JP2005051691A - Switching hub - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and economically realize an Ethernet network in which an Ethernet (R) terminal that guarantees maximum transmission capacity and an conventional (best-effort type) Ethernet terminal are mixed. <P>SOLUTION: A switching hub provided with a means for transmitting an input frame to an Ethernet (R) transmission path in preference to an input frame without priority display only when the input frame has priority frame, or for transmitting an input frame to the Ethernet transmission path in preference to the input frame without priority display only when the input frame has priority display and also has learned a destination MAC address is provided between Ethernet terminals that guarantee the maximum transmission capacity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a switching hub used in an Ethernet network in which conventional (best effort type) terminals and Ethernet terminals that guarantee the maximum transmission capacity are mixed. Hereinafter, in this specification, each port in an Ethernet terminal, an Ethernet frame, an Ethernet transmission path, an Ethernet network, and a switching hub is simply referred to as a terminal, a frame, a transmission path, a network, and a port, respectively.

  As a method of performing various transmission services, priority of eight stages (network management, voice, video, controlled load, excellent effort, best effort, spare, background) is used with IEEE802.1Q / p tagged frames. Although there is a method, there is a drawback that QoS (for example, maximum transmission capacity) cannot be guaranteed if traffic with the same priority increases.

As a countermeasure, RSVP (Resource Reservation
Protocol: RFC2205), Inserv (Integrated Service), etc., a method for guaranteeing QoS by performing resource reservation has been proposed. Although these methods can guarantee QoS, resource reservation processing is required at a node in the communication path. Since this operation is necessary for each communication request, it is complicated and not widely used. A similar operation is performed in the current public telephone network and is complicated even if the communication charge calculation is omitted.

  In the ATM network, terminals are set in advance using virtual channels, and the virtual network is constructed using channel capacity management means at the network edge (connection point between the network and terminals) and a virtual channel link free capacity database (centralized arrangement). For example, Patent Document 1 discloses a method of performing communication with guaranteed capacity between terminals of a channel.

This is a method that can centrally manage free resources in the network, but it is necessary to set the virtual channels to be managed beforehand, so there is a problem of managing a large number of virtual channels or a problem that limits the communication partner terminal. there were.
Japanese Patent Laid-Open No. 7-221863

  As a problem for solving these problems, there is a route search in a target network as a first problem. Since the target network is an Ethernet network, it has a tree topology (including a bus topology) and does not generate a plurality of routes. Therefore, the route search is not complicated, but at the time of route search, flooding (input) at the node (hub) If a frame is relayed to all transmission lines other than the transmission line), there is a problem that network resources are wasted.

  The second problem is capacity allocation management of transmission paths on the path. It should be noted that the congestion avoidance at the node can be solved by arranging the buffer amount so that the buffer overflow does not occur by considering the concentration condition on the output transmission path.

  Also, to determine the maximum delay time (total transmission waiting time if there is no transmission path propagation delay and buffer overflow (congestion) in the hub) in the network connecting terminals (transmission path is composed of hubs) Therefore, it is necessary to manage the transmission path (path) and the used transmission capacity (frame rate) of the transmission path.

  In order to solve these problems, the applicant of the present application has proposed a network resource management apparatus that guarantees the maximum transmission capacity on the Ethernet network according to Japanese Patent Application No. 2003-271474 (not disclosed at the time of application). This requires the network resource management function to manage the capacity of the entire network, but has the advantage of not requiring control over the switching hub in the network.

  However, in applying this prior application, there is a condition that it is a network of only terminals that guarantee the maximum transmission capacity, and it cannot be applied to a network in which conventional (best effort) terminals are mixed because it is affected by the traffic. It was. Furthermore, the switching hub has a MAC address learned condition (flooding avoidance) at the start of communication. As a countermeasure, a frame for learning the MAC address of the switching hub (learning with the transmission address) is received in advance between terminals. It was necessary to send from the sending terminal to the sending terminal.

  The present invention has been carried out against this background, and the conventional network is changed from a conventional (best effort) terminal to a network in which a terminal having a maximum transmission capacity is guaranteed in a simple and economical manner. It is an object to provide a switching hub that can be changed.

  The present invention solves the problems of the prior application, incorporates priority control in the processing at the switching hub, and preferentially sends a frame of communication between terminals that guarantees the maximum transmission capacity to the transmission line. The conventional (best effort) terminal processing is not prioritized and the influence on the traffic of the terminal that guarantees the maximum transmission capacity is avoided.

  As a result, even if a terminal that guarantees the maximum transmission capacity and a conventional (best effort) terminal coexist, if there is only the switching hub of the present invention between the terminals that guarantee the maximum transmission capacity, communication that guarantees the maximum transmission capacity is possible. It becomes possible.

  In the prior application, there was a condition that the MAC address was learned at the start of communication. However, in the present invention, a process of giving priority to the input frame and sending it to the transmission line only when the destination MAC address has been learned. It can be. As a result, even if there is a frame with an unlearned MAC address at the start of communication, the same non-priority flooding as a frame transmitted from a conventional terminal is performed, and inter-terminal communication guarantees the maximum transmission capacity, which is a priority process during communication. Will have no effect. However, the maximum transmission capacity can be guaranteed when only the switching hub of the present invention exists in the inter-terminal path, and the best-effort transmission is performed when the existing hub is included.

