JP5598782B2 - Switching hub - Google Patents

Description

  The present invention relates to a switching hub.

  2. Description of the Related Art Conventionally, a network relay device that can be handled as one logical port by logically bundling a plurality of physical ports, and includes a packet input unit that inputs a packet and a packet that should be output to the logical port. The destination address information and the identification information for identifying the application that uses the packet, and among the physical ports constituting the logical port, the physical port used to output the packet is used as the destination address information and the identification information. There is known a network relay device that includes a physical port selection unit that selects correspondingly and a packet output unit that outputs a packet to a destination address using the selected physical port (see, for example, Patent Document 1).

  According to the network relay device described in Patent Document 1, more efficient network relay processing can be performed, and it is possible to cope with higher communication speed.

JP 2009-027758 A

  However, in the network relay device described in Patent Document 1, a distribution table for appropriately distributing packets and frames to transmission ports is provided for each line card. Then, in order to prevent the same frame from being transmitted from multiple ports in a transitional state where the registered contents of the distribution table are changed, the registered contents of the distribution table are once erased, and then synchronized between the line cards. It is necessary to update the registered contents of the table. Therefore, when a failure occurs in the port and the port is restored, and when the port is manually switched, a frame loss occurs.

  Accordingly, an object of the present invention is to provide a switching hub in which no frame loss occurs at the time of failure recovery and manual port switching.

  In order to achieve the above object, the present invention includes a plurality of line cards, and the line card stores a MAC (Media Access Control) address and a port ID or LAG ID in association with each other, an FDB (Forwarding Database), and a LAG. A LAG distribution table that stores IDs, distributed IDs, and port IDs in association with each other, a first distribution table that stores distributed IDs in association with port IDs of ports constituting the LAG, and a first distribution table are different. And a second distribution table that stores the distributed ID and the port ID of the ports constituting the LAG in association with each other, and when the line card receives the frame, the line card includes a destination included in the received frame. Performs FDB destination search by MAC address and When a group ID is detected, the frame is transferred to the port corresponding to the port ID. When a LAG ID is detected, the LAG distribution table is referenced, and the LAG distribution table associates the LAG ID with the distributed ID calculated from the frame. When the frame is transferred to the port corresponding to the stored port ID and the destination MAC address is not stored, the frame is transferred as a flooding relay. A switching hub is provided that refers to a first distribution table or a second distribution table and transfers a frame to a port corresponding to a port ID stored in the first distribution table or the second distribution table in association with a distribution ID. .

  According to the switching hub according to the present invention, it is possible to provide a switching hub in which no frame loss occurs at the time of failure recovery and manual port switching.

It is a block diagram of the switching hub which concerns on embodiment of this invention. It is a functional block diagram of the switching hub which concerns on embodiment of this invention. It is a functional block diagram of the receiving unit with which the line card which concerns on this Embodiment is provided. It is a figure which shows the data structure at the time of the normal time of the LAG distribution table which the receiving unit of the line card which concerns on this Embodiment has. It is a figure which shows the data structure when the port of port ID "4/1" becomes unusable and rewritten in the LAG distribution table which the receiving unit of the line card concerning this Embodiment has. It is a functional block diagram of the transmission unit with which the line card which concerns on this Embodiment is provided. It is a figure which shows the outline | summary of operation | movement of the switching hub which concerns on this Embodiment. (A) is a figure which shows the data structure of the 1st distribution table which concerns on this Embodiment, (b) is a figure which shows the data structure of the 2nd distribution table which concerns on this Embodiment.

