CN115766334A

CN115766334A - Three-layer switch, network system and data transmission method

Info

Publication number: CN115766334A
Application number: CN202211642543.4A
Authority: CN
Inventors: 兰文清
Original assignee: Raisecom Technology Co Ltd
Current assignee: Raisecom Technology Co Ltd
Priority date: 2022-12-20
Filing date: 2022-12-20
Publication date: 2023-03-07

Abstract

The application discloses a three-layer switch, a network system and a data transmission method, wherein the three-layer switch comprises: the first port group comprises a plurality of two-layer forwarding ports which are all configured in the first virtual local area network, one port is a specific connection port, and a non-specific connection port is connected with the two-layer ring network; a second port group including three layers of forwarding ports respectively configured in second virtual local area networks different from the first virtual local area network and independent from each other, wherein one of the three layers of forwarding ports is a specific forwarding port, and the non-specific forwarding port is connected with a superior network; the specific connection port and the specific forwarding port are physically connected; the two-layer forwarding of data is carried out between the non-specific connection port and the specific connection port, and the routing forwarding of data is carried out between the specific forwarding port and the non-specific forwarding port. The method and the device shield the influence of the fault switching of the second-layer ring network on the three-layer switch, and achieve the aim that the fault switching time of the third-layer ring network and the fault switching time of the second-layer ring network are kept consistent during the fault switching of the second-layer ring network.

Description

Three-layer switch, network system and data transmission method

Technical Field

The present application relates to the field of switch technologies, and in particular, to a three-layer switch, a network system, and a data transmission method.

Background

In a traditional networking scheme, a two-layer switch and a router are different devices, and the two-layer switch is used as a ring node to form a second-layer ring network to provide a redundancy function. The router is used as a gateway of a two-layer network and is interconnected with an external network.

Because the second layer ring network is a complete ring in physical topology, in order to avoid the ring storm, one link on the ring is blocked according to the ring network protocol, the ring structure of the physical topology is changed into a linear structure of the logical topology, when a certain link in the ring network fails, the original blocked link is released according to the ring network protocol, and the network connection state after the failure switching of the ring network is realized.

In the process of switching the link failure of the ring network, the switching of the two-layer traffic can be realized only by refreshing a local MAC (Media Access Control) forwarding table by the two-layer switch S on the ring network, and an Address Resolution Protocol (ARP) table entry on the router R does not change. That is to say, in the conventional networking scheme, the topology change caused by the failure switching of the two-layer ring network does not affect the forwarding of the router. Because the failure switching time of the two-layer ring network is generally within 50ms, and after the switching of the two-layer ring network is completed, the three-layer service can be recovered immediately, the failure interruption time of the three-layer service is generally within 50ms.

However, with the wide application of the three-layer switch, the three-layer switch integrating the functions of the two-layer switch and the router gradually becomes a node of the ring network, so that the networking structure of the ring network changes, and compared with the traditional router, the content of the ARP entry on the three-layer switch also changes, and the ARP entry of the three-layer switch has a physical port number greater than that of the traditional router, which is specifically shown in table 1 below:

TABLE 1

Traditional router	Three-layer switch
		IP + MAC + output interface	IP + MAC + output interface + output port

In the networking structure applying the three-layer switch, when the topology of the two-layer ring network changes, the three-layer switch needs to learn the ARP again. Although the switching time of the two-layer ring network is within 50ms, after the switching of the two-layer ring network is completed, the three-layer service cannot be recovered before the ARP table entry of the RS of the three-layer switch is not learned again. The time for the three-layer switch RS to relearn the ARP may be in the second level, which may cause the interruption time of the three-layer service to reach the second level, and seriously affect the service performance.

Disclosure of Invention

The present application aims to provide a three-layer switch, a network system and a data transmission method, which are used for solving the problem that during the existing two-layer ring network fault switching period, the ARP entry of the RS of the three-layer switch needs to be learned again and the time may be in the second level, so that the interruption time of the three-layer service may reach the second level, and the service performance is seriously affected.

In a first aspect, an embodiment of the present application provides a three-layer switch, where the three-layer switch includes a first port group and a second port group, where:

the first port group comprises a plurality of two-layer forwarding ports, the two-layer forwarding ports are all configured in the first virtual local area network, one port is set as a specific connection port, and the non-specific connection port is connected with the two-layer ring network;

the second port group comprises a plurality of three-layer forwarding ports, the three-layer forwarding ports are respectively configured in second virtual local area networks which are different from the first virtual local area network and are independent from each other, one three-layer forwarding port is set as a specific forwarding port, and the non-specific forwarding port is connected with a superior network;

the specific connection port and the specific forwarding port are physically connected.