  In other words, the present invention has a MAC address learning function applied to a network including a network resource management function for transmitting a frame with priority display for guaranteeing the maximum transmission capacity and a conventional best effort frame without priority display to a transmission path. The Ethernet switching hub is characterized in that the feature of the present invention is that the input frame is sent to the transmission line in preference to the input frame without priority display only when the input frame has priority display. It is in the place with.

  As a result, in a network in which conventional (best effort type) terminals and terminals that guarantee the maximum transmission capacity are mixed, it is possible to realize communication between terminals that guarantee the maximum transmission capacity by providing the switching hub of the present invention. it can.

  Alternatively, the switching hub of the present invention sends the input frame to the transmission line in preference to the input frame without priority display only when the input frame has priority display and the destination MAC address has been learned. Means may be provided.

  Thereby, it is possible to avoid the influence of the traffic of the terminal whose destination MAC address has not been learned from reaching the communication between terminals that guarantees the maximum transmission capacity.

  As the priority display, 3 bits representing the priority of TCI (Tag Control Information) can be used. In this case, it is desirable to provide means for adding or removing TCI at the network edge for terminals that do not support TCI. Thereby, even if the terminal does not support TCI, priority display can be performed by TCI.

  In addition, it is possible to provide means for processing MAC address learning of a frame with priority display in preference to a frame without priority display. This makes it possible to effectively use network resources by reducing the number of terminals that have not yet learned MAC addresses for transmitting and receiving frames with priority indications and reducing the probability of occurrence of flooding.

  In addition, when the buffer amount of a frame for which priority processing is not performed becomes equal to or larger than the set value Thmax, a PAUSE frame whose transmission is stopped is sent to the corresponding input transmission line, and when the set value Thmin (Thmax> Thmin) is reached, a corresponding operation is performed. Means may be provided for sending a PAUSE frame for canceling transmission suspension to the transmission line. As a result, it is possible to avoid a buffer overflow of a frame for which priority processing is not performed.

  In addition, it has means to set the input frame rate threshold value of the port connected to the terminal manually or by access from the network resource management function, and non-priority is given to the frame with the priority display of the frame rate exceeding the threshold value Means for handling as a frame can be provided. Thereby, it is possible to limit the frame rate of the priority frame and avoid congestion of the priority frame.

Also, the threshold of the input frame rate set by the access from the network resource management function and the protocol for notification when the rate is exceeded are SNMP (Simple Network Management Protocol) or RMON (Remote Network
Monitoring) or RMON2 (Remote Network Monitoring MIB Version 2) can be used.

  Also, when receiving a notification of a source MAC address and a destination MAC address that guarantee the maximum transmission capacity from the network resource management function, the priority processing display of the frame having the MAC address is enabled at the network edge, and the network resource management function When a MAC address notification that does not guarantee the maximum transmission capacity is received from the network, means for canceling the priority processing display of a frame having the MAC address at the network edge can be provided.

  As a case of receiving a MAC address notification that does not guarantee the maximum transmission capacity from the network resource management function, for example, a case where a communication end notification that guarantees the maximum transmission capacity or an abnormal or disturbing communication is received can be considered.

  In the present invention, conventional (best effort) terminals are not prioritized to avoid the influence of traffic of conventional terminals, so that conventional (best effort) terminals and terminals that guarantee the maximum transmission capacity are mixed. However, if there is a switching hub of the present invention between terminals that guarantee the maximum transmission capacity, communication is possible, and the maximum transmission capacity is guaranteed with a conventional (best-effort type) terminal in a simple and economical manner. It is possible to change to a network in which mixed terminals are mixed.

  Even if there is a frame with an unlearned MAC address at the start of communication, the same non-priority flooding as with a conventional frame (best effort type) is performed, and inter-terminal communication guarantees the maximum transmission capacity, which is a priority process during communication. Can be avoided.

  An embodiment of the present invention will be described with reference to FIGS.

  The operation of the switching hub on the network when communication with guaranteed maximum transmission capacity and best effort communication coexist will be described with reference to FIGS.

  In FIG. 1, 1-1 to 1-7 are switching hubs with MAC address learning and priority processing, 2 is a network resource management device having a network resource management function, and 3-1 to 3-4 are terminals that guarantee the maximum transmission capacity. 4-1 to 4-4 are conventional (best effort) terminals, and 5-1 to 5-14 are transmission lines. That is, the first embodiment includes means for sending the input frame to the transmission lines 5-1 to 5-14 in preference to the input frame without priority display only when the input frame has priority display. It is characterized (claim 1).

  In this network, the network resource management device secures a transmission capacity in one path by call processing performed at the start of communication between the end-to-end terminal and the network resource management device. Since this detail is not directly related to the present invention and will be omitted, a brief description will be given. The network resource management device uses a network management protocol of SNMP, RMON, or RMON2 installed in the switching hub. Collect MIB (Management Information Base) information for each switching hub. MIB (management information base) is a standard for network management, and agents (managed devices) hold various network information and information about the devices themselves as variables. These are collectively referred to as MIB, and a network monitoring manager can collect MIB information possessed by such agents by using SNMP and monitor the status of the network and devices (for each port of the switching hub).

