CN102571594B - Method of relay configuration, network node and system - Google Patents

Abstract

The invention discloses a relay configuration method, network node and system. The method includes: obtaining the routing information of the DHCP server; starting a first timer, and listening to the first relay announcement message and the first relay election message within the subnet; if the first timer expires and does not receive The first relay announcement message or the first relay election message starts the second timer and broadcasts the second relay election message to the subnet; the second relay election message includes the current network node election information; if the second timer expires, and the first relay announcement message is not received, and the first relay announcement message including the election information of the second network node with a higher priority than the current network node is not received The relay election message broadcasts a second relay announcement message to the subnet; the second relay announcement message is used to notify the current network node to be the DHCP relay agent. The invention improves the efficiency of configuring DHCP relay.

Description

Method, network node and system for relay configuration

technical field

Embodiments of the present invention relate to communication technologies, and in particular to a relay configuration method, network node and system.

Background technique

Dynamic Host Configuration Protocol (DHCP) uses User Datagram Protocol (UDP) to work, and can automatically assign IP addresses to login Transmission Control Protocol/Internet Protocol (Transmission Control Protocol/Internet Protocol, TCP for short) /IP) network clients. The DHCP protocol is an application based on the UDP layer. The UDP port number used by the DHCP server is 67, and the UDP port number used by the DHCP client is 68.

The DHCP client and DHCP server may be in the same broadcast domain. In this case, the DHCP server and DHCP client can directly send and receive DHCP broadcast packets. Or, the DHCP client and the DHCP server are located in different broadcast domains. In this case, the DHCP broadcast message sent by the DHCP client needs to be forwarded to the DHCP server by other network nodes in the subnet where the DHCP client is located. This network node is called DHCP relay. In the prior art, the DHCP relay needs to be manually configured in the subnet; if there are multiple network nodes that can serve as the DHCP relay in a subnet, it is necessary to manually designate a network node among the network nodes as the DHCP relay.

The existing DHCP relay needs to be manually configured. After the configured DHCP relay exits the subnet, a new DHCP relay needs to be reconfigured. The DHCP relay configuration process is relatively cumbersome; , the operator needs to frequently check whether the DHCP relay is online. If it is not known that the configured DHCP relay has exited the subnet, it may cause the subnet to fail to serve DHCP clients in the subnet because the DHCP relay is not configured. terminal for network configuration.

Contents of the invention

Embodiments of the present invention provide a relay configuration method, network node and system, so as to improve the efficiency of DHCP relay configuration.

An embodiment of the present invention provides a method for relay configuration, including:

Obtain the routing information of the DHCP server;

Start the first timer, and listen to the first relay announcement message and the first relay election message within the scope of the subnet; the first relay announcement message is sent by the first network as a DHCP relay in the subnet The node sends; the DHCP relay is used to relay the data exchanged between the DHCP server and the DHCP client in the subnet according to the routing information of the DHCP server; the first relay election message is sent by The second network node in the subnet that meets the DHCP relay election condition sends, including the election information of the second network node;

If the first timer expires and the first relay announcement message or the first relay election message is not received, start a second timer and broadcast a second relay message to the subnet range A relay election message; the second relay election message includes election information of the current network node;

If the second timer expires, and the first relay announcement message is not received, and the first relay including the election information of the second network node with a higher priority than the current network node is not received election message, broadcasting a second relay announcement message within the subnet; the second relay announcement message is used to notify the current network node to be the DHCP relay agent.

The embodiment of the present invention also provides a network node, including:

The server information obtaining module is used to obtain the routing information of the DHCP server;

The relay message listening module is used to start the first timer, and listen to the first relay announcement message and the first relay election message within the scope of the subnet; the first relay announcement message is sent by the subnet The first network node serving as a DHCP relay in the network sends; the DHCP relay is used to relay and transmit the data exchanged between the DHCP server and the DHCP client in the subnet according to the routing information of the DHCP server; The first relay election message is sent by a second network node that satisfies the DHCP relay election condition in the subnet, and includes election information of the second network node;

A relay election processing module, configured to start a second timer, and broadcast a second relay election message to the subnet; the second relay election message includes election information of the current network node;

A relay announcement processing module, configured to if the second timer expires, and the first relay announcement message is not received, and the second network node including the priority higher than the current network node is not received The election information of the first relay election message, then broadcast the second relay announcement message to the range of the subnet; the second relay announcement message is used to notify the current network node as the DHCP relay.