[Outline of the embodiment]
In a switching hub having a plurality of ports including a reception port that receives a frame from the outside and a transmission port that transmits the frame to the outside, a distribution ID is calculated from the frame received by any of the reception ports of the plurality of ports. A distribution ID calculation unit that adds the distribution ID to the frame, a first distribution table that stores a port ID that identifies a transmission port that transmits the frame to the outside in association with the distribution ID, and A second distribution table that stores the port ID in association with the distribution ID so as to have a different relationship with the one distribution table, and first table identification information that identifies the first distribution table, or the second distribution table A sorting table for adding second table identification information for identifying a table to the frame. And when the first table identification information is added to the frame, the second distribution table is referred to when the second table is added to the frame. Switching provided with a transmission-side distribution table access unit that obtains the port ID stored in the first distribution table or the second distribution table in association with the distributed ID added to the frame with reference to the table A hub is provided.
[Embodiment]
FIG. 1 shows an outline of a configuration of a switching hub according to an embodiment of the present invention, and FIG. 2 shows an outline of a functional configuration of a line card according to an embodiment of the present invention.
(Outline of the configuration of the switching hub 1 and the line card 2)
A switching hub 1 according to an embodiment of the present invention is a chassis type switching hub that relays information such as a frame, and includes a plurality of line cards (for example, a line card 2, a line card 2a, a line card 2n), and a plurality of line cards. And a relay path 3 as a communication path for relaying information such as frames between the line cards. Each line card is connected to the relay path 3 (for example, the port 13 and the port 14 in the line card 2, the port 13a and the port 14a in the line card 2a, and the port 13b and the port 14b in the line card 2n). , Ports connected to the transmission line (for example, transmission lines 4, 4n, 5, 5n, 6, 6n) (for example, the port 10 of the line card 2 is connected to the transmission line 4, and similarly the ports 10n, 11, 11n , 12 and 12n are connected to transmission lines 4n, 5, 5n, 6 and 6n, respectively).

  In the present embodiment, a Link Aggregation Group (LAG) is configured from a plurality of ports selected from among the ports connected to the transmission paths of each line card. Here, LAG is a technique defined in IEEE Std 802.3-2005, and is a technique for bundling a plurality of physical lines into one logical line. Since the plurality of line cards have the same configuration and function in the present embodiment, the line card 2 will be described in detail below.

As shown in FIG. 2, the line card 2 includes a plurality of ports (for example, ports 10, 10a, 10n) including a plurality of reception ports that receive information such as frames from the outside and a plurality of transmission ports that transmit frames to the outside. ), An I / F circuit 20 as an interface unit that controls transmission and reception of information at a plurality of ports, a receiving unit 30 that determines from which port a received frame is transmitted, and a determination based on the determination of the receiving unit 30 And a transmission unit 40 that transmits a frame from a predetermined port.
(I / F circuit 20)
The I / F circuit 20 receives a frame received by any one of the plurality of receiving ports from the port, and supplies the frame to the receiving unit 30. The I / F circuit 20 adds an internal header to the received frame, stores the port ID of the port that received the frame in the internal header, and then supplies the frame with the internal header to the receiving unit 30.

The I / F circuit 20 transmits the frame received from the transmission unit 40 from a predetermined port. The I / F circuit 20 supplies the frame to the port set as the transmission port in the transmission port bitmap of the internal header added to the received frame. The I / F circuit 20 deletes the internal header added to the frame when supplying the frame to the port.
(Receiving unit 30)
FIG. 3A shows an example of a functional configuration of a receiving unit included in the line card according to the present embodiment.

The receiving unit 30 according to the present embodiment includes a distributed ID calculation unit 300, a distribution table identification information adding unit 305, an FDB access circuit 310, an FDB 315, and a LAG distribution table access circuit 320 as a reception side distribution table access unit. And a LAG sorting table 332.
(Distributed ID calculation unit 300)
The distributed ID calculation unit 300 calculates a distributed ID from a frame received by any one of a plurality of receiving ports, and adds the calculated distributed ID to the frame. For example, the distributed ID calculation unit 300 receives a frame received by any one of the plurality of ports from the I / F circuit 20 and calculates a distributed ID using a MAC (Media Access Control) address included in the frame. Then, the distributed ID calculation unit 300 adds the calculated distributed ID to the internal header of the frame. The distributed ID calculation unit 300 supplies the frame to which the distributed ID is added to the sorting table identification information adding unit 305.
(Distribution table identification information adding unit 305)
The distribution table identification information adding unit 305 determines which one of the first distribution table 330 and the second distribution table 335 included in the transmission unit 40 is used according to the communication states of a plurality of ports constituting the LAG. Specifically, the distribution table identification information adding unit 305, when a failure has not occurred in any of a plurality of ports constituting the LAG, or when using a plurality of currently used transmission ports as they are, First table identification information for identifying the first distribution table 330 is added to the frame received from the distributed ID calculation unit 300.