  Since each terminal determines its maximum delay time on a transmission line connecting the terminals, it is necessary to manage the transmission capacity (frame rate) used in the transmission line. One example is TCPVegas. TCPReno, which is generally used, adjusts the window size that has become too large using segment loss. Accordingly, the window size becomes unnecessarily small immediately after the occurrence of the segment loss, so that the throughput is lowered. On the other hand, TCPVegas observes the RTT (Round Trip Time) of the transmitted segment, and uses the fluctuation to adjust the window size.

  That is, if the RTT increases, it is determined that the network is congested and the window size is reduced. If the RTT is reduced, the window size is increased. Thereby, the transmission rate can be controlled. Note that if the transmission is performed with a frame interval rather than concentrated on the time within the window, the peak rate can be lowered, and there is an advantage that the buffer capacity in the switching hub can be reduced. The present invention is based on the premise that each terminal manages the used transmission capacity of the transmission path.

  At the time of this call processing, the switching hub learns the MAC address of the destination terminal by the MAC address learning logic that performs MAC address learning by the source MAC address, as shown in FIG. You can send data without waking up.

  When the terminal 3-1 and the terminal 3-4 shown in FIG. 1 perform communication with a guaranteed maximum transmission capacity, and the terminal 4-1 and the terminal 4-4 perform best effort communication, the switching hub 1- The transmission queues 1, 1-2, 1-4, 1-5, and 1-7 may overflow due to an increase in traffic, and there is a risk of being affected by best-effort communication between communications in which the maximum transmission capacity is guaranteed. .

  In such a network in which maximum transmission capacity guarantee communication and best effort type communication are mixed, a switching hub that preferentially sends out to the transmission line only when there is a priority display in the frame performing the operation shown in FIGS. By doing so, the influence from conventional (best effort) terminals can be avoided, and the maximum delay time (transmission path propagation delay and switching) in the transmission network (consisting of transmission path and switching hub) connecting the terminals. The frame transmission waiting time in the hub can be determined. 2, 3, and 4 indicate an operation of “registering or referring to the MAC address table”.

  When a frame is received as shown in FIG. 3, the MAC address learning logic performs MAC address learning of the transmission source MAC address, and learns the transmission source MAC address of the received frame. That is, when the source MAC address is read and the source MAC address is not in the MAC address table, if the MAC address table is empty, the source MAC address and the received port number x are registered in the MAC address table.

  By referring to the MAC address table, it is determined whether the received frame is an output port or the frame is discarded in the transfer logic shown in FIG. In this forwarding logic, the switching hub reads the destination MAC address. At that time, if the destination MAC address is broadcast (FF-FF-FF-FF-FF-FF), the switching hub maps the frames to the transmission queues of all ports except the received port. If it is not broadcast, it is checked whether the destination MAC address is in the MAC address table. When there is no destination MAC address in the MAC address table, flooding (mapping to the transmission queue of all ports other than the reception port) is performed. If there is a destination MAC address in the MAC address table, if the destination MAC address is connected to the port that received it, the frame is discarded, and if it is connected to another port, it is mapped to the transmission queue of that port. The

  In the transmission queue of the output port determined by this transfer logic, when the frame has priority display as shown in FIG. 5, the frame with priority display is mapped to the corresponding transmission queue. If the priority queue is transmitting, the effect can be eliminated by interrupting the non-priority queue and transmitting the priority queue immediately. Give priority to traffic with priority indication and send it to the transmission line. However, the non-priority frame being transmitted needs to be retransmitted, and the non-priority transmission efficiency decreases. In order to avoid this decrease, the one frame may be transmitted after being transmitted. That is, this method can be used when a delay of a maximum of one frame time can be tolerated.

  As described above, the preferentially displayed frame can have the same characteristics as when there is no non-priority frame.

  Flooding occurs when the MAC address on the communication side is unlearned for some reason at the start of communication in which the maximum transmission capacity is guaranteed in the communication shown in the first embodiment, which has an effect on traffic that has already guaranteed the maximum transmission capacity. In this case, in addition to the priority display condition, it will be described that it can be avoided by performing priority processing only when the MAC address has been learned and sending it to the transmission line. With reference to FIG. 6, description will be made on the operation of sending priority to the transmission line in the switching hub only when the input frame has priority display and the destination MAC address has been learned. 6 indicates an operation of “registering or referring to the MAC address table”. That is, the second embodiment is characterized in that when the input frame has priority display and the destination MAC address has already been learned, a means for sending the input frame to the transmission path is provided (claim 2). .

  The frame whose output port is determined by the transfer logic reads whether or not the frame has priority display as shown in FIG. In the case of a frame with priority display, the switching hub transfers the frame to the transmission queue having a high priority only when the destination MAC address of the frame is in the MAC address table (learned). In other cases (unlearned), the frame with priority display is transferred to a transmission queue with a low priority.

  As a result, even if there is a frame with an unlearned MAC address at the start of communication, the same non-priority flooding as with a conventional terminal frame occurs, and this affects the inter-terminal communication that guarantees the maximum transmission capacity, which is the priority processing already in communication Will not give. This is a safety measure when unlearning occurs. However, the maximum transmission capacity can be guaranteed when only the switching hub of the present invention exists in the inter-terminal path, and the best-effort transfer is performed when the existing hub is included.

  FIG. 7 and FIG. 8 show that TCI (Tag Control Information) standardized by IEEE 802.1Q / p can be used for the frame priority display in the switching hubs shown in the first and second embodiments. (Claim 3).