In one or more possible embodiments, the three-tier switch further comprises:

and the data processing unit is used for performing two-layer forwarding of data between a non-specific connection port and a specific connection port according to a locally stored MAC address forwarding table and performing routing forwarding of data between the specific forwarding port and the non-specific forwarding port according to a locally stored routing table.

In one or more possible embodiments, the IP address and the MAC address of a specific forwarding port in the MAC address forwarding table are a gateway IP address and a gateway MAC address, respectively;

and the port number corresponding to the gateway MAC address in the MAC address table is a specific connection port, so that the non-specific connection port in the first port group carries out two-layer forwarding to the specific connection port.

In one or more possible embodiments, the entry of the MAC address forwarding table includes a MAC address, a VLAN ID, and a port number;

the data processing unit specifically establishes an MAC address forwarding table in the following way:

receiving an ARP request data packet broadcasted by a terminal, wherein the ARP request data packet carries the IP of the terminal as a source IP address, the MAC of the terminal as a source MAC address and the IP of a gateway as a target IP;

learning a source MAC address in the ARP request data packet, determining a table entry corresponding to a terminal MAC address, and sending the ARP request data packet from the specific connection port;

after receiving the ARP request data packet through a specific forwarding port, sending an ARP response data packet from the specific forwarding port, wherein the ARP response data packet carries the MAC of the gateway as a source MAC, and the MAC of the terminal is used as a target MAC;

after receiving the ARP response data packet through a specific connection port, learning a source MAC address in the ARP response data packet, and determining a table entry corresponding to a gateway MAC address;

and inquiring an MAC address according to the destination MAC address in the ARP response data packet to obtain an output port, sending the ARP response data packet from the determined output port through a two-layer ring network and finally reaching the terminal, so that the terminal takes the source MAC address in the ARP response data packet as the MAC address of the gateway recorded locally.

In one or more possible embodiments, the routing table includes a static routing table entry whose destination IP is a remote server IP and a direct routing table entry whose destination IP is a terminal IP;

the data processing unit specifically establishes a direct routing table entry by the following method:

receiving an ARP request data packet from a terminal forwarded by a specific connection port through a specific forwarding port, wherein the ARP request data packet carries the IP of the terminal as a source IP address, the MAC of the terminal as a source MAC address and the IP of a gateway as a target IP;

and learning and constructing a new ARP table item for the source IP address and the source MAC address in the ARP request data packet, and generating a direct routing table item based on the new ARP table item.

In one or more possible embodiments, the data processing unit is specifically configured to receive an uplink IP data packet from a non-specific connection port, search a table entry corresponding to a gateway MAC address in a MAC address forwarding table according to a destination MAC address, acquire a corresponding output port as the specific connection port, and forward the uplink IP data packet to the specific connection port;

the data processing unit is specifically configured to receive a downlink IP packet from a specific forwarding port through a specific connection port, determine an egress port corresponding to a destination MAC address in an MAC address forwarding table as a non-specific connection port, and forward the downlink IP packet to the non-specific connection port;

the uplink IP data packet carries the IP address of the terminal as a source IP address, the MAC address of the terminal as a source MAC address, the IP address of the far-end server as a destination IP address, the MAC address of the gateway as a destination MAC address, and the downlink IP data packet carries the MAC address of the terminal as a destination MAC address.

In one or more possible embodiments, the data processing unit is specifically configured to, after receiving an uplink IP packet through a specific forwarding port, obtain a destination IP address of the uplink IP packet, search a local static routing table according to the obtained destination IP address, modify a two-layer header of the IP packet according to the obtained egress interface VLAN ID and a next-hop IP address, and forward the modified two-layer header to a corresponding non-specific forwarding port;

the data processing unit is specifically configured to, after receiving a downlink IP packet through a non-specific forwarding port, search a directly-connected routing table entry and an ARP table entry stored locally according to a destination IP address therein to determine an MAC address and an egress interface VLAN ID corresponding to the destination IP address, modify the destination MAC address and the egress interface VLAN ID as the downlink IP packet, and forward the modified destination MAC address and the egress interface VLAN ID to the specific forwarding port.

