An ultra-low latency switching device and a method for controlling forwarding actions thereof

Abstract

This disclosure discloses an ultra-low latency switching device and a method for controlling forwarding actions thereon. In this method, the source MAC address and source IP address of the incoming packets arriving at the internal port are used to update the exception forwarding address mapping table; wherein, the direct-connection port of the internal port is mapped to the external forwarding port of the ultra-low latency switch; the Ethernet header of the outgoing packets arriving at the internal port is cached according to the specified number of cache bytes for the outgoing direction of the internal port; based on the specified IP address in the exception forwarding action access control ACL entry of the internal port, the mapped MAC address of the specified IP address is found in the exception forwarding address mapping table; the destination MAC address of the cached outgoing packet's Ethernet header is determined as the mapped MAC address; and the outgoing packets are processed based on the exception forwarding action ACL entry.

Description

Technical Field

[0001] This disclosure relates to communication technology, specifically to an ultra-low latency switching device and a method for controlling forwarding actions thereon. Background Technology

[0002] Currently, the financial and securities industry has an increasingly strong demand for high-frequency trading, resulting in an explosive growth in demand for ultra-low latency trading systems composed of ultra-low latency switches. It is against this demand background that ultra-low latency switches have emerged with advantages such as extremely low latency and extremely simple functions.

[0003] Ultra-low latency switches forward packets using a pass-through forwarding mode. However, in some business scenarios, it's necessary to configure Access Control List (ACL) entries to filter specific IPs. This can lead to the packet's initial portion being forwarded in the previous interface clock cycle, while the remaining portion is discarded in the next interface clock cycle due to the ACL filtering match. Similarly, when setting ACL entries that allow forwarding IP addresses for ports that are previously prohibited from forwarding, the packet's initial portion is discarded in the previous interface clock cycle, while the remaining portion is allowed to forward in the next interface clock cycle due to the ACL filtering match. This results in incomplete packets being forwarded to other communication devices.

[0004] To ensure the integrity of the forwarded message, it is necessary to cache the message content, including the IP header, but this will increase the forwarding latency. Summary of the Invention

[0005] The purpose of this disclosure is to provide an ultra-low latency switching device and a method for controlling forwarding actions of the same, so as to control the forwarding actions of a specified port while reducing forwarding latency.

[0006] To achieve the above objectives, this disclosure provides a method for controlling forwarding actions in an ultra-low latency switching device. The method includes: updating an exception forwarding address mapping table based on the source MAC address and source IP address of an incoming packet arriving at an internal port; wherein the direct-connected routing port of the internal port is mapped to an external forwarding port of the ultra-low latency switch; caching the Ethernet header of an outgoing packet arriving at the internal port according to a specified number of cache bytes for the outgoing direction of the internal port; finding the mapped MAC address of the specified IP address in the exception forwarding action access control ACL entry of the internal port in the exception forwarding address mapping table; determining the destination MAC address of the cached outgoing packet's Ethernet header as the mapped MAC address; and processing the outgoing packet based on the exception forwarding action ACL entry.

[0007] To achieve the above objectives, this disclosure also provides an ultra-low latency switching device, which includes: a setting unit for setting the default forwarding action of the outbound default forwarding action register of an internal port; setting the exception forwarding action ACL table of the exception forwarding action access control ACL register of the internal port; setting a specified number of cache bytes and a specified cache space of the outbound cache register of the internal port, and setting an exception forwarding address mapping register for the internal port to be empty; the internal port being located in an internal forwarding unit and directly connected to a flow port of the switching unit; an internal switching unit for updating the exception forwarding address mapping table of the exception forwarding address mapping register based on the source MAC address and source IP address of the incoming packets arriving at the internal port; caching the Ethernet header of the outbound packets arriving at the internal port in a specified cache space according to the specified number of cache bytes; finding the mapped MAC address of the specified IP address in the exception forwarding address mapping table based on the specified IP address of the exception forwarding action access control ACL table entry of the internal port; determining the destination MAC address of the Ethernet header of the cached outbound packets as the mapped MAC address; and processing the outbound packets based on the exception forwarding action ACL table entry.