  In addition, the distribution table identification information adding unit 305 changes any or all of the plurality of used ports to other transmission ports when a failure occurs in any of the plurality of ports constituting the LAG. In this case, second table identification information for identifying the second distribution table 335 is added to the frame received from the distributed ID calculation unit 300.

The sorting table identification information adding unit 305 uses the 1-bit area of the internal header of the frame, for example, to give the first table identification information (for example, “0”) or the second table identification information (for example, “1”). Append to the inner header of the frame. The sorting table identification information adding unit 305 supplies the frame to which the first table identification information or the second table identification information is added to the FDB access circuit 310. In this embodiment, the distribution table identification information adding unit 305 is arranged at the subsequent stage of the distributed ID calculation unit 300. However, the present invention is not limited to this. For example, the distribution table identification information adding unit 305 may be arranged after the LAG distribution table access circuit 320.
(FDB access circuit 310 and FDB315)
A forwarding database (FDB) 315 stores at least a MAC address included in a frame and a port ID or LAG ID as a port identifier for uniquely identifying a port that has received the frame as registered contents.

  The FDB access circuit 310 has a function of searching the FDB 315 using a transmission source MAC address and a destination MAC address included in a frame received from the distribution table identification information adding unit 305, and a function of changing registration contents of the FDB 315. That is, the FDB access circuit 310 has a function of performing source MAC address learning, frame destination search, and the like.

  For example, the FDB access circuit 310 compares the destination MAC address included in the frame with the distributed ID added received from the distribution table identification information adding unit 305 with the MAC address stored in the FDB 315. If the FDB access circuit 310 determines that the same MAC address as the destination MAC address is not stored in the FDB 315, the FDB access circuit 310 supplies the frame to the LAG distribution table access circuit 320 as a flooding relay. When the FDB access circuit 320 supplies the frame to the LAG sorting table access circuit 320 as a flooding relay, the FDB access circuit 320 stores an identifier that identifies flooding as a destination in the internal header of the frame.

  The FDB access circuit 310 compares the destination MAC address included in the frame received from the distribution table identification information adding unit 305 with the MAC address stored in the FDB 315, and as a result, the same MAC address as the destination MAC address. When the port ID stored in the FDB 315 in association with the MAC address is detected, the port ID is stored as the destination in the internal header of the frame. Then, the FDB access circuit 310 supplies the frame including the destination port ID in the internal header to the LAG sorting table access circuit 320 as forwarding relay (unicast).

The FDB access circuit 310 compares the destination MAC address included in the frame received from the distribution table identification information adding unit 305 with the MAC address stored in the FDB 315, and as a result, the same MAC address as the destination MAC address. When the LAG ID stored in the FDB 315 in association with the MAC address is detected, the frame is supplied to the LAG distribution table access circuit 320 together with the LAG ID.
(LAG distribution table 332)
The LAG distribution table 332 stores a port ID that identifies a port that is a transmission port that transmits a frame to the outside in association with the LAG ID and the distributed ID. In the present embodiment, each of the plurality of line cards provided in the switching hub 1 has the same LAG distribution table 332. In the present embodiment, an example in which a LAG with a LAG ID “1” is configured by three ports with port IDs “3/1”, “4/1”, and “5/1” is shown. “3/1” means identifying the first port of the third line card.