In a second aspect, an embodiment of the present application further provides a three-layer network system, including a two-layer ring network, a terminal connected to a node of the ring network, and a superior network in which the terminal is not in the same network segment, where the system further includes:

the above-mentioned first aspect provides the three-layer switch, wherein:

the three-layer switch is accessed to the two-layer ring network through two non-specific connection ports in the first port group, is connected with a superior network through the non-specific forwarding ports in the second port group, performs two-layer forwarding of data between the non-specific connection ports and the specific connection ports according to a locally stored MAC address forwarding table, and performs routing forwarding of data between the specific forwarding ports and the non-specific forwarding ports according to a locally stored routing table.

In a third aspect, an embodiment of the present application further provides a data transmission method, including:

according to a locally stored MAC address forwarding table, performing two-layer forwarding of data between a non-specific connection port and a specific connection port in a first port group;

and carrying out routing forwarding on the data between the specific forwarding port and the non-specific forwarding port in the second port group according to the locally stored routing table.

establishing a MAC address forwarding table by the following method:

after receiving the ARP request data packet through a specific forwarding port, sending an ARP response data packet from the specific forwarding port, wherein the ARP response data packet carries the MAC of the gateway as a source MAC, and the MAC of the terminal as a target MAC;

and inquiring an MAC address according to the destination MAC address in the ARP response data packet to obtain an output port, sending the ARP response data packet from the determined output port to a terminal through a two-layer ring network, so that the terminal takes the source MAC address in the ARP response data packet as the MAC address of the gateway recorded locally.

establishing a direct routing table entry by the following method:

In one or more possible embodiments, performing two-layer forwarding of data between a non-connection-specific port and a connection-specific port in a first port group according to a locally stored MAC address forwarding table includes:

receiving an uplink IP data packet from a non-specific connection port, searching a table entry corresponding to a gateway MAC address in an MAC address forwarding table according to a target MAC address, acquiring a corresponding output port as the specific connection port, and forwarding the uplink IP data packet to the specific connection port;

receiving a downlink IP data packet from a specific forwarding port through a specific connection port, determining an output port corresponding to a destination MAC address in an MAC address forwarding table as a non-specific connection port, and forwarding the downlink IP data packet to the non-specific connection port;

In one or more possible embodiments, performing routing forwarding of data between the specific forwarding port and the non-specific forwarding port according to a locally stored routing table includes:

after receiving an uplink IP data packet through a specific forwarding port, acquiring a target IP address of the uplink IP data packet, searching a local static routing table according to the acquired target IP address, modifying a two-layer header of the IP data packet according to the acquired output interface VLAN ID and a next-hop IP address, and forwarding the modified two-layer header to a corresponding non-specific forwarding port;

after a downlink IP data packet is received through a non-specific forwarding port, a direct connection routing table item and an ARP table item which are locally stored are searched according to a target IP address in the downlink IP data packet, an MAC address and an output interface VLAN ID which correspond to the target IP address are determined, the target MAC address and the output interface VLAN ID which serve as the downlink IP data packet are modified, and then the downlink IP data packet is forwarded to the specific forwarding port.

In a fourth aspect, an embodiment of the present application provides a data transmission method, which is applied to the three-layer network system provided in the second aspect, and includes:

the terminal carries out data communication with a remote server positioned on the upper network through the two-layer ring network and the three-layer switch;

the data communication includes: according to the flow direction of communication data, performing two-layer forwarding of data between the non-specific connection end port and the specific connection port of the three-layer switch according to a local MAC address forwarding table; and carrying out routing forwarding of data between the specific forwarding port and the non-specific forwarding port according to a routing table.

In a fifth aspect, another embodiment of the present application further provides a computer storage medium, where a computer program is stored, and the computer program is used to enable a computer to execute the data transmission method provided in the first aspect of the embodiment of the present application.

In the embodiment of the application, for a ring network networking structure using a three-layer switch as a ring node, two physical ports of the three-layer switch are interconnected, the ports of the three-layer switch are divided into two groups which are respectively used for two-layer forwarding and route forwarding, a specific port is respectively assigned to the two groups of ports for physical connection, and the port located at the three-layer forwarding is assigned to a gateway for the two-layer forwarding, so that when the ring network topology changes, the ARP table entry of the three-layer switch is unchanged, the interruption time of the three-layer service is consistent with the fault switching time of the two-layer ring network, which reaches 50ms, and the network reliability is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1a is a schematic diagram of a networking structure using a two-layer switch when no link failure occurs in the related art;