[0008] The beneficial effect of this disclosure is that it reduces the packet content that needs to be cached for ACL entry matching and comparison to a minimum number of bytes, and controls the forwarding action of a specified port while reducing forwarding latency. Attached Figure Description

[0009] Figure 1 A flowchart illustrating an embodiment of a method for controlling ultra-low latency switching and forwarding actions;

[0010] Figure 2A-2B This is a schematic diagram of an embodiment of the control and forwarding actions of an ultra-low latency switching device provided in this disclosure;

[0011] Figures 3A-3B This is a schematic diagram of Embodiment 2 of the control and forwarding actions of the ultra-low latency switching equipment provided in this disclosure;

[0012] Figure 4 This disclosure provides a schematic diagram of an ultra-low latency switching and forwarding device for controlling forwarding actions. Detailed Implementation

[0013] The following detailed description will be provided with reference to several examples illustrated in the accompanying figures. In this detailed description, numerous specific details are used to provide a comprehensive understanding of this disclosure. Known methods, steps, components, and circuits are not described in detail in the examples to avoid obscuring their meaning.

[0014] In the terminology used, the term "including" means including but not limited to; the term "containing" means including but not limited to; the terms "above," "within," and "below" include the number itself; the terms "greater than" and "less than" mean not including the number itself. The term "based on" means based on at least a portion of them.

[0015] Figure 1 The figure shown is an embodiment of a method for controlling forwarding actions in an ultra-low latency switching device provided in this disclosure. The method includes:

[0016] Step 101: Update the exception forwarding address mapping table based on the source MAC address and source IP address of the incoming packets arriving at the internal port; wherein, the routing port directly connected to the internal port is mapped to the external forwarding port of the ultra-low latency switch.

[0017] Step 102: Cache the Ethernet header of outgoing packets arriving at the internal port according to the specified number of buffer bytes for the outgoing direction of the internal port.

[0018] Step 103: Based on the specified IP address of the access control ACL entry for the exception forwarding action of the internal port, find the mapped MAC address of the specified IP address in the exception forwarding address mapping table;

[0019] Step 104: Determine the destination MAC address of the cached Ethernet header as the mapped MAC address, and process the outgoing packets based on the matching exception forwarding action ACL entry.

[0020] Figure 1 The beneficial effect of the method implementation is that it reduces the packet content that needs to be cached for ACL entry matching and comparison to the minimum number of bytes, and controls the forwarding action of the specified port while reducing forwarding latency.

[0021] Figure 2A-2B This is a schematic diagram of an embodiment of the control and forwarding action of an ultra-low latency switching device provided for this disclosure.

[0022] Figure 2A In this disclosure, an internal switching unit S2 with a PCIe physical layer interface (PIPE) chip is added to the ultra-low latency switch 20.

[0023] The CPU of the ultra-low latency switch 20 sets the mapping relationship between the external forwarding ports 1-11 of the switching unit S1 and the ports 21-31 on the switching chip S1 that serve as flow guides; the CPU sets the internal ports P21 and P25 directly connected to the flow guide ports 21 and 25 to send the packets received to P31; and configures the packets received by P31 to be sent to P21 and P25.

[0024] The CPU of the ultra-low latency switch 20 sets the default forwarding action of the outbound default forwarding action register of internal port P21 to Deny forwarding; sets the exception forwarding action ACL table of the exception forwarding action register of internal port P21 to Permit forwarding corresponding to IP address IP1; sets the specified number of buffer bytes of the outbound buffer register of internal port P21; sets the specified buffer space of internal port P21; and sets the exception forwarding address mapping register of internal port P21 to be empty.