The embodiment of the present invention also provides a DHCP relay configuration system, including: a DHCP client, a first DHCP relay and a first DHCP server; the DHCP client and the first DHCP relay are located in the same subnet;

The first DHCP relay is elected by a plurality of network nodes included in the subnet, and is used to relay and transmit the data exchanged between the DHCP server and the DHCP client; participate in the election of the first DHCP relay The network node of is the above-mentioned network node provided by the embodiment of the present invention.

In the relay configuration method, network node and system provided by the embodiments of the present invention, the network node can obtain the routing information of the DHCP server, and determine that the subnet where the DHCP client is located is currently the DHCP server by listening to the first relay announcement message. The online status of the first relay network node; by listening to the first relay election message, to obtain the participation of the second network node in the subnet in the DHCP relay election; and by broadcasting the second relay election Message to participate in the DHCP relay election, and broadcast the second relay announcement message to self-promote as a DHCP relay, thus realizing the automatic configuration of the DHCP relay in the subnet, eliminating the cumbersome manual configuration, Improves the efficiency of DHCP relay configuration and reduces the cost required to configure DHCP relay.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a flowchart of a method for relay configuration provided in Embodiment 1 of the present invention;

Fig. 2a is an application scenario example 1 of the relay configuration method provided by the embodiment of the present invention;

Fig. 2b is an application scenario example 2 of the relay configuration method provided by the embodiment of the present invention;

FIG. 3a is a first schematic diagram of the state control of the state machine running inside the network node provided by Embodiment 2 of the present invention;

FIG. 3b is a second schematic diagram of the state control of the state machine running inside the network node provided by Embodiment 2 of the present invention;

FIG. 3c is a third schematic diagram of the state control of the state machine running inside the network node provided by Embodiment 2 of the present invention;

Fig. 3d is an illustration of each schematic diagram provided by Embodiment 2 of the present invention;

FIG. 4 is an example of the format of a message related to DHCP relay automatic configuration provided by Embodiment 3 of the present invention;

FIG. 5 is a schematic structural diagram of a network node provided by Embodiment 4 of the present invention;

FIG. 6 is a schematic structural diagram of a relay configuration system provided by Embodiment 5 of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The serial numbers of the following embodiments of the present invention are for description only, and do not represent the advantages and disadvantages of the embodiments.

FIG. 1 is a flow chart of a relay configuration method provided by Embodiment 1 of the present invention. The executor of this embodiment may be: a certain network node in the subnet where the DHCP client is located, that is, the current network node described below. The methods shown in Figure 1 include:

11: Obtain the routing information of the DHCP server.

The routing information of the DHCP server may include: address information of the DHCP server and next-hop address information of the DHCP server, etc.; wherein, the number of the DHCP servers may be one or more. In the embodiment of the present invention, the DHCP server and the DHCP client are not in the same broadcast domain, for example: the DHCP server is located in the public network, or the DHCP server is located in another subnet other than the subnet where the DHCP client is located wait. If the DHCP server is located in another subnet, the routing information of the DHCP server may further include: information of the subnet where the DHCP server is located, and the like.

The way to obtain the routing information of the DHCP server is not limited, for example: the routing information of the DHCP server may be pre-configured on the current network node; or, according to the received routing information including the DHCP server Broadcasting a message to obtain routing information of the DHCP server; the broadcasting message includes: a first relay announcement message, or other DHCP messages except the first relay announcement message.

12: Start the first timer, and listen to the first relay announcement message and the first relay election message within the scope of the subnet; A network node sends; the DHCP relay is used to relay and transmit the data exchanged between the DHCP server and the DHCP client in the subnet according to the routing information of the DHCP server; the first relay election report The message is sent by a second network node that meets the DHCP relay election condition in the subnet, and includes election information of the second network node.

Within the range of the subnet where the DHCP client is located, the first network node currently serving as a DHCP relay may periodically broadcast a first relay announcement message to the range of the subnet at intervals of the first preset duration; the first The relay announcement message is used to announce that the first network node is the DHCP relay agent.