FIG. 1b is a schematic diagram of a networking architecture employing a two-layer switch when a link failure occurs in the related art;

fig. 2a is a schematic diagram of a networking structure of an application three-layer switch when no link failure occurs in the related art;

fig. 2b is a schematic diagram of a networking structure employing a three-layer switch when a link failure occurs in the related art;

fig. 3 is a schematic port layout diagram of a three-layer switch provided in an embodiment of the present application;

fig. 4 is a schematic topology structure of a three-layer network system in an embodiment of the present application;

fig. 5 is a flow diagram illustrating a process of constructing an MAC address forwarding table and a direct routing table in the embodiment of the present application;

FIG. 6 is a schematic diagram of data flow in the uplink direction according to an embodiment of the present disclosure;

fig. 7 is a schematic diagram of data flow in a downlink direction in the embodiment of the present application;

fig. 8 is a schematic diagram of a data flow in an uplink direction when a failed link forms a new blocked link in the embodiment of the present application.

Detailed Description

To further explain the technical solutions provided by the embodiments of the present application, the following detailed description is made with reference to the accompanying drawings and the specific embodiments.

Because the ring network is a complete ring in physical topology, in order to avoid a ring storm, a link on the ring is blocked according to a ring network protocol, and the ring structure of the physical topology is changed into a linear structure of a logical topology, fig. 1a shows a network connection state of a typical networking structure using a two-layer switch in a normal state (i.e., when links between nodes in a network are normal), and fig. 1a schematically shows a path where a terminal T and a network side perform traffic exchange: after being forwarded by the router R, the flow from the network side enters a ring network formed by two layers of switches and finally reaches a terminal T; the flow from the terminal T enters a ring network formed by two layers of switches, and reaches a network side after being forwarded by the router R.

Fig. 1b shows the network connection status after the original blocking link is released according to the ring network protocol to implement the failure switching of the ring network when a certain link in the ring network fails; fig. 1b still schematically shows the path of traffic exchange between the terminal T and the network side: after being forwarded by the router R, the flow from the network side enters a ring network formed by two layers of switches and still can reach the terminal T; the flow from the terminal T enters a ring network formed by a two-layer switch, and reaches a network side after being forwarded by a router R.

In the process of switching the ring network link failure, the switching of the two-layer flow can be realized only by refreshing the local MAC address forwarding table by the two-layer switch S on the ring network, and the ARP table entry on the router R does not change, that is, in the traditional networking scheme, the topology change caused by the failure switching of the two-layer ring network does not affect the forwarding of the router. Because the failure switching time of the two-layer ring network is generally within 50ms, the three-layer service can be recovered immediately after the switching of the two-layer ring network is completed, and therefore the failure interruption time of the three-layer service is generally within 50ms.

However, with the wide application of the three-layer switch, the three-layer switch integrating the functions of the two-layer switch and the router gradually becomes a node of the ring network, so that the networking structure of the ring network changes, and compared with the traditional router, the content of the ARP entry on the three-layer switch also changes, and the ARP entry of the three-layer switch has a larger physical port number than the traditional router.

Fig. 2a shows a network connection state of a typical networking structure using a three-layer switch in a normal state, where a two-layer ring network has a link blockage, a message of a terminal T (IP 1, MAC 1) enters from a port 1 of a three-layer switch RS, and the three-layer switch RS learns that an ARP entry of the terminal T is IP1+ MAC1+ egress interface + port 1; when the link of the ring network fails, the topology of the two-layer ring network changes, as shown in fig. 2b, the blocking link is restored to the forwarding state, the failed link becomes the blocking state, and then the three-layer switch RS learns that the ARP entry of the end user T is changed into IP1+ MAC1+ egress interface + port 2. That is, in the networking structure using the three-layer switch, when the topology of the two-layer ring network changes, the three-layer switch needs to learn the ARP again. Although the switching time of the two-layer ring network is within 50ms, after the switching of the two-layer ring network is completed, the three-layer service cannot be recovered before the ARP table entry of the RS of the three-layer switch is not learned again. The time for the three-layer switch RS to relearn the ARP may be in the second level, which may cause the interruption time of the three-layer service to reach the second level, and seriously affect the service performance.