As shown in FIG. 7, this TCI has priority, CFI (Canonical Format
Indicator) and a VLAN (Virtual-LAN) identifier.

  In TCI, 3 bits are assigned as the priority, and when the value of the VLAN identifier field is all 0 (0x000), the TCI tag does not represent the VLAN relevance, and each device (switching hub) prioritizes the frame. Can be processed. In addition, since this VLAN identifier field is used to construct a VLAN, if GVRP (GARP VLAN Registration Protocol: IEEE802.1Q) is used, unnecessary broadcasts and unknown unicast traffic are removed, and multicast routes (Capacity allocation is required for all the multicast routes).

  The priority given by the TCI tag is given to the frame. As a result, frames can be preferentially processed according to the type of traffic in the switching hub. For example, when mapping received frames to two transmission queues, a frame corresponding to a high priority level is a frame of level 5 or higher (network management, voice, video, data guaranteeing transmission capacity) shown in FIG. A frame of less than level 5 is assigned to the queue corresponding to the low priority. However, it is necessary to manage the maximum transmission capacity by the network resource management device. Further, when priority levels of 5 or higher (levels 5, 6, and 7) are processed as one priority queue, the priority difference between them is eliminated and they are handled as one level.

  With the priority display by the TCI tag, the frame can be preferentially processed in the switching hub and sent to the transmission line. It is assumed that the frame with priority display shown below is assigned to priority level 5 or higher, and other frames (best effort type) are assigned to priority level 5 or lower.

  In the switching hub shown in the third embodiment, the operation of adding or removing the TCI in the switching hub corresponding to the edge on the network in order to guarantee the maximum transmission capacity in the frame between the terminals not supporting the TCI is shown in FIGS. Will be described with reference to FIG. In FIG. 9 and FIG. 11, a broken line arrow (thin line) indicates an operation of “reference to the priority tagging management table”, and a broken line arrow (thick line) indicates an operation of “register or refer to the MAC address table”. 10 and 12 indicate the operation of “refer to the priority tagging management table”. That is, the fourth embodiment includes means for adding or removing TCI at a network edge for a terminal that does not support TCI (claim 4).

  When each terminal in FIG. 1 is not a TCI-compatible terminal, when the switching hub 1-1 at the transmission side network edge receives a frame from the terminal 3-1, a TCI tag is attached to the frame as shown in FIGS. Read whether or not. When a TCI tag is attached, the priority displayed on the TCI tag is used. When the TCI tag is not attached, the destination MAC address and the source MAC address of the frame are read, and the destination MAC address and the source MAC address between the end-to-end terminals for which maximum transmission capacity is to be guaranteed, and the input are input. By referring to a priority tagging management table in which ports are registered in advance (set manually or by access from a network resource management device), it is checked whether the frame is a communication frame between terminals that guarantees the maximum transmission capacity.

  For example, the switching hub 1-1 registers both MAC addresses between terminals (terminal 3-1 and terminal 3-4) that guarantee the maximum transmission capacity in the priority tagging management table in advance. Only in the case of a frame in communication between the terminals, the switching hub attaches a TCI tag to the frame and preferentially displays it. For frames that do not guarantee the maximum transmission capacity (not listed in the priority tagging management table), the frames are handled as a best effort type (switch default).

  As a result, even if a frame between terminals not supporting TCI is transmitted, the maximum transmission capacity can be guaranteed by adding a TCI tag within the switching hub.

  Each switching hub learns the source MAC address of the frame to which the TCI tag is added in the MAC address table by the MAC address learning logic. Since the output destination port of the frame received during the MAC address learning process is determined by the transfer logic, the switching hub maps to the transmission queue for the priority given to the frame and transfers it to the next node.

  When the switching hub 1-7 at the edge of the receiving network in FIG. 1 sends the frame transmitted from the terminal 3-1 to the terminal 3-4, the TCI tag added to the frame by the switching hub 1-1 is shown in FIG. As shown in FIG. 12, after the frame is taken out from the transmission queue by the switching hub 1-7, it is checked whether it is a frame for communication between terminals that guarantees the maximum transmission capacity in the same manner as the switching hub at the edge of the transmission side network. .

  For example, the switching hub 1-7 stores both MAC addresses between terminals (terminal 3-1 and terminal 3-4) that guarantee the maximum transmission capacity and the port to which each terminal is connected in advance in the priority tagging management table. sign up. Only in the case of a frame in communication between the terminals, the switching hub deletes the TCI tag from the frame with the TCI tag. The other frames are sent as they are.

  As described above, even in a frame between terminals not supporting TCI, the switching hub can guarantee the maximum transmission capacity by registering the MAC address between terminals not supporting TCI in advance in the priority tagging management table.

  In the switching hub shown in the first embodiment and the second embodiment, an operation that makes it difficult for flooding to occur in communication with a guaranteed maximum transmission capacity by preferentially processing the source MAC address learning of a frame given a high priority. An example will be described with reference to FIGS. 13 indicates the operation of “registering or referring to the MAC address table”. That is, the fifth embodiment includes means for processing MAC address learning of a frame with priority display in preference to a frame without priority display.

  When starting communication from the terminal 3-1 to the terminal 3-4, the switching hub 1-1 receives a frame with a priority display with a TCI tag attached from the terminal 3-1.