The second network node meeting the DHCP relay election condition in the subnet may send the first relay election message for participating in the DHCP relay election in the subnet. The second network node may periodically broadcast the first relay election message to the subnet at intervals of the second preset time length. When there is a first network node serving as a DHCP relay in the subnet, the first network node broadcasts a first relay announcement message to the subnet, and the first relay announcement message is used to notify the first network The node acts as the DHCP relay.

Optionally, if the first relay announcement message or the first relay election message is received within the timing range of the first timer, restart the first timer.

13: If the first timer expires and the first relay announcement message or the first relay election message is not received, start a second timer and broadcast the first relay announcement message to the subnet range Two relay election messages; the second relay election message includes election information of the current network node.

The current network node can broadcast the second relay election message to the subnet for participating in the election of the DHCP relay agent in the subnet. Optionally, the current network node may periodically broadcast the second relay election message to the subnet at intervals of the second preset time length.

14: If the second timer expires, and the first relay announcement message is not received, and the first relay announcement message including the election information of the second network node with a higher priority than the current network node is not received A relay election message broadcasts a second relay announcement message within the subnet; the second relay announcement message is used to notify the current network node as the DHCP relay agent.

Optionally, if the first relay announcement message is received within the timing range of the second timer, or the first relay announcement message including election information of a second network node with a higher priority than the current network node is received 12 and 13 can be executed if the election message is relayed.

Optionally, the election information of the second network node is a second identification code of the second network node. Before broadcasting the second relay announcement message to the subnet, the method may further include: determining the first relay election message received within the timing range of the second timer; obtaining the determined The second identification code of the second network node included in the first relay election message; determining the priority of the second network node by comparing the size of the second identification code with the first identification code and the priority of the first network node. For example: comparing the second identification code of the second network node with the first identification code of the current network node; determining whether the priority of the election information of the second network node is greater than The priority of the election information of the current network node.

The foregoing first identification code, second identification code, and judgment criterion may be set according to actual needs, and are not limited in this embodiment of the present invention. An optional implementation such as:

Judgment criterion 1: The one with the smaller MAC address is preferred. The second identification code of the second network node is: the second MAC address of the second network node; the first identification code of the current network node is: the first MAC address of the current network node. If the second MAC address of the second network node is smaller than the first MAC address of the current network node, the priority of the election information of the second network node is higher than the priority of the election information of the current network node; otherwise, the second network node The priority of the election information is lower than the priority of the election information of the current network node.

Judgment criterion 2: The one with the larger MAC address is preferred. If the second MAC address of the second network node is greater than the first MAC address of the current network node, the priority of the election information of the second network node is higher than the priority of the election information of the current network node; otherwise, the second network node The priority of the election information is lower than the priority of the election information of the current network node.

Judgment criterion 3: The one with the larger random number is preferred. The second identification code of the second network node is: the second random number generated by the second network node; the first identification code of the current network node is: the first random number generated by the current network node. If the second random number of the second network node is smaller than the first random number of the current network node, the priority of the election information of the second network node is higher than the priority of the election information of the current network node; otherwise, the second network node The priority of the election information is lower than the priority of the election information of the current network node.

Judgment criterion 4: The one with the larger random number is preferred. If the second random number of the second network node is greater than the first random number of the current network node, the priority of the election information of the second network node is higher than the priority of the election information of the current network node; otherwise, the second network node The priority of the election information is lower than the priority of the election information of the current network node.

It can be understood that the above identification codes and judgment criteria are only optional examples, and should not be construed as limitations on the technical solutions of the embodiments of the present invention.

Optionally, after the current network node broadcasts the second relay announcement message to the subnet, other network nodes in the subnet determine that the current network node is the DHCP relay agent; because The current network node obtains the routing information of the DHCP server, and after the current network node acts as the DHCP relay, the DHCP client within the subnet range and the DHCP server can communicate via the DHCP server. The above DHCP relay performs data exchange.

In the method provided in this embodiment, the network node in the subnet where the DHCP client is located can obtain the routing information of the DHCP server, and determine the current DHCP relay agent in the subnet by listening to the first relay announcement message. The online status of a network node; by listening to the first relay election message, the second network node in the subnet participates in the DHCP relay election; and can participate by broadcasting the second relay election message The DHCP relay election, and broadcasting the second relay announcement message to self-promote as a DHCP relay, thereby realizing the automatic configuration of the DHCP relay in the subnet.