[0025] The CPU of the ultra-low latency switch 20 sets the default forwarding action of the outbound default forwarding action register of the internal port P25 to disable forwarding; sets the exception forwarding action ACL table of the internal port P25 to record the IP address IP2 corresponding to the allowed forwarding; sets the specified number of buffer bytes in the outbound buffer register of the internal port P25; sets the specified buffer space of the internal port P25; and sets the exception forwarding address mapping register of the internal port P25 to be empty.

[0026] The outgoing buffer registers of internal ports P21 and P25 each have the same number of specified buffer bytes, which is equal to the first byte of the message preamble to the last byte of the message Ethernet header, thus ensuring that the forwarding latency of all external forwarding ports on the ultra-low latency switch 20 is the same.

[0027] Transaction request messages 201 and 202 from clients C1 and C2 arrive at port 1 and port 5 respectively. Switching unit S1 sends the message content of transaction request messages 201 and 202 received within each interface clock cycle through the mapped routing ports 21 and 25.

[0028] Internal switching unit S2, based on the source MAC address MAC1 and source IP address IP1 of the transaction request message 201 received by internal port P21 within a continuous interface clock cycle, searches the exception forwarding address mapping register of internal port P21. If the mapping relationship between MAC1 and IP1 is not found, internal switching unit S2 records the mapping relationship between MAC1 and IP1 in the exception forwarding address mapping register of internal port P21. Internal switching unit S2 then sends the message content of the transaction request message 201 received within the continuous interface clock cycle to internal port P31.

[0029] Internal switching unit S2, based on the source MAC address MAC2 and source IP address IP2 of the transaction request message 202 received by internal port P25 within a continuous interface clock cycle, looks up the exception forwarding address mapping register of internal port P25. If internal switching unit S2 does not find the mapping relationship between MAC2 and IP2, it records the mapping relationship between MAC2 and IP2 in the exception forwarding address mapping register of internal port P25. Internal switching unit S2 then sends the message content of the transaction request message 202 received within the continuous interface clock cycle to internal port P31.

[0030] The switching unit S1 receives transaction request messages 201 and 202 through the flow port 31 within a continuous interface clock cycle, and sends them to the server S1 through the mapped external forwarding port 11.

[0031] Figure 2B In the process, server S1 sends a transaction response message 301 to client C1; the destination MAC address is MAC 1; and the destination IP address is IP1.

[0032] Switching unit S1 receives the Ethernet header of transaction request message 301 through external forwarding port 11 within the current interface clock and sends it through flow port 31.

[0033] Internal switching unit S2 receives the Ethernet header of transaction response message 301 through internal port P31 within the current interface clock, and copies it twice, sending it to internal ports P21 and P25 respectively.

[0034] The internal switching unit S2 caches the Ethernet header of the transaction response message 301 received within the current interface clock, i.e., the message content from the first bit of the transaction response message 301 to the last bit of the Ethernet header, according to the specified number of cache bytes and the specified cache space in the outgoing buffer register of the internal port P21.

[0035] Internal switching unit S2 searches the exception forwarding action ACL register of internal port P21 and reads the IP address IP1 from the exception forwarding action ACL table record of internal port P21.

[0036] The internal switching unit S2 finds the mapped MAC address MAC1 of IP1 by searching the exception address mapping register of internal port P21.

[0037] Internal switching unit S2 determines that the destination MAC address MAC1 of the Ethernet header of the cached transaction response message 301 is the mapped MAC address MAC1. Based on the allow forwarding action in the exception forwarding action ACL table of internal port P21, it sends the Ethernet header of the transaction response message 301 cached in the specified cache space of internal port P21 through internal port P21.

[0038] The internal switching unit S2 caches the Ethernet header of the transaction response message 301 received within the current interface clock according to the specified number of cache bytes and the specified cache space in the outgoing buffer register of the internal port P25.

[0039] Internal switching unit S2 searches the exception forwarding action ACL register of internal port P25 and reads the IP address IP2 from the exception forwarding action ACL table record of internal port P25.

