packet is simultaneously transmitted from a plurality of output ports. This has the advantage that the required time is greatly reduced as compared with the case where packets are sequentially transmitted from each output port by switching.

According to the second aspect of the present invention, when a big pipe faster than the input port and the output port is added and the big pipe is connected to the input port and the output port through the switching unit and the repeater unit, Servers and backbones can be connected to pipes,
There is an advantage that a large-scale network can be constructed by constructing a hierarchical network. Further, by connecting the server via a big pipe, a client / server system can be constructed. That is, if a terminal is connected only to the input port and the output port, a peer-to-peer LAN will be constructed.
By having a big pipe, a client / server type LAN can also be constructed.

According to the third aspect of the present invention, a dedicated service port for connecting a network service server for performing QoS control is added, and the service port and the network service server are connected by a dedicated VLAN group channel. In this case, there is an advantage that QoS control can be performed by connecting a network service server to a service port provided separately from an input port or an output port or a big pipe.

According to a fourth aspect of the present invention, the switching hubs according to the first or second aspect are connected to each other so that
A dedicated service port for connecting a network service switch for performing oS control is added, and a dedicated V is connected between the service port and the network service switch.
The connection using the LAN group channel has an advantage that QoS control can be performed by connecting a network service switch to an input port, an output port, or a service port provided separately from the big pipe. In addition, since the network service switch connects the two switching hubs to each other, there is an advantage that a packet can be transmitted between the switching hubs and a relatively large-scale network can be constructed.

According to a fifth aspect of the present invention, there is provided a VLAN group table in which at least a VLAN group ID of a terminal connected to each port is registered.
A VLAN group ID for broadcast or multicast is read from the VLAN group table depending on whether the type of the received packet is broadcast or multicast, and the destination of the received packet is set to VLAN.
Replace with the group ID and V
VLAN group I after replacement with LAN group ID
In the case where forwarding is determined for each port so as to forward received packets having the same VLAN group ID by collating with D, the VLAN group ID is collated at each port. There is an advantage that the collation processing to be performed is decentralized, and the speed can be further increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment.

FIG. 2 is a diagram showing a format of a MAC / LLC frame used in the embodiment.

FIG. 3 is a diagram showing a format of a header part of an IP protocol used in the embodiment.

FIG. 4 is a block diagram showing a second embodiment.

FIG. 5 is a system configuration diagram of a third embodiment.

6A and 6B show main parts of the above, wherein FIG. 6A is a block diagram of a branch line interface, and FIG. 6B is a block diagram of a big pipe interface.

FIG. 7 is a system configuration diagram of a fourth embodiment.

FIG. 8 is a block diagram showing a fifth embodiment.

FIG. 9 is a system configuration diagram of a sixth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Branch line interface 2 Switch core 3 Big pipe interface 4 Service port 23 Repeater selection part 24 Repeat buffer 25 Port selection part 33 Unicast switching 41 Management part 42 VLAN group table 43 Dynamic bus connection control part A Switching hub B Network service server C network Service switch

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[Procedure amendment]

[Submission date] May 6, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

In this embodiment, four input ports and four output ports are provided. The input and output ports Ru is connected single transmission line. Also, a pair of branch interfaces by an input port and an output port is configured in the present embodiment.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

By the way, LLC information is LLC (Logical
Link Control) A PDU (Protocol Data Unit), which is defined in IEEE802.2 and shown in FIG.
Like DSAP (Destination Service Access Point)
t) Address, SSAP (Source Service Access Point)
) Has an address. The DSAP has a 1-bit I / G for identifying an individual or a group as shown in FIG. 2 (d), and the SSAP has a 1-bit C / D indicating a command or a response as shown in FIG. 2 (e). I / G having R = 0 indicates an individual, and I / G = 1 indicates a group. Also, C / R = 0 indicates a command, and C / R = 1 indicates a response. LLC P
It is also possible to use a header specified in IEEE802.10 as an option instead of the DU. This header includes a clear header and a protected header as shown in FIG. As shown in FIG. 2 (g), the clear header is an 802.110 LASP (Logical Service Access).
Point) and SAID (Security Association Identif)
ier) and an MDF (Manegemnt Defined Field), and the protected header comprises a source address. The VLAN ID is put in the SAID . I EE
At the drafting stage of E802.1Q , MAC header is issued.
Ethernet encoded next to source MAC address
Doug is placed, in which VLAN identifier (VID) is
However, after standardization is decided, implement according to this
Is done.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (5)

[Claims] 1. A unicast system in which a plurality of input ports and output ports are connected one-to-one between an input port and an output port, and a connection relationship is dynamically changed according to a destination of a received packet. The switching unit is connected between the input port and the output port via a repeat buffer.
A repeater unit that connects to the pair N and dynamically changes the connection relationship according to the destination of the received packet; and dynamically adjusts the received packet so as to appropriately pass through the switching unit and the repeater unit according to the destination of the received packet. A switching hub, comprising: a switching control unit for switching. 2. A big pipe, which is faster than the input port and the output port, is connected to the input port and the output port through the switching unit and the repeater unit. The switching hub according to claim 1. 3. A dedicated service port for connecting a network service server that performs QoS control is added, and the service port and the network service server are connected by a dedicated VLAN group channel. The switching hub according to claim 1 or 2. 4. A dedicated service port for connecting a network service switch for performing QoS control by interconnecting the switching hubs according to claim 1 or 2 is provided. 3. The method of claim 1 or 2, wherein the connection is established by a dedicated VLAN group channel.
The switching hub as described. 5. A VLAN group table in which at least a VLAN group ID of a terminal connected to each port is registered, wherein each port has a broadcast packet and a multicast packet according to whether the type of a received packet is broadcast or multicast. One of the VLAN group IDs is read from the VLAN group table, the destination of the received packet is replaced with the VLAN group ID, the VLAN group ID of the received packet is compared with the replaced VLAN group ID, and the received packet whose VLAN group ID matches is received. 3. The switching hub according to claim 1, wherein forwarding judgment is performed for each port so as to perform packet forwarding.