By adopting the technical solution provided by this embodiment, in the case of subnet expansion, evolution upgrade or failure, etc., a DHCP relay can be generated through election between network nodes, and the DHCP relay can be the DHCP server and the DHCP client in the subnet. Forward the exchanged data, thereby obtaining the network configuration information of the DHCP client. In this embodiment, the DHCP relay does not need to be manually configured, which improves the efficiency of configuring the DHCP relay and reduces the cost required for configuring the DHCP relay.

Fig. 2a and Fig. 2b are two examples of application scenarios of the DHCP relay configuration method provided by the embodiment of the present invention. As shown in Figure 2a, in the subnet where the DHCP client is located, the network node as a DHCP relay is integrated with a gateway function, and the DHCP client directly interacts with the DHCP server through the DHCP relay. As shown in Figure 2b, in the subnet where the DHCP client is located, the network node serving as the DHCP relay is separated from the gateway functional entity, and the DHCP client interacts with the DHCP server through the DHCP relay and through the gateway. The above two application scenarios are only examples of application scenarios of the embodiments of the present invention, and the DHCP relay and gateway may be integrated into one device entity or separated into different device entities. The embodiment of the present invention only illustrates the function of the DHCP relay, and does not limit whether the DHCP relay is integrated with a gateway function.

FIG. 3a is a first schematic diagram of state control of a state machine running inside a network node provided by Embodiment 2 of the present invention. The meaning of the legend used in Figure 3a is shown in Figure 3d, and the meaning of each state that the network node is in, the operation of the network node in each state, and the description of the conditions that the network node needs to satisfy when transitioning between different states, see Table 1.

Table 1

Within the scope of the subnet, the DHCP relay manually configured by the user is the official DHCP relay. The official DHCP relay 2 state described in FIG. 3a and Table 1 above reflects an application scenario in which the automatic configuration of the DCHP relay is compatible with the user configuration. A network node in any state other than the official DHCP relay 2 state in the subnet can be configured as an official DHCP relay agent, and the network node then transfers to the official DHCP relay 2 state. The state machine example of the network node As shown in Figure 3b.

The network node in the official DHCP relay 2 state can also enable or disable the automatic configuration function of the DHCP relay. If the network node configured as an official DHCP relay agent disables the DHCP relay automatic configuration function, it does not process messages related to the DHCP relay automatic configuration. If the network node configured as an official DHCP relay agent enables the automatic configuration function of the DHCP relay agent, the network node can not only handle and run its basic functions as an official DHCP relay agent, but also participate in the automatic configuration of the DHCP relay agent as an ordinary network node. During the configuration process.

Optionally, a network node in any state other than the termination 6 state in the subnet can close the DHCP relay automatic configuration function of the network node, and the network node then turns into the termination 6 state, and the state of the network node A machine example is shown in Figure 3c.

Optionally, the network node in the configuration 1 state reads the configuration data, and the configuration data may include: information on whether to enable the automatic configuration function of the DHCP relay; it may also include: information on whether to configure it as a formal DHCP relay, the first timing The timing duration of the timer, the timing duration of the second timer, the first preset duration, and/or the second preset duration and other information. The above various duration information can be pre-configured through different values of configuration parameters of the network nodes. Among them, the name and value of the configuration parameters and the description of the meaning of each configuration parameter are shown in Table 2.

Table 2

Optionally, the DHCP relay automatically configures related messages, such as relay announcement messages, relay election messages, etc., and may adopt the format of an Address Resolution Protocol (ARP) broadcast message. The 28th-44th bits of the existing ARP broadcast message are reserved bits, and the meanings of the messages related to the automatic configuration of the DHCP relay agent can be defined based on the extension of these bits.

FIG. 4 is an example of the format of a message related to DHCP relay automatic configuration provided by Embodiment 3 of the present invention. In the ARP packet shown in Figure 4:

The 28th-32nd bytes are the message type identification: these bytes can be filled with the message identification code, such as the ASCII code of "DARRDARR" and other identification codes, which are used to identify the message as a message related to DHCP relay automatic configuration. arts.