[0040] The internal switching unit S2, based on the discovery of IP2 in the exception address mapping register of internal port P25, finds the mapped MAC address MAC2 of IP2.

[0041] Internal switching unit S2 determines that the destination MAC address MAC1 of the Ethernet header of the cached transaction response message 301 is different from the found mapped MAC address MAC2. Based on the default forwarding action of internal port P25, it prohibits forwarding and discards the Ethernet header of the transaction response message 301 cached in the designated cache space of internal port P25.

[0042] In the subsequent interface clock, the switching unit S1 receives the other fields of the transaction request message 301 through the external forwarding port 11 and sends it through the diversion port 31.

[0043] Internal switching unit S2 receives the other fields of transaction response message 301 through internal port P31 within the subsequent interface clock, and copies them twice and sends them to internal ports P21 and P25 respectively.

[0044] The internal switching unit S2 sends the other fields of the copied transaction response message 301 through the internal port P21. When it is recognized that the end fields of the transaction response message 301, such as the FCS (Frame Check Sequence) field, have been sent through the internal port P21, it is determined that the entire message transmission has been completed.

[0045] Internal switching unit S2 discards other fields of the transaction response message 301 copied to internal port P25. When it is recognized that the other fields of the discarded transaction response message 301 include the end field, it is determined that the entire message has been discarded.

[0046] Afterwards, server S1 sends a transaction response message to client C1 again, and ultra-low latency switch 20 controls the forwarding actions of internal ports P21 and P25 according to the above content.

[0047] When server S1 sends a transaction response message to client C2, the way ultra-low latency switch 20 controls the forwarding action of internal port P25 is the same as the way transaction response message 301 is forwarded via internal port P21, and the way ultra-low latency switch 20 controls the forwarding action of internal port P21 is the same as the way transaction response message 301 is forwarded via internal port P25.

[0048] Figures 3A-3B This is a schematic diagram of Embodiment 2 of the control and forwarding action of the ultra-low latency switching device provided in this disclosure.

[0049] Figure 3A In this disclosure, an internal switching unit S2 with a PCIE physical layer interface chip is added to the ultra-low latency switch 20.

[0050] The CPU of the ultra-low latency switch 20 sets the mapping relationship between the external forwarding ports 1-11 of the switching unit S1 and the ports 21-31 on the switching chip S1 that serve as flow guides; the CPU sets the internal port P21 directly connected to the flow guide 21 to send the received packets to P31; and configures the packets received by P31 to be sent to P21.

[0051] exist Figure 3A , 3B In the scenario shown, only clients C3 and C5 are allowed to forward Ethernet data packets with client C6. Client C4 has a higher security level, so it is only allowed to send Ethernet data packets to client C6, while client C6 is prohibited from sending Ethernet data packets to client C4.

[0052] The CPU of the ultra-low latency switch 20 sets the default forwarding action of the outbound default forwarding action register of the internal port P21 to allow forwarding; and sets the exception forwarding action ACL table of the internal port P21 to prohibit forwarding for IP address IP4.

[0053] Ethernet data packets 401, 402, and 403 from clients C3, C4, and C5 arrive at port 1. Switching unit S1 sends the contents of the Ethernet data packets 401, 402, and 403 received within each interface clock cycle through the mapped routing port 21.

[0054] The internal switching unit S2 searches for the exception forwarding address mapping register of the internal port P21 based on the source MAC address and source IP address of the Ethernet data packets 401, 402, and 403 received by the internal port P21 during continuous interface clock cycles.

[0055] Internal switching unit S2 determines the mapping relationship between source MAC3 and IP3 of the unsearched Ethernet data packet 401, and records the mapping relationship between MAC3 and IP3 in the exception forwarding address mapping register of internal port P21.

[0056] Internal switching unit S2 determines the mapping relationship between source MAC4 and IP4 of the unlooked Ethernet data packet 402, and records the mapping relationship between MAC4 and IP4 in the exception forwarding address mapping register of internal port P21.