  FIG. 3B shows port IDs “3/1”, “4/1”, “5/1” constituting the LAG with the LAG ID “1” in the LAG distribution table included in the receiving unit of the line card according to the present embodiment. ”Shows a normal data configuration in which all three ports can be used. Port IDs “3/1”, “4/1”, and “5/1” are stored in association with the distribution IDs “0” to “7”. In the present embodiment, since eight distributed IDs “0” to “7” are provided, one LAG can be configured from a maximum of eight ports. When a LAG is configured from eight or more ports, the number of distributed IDs may be increased.

  FIG. 3C shows a data configuration when the port with the port ID “4/1” becomes unusable and rewritten in the LAG sorting table included in the receiving unit of the line card according to the present embodiment. Port IDs “3/1” and “5/1” are stored in association with the distribution IDs “0” to “7”.

For example, as illustrated in FIG. 3B, the LAG sorting table 332 included in the reception unit 30 is configured so that any of the plurality of ports configuring the LAG does not have a failure or the plurality of currently used transmission ports are used as they are. When the port ID is continuously used, that is, in a normal state, the port ID “4/1” is stored. Here, when the port ID “4/1” cannot be used, the LAG distribution table access circuit 320 rewrites the stored contents of the LAG distribution table 332 as shown in FIG. 3C, for example.
(LAG distribution table access circuit 320)
When the LAG distribution table access circuit 320 receives a frame together with the LAG ID from the FDB access circuit 310, the LAG distribution table access circuit 320 refers to the LAG distribution table 332 using the LAG ID. Then, the port ID stored in the LAG sorting table 332 in association with the LAG ID and the distributed ID added to the internal header of the frame is stored as the destination port in the internal header of the frame. The LAG distribution table access circuit 320 supplies the frame storing the destination port ID from the port 13 to the relay path 3.

  Further, the LAG distribution table access circuit 320 is a case where the frame received from the FDB access circuit 310 is a frame as a forwarding relay, and when the destination port ID is included in the internal header, the frame is used as it is. , And supplied from the port 13 to the relay path 3.

  Further, when the frame received from the FDB access circuit 310 is a frame as a flooding relay, the LAG sorting table access circuit 320 supplies the frame from the port 13 to the relay path 3 as it is.

In addition, when forwarding and forwarding a frame in which the port ID is stored in the internal header, the distributed ID added to the frame is not essential, and the FDB access circuit 310 or the LAG distribution table access circuit 320 obtains the distributed ID from the frame. It can also be deleted.
(Relay route 3)
The relay path 3 receives the frame from the receiving unit 30 and relays the frame to the transmission unit 40 of the line card having the destination port. When the port ID is stored as the destination in the internal header of the frame received from the receiving unit 30, the relay path 3 relays the frame to the line card having the port of the port ID. When the flooding identifier is stored as a destination in the internal header of the frame received from the receiving unit 30, the relay path 3 relays the frame to all line cards except the line card that has received the frame.
(Transmission unit 40)
FIG. 4 shows an example of the functional configuration of the transmission unit provided in the line card according to the present embodiment.

The transmission unit 40 according to the present embodiment includes a transmission side distribution table access circuit 400 as a transmission side distribution table access unit, a transmission port bitmap setting unit 405, a first distribution table 330, and a second distribution table 335. Have
(First distribution table 330 and second distribution table 335)
The first distribution table 330 and the second distribution table 335 store port IDs that identify ports that are transmission ports that transmit frames to the outside in association with the distribution IDs.

  FIG. 5B (a) shows the data structure of the first distribution table 330. The first distribution table 330 is used, for example, when there is no failure in a plurality of ports constituting the LAG, or when a plurality of currently used transmission ports are continuously used as they are. In FIG. 5B (a), normal data in which all three ports with port IDs “3/1”, “4/1”, and “5/1” constituting the LAG with the LAG ID “1” are usable. A configuration is shown, and port IDs “3/1”, “4/1”, and “5/1” are stored in association with the distribution IDs “0” to “7”.