  The switching hub 1-1 that has received the TCI-tagged frame at the port X of the switching hub 1-1 reads the destination MAC address, the source MAC address, and the TCI tag as shown in FIG.

  A frame with priority display is learned in the MAC address table of the switching hub with priority by the MAC address learning logic shown in FIG. 13 regardless of whether it has been learned or not learned. For frames without priority display, the MAC address learning logic is terminated if the MAC address table has already been learned, and if it has not been learned, the source MAC address is set to the MAC address only when the frame with priority display is not being learned. Register in the table.

  Since the frame transmitted from the terminal 3-1 has priority display, the switching hub 1-1 learns with priority given to the MAC address of the terminal 3-1.

  Conventional MAC address learning is not necessarily performed when a frame is received. Even if unlearned, communication is not disabled and flooded instead of being directed to a specific port. It is learned when the traffic peak has passed and the switching hub has time to learn. For frames with high priority display, MAC address pre-learning shown in FIG. 13 is performed to prevent MAC address unlearning. Also, if there is no space in the MAC address table, it is not learned until the MAC address learned earlier is aged, but it is stored in the MAC address table using the FIFO (First In First Out) method or the LRU (Least Recently Used) method. Learn the source MAC address.

  As described above, a frame for which the maximum transmission capacity is guaranteed can be preferentially displayed and transmitted to the transmission line, and the source MAC address can be preferentially learned in the MAC address table for that frame.

  When communication traffic in which the maximum transmission capacity is guaranteed increases, the queue in the switching hub for best effort communication (non-priority) increases, and frame discard occurs. As an avoidance, the switching hub shown in the first embodiment and the second embodiment performs an operation for avoiding buffer overflow (transmission queue overflow) in a transmission queue for a frame not subjected to priority processing by a PAUSE frame (IEEE802.3x). Will be described with reference to FIG. That is, when the buffer amount of the frame not subjected to the priority processing becomes equal to or larger than the set value Thmax, a PAUSE frame whose transmission is stopped is sent to the corresponding input transmission line, and when the set value Thmin (Thmax> Thmin) is reached, it corresponds. Means for sending a PAUSE frame for canceling transmission stop to the transmission line is provided.

As shown in FIG. 14 to FIG. 16, when the transmission queue for a frame for which priority processing is not performed exceeds the set value Thmax (upper limit threshold), the PAUSE frame control set to the initial value Reset is set and the corresponding A PAUSE frame is transmitted to the source MAC address, and transmission from the terminal having the MAC address is stopped. If the transmission queue setting value Thmin (lower threshold) is reached, the PAUSE frame control is set to Reset, and a PAUSE cancellation frame for canceling transmission suspension is transmitted to the terminal again. Here, as shown in FIG.
Thmax> Thmin
It is. In the PAUSE frame control, the frame sent to the transmission queue is compared with each threshold value to control the transmission of the PAUSE frame. As a result, when the total traffic of the frame that guarantees the maximum transmission capacity becomes large, the frame is accumulated in the transmission queue with a low priority, but the buffer does not overflow, and reaches the set value Thmax of the transmission queue before the buffer overflows. Then, the buffer overflow can be avoided by transmitting the PAUSE frame. If the transmission queue overflows for a frame received before transmitting the PAUSE frame, the frame is discarded. Similarly, the frame is discarded even if the transmission queue overflows due to a frame with priority indication, but this event does not occur unless the capacity management fails or fails. Thereby, the transmission capacity in the switching hub can be used efficiently.

  In the first embodiment and the second embodiment, in order to prevent the influence of a terminal in which the maximum transmission capacity is guaranteed from being in an abnormal state, a threshold value of the input frame rate of the switching hub is set, and the frame exceeds the threshold value. An operation for performing the same processing as that for a non-priority frame (best effort type) when there is priority display will be described with reference to FIG. That is, the seventh embodiment includes means for setting a threshold value of an input frame rate of a port connected to a terminal manually or by access from a network resource management apparatus, and a frame having a priority display of a frame rate exceeding the threshold value. On the other hand, a means for handling as a non-priority frame is provided.

  The frame whose output port is determined by the transfer logic reads whether or not the frame has priority display as shown in FIG. In the case of a frame with priority indication, the switching hub compares whether the frame exceeds a preset frame rate threshold before transferring the frame to a transmission queue having a high priority. If the threshold is not exceeded, the switching hub forwards the frame to a higher priority transmission queue. If it exceeds, the switching hub transfers the frame to a transmission queue with a low priority and sends it to the next node in the same manner as the best effort type.

  This threshold sets a frame rate guaranteed in the transmission path. For example, when a maximum transmission capacity of 10 Mbps is guaranteed in a certain transmission line, the threshold value is 10 Mbps. This function may be arranged at any switching hub, but it is efficient to arrange this function at the network edge.

  FIG. 19 to FIG. 22 show an example in which SNMP, RMON, or RMON2 is used as the threshold of the input frame rate set by the access from the network resource management device and the notification protocol when the rate is exceeded in the seventh embodiment. It explains using.

In FIG. 19, 6 is a network resource management device corresponding to SNMP, 7-1 to 7-3 are switching hubs equipped with SNMP and RMON functions, 8-1 and 8-2 are terminals, and 9-1 to 9-9. -5 is composed of a transmission line. That is, in the eighth embodiment, an SNMP (Simple Network Management Protocol: RFC1157) or RMON (Remote Network) is used as the input frame rate threshold set by access from the network resource management device and the notification protocol when the rate is exceeded.
Monitoring: RFC2819) or RMON2 (Remote Network Monitoring MIB Version 2) is used (claim 8).