[0057] Internal switching unit S2 determines the mapping relationship between the source MAC5 and IP5 of the unsearched Ethernet data packet 403, and records the mapping relationship between MAC5 and IP5 in the exception forwarding address mapping register of internal port P21.

[0058] The internal switching unit S2 of MAC4 and IP4 sends the message contents of Ethernet data packets 401, 402, and 403 received within a continuous interface clock cycle to the internal port P31.

[0059] Switching unit S1 receives Ethernet data packets 401, 402, and 403 through the flow port 31 within a continuous interface clock cycle and sends them to server S1 through the mapped external forwarding port 11.

[0060] Figure 3B In the above, client C6 sends Ethernet data packets 501, 502, and 503 to clients C3, C4, and C5 respectively. Among them, the destination MAC address of Ethernet data packet 501 is MAC 3 and the destination IP address is IP3; the destination MAC address of Ethernet data packet 502 is MAC 4 and the destination IP address is IP4; the destination MAC address of Ethernet data packet 503 is MAC 5 and the destination IP address is IP5.

[0061] Switching unit S1 transmits the contents of Ethernet data packets 501, 502, and 503 received within each interface clock cycle through external forwarding port 11 via flow port 31.

[0062] Internal switching unit S2 sends the contents of Ethernet data packets 501, 502, and 503 received within each interface clock cycle to internal port P21 via internal port P31.

[0063] The internal switching unit S2 caches the Ethernet headers of Ethernet data packets 501, 502, and 503 received within multiple consecutive interface clock cycles according to the specified number of cache bytes and the specified cache space in the outgoing buffer register of the internal port P21.

[0064] Internal switching unit S2 searches for the IP address IP4 in the exception forwarding action ACL table of the exception forwarding action ACL register of internal port P21, and searches for the exception address mapping register of internal port P21 to find the MAC4 mapped to the specified IP4.

[0065] Internal switching unit S2 determines that the destination MAC address MAC1 of the Ethernet header of the cached Ethernet datagram 501 is different from the found mapped MAC address MAC4. Based on the default forwarding action of internal port P21, it allows forwarding and sends the Ethernet header of the cached Ethernet datagram 501 through internal port P21. Internal switching unit S2 determines that the destination MAC address MAC4 of the Ethernet header of the cached Ethernet datagram 502 is the same as the found mapped MAC address MAC4. Based on the prohibition forwarding action of the ACL entry in the exception forwarding action ACL table of the exception forwarding action register of internal port P21, internal switching unit S2 discards the Ethernet header of the cached Ethernet datagram 502.

[0066] Internal switching unit S2 determines that the destination MAC address MAC6 of the Ethernet header of the cached Ethernet data packet 503 is different from the found mapped MAC address MAC4. Based on the default forwarding action of internal port P21, forwarding is allowed, and the Ethernet header of the cached Ethernet data packet 503 is sent through internal port P21.

[0067] In subsequent interface clock cycles, switching unit S1 receives other fields of Ethernet data packets 501, 502, and 503 through external forwarding port 11 and sends them through routing port 31.

[0068] Internal switching unit S2 receives the other fields of Ethernet data packets 501, 502, and 503 through internal port P31 within the subsequent interface clock and sends them to internal port P21.

[0069] The internal switching unit S2 sends other fields of Ethernet data packets 501 and 503 through the internal port P21. When it is recognized that the end fields of Ethernet data packets 501 and 503, such as the FCS (Frame Check Sequence) field, have been sent through the internal port P21, it is determined that the entire message transmission has been completed.

[0070] The internal switching unit S2 discards the other fields of Ethernet data packet 502. When it is detected that the other fields of the discarded transaction response packet 301 include the end field, it is determined that the entire packet has been discarded.

[0071] Afterwards, client C6 sends Ethernet data packets to clients C3, C4, and C5 again, and ultra-low latency switch 20 controls the forwarding action of internal port P21 according to the above content.