FIG. 5B (b) shows the data structure of the second distribution table 335. The second distribution table 335 changes, for example, if any of a plurality of ports constituting the LAG has failed, or changes any or all of the plurality of transmission ports used to other transmission ports. Used in cases. In FIG. 5B (b), the port ID “4/1” of the three ports ID “3/1”, “4/1”, and “5/1” configuring the LAG with the LAG ID “1” is shown. A data configuration when the port is unusable is shown, and port IDs “3/1” and “5/1” are stored in association with the distribution IDs “0” to “7”.
(Transmission side distribution table access circuit 400)
When an identifier for identifying flooding (or an identifier indicating multicast) is stored as a destination in the internal header of the frame, the transmission-side distribution table access circuit 400 stores the first table identification information in the frame. Is added, the first sorting table 330 is referred to, and when the second table identification information is added to the frame, the second sorting table 335 is referred to.

  For example, the transmission-side distribution table access circuit 400 refers to the first distribution table 330 or the second distribution table 335 using the distribution ID added to the frame. Then, the transmission-side distribution table access circuit 400 acquires the port ID stored in the first distribution table 330 or the second distribution table 335 in association with the distribution ID, and transmits the frame together with the port ID to the transmission port bitmap. This is supplied to the setting unit 405. The port ID acquired from the first distribution table 330 or the second distribution table 335 may be stored in the internal header of the frame together with an identifier that identifies flooding as a destination.

Further, when the port ID is stored as the destination in the internal header of the frame, the transmission side distribution table access circuit 400 transmits the frame to the transmission port bitmap without referring to the first distribution table 330 and the second distribution table 335. This is supplied to the setting unit 405.
(Transmission port bitmap setting unit 405)
The transmission port bitmap setting unit 405 sets a transmission bitmap in the internal header of the frame. The transmission bitmap has, for example, the number of bits corresponding to the number of ports connected to the transmission path of the line card, and each bit of the plurality of bits is associated with each port of the plurality of ports. For example, “1” is set in the bit associated with the port that is the transmission port, and “0” is set in the bit associated with the port that is not the transmission port.

  When the port ID is stored as the destination in the internal header of the frame received from the transmission-side distribution table access circuit 400, the transmission port bitmap setting unit 405 associates the transmission bitmap with the port of the port ID. Set “1” in the bit and “0” in the other bits.

  In addition, when the flooding identifier is stored as the destination in the internal header of the frame received from the transmission-side distribution table access circuit 400, the transmission port bitmap setting unit 405 sets the LAG ID “1” as a port that does not constitute the LAG. The associated bit is set to “1”, and is acquired from the first distribution table 330 or the second distribution table 335 in the transmission-side distribution table access circuit 400 among the ports constituting the LAG with the LAG ID “1”. “1” is set to the bit associated with the port with the port ID, and “0” is set to the bits associated with the ports constituting the LAG with the other LAG ID “1”. It should be noted that a port that does not constitute a LAG with a LAG ID “1” and that constitutes a LAG with another LAG ID is the same as the above for the LAG with the other LAG ID. “1” is set to the bit associated with the port of the ID, and “0” is set to the bit associated with the other port constituting the LAG of the other LAG ID “1”. In this case, the transmission unit 40, for the LAG of the other LAG ID, associates with the distributed ID and stores the port IDs of the ports constituting the LAG of the other LAG ID and the second distribution table 330 335.

  The transmission port bitmap setting unit 405 supplies the frame in which the transmission bitmap is set to the I / F circuit 20.

When the I / F circuit 20 receives the frame from the transmission port bitmap setting unit 405, the I / F circuit 20 transmits the frame from the port associated with the bit set to “1” in the transmission bitmap.
(Switching hub operation)
FIG. 5A shows an outline of the operation of the switching hub according to the present embodiment, FIG. 5B (a) shows the data configuration of the first distribution table according to the present embodiment, and FIG. The data structure of the 2nd distribution table which concerns on embodiment is shown.