In view of the above technical problems in the related art, the present application provides a three-layer switch, which includes a first port group and a second port group, wherein:

the specific connection port and other non-specific connection ports in the embodiment of the present application form a two-layer forwarding path respectively;

the second port group comprises a plurality of three-layer forwarding ports, the three-layer forwarding ports are respectively configured in second virtual local area networks which are different from the first virtual local area network and are independent from each other, one three-layer forwarding port is set as a specific forwarding port, and the non-specific forwarding port is connected with a superior network; the ports except the specific forwarding port in the three layers of forwarding ports are non-specific forwarding ports;

In one or more possible embodiments, the three-tier switch further comprises:

and the data processing unit is used for carrying out two-layer forwarding of data between the non-specific connection port and the specific connection port according to the locally stored MAC address forwarding table and carrying out routing forwarding of the data between the specific forwarding port and the non-specific forwarding port according to the locally stored routing table.

According to the method, when ring network topology changes are achieved, ARP table entries of the three-layer switch are unchanged, the interruption time of three-layer services is consistent with the fault switching time of the two-layer ring network, 50ms is achieved, and network reliability is improved.

As shown in fig. 3, in the three-layer switch according to the embodiment of the present application, ports 1-20 of the three-layer switch are set as a first port group, and port 20 is a specific connection port; ports 21-28 are arranged as a second port group, port 21 being a specific forwarding port; port 20 and port 21 are physically connected by a network cable; the data received by the port 1-port 19 is forwarded by the port 20 in two layers according to the corresponding MAC address forwarding table, and then forwarded by the port 21 in three layers according to the routing forwarding table.

Thus, in the embodiment of the present application, the three-layer switch is virtually virtualized into a virtual two-layer switch including the first port group and the corresponding local MAC address forwarding table, and a virtual router including the second port group and the corresponding routing forwarding table, and data forwarding is performed through the virtual switch and the virtual router. In the three-layer switch, for the first port group and the second port group, each has its own forwarding table, and the number of ports in the uplink port group and the number of ports in the second port group may be determined by those skilled in the art according to the actual application scenario, but the sum of the number of ports in the uplink port group and the number of ports in the second port group is not greater than the number of ports of the three-layer switch; the first virtual local area network to which the ports in the first port group belong and the virtual local area network to which the ports in the second port group belong are completely different, the virtual local area networks to which the ports in the second port group belong are also completely different, and the specific allocation can be determined by those skilled in the art according to networking requirements.

In the three-layer switch provided by the application, no matter which unspecific connection port in the first port group receives data, the data is transmitted to the specific connection port through the second layer, then is transmitted to the specific transmission port in the second port group, and the subsequent three-layer transmission is carried out by the specific transmission port, so that when the three-layer switch is used as a ring network node, if the inner link fails and only the two-layer transmission is switched, the switching time is consistent with the switching time of the two-layer ring network, and the service performance is ensured.

In one or more possible embodiments, the data processing unit performs two-layer forwarding of data between the non-specific connection port and the specific connection port according to a locally stored MAC address forwarding table, and specifically includes:

In one or more possible embodiments, the data processing unit performs routing forwarding of data between the specific forwarding port and the non-specific forwarding port according to a locally stored routing table, specifically including:

The embodiment of the application provides a data transmission method, which is applied to the three-layer switch and comprises the following steps:

In one or more possible embodiments, the above description is referred to in a manner of performing two-layer forwarding of data between a non-specific connection port and a specific connection port in the first port group according to a locally stored MAC address forwarding table, and the above description is referred to in a manner of performing routing forwarding of data between the specific forwarding port and the non-specific forwarding port according to a locally stored routing table, which is not described in detail herein.

An embodiment of the present application further provides a three-layer network system, as shown in fig. 4, including a two-layer ring network, a terminal connected to a node of the two-layer ring network, and a superior network in which the terminal is not in the same network segment, where the system further includes: above-mentioned three-layer switch, three-layer switch are as the node of two-layer looped netowrk and the gateway and higher level network connection as two-layer network simultaneously, wherein:

In fig. 4, the three-layer switch is the above-mentioned three-layer switch of the present application, and is directly incorporated herein by reference. The port 1 and the port 2 in the first port group in the three-layer switch are used as ring ports and accessed into a two-layer ring network, the port 28 is used as a non-specific forwarding port in the second port group and connected with a superior network, a specific connection port (port 20) in the first port group and a specific forwarding port (port 21) in the second port group are connected through a network cable, all ports in the first port group only start the two-layer forwarding function, but not start the three-layer forwarding function, and the ports in the first port group are all added into the VLAN1. In fact, the first port group and the corresponding MAC address forwarding table form a virtual layer two switch; further, the port 20 closes the port security policy to avoid identifying that the source MAC is the own MAC of the switch when receiving the message forwarded from the port 21, and determines that the message is sent by itself to terminate forwarding of the message; each port (port 21-port 28) in the second port group only starts the three-layer forwarding function, and adds an independent virtual local area network, for example: port 21 joins VLAN 3001, port 22 joins VLAN3002, \8230 \ 8230;, port 28 joins VLAN3008, and thus, port 21 to port 28 are two-layer isolated from each other and two-layer traffic cannot be communicated. In effect, the second port set and the corresponding routing forwarding table constitute a virtual router. Further, since the port 20 and the port 21 are connected by network cables, the IP address of the port 21 is used as a gateway address of a two-layer network to which the first port group belongs, the port 28 is created as a three-layer interface to implement connection with an external upper-level network, and traffic interworking between the port 21 and the port 28 is implemented by three-layer routing forwarding, at this time, the three-layer switch is equivalent to a network structure serving as a "virtual two-layer switch + a virtual router" in this network structure.

In one or more possible embodiments, the IP address and the MAC address of the specific forwarding port in the MAC address forwarding table are a gateway IP address and a gateway MAC address, respectively;

The table entry of the MAC address forwarding table in the embodiment of the application comprises an MAC address, a VLAN ID and a port number; the method comprises the steps of obtaining an MAC address of a gateway through an APR request in a three-layer switch, and constructing an MAC address forwarding table, wherein a routing table in the embodiment of the method comprises a static routing table item with a target IP as a remote server IP and a direct routing table item with a target IP as a terminal IP. Illustratively, the ports on the three-layer switch are configured as follows: the port 21 is configured as a gateway for layer two forwarding, and as the IP address and VLAN ID of the port 21 of the gateway, the IP of the port 21 is 192.168.1.1, VLAN:3001, and a static routing table entry to each remote server is provided on the three-layer switch, the static routing table entry includes: destination IP address, mask, next hop address and egress interface, as an example, the following table 2 is a static routing table entry to the remote server N:

TABLE 2

Destination IP address	Mask code	Next hop	Outlet interface
				IPN	255.255.255.255	10.0.0.1	VLAN 3008

Fig. 5 shows a process of constructing a MAC address forwarding table and a direct routing table through an APR request process in the embodiment of the present application, which specifically includes the following steps:

step S501: a terminal T broadcasts and sends an ARP request data packet to request to acquire the MAC address of a gateway (port 21) 192.168.1.1; the three-layer switch receives an ARP request data packet broadcasted by the terminal, wherein the ARP request data packet carries the IP of the terminal as a source IP address, the MAC of the terminal as a source MAC address and the IP of the gateway as a target IP;

step S502: the three-layer switch learns the source MAC address in the ARP request data packet, determines the table entry corresponding to the terminal MAC address and sends the ARP request data packet out of the specific connection port;

the port 1 of the three-layer switch receives the ARP request data packet transmitted by the ring network, learns the source MAC address in the ARP request data packet, and sends the ARP request data packet out of the port 20 after newly establishing an MAC address forwarding table item shown in the following table 3 in a local MAC address forwarding table;

TABLE 3

MAC address	VLAN ID	Port number
			MAC1
	1	1

Step S503, after the three-layer switch receives the ARP request data packet through a specific forwarding port, learning and constructing a new ARP table item for a source IP address and a source MAC address in the ARP request data packet, and generating a direct routing table item based on the new ARP table item;

after receiving the ARP request packet, the port 21 of the three-layer switch acquires the source IP address and the source MAC address thereof, learns and constructs a new ARP entry shown in table 4 below, and generates a direct routing entry shown in table 5 based on the new ARP entry;

TABLE 4

Destination IP address	Destination MAC address	Three-layer interface	Port
				IP1	MAC1	VLAN	3001	21

TABLE 5

Destination IP address	Mask code	Next hop	Outlet interface
				IP1	255.255.255.255	IP1	VLAN	3001

Step S504, the three-layer switch sends out ARP response data packet from the specific forwarding port, the ARP response data packet carries the MAC of the gateway as the source MAC, and the MAC of the terminal is as the destination MAC;

the three-layer switch learns the destination IP address in the ARP request data packet: the received ARP request packet requests its MAC address, and thus an ARP reply packet for the ARP request packet of the terminal T is sent from the port 21, where the source MAC address is the local MAC address MAC RS;

because the port 20 and the port 21 of the three-layer switch are physically connected, the ARP request data packet sent from the port 20 of the three-layer switch is directly received by the port 21, and enters the three-layer switch from the port 21; similarly, the ARP reply packet sent from the port 21 of the three-layer switch is received directly from the port 20, and then enters the three-layer switch from the port 20.