[0072] exist Figure 2A-2B , Figures 3A-3B In the embodiment shown, if the internal switching unit S2 finds the same mapping relationship in the exception forwarding address mapping register of internal port P21 or P25 based on the source MAC address and source IP address of the received data packet, it will not update the mapping.

[0073] exist Figure 2A-2B , Figures 3A-3B In the embodiment shown, the internal switching unit S2 updates the mapping relationship if the mapping relationship found in the exception forwarding address mapping register of internal port P21 or P25 has different MAC addresses or IP addresses based on the source MAC address and source IP address of the received data packet.

[0074] exist Figure 2A-2B , Figures 3A-3B In the illustrated embodiment, the internal switching unit S2, based on the source MAC address and source IP address of the received data packet, does not find a mapping relationship in the exception forwarding address mapping register of internal port P21 or P25, and the number of stored mapping relationships has reached its maximum value. Starting from the first address mapping relationship in the exception forwarding address mapping register of internal port P21 or P25, it performs a cyclic overwrite based on the newly learned mapping relationship of the source MAC address and source IP address of the inbound packet, that is, first overwrites the first address mapping relationship, then overwrites the second address mapping relationship, and so on.

[0075] Figure 4 This disclosure provides a schematic diagram of an ultra-low latency switching and forwarding device for controlling forwarding actions. The device 600 includes a network interface, a CPU 61, a storage unit 62, a switching unit 63, and an internal switching unit 64. The switching unit 63 can be an FPGA or ASIC chip with switching functionality; the internal switching unit 64's statistics unit is a PIPE chip; the processor 61 executes the setting module 621 by running processor-executable instructions in the memory 62.

[0076] Setting unit 621 is used to set the default forwarding action of the outbound default forwarding action register of the internal port; set the exception forwarding action ACL table of the exception forwarding action access control ACL register of the internal port; set the specified number of cache bytes and specified cache space of the outbound cache register of the internal port; and set the exception forwarding address mapping register of the internal port when it is empty; the internal port is located in the internal forwarding unit and is directly connected to the switching unit's flow port.

[0077] The internal switching unit 64 updates the exception forwarding address mapping table in the exception forwarding address mapping register based on the source MAC address and source IP address of the incoming packets arriving at the internal port; caches the Ethernet header of the first outgoing packet arriving at the internal port in a specified cache space according to a specified number of cache bytes; looks up the mapped MAC address of the specified IP address in the exception forwarding action access control ACL entry of the internal port in the exception forwarding address mapping table; determines the first destination MAC address of the Ethernet header of the cached first outgoing packet as the mapped MAC address; and processes the first outgoing packet based on the exception forwarding action ACL entry.

[0078] The internal switching unit 64 is also used to cache the Ethernet header of the second outgoing packet arriving at the internal port according to a specified number of cached bytes; based on a specified IP address, it looks up the mapped MAC address in the exception forwarding address mapping table to determine that the second destination MAC address of the cached second outgoing packet's Ethernet header is different from the mapped MAC address; and processes the second outgoing packet based on the default forwarding action of the internal port.

[0079] Setting unit 621 is used to set the default forwarding action to allow forwarding and to set the forwarding action of the exception forwarding action ACL entry to prohibit forwarding; or, setting unit 621 is used to set the default forwarding action to prohibit forwarding and to set the forwarding action of the exception forwarding action ACL entry to allow forwarding.

[0080] The internal switching unit 64 updates the exception forwarding address mapping table by: if no address mapping relationship matching the source IP address of the incoming packet is found in the exception forwarding address mapping table, determining that the number of recorded address mapping relationships in the exception forwarding address mapping table has reached the maximum value, and starting from the first address mapping relationship in the exception forwarding address mapping table, performing a cyclic overwrite based on the mapping relationship between the source MAC address and the source IP address of the incoming packet.