  As shown in FIG. 5A, the switching hub 1 includes line cards 2, 2a, 2b, and 2c. The port 10 of the line card 2 is connected to the transmission path 4 and the port 13 is connected to the relay path 3. Similarly, the port 11 of the line card 2 a is connected to the transmission path 5, and the port 14 is connected to the relay path 3. The port 17 of the line card 2 b is connected to the transmission path 7, and the port 15 is connected to the relay path 3. Further, the port 18 of the line card 2 c is connected to the transmission path 8, and the port 16 is connected to the relay path 3. Here, the port ID of the port 10 is “1/1”, the port ID of the port 11 is “3/1”, the port ID of the port 17 is “4/1”, and the port ID of the port 18 is “5/1”. And The port 11, the port 17, and the port 18 constitute one LAG.

As shown in FIG. 5B (a), the first distribution table 330 used when no failure has occurred in a port or when a plurality of currently used transmission ports are continuously used as they are is assigned to the distribution ID. The port ID is stored in association with each other. For example, if no failure has occurred in the port, the first distribution table 330 stores the port ID “3/1” in association with the distribution IDs “0”, “3”, and “6”, and the distribution ID “3/1”. The port ID “4/1” is stored in association with “1”, “4”, and “7”, and the port ID “5/1” is stored in association with the distribution IDs “2” and “5”.
(Flooding relay: When there is no failure in the port)
First, a case where a frame is relayed as flooding will be described. As an example, when the port 10 receives a frame, the distributed ID calculation unit 300 included in the line card 2 calculates a distributed ID from the MAC address included in the frame. For example, when the value of the distribution ID calculated by the distribution ID calculation unit 300 is “1”, the distribution ID calculation unit 300 adds the distribution ID “1” to the frame. The distribution table identification information adding unit 305 included in the line card 2 adds the first table identification information to the frame because no failure has occurred in the port.

The transmission-side distribution table access circuits 400 of the line cards 2a to 2c that have received the frame with the first table identification information refer to the first distribution table 330, respectively. In the case of the first distribution table 330 shown in FIG. 5B (a), the port ID corresponding to the distribution ID “1” is “4/1”, so the frame is transmitted from the port 17 included in the line card 2b.
(Flooding relay: After a port failure)
For example, when a failure occurs in the port 17, the second distribution table 335 stores the port ID “3/1” in association with the distribution IDs “0”, “2”, “4”, “6”, The port ID “5/1” is stored in association with the distribution ID “1”, “3”, “5”, “7”. That is, the second distribution table 335 stores port IDs excluding the port ID corresponding to the port where the failure has occurred.

  When the port 10 receives the frame, the distributed ID calculation unit 300 included in the line card 2 calculates the distributed ID from the MAC address included in the frame. For example, when the value of the distribution ID calculated by the distribution ID calculation unit 300 is “1”, the distribution ID calculation unit 300 adds the distribution ID “1” to the frame. The distribution table identification information adding unit 305 included in the line card 2 adds the second table identification information to the frame because a failure has occurred in the port.

  The transmission side distribution table access circuits 400 of the line cards 2a to 2c that have received the frame with the second table identification information refer to the second distribution table 335, respectively. In the case of the first distribution table 330 shown in FIG. 5B (b), since the port ID corresponding to the distribution ID “1” is “5/1”, the frame is transmitted from the port 18 of the line card 2c.