The 36th-44th bytes are options (Option), including: type (Type) option, payload length (Length) option, value (Value) option, etc. If an ARP broadcast message does not carry an option (Option), all bytes of the option (Option) are filled with 0; if the value of the type (Type) option is equal to 0, it means that the type (Type) option is an invalid option; The payload length (Length) option is in bytes and can take values from 0 to 8. When the value of the payload length (Length) option is greater than 8, it means that the payload length (Length) option is an invalid option; the value (Value) The length of the value of the option is 0-8 bytes. If the length of the value of the value (Value) option is less than 8, the tail of the value (Value) option is filled with 0.

The meanings of the different values of the specific options in the above options (Option) are shown in Table 3.

table 3

Optionally, in the above table 3: the options carrying the routing information of the DHCP server, such as the address of the DHCP server and the next-hop address to reach the DHCP server, etc., can be carried in the DHCP relay announcement message; Options of the election information, such as software or hardware identifiers, or random numbers, etc., may be carried in the DHCP relay election message and sent.

Optionally, in order to prevent the abnormal refresh of the neighbor table entry of the network neighbor, the body part of the ARP broadcast message as shown in Figure 4 conforms to the conflict detection message format of RFC 5227, namely: source IP address (SPA) The values of the domain and the source MAC address domain (SHA) do not match, and the values of the destination IP address (TPA) domain and the destination MAC address domain (THA) do not match. Examples of values for these fields are:

Source IP Address (SPA) field = 0.0.0.0;

Source MAC address domain (SHA) domain=the interface MAC address of the network node that sends this message;

Purpose IP address (SPA) field=the interface IP address of the network node that sends this message;

Source MAC address field (SHA) field=0x000000000000.

If the value of the source IP address (SPA) domain and the source MAC address domain (SHA) do not match in the ARP broadcast message received by the network node, the value of the destination IP address (TPA) domain and the destination MAC address domain (THA) value does not match, the network node will not refresh the neighbor table entry of the network node after receiving the ARP broadcast message, thus avoiding the possible introduction of the ARP broadcast message into the neighbor table maintained by the network node. The error message is conducive to achieving compatibility with existing systems.

FIG. 5 is a schematic structural diagram of a network node provided by Embodiment 4 of the present invention. The network node shown in FIG. 5 includes: a server information acquisition module 51 , a relay packet interception module 52 , a relay election processing module 54 and a relay announcement processing module 55 .

The server information acquiring module 51 can be used to acquire routing information of the DHCP server.

The relay message listening module 52 can be used for starting the first timer, and listens to the first relay announcement message and the first relay election message within the scope of the subnet; The first network node serving as a DHCP relay in the network sends; the DHCP relay is used to relay and transmit the data exchanged between the DHCP server and the DHCP client in the subnet according to the routing information of the DHCP server; The first relay election message is sent by a second network node that meets the DHCP relay election condition in the subnet, and includes election information of the second network node.

The relay election processing module 54 may be configured to start a second timer, and broadcast a second relay election message to the subnet; the second relay election message includes election information of the current network node.

The relay announcement processing module 55 may be configured to if the second timer expires, and the first relay announcement message is not received, and the second network node including the priority higher than the current network node is not received The election information of the first relay election message, then broadcast the second relay announcement message to the range of the subnet; the second relay announcement message is used to notify the current network node as the DHCP relay.

Optionally, the relay message listening module 52 is further configured to: if the first relay announcement message or the first relay election message is received within the timing range of the first timer, then restarting the first timer.

Optionally, the specific function of the server information obtaining module 51 is different depending on the way of obtaining the routing information of the DHCP server. For example: the server information obtaining module 51 may be specifically configured to pre-configure the routing information of the DHCP server on the current network node. Or, the server information obtaining module 51 can be specifically configured to obtain the routing information of the DHCP server according to the received broadcast message including the routing information of the DHCP server; the broadcast message includes: the first A subsequent announcement message, or other DHCP messages except the first relay announcement message.

Optionally, the network node provided in this embodiment may further include: an election packet determination module 531 , a packet election information acquisition module 532 and a priority determination module 533 .