[0081] The internal switching unit 64 updates the exception forwarding address mapping table by: finding no address mapping relationship matching the source IP address of the incoming packet in the exception forwarding address mapping table; determining that the number of recorded address mapping relationships in the exception forwarding address mapping table has not reached the maximum value, and adding new address mapping relationships corresponding to the source MAC address and source IP address of the incoming packet.

[0082] The internal switching unit 64 updates the exception forwarding address mapping table by: finding an address mapping relationship that matches the source IP address of the incoming packet in the exception forwarding address mapping table; if it is determined that the found address mapping relationship records the source MAC address and source IP address of the incoming packet, then the found address mapping relationship is not updated.

[0083] The internal switching unit 64 updates the exception forwarding address mapping table by: finding the address mapping relationship that matches the source IP address of the incoming packet in the exception forwarding address mapping table, determining that the MAC address recorded in the found address mapping relationship is inconsistent with the source MAC address of the incoming packet, and updating the found address mapping relationship based on the source MAC address and source IP address of the incoming packet.

[0084] In this disclosure, a machine-readable storage medium can be any electronic, magnetic, optical, or other physical storage device used to store or contain information (such as executable instructions, data, etc.). For example, any machine-readable storage medium herein can be any type of random access memory (RAM), volatile memory, non-volatile memory, flash memory, storage drive (such as a hard disk drive), solid-state drive, any type of optical disc (such as an optical disc, DVD, etc.), and similar devices, or combinations thereof. Furthermore, any machine-readable storage medium herein can be a non-transitory machine-readable storage medium.

[0085] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for controlling forwarding actions in an ultra-low latency switching device, characterized in that, The method includes, The exception forwarding address mapping table is updated based on the source MAC address and source IP address of the incoming packets arriving at the internal port; wherein the direct-connection port of the internal port is mapped to the external forwarding port of the ultra-low latency switch. The Ethernet header of the first outgoing packet arriving at the internal port is cached according to the specified number of cache bytes for the outgoing direction of the internal port. Based on the specified IP address of the access control ACL entry for the exception forwarding action of the internal port, the mapped MAC address of the specified IP address is found in the exception forwarding address mapping table; The first destination MAC address in the Ethernet header of the first outgoing packet that is cached is determined to be the mapped MAC address; The first outgoing packet is processed based on the exception forwarding action ACL entry.

2. The method according to claim 1, characterized in that, The method also includes The Ethernet header of the second outgoing packet arriving at the internal port is cached according to the specified number of cache bytes for the outgoing direction of the internal port. Based on the specified IP address, the mapped MAC address is found in the exception forwarding address mapping table. The second destination MAC address in the Ethernet header of the cached second outgoing packet is determined to be different from the mapped MAC address; The second outgoing packet is processed based on the default forwarding action of the internal port.

3. The method according to claim 1, characterized in that, The default forwarding action for the internal port is to allow forwarding; the forwarding action for the exception forwarding action ACL entry is to prohibit forwarding. or, The default forwarding action for the internal port is to disable forwarding; The forwarding action of the exception forwarding action ACL entry is to allow forwarding.

4. The method according to claim 1, characterized in that, Based on the source MAC address and source IP address of the inbound packets arriving at the internal port, the exception forwarding address mapping table is updated as follows: No address mapping relationship matching the source IP address of the inbound packet was found in the exception forwarding address mapping table. If the number of recorded address mappings in the exception forwarding address mapping table reaches its maximum value, then starting from the first address mapping in the exception forwarding address mapping table, perform a cyclic overwrite based on the mapping relationship between the source MAC address and source IP address of the inbound packet; or, No address mapping relationship matching the source IP address of the inbound packet was found in the exception forwarding address mapping table. If it is determined that the number of recorded address mapping relationships in the exception forwarding address mapping table has not reached the maximum value, a new address mapping relationship corresponding to the source MAC address and source IP address of the inbound packet is added.