  The switching hub supports RMON function group 1 (statistical information), group 2 (history), group 3 (alarm), and group 9 (event). Group 1 (statistical information) provides data for all ports. Group 2 (history) provides data regarding ports for a certain history period. Group 3 (Alarm) can create an alarm and set conditions for generating an alarm when a change is detected based on the MIB object. Group 9 (Event) can create an event and set the action of the event when the associated alarm occurs.

  By using this RMON alarm, it is possible to monitor whether the MIB object is in a target transition state. Alarms are periodically sampled from object values and compared to a set threshold. In RMON, there are two types of sampling: absolute values and delta (difference) values. In the eighth embodiment, the sample value is compared with the threshold value by the absolute value sampling shown in FIG. When the sample value exceeds the alarm threshold, an associated event is generated. This threshold is set based on the transmission capacity secured by the network resource management device. For example, when the transmission capacity secured by the network resource management apparatus is 10 Mbps, the threshold value is 10 Mbps. Also, SNMP is used as means for notifying the network resource management device when an RMON is accessed, a threshold value is set, or an event is generated.

  The network resource management device 6 is connected to the port 1 of the switching hub 7-1, the port 3 of the switching hub 7-1 and the port 5 of the switching hub 7-2, the port 6 of the switching hub 7-1 and the switching hub 7-3. Are connected in cascade between the two ports. The terminal 8-1 is connected to the port 3 of the switching hub 7-2, and the terminal 8-2 is connected to the port 4 of the switching hub 7-3.

  In this network configuration, the switching hubs 7-2 and 7-3 transmit stream data from the terminal 8-1 to the terminal 8-2 using the method shown in FIG. Measure the used transmission capacity. That is, according to FIG. 21, the network resource management device transmits the traffic threshold and the port to be measured to the switching hub by the SNMPSet request. In the switching hub, after receiving the SNMPSet request, the RMON sets a threshold and a port for rate measurement, and transmits a Get response after setting to the network resource management device. The switching hub measures the rate of frames flowing to the set port.

  At this time, when the rate exceeds the threshold value, the switching hub notifies the network resource management device that the rate has exceeded the threshold value by SNMP trap. Receiving this, the network resource management device knows that the rate has exceeded the threshold after receiving SNMP trap. When the rate does not exceed the threshold, if the network resource management device wants to know the rate status, the network resource management device transmits an SNMP Get request to the set switching hub. The switching hub that has received the SNMPGet request returns the current value to the network resource management apparatus by an SNMPGet response.

  When the rate measurement is finished, the network resource management device transmits to the switching hub so as to cancel the traffic threshold by an SNMPSet request. The switching hub cancels the traffic threshold after receiving the SNMPSet request, and then transmits a Get response to the network resource management device.

  In this way, each switching hub has a switching hub port (switching) on one path between the terminal 8-1 and the terminal 8-2 based on the threshold set by the SNMPSet request transmitted from the network resource management device 6. The frame rates of the port 3 of the hub 7-2, the port 3 of the switching hub 7-1 and the port 2) of the switching hub 7-3 are measured. When the frame rate exceeds the set threshold value, the switching hub notifies the network resource management device by SNMP trap. Thereby, the network resource management apparatus can know the abnormality of the frame transmission rate of the terminal. This is a measure against excessive traffic of the frame.

  Further, when the network resource management apparatus wants to inquire the status of the frame rate to the switching hub with an SNMPGet request, the switching hub sends the current value to the network resource management apparatus with an SNMPGet response in response to the inquiry. This frame rate measurement is continued unless an SNMPSet request for canceling the threshold set by the switching hub is received from the network resource management device and an SNMPGet response is sent to the network resource management device. Here, the operation of SNMP is shown in FIG.

  As described above, the threshold of the frame rate is set at each switching hub port on the route, and when a frame rate exceeding the threshold is received, the network resource management apparatus can be notified by using SNMP, RMON, or RMON2. it can.

  In a frame between end-to-end terminals, a method for ensuring the start of communication for guaranteeing the maximum transmission capacity or the operation for terminating the communication for guaranteeing the maximum transfer capacity, or the maximum transmission capacity for abnormal and jamming communication We will show how to make the operation that cannot be guaranteed more reliable. In the switching hub arranged at the network edge according to the first or second embodiment, when a notification of the source MAC address and the destination MAC address and priority for guaranteeing the maximum transmission capacity is received from the network resource management device, the information is Store in the priority processing display management table. The operation for changing the priority processing display of a frame having the MAC address will be described with reference to FIGS. In FIG. 23 and FIG. 25, a broken line arrow (thick line) indicates an operation of “registering or referring to the MAC address table”, and a broken line arrow (thin line) indicates an operation of “refer to the priority processing display management table”. 24 and 26 indicate an operation of “refer to the priority processing display management table”. That is, in the ninth embodiment, the priority processing display of the frame having the MAC address at the network edge is validated by the priority processing display management table set by the network resource management device. When receiving a MAC address notification that does not guarantee the maximum transmission capacity from the network resource management device, the information corresponding to the MAC address is deleted from the priority processing display management table, and the priority processing display of the frame is canceled at the network edge. (Claim 9).