Step S505, after receiving the ARP response data packet through a specific connection port, learning a source MAC address in the ARP response data packet, and determining a table entry corresponding to a gateway MAC address;

after receiving the ARP reply packet, the port 20 of the three-layer switch learns the source MAC address therein, and creates a new MAC address forwarding table entry in the local MAC address forwarding table, as shown in table 6 below.

TABLE 6

MAC address	VLAN ID	Port number
			MAC1
	1	1
			MAC RS	1	20

Step S506, the three-layer switch inquires the MAC address according to the destination MAC address in the ARP response data packet to obtain an output port, the ARP response data packet is sent from the determined output port to the terminal through the two-layer ring network, and therefore the terminal takes the source MAC address in the ARP response data packet as the MAC address of the gateway recorded locally.

The three-layer switch searches an MAC address forwarding table according to the target MAC address in the ARP response data packet, hits an MAC1 table entry to obtain an output port 1, and sends the ARP response data packet from the port 1 to a terminal T through a two-layer ring network.

And step S507, after receiving the ARP response data packet, the terminal T acquires and locally records the MAC address of the gateway as the MAC RS.

Thus, not only the gateway address is acquired through the above steps S501 to S507, but also the MAC address can be learned for the terminal that initiated the ARP request.

The embodiment of the application provides a data transmission method, which is applied to the three-layer network system and comprises the following steps:

the terminal is in data communication with a remote server on the upper network through the two-layer ring network and the three-layer switch;

Based on the above three-layer network system, a method for data communication between a terminal and an upper-level network through a ring network will be described below, and the following example will be described with respect to data communication between the terminal T (IP address: IP1, MAC address: MAC 1) and a remote server N (IP address: IPN).

The data transmission method between the terminal and the remote server comprises data transmission in the uplink direction and data transmission in the downlink direction.

As shown in fig. 6, the data transmission in the uplink direction mainly includes:

step S600: a terminal T sends an uplink IP data packet to a remote server N through a two-layer ring network, wherein a source IP address in the uplink IP data packet is IP1, a source MAC address is MAC1, a destination IP address is IPN, and the destination MAC address is: the MAC address of the RS of the three-layer switch;

in this step, when the terminal T needs to send an uplink IP data packet to the remote server N, the terminal T needs to forward the communication with the remote server N by means of the gateway because the remote server N and the terminal T are not in the same network segment; in the application, a port of the three-layer switch is required to serve as a gateway, and the gateway MAC address is acquired before the terminal T can send an IP packet to a remote server across network segments and is locally recorded.

Step S601: after receiving the uplink IP data packet from the ring network, the port 1 of the three-layer switch searches for an MAC address forwarding table to hit a table entry of an MAC address RS of a specific connection port, acquires an output port 20, and sends the output port 20 to a port 21 of the three-layer switch connected through a network cable;

in this step, the entry in the MAC address forwarding table may be preset, or may be learned through learning.

Step S602: after receiving the uplink IP packet from the port 21, the three-layer switch acquires the destination IP address of the IP packet, searches for a local static routing table, modifies the two-layer header of the IP packet according to the acquired egress interface VLAN3008 and next hop 10.0.0.1 information, and transmits the modified IP packet from the port 28 to finally reach the remote server N.

As shown in fig. 7, the data transmission in the downlink direction mainly includes:

step S700: a remote server N sends a downlink IP data packet to a terminal T through a two-layer ring network, wherein a target IP address in the downlink IP data packet is IP1;

step S701: after receiving the downlink IP data packet, the port of the three-layer switch searches for a directly connected routing table entry stored locally according to the destination IP address, and determines next hop information according to the directly connected routing table entry shown in table 5: further, the MAC address corresponding to the corresponding destination IP address in table 4 is obtained as MAC1, the VLAN ID of the outgoing interface is 3001, and the port number is 21; modifying the destination MAC address of the downlink IP data packet into MAC1, and sending the downlink IP data packet from the port 21 after modifying the VLAN ID into 3001;

step S702: a port 20 of the three-layer switch receives the downlink IP data packet sent by a port 21 through a network cable, determines that an output port corresponding to a message with a destination MAC of MAC1 is port 1 in a locally stored MAC address forwarding table, and sends the downlink IP data packet from the port 1 through a two-layer ring network and finally reaches a terminal T.