The election message determining module 531 may be configured to determine the first relay election message received within the timing range of the second timer.

The packet election information acquisition module 532 may be configured to acquire the determined election information of the second network node included in the first relay election packet, where the election information of the second network node is the election information of the second network node Second identification code.

The priority determining module 533 may be configured to determine the priority of the second network node and the priority of the first network node by comparing the size of the second identification code with the first identification code, for example: in the When the second identification code is smaller than or greater than the first identification code of the current network node, it is determined that the priority of the election information of the second network node is lower than that of the current network node.

The network node provided by this embodiment can obtain the routing information of the DHCP server, and determine the online status of the first network node currently serving as the DHCP relay in the subnet where the DHCP client is located by listening to the first relay announcement message; Listen to the first relay election message to obtain the participation of the second network node in the subnet in the DHCP relay election; and participate in the DHCP relay election by broadcasting the second relay election message, and by broadcasting The second relay announcement message is self-proclaimed as a DHCP relay, thereby realizing the automatic configuration of the DHCP relay in the subnet, eliminating the cumbersome manual configuration, improving the efficiency of the DHCP relay configuration, and reducing the The cost required to configure DHCP relay.

FIG. 6 is a schematic structural diagram of a relay configuration system provided by Embodiment 5 of the present invention. The system shown in FIG. 6 includes: a DHCP client 61 , a first DHCP relay 62 and a DHCP server 63 . The DHCP client 61 and the first DHCP relay 62 are located in the subnet, and the DHCP server 63 is located outside the subnet. Wherein, the first DHCP relay 62 is elected by a plurality of network nodes included in the subnet, and is used to relay and transmit the data exchanged between the DHCP server and the DHCP client; participate in the election of the first DHCP The subsequent network nodes have the structure of the network nodes described in the corresponding embodiment in FIG. 5 .

Optionally, the system shown in FIG. 6 may further include: a second DHCP relay 64 . The function of the second DHCP relay 64 can be the same as the function of the first DHCP relay 61, that is, for relaying the data exchanged between the DHCP server 63 and the DHCP client 61 (as shown in Figure 6); or , the function of the second DHCP relay 64 may also be different from that of the first DHCP relay 61, that is, it is used to relay data exchanged between the client and other DHCP servers except the DHCP server 63 shown in FIG. 6 . The second DHCP relay 64 is manually configured by any network node of a plurality of network nodes included in the subnet, and as a network node of the second DHCP relay, does not participate in the first DHCP For the election of the relay, its working mechanism can refer to the corresponding record about "official DHCP relay" in Fig. 5, and will not be repeated here.

Those skilled in the art can understand that the accompanying drawing is only a schematic diagram of an embodiment, and the modules or processes in the accompanying drawing are not necessarily necessary for implementing the present invention.

Those of ordinary skill in the art can understand that: the modules in the network node in the embodiment can be distributed in the network node in the embodiment according to the description in the embodiment, and can also be changed accordingly and located in one or more network nodes different from this embodiment . The modules in the above embodiments can be combined into one module, and can also be further split into multiple sub-modules.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by program instructions and related hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (13)