  Here, the priority processing display management table will be described.

  The priority processing display management tables shown in FIGS. 23 to 26 are registered by notifying the network resource management device of the telnet access and the MAC address guaranteeing the maximum transmission capacity by the SNMPSet request. Alternatively, the priority can be changed or deleted from the priority processing display management table by notifying the end-to-end MAC address that does not guarantee the maximum transmission capacity, and the frame priority display can be changed.

  Accordingly, the switching hub that has received the notification of the end-to-end MAC address that guarantees the maximum transmission capacity from the network resource management device enables the priority display of the frame having the MAC address. In addition, the switching hub that has received the end-to-end MAC address notification that does not guarantee the maximum transmission capacity from the network resource management device can cancel the priority display of the frame having the MAC address.

  The operation of the switching hub at the transmission-side network edge for the preferentially displayed frame (frame with TCI tag) will be described.

  When a frame with a TCI tag is transmitted to a network composed of switching hubs having this priority processing display management table, as shown in FIG. 23 and FIG. 24 at a port with a switching hub arranged at the transmission-side network edge. The priority processing display management table is referred to from the source MAC address and the destination MAC address.

  If the End-to-End MAC address for the frame is not described in the priority processing display management table, the frame is transferred as it is to the next processing (MAC address learning and transfer processing). Since this frame is not a frame with a guaranteed transmission capacity, if priority display is given to the received frame, priority display is canceled and the default (best effort type) of the switch is given to that frame.

  If the End-to-End MAC address for the frame is described in the priority processing display management table, this frame is a frame that guarantees the transmission capacity (a frame that performs priority processing), so the switching hub The priority is compared with the priority described in the priority processing display management table. If these two priorities are the same, the frame is transferred to the next process as it is, and prioritized and sent to the next node.

  When the priority of the received frame is different from the priority described in the priority processing display management table, communication that guarantees the maximum transmission capacity can be performed by changing the same as the information described in the priority processing display management table. Alternatively, if there is a discrepancy with the priority processing display management table due to an abnormality, jamming communication, or the like, the frame is transferred to the next processing after being changed to the priority described in the priority processing display management table. Thereby, there is no contradiction in the priority processing management for the frame.

  An operation for performing priority processing (maximum transmission capacity guarantee) in a switching hub arranged at the transmission-side network edge with respect to a conventional frame (a frame transmitted from a TCI tag incompatible terminal or a best effort type) will be described.

  When a conventional frame (without a TCI tag) is received at a port having a switching hub arranged on the transmission side edge having the priority processing display management table, as shown in FIGS. 23 and 24, the source MAC address and the destination MAC The priority processing display management table is referred to from the address. If the End-to-End MAC address for the frame is not described in the priority processing display management table, the frame is subjected to conventional best-effort communication, so that the frame is subjected to the next processing (MAC address learning and transfer). Process).

  When the End-to-End MAC address for the frame is described in the priority processing display management table, the switching hub is described in the priority processing display management table because the frame guarantees the maximum transmission capacity. A TCI tag indicating the priority is added to the frame.

  In this way, the frame transmitted by the switching hub at the transmission side network edge transfers the frame to the reception side network edge via each switching hub arranged in the network.

  Next, the operation of the switching hub at the receiving network edge that transmits a frame to a terminal that does not support the TCI tag will be described below.

  After the switching hub arranged at the receiving network edge takes out the frame from the transmission queue, the priority processing display management table is referred to from the transmission source MAC address and the destination MAC address as shown in FIGS. The switching hub at the receiving network edge registers both MAC addresses between end-to-end terminals that guarantee the maximum transfer capacity and the ports to which the terminals are connected in advance in the priority processing display management table. . This can be done by notifying the network resource management device that each end-to-end terminal does not support the TCI tag at the start of communication for guaranteeing the transmission capacity. Only in the case of a frame in communication between the terminals, the switching hub deletes the TCI tag from the frame with the TCI tag. The other frames are sent as they are.

  As described above, since the switching hub adds the priority described in the priority processing display management table to the received frame, it is possible to change the priority at the end-to-end transmission / reception. Further, the processing by the switching hub is only the priority changing operation, and the frame transfer can be performed without influence on the frame with the TCI tag transmitted from the terminal belonging to the VLAN.

  The present invention can be implemented as a program that, when installed in a general-purpose information processing apparatus, causes the information processing apparatus to realize functions corresponding to the respective means of the switching hub of the present invention. The program is recorded on a recording medium and installed in the information processing apparatus (claim 11), or installed in the information processing apparatus via a communication line, so that the information processing apparatus has each of the switching hubs of the present invention. Functions corresponding to the means can be realized.

  As described above, the present invention introduces priority control to the processing of the MAC address learning function and the switching hub with priority processing, and gives priority to the frame with priority display of communication between terminals that guarantees the maximum transmission capacity to the transmission path. Send it out. Only the switching hub of the present invention can be provided between the terminals that guarantee the maximum transmission capacity even if both terminals coexist by avoiding the influence of the traffic of the conventional terminals by making the processing of the conventional (best effort) terminal non-prioritized. Communication is possible.