When the failure of the port 17 is recovered, the distribution table identification information adding unit 305 included in the line card 2 adds the first table identification information to the newly received frame. Thereby, switching hub 1 concerning this embodiment switches the port which should transmit a frame.
(Forwarding relay)
Next, a case where a frame is forwarded and relayed will be described. As an example, when the port 10 receives a frame, the FDB access circuit 310 refers to the FDB 315 and acquires the port ID or LAG ID stored in the FDB 315 in association with the MAC address included in the received frame. Then, the FDB access circuit 310 transfers the frame to a line card or LAG having a port identified by the acquired port ID or LAG ID. Then, the transmission side distribution table access circuit 400 of the line card that has received the frame receives the frame received from the receiving unit 30 from the port or LAG identified by the port ID or LAG ID stored in the internal header of the frame. Send to the outside.
(Effect of embodiment)
Since the switching hub 1 according to the embodiment of the present invention includes the line card 2 having the first distribution table 330 and the second distribution table 335 in advance, a failure such as a failure occurs in a transmission port to which a frame is to be transmitted. Or after changing the currently used transmission port to another transmission port, when the transmission port is restored, or when the changed other transmission port is returned to the transmission port before the change, the first distribution table The transmission ports to which frames are to be transmitted can be switched simultaneously by simply switching the table used from 330 to the second distribution table 335 or from the second distribution table 335 to the first distribution table 330. As a result, the switching hub 1 does not lose a frame when a transmission port is restored after a failure such as a failure occurs in one of the transmission ports or after changing the transmission port currently used to another transmission port. You can switch ports.

  Further, the switching hub 1 according to the present embodiment switches the table to be used from the first distribution table 330 to the second distribution table 335 when the port to be transmitted is manually switched from one port to another port. Therefore, the port can be switched without losing a frame (that is, degeneration can be performed without frame loss). Thereby, even when replacing a faulty line card among a plurality of line cards included in the switching hub 1, the line card can be replaced smoothly without losing a frame.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

1 switching hub 2, 2a, 2b, 2c, 2n line card 3 relay path 4, 4a, 4n, 5, 5n, 6, 6n, 7, 8 transmission path 10, 10a, 10n, 11, 11n, 12, 12n port 13, 13a, 13b, 14, 14a, 14b Port 15, 16, 17, 18 Port 20 I / F circuit 30 Reception unit 40 Transmission unit 300 Distributed ID calculation unit 305 Distribution table identification information addition unit 310 FDB access circuit 315 FDB
320 LAG distribution table access circuit 330 First distribution table 332 LAG distribution table 335 Second distribution table 400 Transmission-side distribution table access circuit 405 Transmission port bitmap setting unit

Claims (1)

With multiple line cards,
The line card is
FDB (Forwarding Database) that stores MAC (Media Access Control) address and port ID or LAG (Link Aggregation Group) ID in association with each other;
A LAG distribution table that stores LAG IDs, distributed IDs, and port IDs in association with each other;
A first distribution table for storing in association with the port ID of the plurality of ports to a plurality of ports disorders constituting the dispersion ID and the LAG when not occurred constituting the LAG,
The distributed ID when a failure occurs in any of the plurality of ports constituting the LAG and the port IDs of the plurality of ports constituting the LAG excluding the port where the failure occurs are associated with each other A second sorting table for storing;
With
When the line card receives the frame, the line card searches the FDB for the destination MAC address included in the received frame, and when detecting the port ID, transfers the frame to the port corresponding to the port ID. When the LAG ID is detected, the LAG distribution table is referred to, and the LAG distribution table stores the LAG ID and the port corresponding to the port ID stored in association with the distributed ID calculated from the frame. Forward the frame, and if the destination MAC address is not stored, forward the frame as a flooding relay;
The line card adds first table identification information for identifying the first distribution table to the received frame when a failure has not occurred in a plurality of ports constituting the LAG, and the plurality of ports constituting the LAG. If any of the failure occurs, the second table identification information for identifying the second distribution table is added to the received frame,
The line card refers to the first distribution table when the first table identification information is added to the frame transferred as flooding relay, and when the second table identification information is added, Referring to the second distribution table and transferring the frame to a port corresponding to a port ID stored in association with the distribution ID in the first distribution table or the second distribution table;
Switching hub.

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