1. A method for relay configuration, comprising: The current network node obtains the routing information of the Dynamic Host Configuration Protocol DHCP server; wherein, the current network node refers to a certain network node in the subnet where the DHCP client is located; The current network node starts a first timer, and listens to a first relay announcement message and a first relay election message within a subnet; The DHCP relay is used to relay and transmit the data exchanged between the DHCP server and the DHCP client in the subnet according to the routing information of the DHCP server; the first relay The relay election message is sent by a second network node that meets the DHCP relay election condition in the subnet, including election information of the second network node; If the first timer expires and the first relay announcement message or the first relay election message is not received, the current network node starts a second timer and reports to the subnet range broadcasting a second relay election message; the second relay election message includes the election information of the current network node; If the second timer expires, and the first relay announcement message is not received, and the first relay including the election information of the second network node with a higher priority than the current network node is not received election message, and the current network node broadcasts a second relay announcement message to the subnet; the second relay announcement message is used to notify the current network node to be the DHCP relay agent. 2. The method according to claim 1, characterized in that the method further comprises: If the first relay announcement message or the first relay election message is received within the timing range of the first timer, restart the first timer. 3. The method of claim 1, wherein, The election information of the second network node is a second identification code of the second network node; Before broadcasting the second relay announcement message to the subnet, the method further includes: determining the first relay election message received within the timing range of the second timer; obtaining the determined The second identification code of the second network node included in the first relay election message; by comparing the size of the second identification code with the first identification code of the current network node, determine the second network node The node priority and the priority of the first network node are high or low. 4. The method of claim 3, wherein, The second identification code is the second MAC address of the second network node, and the first identification code is the first MAC address of the current network node; or, The second identification code is a second random number generated by the second network node, and the first identification code is a first random number generated by the current network node. 5. The method according to any one of claims 1 to 4, wherein said obtaining the routing information of the DHCP server comprises: Pre-configuring the routing information of the DHCP server on the current network node; or, Obtain the routing information of the DHCP server according to the received broadcast message including the routing information of the DHCP server; the broadcast message includes: the first relay announcement message, or except the first relay announcement message Other DHCP messages other than the announcement message. 6. The method according to any one of claims 1 to 4, wherein the broadcasting of the second relay announcement message to the range of the subnet includes, at intervals of the first preset duration, periodically broadcasting to The subnet range broadcasts the second relay announcement message. 7. The method according to any one of claims 1 to 4, characterized in that the method further comprises periodically broadcasting the second relay election report to the subnet range at intervals of a second preset duration arts. 8. A network node, characterized in that, comprising: The server information obtaining module is used to obtain the routing information of the Dynamic Host Configuration Protocol DHCP server; The relay message listening module is used to start the first timer, and listen to the first relay announcement message and the first relay election message within the scope of the subnet; the first relay announcement message is sent by the subnet The first network node serving as a DHCP relay in the network sends; the DHCP relay is used to relay and transmit the data exchanged between the DHCP server and the DHCP client in the subnet according to the routing information of the DHCP server; The first relay election message is sent by a second network node that satisfies the DHCP relay election condition in the subnet, and includes election information of the second network node; A relay election processing module, configured to start a second timer, and broadcast a second relay election message to the subnet; the second relay election message includes election information of the current network node; wherein, The current network node refers to a certain network node in the subnet where the DHCP client is located; A relay announcement processing module, configured to if the second timer expires, and the first relay announcement message is not received, and the second network node including the priority higher than the current network node is not received The election information of the first relay election message, then broadcast the second relay announcement message to the range of the subnet; the second relay announcement message is used to notify the current network node as the DHCP relay. 9. The network node according to claim 8, characterized in that, The relay message listening module is further configured to restart the first relay announcement message or the first relay election message if the first relay announcement message or the first relay election message is received within the timing range of the first timer. a timer. 10. The network node according to claim 8, further comprising: An election message determination module, configured to determine the first relay election message received within the timing range of the second timer; A message election information acquisition module, configured to acquire the determined election information of the second network node included in the first relay election message, where the election information of the second network node is the election information of the second network node second identification code; A priority determination module, configured to determine whether the priority of the second network node is higher than the priority of the first network node by comparing the size of the second identification code with the first identification code of the current network node. 11. The network node according to any one of claims 8-10, characterized in that, The server information obtaining module is specifically configured to pre-configure routing information of the DHCP server on the current network node; or, The server information obtaining module is specifically configured to obtain the routing information of the DHCP server according to the received broadcast message including the routing information of the DHCP server; the broadcast message includes: the first relay announcement message, or other DHCP messages except the first relay announcement message. 12. A relay configuration system, comprising: A DHCP client, a first DHCP relay and a DHCP server; the DHCP client and the first DHCP relay are located in a subnet, and the DHCP server is located outside the subnet; The first DHCP relay is elected by a plurality of network nodes included in the subnet, and is used to relay and transmit the data exchanged between the DHCP server and the DHCP client; participate in the election of the first DHCP relay The network node is the network node according to any one of claims 8 to 11. 13. The system of claim 12, further comprising: a second DHCP relay, configured to relay data exchanged between the DHCP server and the DHCP client; The second DHCP relay is generated by any network node of the plurality of network nodes included in the subnet through manual configuration, and as the network node of the second DHCP relay, does not participate in the first DHCP relay election.