  Also, priority is sent to the transmission path only when the input frame has priority display and the destination MAC address has been learned. As a result, even if there is a frame with an unlearned MAC address at the start of communication, the same non-priority flooding as with a conventional terminal frame occurs, which has an effect on inter-terminal communication that guarantees the maximum transmission capacity, which is a priority process during communication. Can be avoided.

  Thus, by providing the switching hub of the present invention with respect to the conventional network, it is possible to realize a network in which a terminal that guarantees the maximum transmission capacity without significant change and a conventional (best effort) terminal are mixed. Therefore, it is possible to flexibly cope with the needs of a wide variety of users and improve the service quality for the users.

The network block diagram which shows one Example of this invention. The flowchart showing the process of the frame in a switching hub. The flowchart showing the "MAC address learning logic" in FIG. The flowchart showing the "transfer logic" in FIG. FIG. 2 is a flowchart showing “transmission queue at each output port” in FIG. 1. FIG. 2 is a flowchart in the case of “sending queue at each output port” in FIG. 1 when priority is given to an input frame and the destination MAC address is learned to the destination only when it is learned. The figure which shows a TCI (Tag Control Information) tag format. The figure which shows the priority level in IEEE802.1p. The flowchart showing the process which adds TCI to a frame within a switching hub. 10 is a flowchart showing “TCI tagging logic” in FIG. 9. The flowchart showing the process which deletes TCI from a flame | frame within a switching hub. FIG. 12 is a flowchart showing “TCI tag removal logic” in FIG. 11. The flowchart showing MAC address learning of the frame with priority display. The flowchart showing the case where a PAUSE frame is used in the “transmission queue at each output port” in FIG. The flowchart showing the PAUSE frame transmission logic in FIG. The flowchart showing the PAUSE cancellation | release frame transmission logic in FIG. The figure which shows an example showing the threshold value for PAUSE frame transmission set to the transmission queue. FIG. 3 is a flowchart showing that when a frame with priority display exceeds a set frame rate threshold value in the “transmission queue at each output port” in FIG. The figure which shows an example of the network structure in the case of measuring the rate in the port of a switching hub. The figure which shows an example of the absolute value sampling by RMON. The flowchart showing the method of measuring a rate in the specific port of a switching hub. The figure which shows operation | movement of SNMP. The flowchart showing the process which validates the priority display of a frame in the switching hub by this invention. 24 is a flowchart showing “priority processing display logic” in FIG. The flowchart showing the process which cancel | releases the priority display of a frame in the switching hub by this invention. The flowchart showing the "priority process display cancellation logic" in FIG.

Explanation of symbols

1-1 to 1-7, 7-1 to 7-3 Switching hub 2 and 6 Network resource management devices 3-1 to 3-4, 8-1, and 8-2 Terminals (maximum transmission capacity is guaranteed)
4-1 to 4-4 terminal (conventional type)
5-1 to 5-14, 9-1 to 9-5 Transmission path

Claims (11)

Ethernet (registered trademark) having a MAC address learning function applied to a network including a network resource management function for transmitting a frame with priority display for guaranteeing the maximum transmission capacity and a conventional best effort frame without priority display to a transmission path Switching hub for
A switching hub comprising means for sending an input frame to the transmission line in preference to an input frame without priority display only when the input frame has priority display. In an Ethernet switching hub having a MAC address learning function applied to a network including a network resource management function for transmitting a frame with priority display for guaranteeing the maximum transmission capacity and a conventional best effort frame without priority display to a transmission path ,
A means for sending the input frame to the transmission line in preference to an input frame without priority display only when the input frame has priority display and the destination MAC address has been learned. Switching hub.   The switching hub according to claim 1 or 2, wherein 3 bits representing a priority of TCI (Tag Control Information) are used as the priority display.   4. The switching hub according to claim 3, further comprising means for adding or removing TCI at a network edge for a terminal not supporting TCI.   3. The switching hub according to claim 1, further comprising means for processing MAC address learning of a frame with priority display in preference to a frame without priority display.   When the buffer amount of a frame for which priority processing is not performed becomes equal to or larger than the set value Thmax, a PAUSE frame whose transmission is stopped is sent to the corresponding input transmission line, and when the set value Thmin (Thmax> Thmin) is reached, the corresponding transmission line The switching hub according to claim 1, further comprising means for transmitting a PAUSE frame for canceling transmission stop to the network. Comprising means for setting a threshold of an input frame rate of a port connected to a terminal manually or by access from a network resource management function;
The switching hub according to claim 1, further comprising means for handling a frame having a priority display with a frame rate exceeding the threshold as a non-priority frame. SNMP (Simple Network Management Protocol) or RMON (Remote Network) as the threshold of the input frame rate set by access from the network resource management function and the notification protocol when the rate is exceeded
The switching hub according to claim 1 or 2, wherein RMON2 (Remote Network Monitoring MIB Version2) is used. When a notification of the source MAC address and destination MAC address that guarantees the maximum transmission capacity is received from the network resource management function, the priority processing display of the frame having the MAC address is enabled at the network edge, and the maximum is received from the network resource management function. The switching hub according to claim 1, further comprising means for canceling a priority processing display of a frame having the MAC address at a network edge when receiving a MAC address notification that does not guarantee a transmission capacity.   A program that, when installed in an information processing apparatus, causes the information processing apparatus to realize functions corresponding to the respective means of the switching hub according to any one of claims 1 to 9.   The information processing apparatus-readable recording medium on which the program according to claim 10 is recorded.

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