5. The method according to claim 1, characterized in that, Based on the source MAC address and source IP address of the inbound packets arriving at the internal port, the exception forwarding address mapping table is updated as follows: In the exception forwarding address mapping table, find the address mapping relationship that matches the source IP address of the inbound packet; If the found address mapping relationship records the source MAC address and source IP address of the inbound packet, then the found address mapping relationship is not updated; or, In the exception forwarding address mapping table, find the address mapping relationship that matches the source IP address of the inbound packet; If the MAC address of the found address mapping record is inconsistent with the source MAC address of the incoming packet, the found address mapping relationship is updated based on the source MAC address and source IP address of the incoming packet.

6. An ultra-low latency switching device, characterized in that, The device includes a setting unit and an internal switching unit. The setting unit is used to set the default forwarding action of the outgoing default forwarding action register of the internal port; set the exception forwarding action ACL table of the exception forwarding action access control ACL register of the internal port; set the specified number of cache bytes and the specified cache space of the outgoing cache register of the internal port; and set the exception forwarding address mapping register of the internal port to be empty; the internal port is located in the internal forwarding unit and is directly connected to the flow port of the switching unit. The internal switching unit updates the exception forwarding address mapping table of the exception forwarding address mapping register based on the source MAC address and source IP address of the incoming packets arriving at the internal port; caches the Ethernet header of the first outgoing packet arriving at the internal port in the specified cache space according to the specified number of cache bytes; and finds the mapped MAC address of the specified IP address in the exception forwarding action access control ACL entry of the internal port in the exception forwarding address mapping table. The first destination MAC address in the Ethernet header of the first outgoing packet that is cached is determined to be the mapped MAC address; The first outgoing packet is processed based on the exception forwarding action ACL entry.

7. The device according to claim 6, characterized in that, The internal switching unit is further configured to cache the Ethernet header of the second outgoing packet arriving at the internal port according to the specified number of cache bytes; based on the specified IP address, look up the mapped MAC address in the exception forwarding address mapping table to determine that the second destination MAC address of the cached second outgoing packet's Ethernet header is different from the mapped MAC address; and process the second outgoing packet based on the default forwarding action of the internal port.

8. The device according to claim 6, characterized in that, The setting unit is used to set the default forwarding action to allow forwarding and to set the forwarding action of the exception forwarding action ACL entry to prohibit forwarding. or, The setting unit is used to set the default forwarding action to prohibit forwarding; Set the forwarding action of the exception forwarding action ACL entry to allow forwarding.

9. The device according to claim 6, characterized in that, The internal switching unit updates the exception forwarding address mapping table based on the source MAC address and source IP address of the inbound packets arriving at the internal port, including: If the internal switching unit does not find a matching address mapping relationship for the source IP address of the incoming packet in the exception forwarding address mapping table, it determines that the number of recorded address mapping relationships in the exception forwarding address mapping table has reached its maximum value. Starting from the first address mapping relationship in the exception forwarding address mapping table, it performs a cyclic overwrite based on the mapping relationship between the source MAC address and source IP address of the incoming packet; or... The internal switching unit does not find an address mapping relationship matching the source IP address of the incoming packet in the exception forwarding address mapping table; it determines that the number of recorded address mapping relationships in the exception forwarding address mapping table has not reached the maximum value, and adds a new address mapping relationship corresponding to the source MAC address and source IP address of the incoming packet.

10. The device according to claim 6, characterized in that, The internal switching unit updates the exception forwarding address mapping table based on the source MAC address and source IP address of the inbound packets arriving at the internal port, including: The internal switching unit, in the exception forwarding address mapping table, finds an address mapping relationship that matches the source IP address of the incoming packet; if it determines that the found address mapping relationship records the source MAC address and source IP address of the incoming packet, then it does not update the found address mapping relationship; or, The internal switching unit finds the address mapping relationship that matches the source IP address of the incoming packet in the exception forwarding address mapping table, determines that the MAC address recorded in the found address mapping relationship is inconsistent with the source MAC address of the incoming packet, and updates the found address mapping relationship based on the source MAC address and source IP address of the incoming packet.

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