Further, the above-described method for data communication between a terminal and a higher-level network through a ring network is based on the three-layer network system shown in fig. 4, in the three-layer network system shown in fig. 4, a link between ring nodes in a two-layer ring network is in a normal state, and a link on the ring is blocked according to a ring network protocol, so as to avoid a ring storm; however, when a link in the ring network fails, the originally blocked link is released according to the ring network protection mechanism, and the failed link forms a new blocked link, at this time, the data flow in the uplink direction is as shown in fig. 8, an uplink data packet sent by the terminal T reaches the port 2 of the three-layer switch through the ring network, the table entry of the MAC address forwarding table hitting the gateway MAC address MAC RS is searched, the output port 20 is obtained, and the output port 20 is sent to the port 21 of the three-layer switch connected through the network cable from the port 20; the ARP table entry of the IP1 maintained on the three-layer switch is not changed and is always shown in the table 4, but is not changed due to different access ports, in the process of switching the fault of the two-layer ring network, only the switching needs to be carried out in the two-layer ring network, the ARP table entry stored in the three-layer switch is not influenced, the relearning of the ARP table entry is not needed, and therefore the interruption time of the three-layer service depends on the fault switching time of the two-layer ring network and is still usually less than 50ms.

The embodiment of the application optimizes the three-layer service performance of the three-layer switch in the ring network topology change by virtualizing the three-layer switch into the two-layer switch and the router, without increasing the complexity of software, new hardware resources (CPU, memory and the like) and a new software system; in the networking scheme of using a three-layer switch as a ring node, the time of three-layer service interruption caused by switching the failure of a two-layer ring network is optimized from second level to within 50ms.

While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A three-tier switch, the three-tier switch comprising a first port group and a second port group, wherein:

2. The triple layer switch of claim 1, further comprising:

3. The triple-layer switch of claim 2,

the IP address and the MAC address of a specific forwarding port in the MAC address forwarding table are a gateway IP address and a gateway MAC address respectively;

4. The triple layer switch of claim 3,

the table entry of the MAC address forwarding table comprises an MAC address, a VLAN ID and a port number;

5. The triple-layer switch of claim 1, wherein the routing tables comprise static routing table entries with destination IP as far-end server IP and direct routing table entries with destination IP as terminal IP;

and learning and constructing a new ARP table entry for the source IP address and the source MAC address in the ARP request data packet, and generating a direct routing table entry based on the new ARP table entry.

6. The triple-layer switch according to any of claims 1 to 5,

the data processing unit is specifically configured to receive an uplink IP packet from a non-specific connection port, search a table entry corresponding to a gateway MAC address in an MAC address forwarding table according to a destination MAC address, acquire a corresponding egress port as the specific connection port, and forward the uplink IP packet to the specific connection port;

7. The three-layer switch according to any of claims 1 to 5,

the data processing unit is specifically configured to obtain a destination IP address of the uplink IP data packet after receiving the uplink IP data packet through the specific forwarding port, search a local static routing table according to the obtained destination IP address, modify a two-layer header of the IP data packet according to the obtained output interface VLAN ID and the next-hop IP address, and forward the modified two-layer header to the corresponding non-specific forwarding port;

8. The utility model provides a three-layer network system, includes two layers of looped netowss, the terminal of being connected with the looped netowss node, with the higher level network of terminal not in same network segment, its characterized in that, the system still includes:

the three-tier switch of at least one of claims 1 to 7, wherein:

9. A method of data transmission, comprising:

10. The method of claim 9, wherein the IP address and the MAC address of a specific forwarding port in the MAC address forwarding table are a gateway IP address and a gateway MAC address, respectively;

11. The method of claim 10, wherein the entries of the MAC address forwarding table comprise MAC addresses, VLAN IDs, port numbers;

establishing a MAC address forwarding table by the following method:

12. The method of claim 9, wherein the routing table comprises a static routing table entry whose destination IP is a remote server IP and a direct routing table entry whose destination IP is a terminal IP;

establishing a direct routing table entry by the following method:

13. The method of claim 9, wherein performing a two-layer forwarding of data between a port that is not specific and a port that is specific in the first port group according to a locally stored MAC address forwarding table comprises:

14. The method of claim 9, wherein routing forwarding data between the specific forwarding port and the non-specific forwarding port according to a locally stored routing table comprises:

15. A data transmission method applied to the three-layer network system according to claim 8, comprising: