CN105592172A - Dynamic host configuration protocol (DHCP) reconnection method, DHCP server and system - Google Patents

Abstract

The present invention relates to a dynamic host configuration protocol reconnection method, a DHCP server and a system. The method comprises: when a terminal is switched from a first DHCP server to a second DHCP server, broadcasting a first DHCP request message; After receiving the first DHCP request message, the server returns a DHCPNAK message to the terminal to inform the terminal to start a new reconnection process after judging that if there is no relevant device information of the maintenance terminal. The invention saves the time delay caused by multiple DHCPREQUEST retries of the downlink device, and achieves the purpose of fast reconnection.

Description

Dynamic host configuration protocol reconnection method, DHCP server and system

technical field

The invention relates to the technical field of network communication, in particular to a dynamic host configuration protocol reconnection method, a DHCP server and a system.

Background technique

Dynamic Host Configuration Protocol (DHCP, DynamicHostConfigurationProtocol) is a LAN network protocol, using the UDP protocol to work, based on the Client/Server working mode, to provide IP addresses and configuration parameters for hosts on the Internet, mainly for two purposes: to the internal network or network Service providers automatically assign IP addresses to users or internal network administrators as a means of centrally managing all computers.

At present, with the wide application of downlink devices such as mobile phones, it is becoming more and more important to obtain addresses through DHCP. However, if the downlink device switches to DHCPServer, the DHCPServer will follow RFC2131 specification 4.3 for the DHCPREQUEST message sent by the downlink device. Section .2 needs to be silently processed, and the purpose is to deal with the situation that there are multiple DHCPServers on the same line (see Figure 1). This causes the downlink device to send multiple DHCPREQUESTs in a row without getting a response, and has to wait for the end of the retry, resend the DHCPDISCOVER message to start a new connection process to obtain the address, thus causing a long delay in the reconnection of the downlink device , giving poor user experience.

Contents of the invention

The main purpose of the present invention is to provide a dynamic host configuration protocol reconnection method, a DHCP server and a system, aiming to solve the problem of a large delay in acquiring addresses caused by switching DHCP servers for downlink devices, and to realize fast DHCP of downlink devices. Reconnection.

In order to achieve the above object, the present invention proposes a dynamic host configuration protocol reconnection method, comprising:

When the terminal switches from the first DHCP server to the second DHCP server, it broadcasts the first DHCP request message to the outside;

After receiving the first DHCP request message, the second DHCP server returns a DHCPNAK message to the terminal to notify the terminal to open a new Reconnection process.

Preferably, the method also includes:

After receiving the DHCPNAK message, the terminal sends a second DHCP request message to the second DHCP server to confirm selection of the second DHCP server;

The second DHCP server returns a DHCPACK packet to the terminal.

Preferably, the method also includes:

After receiving the DHCPNAK message, the terminal broadcasts a DISCOVER message;

After receiving the DISCOVER message, the second DHCP server returns a DHCPOFFER message to the terminal;

After receiving the DHCPOFFER message, the terminal sends a second DHCP request message to the second DHCP server to confirm selection of the second DHCP server;

The second DHCP server returns a DHCPACK packet to the terminal.

Preferably, when the terminal switches from the first DHCP server to the second DHCP server, before the step of broadcasting the first DHCP request message, the terminal further includes:

After the terminal accesses the first DHCP server, it broadcasts a DISCOVER message;

After receiving the DISCOVER message, the first DHCP server returns a DHCPOFFER message to the terminal;

After receiving the DHCPOFFER message, the terminal sends a second DHCP request message to the first DHCP server to confirm selection of the first DHCP server;

The first DHCP server returns a DHCPACK packet to the terminal.

The embodiment of the present invention also proposes a dynamic host configuration protocol reconnection method, including:

The DHCP server receives the first DHCP request message broadcast by the terminal;

According to the first DHCP request message, determine whether the related device information of the terminal is maintained;

If the relevant device information of the terminal is not maintained, a DHCPNAK message is returned to the terminal to inform the terminal to start a new reconnection process.

Preferably, the method also includes:

receiving a second DHCP request message sent by the terminal, where the second DHCP request message confirms selection of the DHCP server;

Return a DHCPACK message to the terminal.

Preferably, the method also includes:

receiving a DISCOVER message broadcast by the terminal;

Returning a DHCPOFFER message to the terminal according to the DISCOVER message;

receiving a second DHCP request message sent by the terminal, where the second DHCP request message confirms selection of the DHCP server;

Return a DHCPACK message to the terminal.

The embodiment of the present invention also proposes a DHCP server for dynamic host configuration protocol reconnection, including:

A receiving module, configured to receive the first DHCP request message broadcast by the terminal;

A judging module, configured to judge whether relevant device information of the terminal is maintained according to the first DHCP request message;

The sending module is configured to return a DHCPNAK message to the terminal when the judging module judges that the relevant device information of the terminal is not maintained, so as to inform the terminal to start a new reconnection process.

Preferably, the receiving module in this method is further configured to receive a second DHCP request message sent by the terminal, and the second DHCP request message confirms selection of the DHCP server;

The sending module is further configured to return a DHCPACK message to the terminal.

Preferably, the method

The receiving module is further configured to receive a DISCOVER message broadcast by the terminal;

The sending module is further configured to return a DHCPOFFER message to the terminal according to the DISCOVER message;

The receiving module is further configured to receive a second DHCP request message sent by the terminal, and the second DHCP request message confirms selection of the DHCP server;

The sending module is further configured to return a DHCPACK message to the terminal.

The embodiment of the present invention also proposes a system for reconnecting with a dynamic host configuration protocol, including a first DHCP server, a second DHCP server, and a terminal respectively communicating with the first DHCP server and the second DHCP server; wherein:

The second DHCP server is the DHCP server according to any one of claims 8-10;

The terminal is configured to broadcast the first DHCP request message when switching from the first DHCP server to the second DHCP server; and receive the DHCPNAK message returned by the second DHCP server, and according to the DHCPNAK message The text starts a new reconnection process.

A dynamic host configuration protocol reconnection method, a DHCP server and a system proposed in the embodiment of the present invention will not simultaneously connect to multiple DHCP servers for a terminal (downlink device). If the downlink device sends a DHCPREQUEST request message , the DHCP server judges that the relevant device information is not maintained, and then directly replies to the DHCPNAK message, prompting the connected device to immediately send DHCPDISCOVER, and start a new process of obtaining an address, thereby eliminating the delay caused by multiple DHCPREQUEST retries of the connected device. , the purpose of fast reconnection is achieved.

Description of drawings

Fig. 1 is the interaction flow chart of DHCP according to the standard when the existing terminal switches the network;

FIG. 2 is a schematic flow diagram of an embodiment of a method for reconnecting a dynamic host configuration protocol according to the present invention;

FIG. 3 is a schematic flow diagram of another embodiment of the DHCP reconnection method of the present invention;

Fig. 4 is a schematic flow chart of another embodiment of the DHCP reconnection method of the present invention;

Fig. 5 is a detailed schematic flow diagram of an embodiment of the dynamic host configuration protocol reconnection method shown in Fig. 4;

FIG. 6 is a schematic flow diagram of another embodiment of the DHCP reconnection method of the present invention;

FIG. 7 is a schematic flow diagram of another embodiment of the DHCP reconnection method of the present invention;

Fig. 8 is a schematic flow chart of another embodiment of the DHCP reconnection method of the present invention;

FIG. 9 is a schematic flow chart of another embodiment of the DHCP reconnection method of the present invention;

Fig. 10 is a schematic diagram of functional modules of an embodiment of the DHCP server of the reconnection of the dynamic host configuration protocol of the present invention;

FIG. 11 is a schematic structural diagram of an embodiment of a system for dynamic host configuration protocol reconnection according to the present invention.

The structural representation of an embodiment;

Fig. 5 is a schematic structural diagram of another embodiment of the intelligent user portrait device based on the big data platform of the Internet of Things according to the present invention.

In order to make the technical solution of the present invention clearer and clearer, it will be further described below in conjunction with the accompanying drawings.

detailed description

The solution of the embodiment of the present invention is mainly: for a terminal (downlink device) that does not connect to multiple DHCP servers at the same time, if the downlink device sends a DHCPREQUEST request message, the DHCP server does not maintain the relevant equipment after judging information, it directly replies to the DHCPNAK message, prompting the connected device to immediately send DHCPDISCOVER, and start a new process of obtaining an address, thereby saving the delay caused by multiple DHCPREQUEST retries of the connected device, and achieving the purpose of fast reconnection.

Firstly, an existing implementation manner of switching a DHCP server by a terminal is described.

Referring to Fig. 1, Fig. 1 is an interactive flow chart of DHCP according to the specification when the terminal (downloaded device) switches the network, and the specific processing flow is as follows:

Step 1, the downlink device A connects to the device where DHCPServer1 (the first DHCP server) is located in a wireless or wired manner;

Step 2, the downlink device A sends a DHCPDISCOVER message;

Step 3, DHCPServer1 replies to the DHCPOFFER message;

Step 4, the downlink device A sends a DHCPREQUEST message to confirm the selection of DHCPServer1;

Step 5, DHCPServer1 replies with a DHCPACK message, and the downlink device A obtains an address;

Step 6: Switch the DHCP server of the connected device A to the device where DHCPServer2 (the second DHCP server) is located; the actual application scenario is: the mobile phone switches the WIFI hotspot, the AC switches the AP, etc.;

Step 7: After switching the DHCP server, the connected device A will send a DHCPREQUEST message;

Step 8, according to the specification requirements of RFC2131, DHCPServer2 should perform silent processing here;

Step 9: After sending multiple DHCPREQUEST messages continuously and receiving no response, the hanging device A waits for the end of the retry and sends a DISCOVER message;

Step 10, DHCPServer2 replies to the DHCPOFFER message;

Step 11, the downlink device A sends a DHCPREQUEST message to confirm the selection of DHCPServer2;

In step 12, DHCPServer2 replies with a DHCPACK message, and the downlink device A obtains an address.

It can be seen from the above process that the existing downlink device switching network implementation method will cause the downlink device to send multiple DHCPREQUESTs in succession without receiving a response, and can only wait for the end of the retry, and resend the DHCPDISCOVER message to start a new connection process The address can only be obtained. As a result, the reconnection delay of the connected device is relatively large, and the user experience is poor.

When the program of this embodiment switches the DHCPServer of the downlink device, if the newly accessed DHCPServer does not maintain the relevant information of the downlink device, it will directly reply the DHCPNAK message, allowing the downlink device to start a new reconnection process immediately, thereby saving the downlink The delay caused by multiple DHCPREQUEST retries of the hanging device achieves the purpose of fast reconnection.

Based on the above analysis, an embodiment of the DHCP reconnection method of the present invention is proposed.

Specifically, as shown in FIG. 2, an embodiment of the present invention proposes a dynamic host configuration protocol reconnection method, including:

Step S101, the terminal broadcasts the first DHCP request message when switching from the first DHCP server to the second DHCP server;

Step S102, after receiving the first DHCP request message, the second DHCP server returns a DHCPNAK message to the terminal to inform the terminal if it determines that the relevant device information of the terminal is not maintained Start a new reconnection process.

In this embodiment, when switching from the first DHCP server to the second DHCP server, the terminal broadcasts the first DHCPREQUEST message to the outside to inform the terminal that it needs to switch from the first DHCP server to the second DHCP server. A DHCPREQUEST message carries the IP address currently used by the terminal.

After the second DHCP server receives the first DHCP request message sent by the terminal, it judges whether the relevant device information of the terminal is maintained locally, and if it is judged that the relevant device information of the terminal is not maintained, the second DHCP server sends the The terminal returns a DHCPNAK message to inform the terminal to start a new reconnection process. That is to say, the second DHCP server informs the terminal through the DHCPNAK message that the current logical parameters cannot meet the terminal's request and cannot provide the corresponding service to the terminal. The terminal restarts the process of obtaining the address.

In this way, the terminal does not need to continuously send multiple DHCPREQUESTs to wait for a response, and does not need to wait for the end of the retry, but can directly resend the DHCPDISCOVER message to start a new connection process to obtain the address, thereby saving the delay caused by the terminal's multiple DHCPREQUEST retries. To achieve the purpose of fast reconnection.

As shown in FIG. 3, another embodiment of the present invention proposes a DHCP reconnection method. Based on the above-mentioned embodiment shown in FIG. 2, it also includes corresponding steps for the terminal to start a new reconnection process, specifically including:

Step S103, after receiving the DHCPNAK message, the terminal sends a second DHCP request message to the second DHCP server to confirm selection of the second DHCP server;

Step S104, the second DHCP server returns a DHCPACK message to the terminal.

Compared with the above-mentioned embodiment shown in FIG. 2 , this embodiment also includes a specific solution for the terminal to start a new reconnection process.

First, after receiving the DHCPNAK message returned by the second DHCP server, the terminal directly sends the second DHCP request message to the second DHCP server, and the second DHCP request message carries the selected second DHCP server to obtain the relevant IP address. information, that is, to confirm the selection of the second DHCP server.

After the second DHCP server receives the second DHCP request message sent by the terminal, it returns a DHCPACK message to the terminal. The DHCPACK message is used as a confirmation message and carries the IP address, route, and subnet mask assigned to the terminal device. , DNS, lease period and other information, the terminal obtains key information such as IP address, route, subnet mask, DNS, lease period, etc. required for Internet access, and the reconnection process ends.

As shown in FIG. 4 , another embodiment of the present invention proposes a method for reconnecting with a dynamic host configuration protocol. Based on the above-mentioned embodiment shown in FIG. 2 , it also includes corresponding steps for the terminal to start a new reconnection process. The implementation method is the same as that of The process of starting a new reconnection by the terminal shown in FIG. 3 above is different. Specifically include:

Step S105, the terminal broadcasts a DISCOVER message after receiving the DHCPNAK message;

Step S106, the second DHCP server returns a DHCPOFFER message to the terminal after receiving the DISCOVER message;

Step S1031, after receiving the DHCPOFFER message, the terminal sends a second DHCP request message to the second DHCP server to confirm selection of the second DHCP server;

Step S1041, the second DHCP server returns a DHCPACK message to the terminal.

Compared with the above-mentioned embodiment shown in FIG. 2 , this embodiment also includes a specific solution for the terminal to start a new reconnection process.

First, after receiving the DHCPNAK message returned by the second DHCP server, the terminal does not directly send the second DHCP request message to the second DHCP server, but broadcasts a DISCOVER message to the outside. The DISCOVER message carries the terminal device identifier, vendor category identifier, host name, and a series of request information, including but not limited to subnet mask, routing, domain name, DNS and other information.

After receiving the DISCOVER message, the second DHCP server returns a DHCPOFFER message to the terminal, and provides the terminal with information such as IP address, route, subnet mask, DNS, and lease period.

After receiving the DHCPOFFER message sent by the second DHCP server, the terminal sends a second DHCP request message to the second DHCP server, where the second DHCP request message carries information for selecting the second DHCP server to obtain the relevant IP address, That is, confirm to select the second DHCP server.

After the second DHCP server receives the second DHCP request message sent by the terminal, it returns a DHCPACK message to the terminal. The DHCPACK message is used as a confirmation message and carries the IP address, route, and subnet mask assigned to the terminal device. , DNS, lease period and other information, the terminal obtains key information such as IP address, route, subnet mask, DNS, lease period, etc. required for Internet access, and the reconnection process ends.

The processing flow of this embodiment is described in detail below in conjunction with FIG. 5:

With reference to Fig. 5, Fig. 5 is in this embodiment, the interaction flowchart when the terminal (download device) switches networks, and specific processing flow is as follows:

Step 1, the downlink device A (terminal) accesses the device where DHCPServer1 (the first DHCP server) is located in a wireless or wired manner;

Step 2, the downlink device A sends a DHCPDISCOVER message;

Step 3, DHCPServer1 replies to the DHCPOFFER message; here, the source of the DHCPOFFER message received by the downlink device can be used to judge whether it meets the application scenario proposed by the present invention: one downlink device will not simultaneously access multiple DHCPServers. If there is only one source, it meets the application scenario of the present invention; if there are multiple sources, it does not meet;

Step 4, the downlink device A sends a DHCPREQUEST message to confirm the selection of DHCPServer1;

Step 5, DHCPServer1 replies with a DHCPACK message, and the downlink device A obtains an address;

Step 6: Switch the DHCP server of the connected device A to the device where DHCPServer2 (the second DHCP server) is located; the actual application scenario is: the mobile phone switches the WIFI hotspot, the AC switches the AP, etc.;

Step 7: After switching the DHCP server, the connected device A will send a DHCPREQUEST message;

Step 8, according to the normative requirement of RFC2131, here DHCPServer2 will carry out quiet processing; And according to the requirement of the present invention, DHCPServer2 directly replies DHCPNAK message, allows the next hanging device to start a new acquisition address process immediately, thereby saving the retry of DHCPREQUEST time;

Step 9: After receiving the DHCPNAK message, the downlink device A sends a DISCOVER message;

Step 10, DHCPServer2 replies to the DHCPOFFER message;

Step 11, the downlink device A sends a DHCPREQUEST message to confirm the selection of DHCPServer2;

In step 12, DHCPServer2 replies with a DHCPACK message, and the downlink device A obtains an address.

In this embodiment, through the above scheme, a terminal (downloaded device) will not be connected to multiple DHCP servers at the same time. If the downlink device sends a DHCPREQUEST request message, the DHCP server does not maintain relevant device information after judging, then Reply directly to the DHCPNAK message, prompting the connected device to send DHCPDISCOVER immediately, and start a new process of obtaining an address, thereby saving the delay caused by multiple DHCPREQUEST retries of the connected device, and achieving the purpose of fast reconnection.

As shown in FIG. 6, another embodiment of the present invention proposes a dynamic host configuration protocol reconnection method. Based on the embodiment shown in FIG. 4 above, when the terminal switches from the first DHCP server to the second DHCP server, the external Before the step of broadcasting the first DHCP request message, it also includes:

Step S107, after the terminal accesses the first DHCP server, it broadcasts a DISCOVER message;

Step S108, the first DHCP server returns a DHCPOFFER message to the terminal after receiving the DISCOVER message;

Step S109, after receiving the DHCPOFFER message, the terminal sends a second DHCP request message to the first DHCP server to confirm selection of the first DHCP server;

Step S110, the first DHCP server returns a DHCPACK message to the terminal.

Compared with the above-mentioned embodiment, this embodiment also includes a solution for the terminal to access the first DHCP server. This process is the same as the existing DHCP specification, and can refer to the specific process shown in FIG. 1 , which will not be repeated here.

It should be noted that this embodiment can also be implemented in combination with the above embodiments shown in FIG. 2 and FIG. 3 , which will not be repeated here.

As shown in FIG. 7, another embodiment of the present invention proposes a method for reconnecting with the Dynamic Host Configuration Protocol, which is a method embodiment proposed from the DHCP server side, and the method includes:

Step S201, the DHCP server receives the first DHCP request message broadcast by the terminal;

Step S202, according to the first DHCP request message, judging whether the related device information of the terminal is maintained;

Step S203, if the relevant device information of the terminal is not maintained, return a DHCPNAK message to the terminal to inform the terminal to start a new reconnection process.

Specifically, in this embodiment, when switching from the first DHCP server to the second DHCP server, the terminal broadcasts the first DHCPREQUEST message to the outside to notify the terminal that it needs to switch from the first DHCP server to the second DHCP server. , the first DHCPREQUEST message carries the IP address currently used by the terminal.

After the second DHCP server receives the first DHCP request message sent by the terminal, it judges whether the relevant device information of the terminal is maintained locally, and if it is judged that the relevant device information of the terminal is not maintained, the second DHCP server sends the The terminal returns a DHCPNAK message to inform the terminal to start a new reconnection process. That is to say, the second DHCP server informs the terminal through the DHCPNAK message that the current logical parameters cannot meet the terminal's request and cannot provide the corresponding service to the terminal. The terminal restarts the process of obtaining the address.

In this way, the terminal does not need to continuously send multiple DHCPREQUESTs to wait for a response, and does not need to wait for the end of the retry, but can directly resend the DHCPDISCOVER message to start a new connection process to obtain the address, thereby saving the delay caused by the terminal's multiple DHCPREQUEST retries. To achieve the purpose of fast reconnection.

As shown in FIG. 8 , another embodiment of the present invention proposes a dynamic host configuration protocol reconnection method, based on the above-mentioned embodiment shown in FIG. 7 , further comprising:

Step S204, receiving a second DHCP request message sent by the terminal, the second DHCP request message confirming selection of the DHCP server;

Step S205, returning a DHCPACK message to the terminal.

Compared with the above-mentioned embodiment shown in FIG. 7 , this embodiment also includes a specific solution for the terminal to start a new reconnection process.

First, after receiving the DHCPNAK message returned by the second DHCP server, the terminal directly sends the second DHCP request message to the second DHCP server, and the second DHCP request message carries the selected second DHCP server to obtain the relevant IP address. information, that is, to confirm the selection of the second DHCP server.

After the second DHCP server receives the second DHCP request message sent by the terminal, it returns a DHCPACK message to the terminal. The DHCPACK message is used as a confirmation message and carries the IP address, route, and subnet mask assigned to the terminal device. , DNS, lease period and other information, the terminal obtains key information such as IP address, route, subnet mask, DNS, lease period, etc. required for Internet access, and the reconnection process ends.

As shown in FIG. 9, another embodiment of the present invention proposes a dynamic host configuration protocol reconnection method. Based on the above-mentioned embodiment shown in FIG. 7, it also includes corresponding steps for the terminal to start a new reconnection process. The terminal shown in FIG. 8 starts a new reconnection process differently. Specifically, it also includes:

Step S206, receiving the DISCOVER message broadcast by the terminal;

Step S207, returning a DHCPOFFER message to the terminal according to the DISCOVER message;

Step S208, receiving a second DHCP request message sent by the terminal, the second DHCP request message confirming selection of the DHCP server;

Step S209, returning a DHCPACK message to the terminal.

First, after receiving the DHCPNAK message returned by the second DHCP server, the terminal does not directly send the second DHCP request message to the second DHCP server, but broadcasts a DISCOVER message to the outside. The DISCOVER message carries the terminal device identifier, vendor category identifier, host name, and a series of request information, including but not limited to subnet mask, routing, domain name, DNS and other information.

After receiving the DISCOVER message, the second DHCP server returns a DHCPOFFER message to the terminal, and provides the terminal with information such as IP address, route, subnet mask, DNS, and lease period.

After receiving the DHCPOFFER message sent by the second DHCP server, the terminal sends a second DHCP request message to the second DHCP server, where the second DHCP request message carries information for selecting the second DHCP server to obtain the relevant IP address, That is, confirm to select the second DHCP server.

After the second DHCP server receives the second DHCP request message sent by the terminal, it returns a DHCPACK message to the terminal. The DHCPACK message is used as a confirmation message and carries the IP address, route, and subnet mask assigned to the terminal device. , DNS, lease period and other information, the terminal obtains key information such as IP address, route, subnet mask, DNS, lease period, etc. required for Internet access, and the reconnection process ends.

In this embodiment, through the above scheme, a terminal (downloaded device) will not be connected to multiple DHCP servers at the same time. If the downlink device sends a DHCPREQUEST request message, the DHCP server does not maintain relevant device information after judging, then Reply directly to the DHCPNAK message, prompting the connected device to send DHCPDISCOVER immediately, and start a new process of obtaining an address, thereby saving the delay caused by multiple DHCPREQUEST retries of the connected device, and achieving the purpose of fast reconnection.

Correspondingly, an embodiment of the DHCP server for dynamic host configuration protocol reconnection of the present invention is proposed.

Specifically, as shown in FIG. 10 , an embodiment of the present invention proposes a DHCP server for dynamic host configuration protocol reconnection, including: a receiving module 301, a judging module 302, and a sending module 303, wherein:

The receiving module 301 is configured to receive the first DHCP request message broadcast by the terminal;

A judging module 302, configured to judge whether relevant device information of the terminal is maintained according to the first DHCP request message;

The sending module 303 is configured to return a DHCPNAK message to the terminal when the judging module judges that the relevant device information of the terminal is not maintained, so as to inform the terminal to start a new reconnection process.

Specifically, in this embodiment, when switching from the first DHCP server to the second DHCP server, the terminal broadcasts the first DHCPREQUEST message to the outside to notify the terminal that it needs to switch from the first DHCP server to the second DHCP server. , the first DHCPREQUEST message carries the IP address currently used by the terminal.

After the second DHCP server receives the first DHCP request message sent by the terminal, it judges whether the relevant device information of the terminal is maintained locally, and if it is judged that the relevant device information of the terminal is not maintained, the second DHCP server sends the The terminal returns a DHCPNAK message to inform the terminal to start a new reconnection process. That is to say, the second DHCP server informs the terminal through the DHCPNAK message that the current logical parameters cannot meet the terminal's request and cannot provide the corresponding service to the terminal. The terminal restarts the process of obtaining the address.

In this way, the terminal does not need to continuously send multiple DHCPREQUESTs to wait for a response, and does not need to wait for the end of the retry, but can directly resend the DHCPDISCOVER message to start a new connection process to obtain the address, thereby saving the delay caused by the terminal's multiple DHCPREQUEST retries. To achieve the purpose of fast reconnection.

Further, as an implementation method for the terminal to start a new reconnection process, the receiving module 301 is also configured to receive a second DHCP request message sent by the terminal, and the second DHCP request message confirms that the selected the DHCP server;

The sending module 303 is further configured to return a DHCPACK message to the terminal.

This embodiment also includes a specific solution for the terminal to start a new reconnection process.

First, after receiving the DHCPNAK message returned by the second DHCP server, the terminal directly sends the second DHCP request message to the second DHCP server, and the second DHCP request message carries the selected second DHCP server to obtain the relevant IP address. information, that is, to confirm the selection of the second DHCP server.

After the second DHCP server receives the second DHCP request message sent by the terminal, it returns a DHCPACK message to the terminal. The DHCPACK message is used as a confirmation message and carries the IP address, route, and subnet mask assigned to the terminal device. , DNS, lease period and other information, the terminal obtains key information such as IP address, route, subnet mask, DNS, lease period, etc. required for Internet access, and the reconnection process ends.

Further, as another implementation method for the terminal to start a new reconnection process, the receiving module 301 is also configured to receive the DISCOVER message broadcast by the terminal;

The sending module 303 is further configured to return a DHCPOFFER message to the terminal according to the DISCOVER message;

The receiving module 301 is further configured to receive a second DHCP request message sent by the terminal, where the second DHCP request message confirms selection of the DHCP server;

The sending module 303 is further configured to return a DHCPACK message to the terminal.

First, after receiving the DHCPNAK message returned by the second DHCP server, the terminal does not directly send the second DHCP request message to the second DHCP server, but broadcasts a DISCOVER message to the outside. The DISCOVER message carries the terminal device identifier, vendor category identifier, host name, and a series of request information, including but not limited to subnet mask, routing, domain name, DNS and other information.

After receiving the DISCOVER message, the second DHCP server returns a DHCPOFFER message to the terminal, and provides the terminal with information such as IP address, route, subnet mask, DNS, and lease period.

After receiving the DHCPOFFER message sent by the second DHCP server, the terminal sends a second DHCP request message to the second DHCP server, where the second DHCP request message carries information for selecting the second DHCP server to obtain the relevant IP address, That is, confirm to select the second DHCP server.

After the second DHCP server receives the second DHCP request message sent by the terminal, it returns a DHCPACK message to the terminal. The DHCPACK message is used as a confirmation message and carries the IP address, route, and subnet mask assigned to the terminal device. , DNS, lease period and other information, the terminal obtains key information such as IP address, route, subnet mask, DNS, lease period, etc. required for Internet access, and the reconnection process ends.

In this embodiment, through the above scheme, a terminal (downloaded device) will not be connected to multiple DHCP servers at the same time. If the downlink device sends a DHCPREQUEST request message, the DHCP server does not maintain relevant device information after judging, then Reply directly to the DHCPNAK message, prompting the connected device to send DHCPDISCOVER immediately, and start a new process of obtaining an address, thereby saving the delay caused by multiple DHCPREQUEST retries of the connected device, and achieving the purpose of fast reconnection.

In addition, as shown in FIG. 11 , an embodiment of the present invention also proposes a dynamic host configuration protocol reconnection system, including a first DHCP server 401, a second DHCP server 402 and the first DHCP server 401, the second The terminals 403 connected by the DHCP server 402 respectively; wherein:

The second DHCP server 402 may be the DHCP server described in the foregoing embodiment;

The terminal 403 is configured to broadcast the first DHCP request message when switching from the first DHCP server 401 to the second DHCP server 402; and receive the DHCPNAK message returned by the second DHCP server 402, and according to The DHCPNAK message starts a new reconnection process.

Wherein, the first DHCP server 401, the second DHCP server 402, and the terminal 403 interact to realize the process of dynamic host configuration protocol reconnection, please refer to the above-mentioned embodiments, which will not be repeated here.

In the embodiment of the present invention, the dynamic host configuration protocol reconnection method, DHCP server and system will not simultaneously connect to multiple DHCP servers for a terminal 403 (downloaded device). If the downlink device sends a DHCPREQUEST request message, the DHCP server After judging that the relevant device information has not been maintained, it will directly reply to the DHCPNAK message, prompting the connected device to immediately send DHCPDISCOVER, and start a new process of obtaining an address, thus saving the delay caused by multiple DHCPREQUEST retries of the connected device, reaching for the purpose of fast reconnection.

The above is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technical fields , are all included in the scope of patent protection of the present invention in the same way.

Claims (11)

1. A Dynamic Host Configuration Protocol reconnection method, characterized in that, comprising: When the terminal switches from the first DHCP server to the second DHCP server, it broadcasts the first DHCP request message to the outside; After receiving the first DHCP request message, the second DHCP server returns a DHCPNAK message to the terminal to notify the terminal to open a new Reconnection process. 2. The method according to claim 1, further comprising: After receiving the DHCPNAK message, the terminal sends a second DHCP request message to the second DHCP server to confirm selection of the second DHCP server; The second DHCP server returns a DHCPACK packet to the terminal. 3. The method according to claim 1, further comprising: After receiving the DHCPNAK message, the terminal broadcasts a DISCOVER message; After receiving the DISCOVER message, the second DHCP server returns a DHCPOFFER message to the terminal; After receiving the DHCPOFFER message, the terminal sends a second DHCP request message to the second DHCP server to confirm selection of the second DHCP server; The second DHCP server returns a DHCPACK message to the terminal. 4. The method according to claim 1, wherein, when the terminal is switched from the first DHCP server to the second DHCP server, before the step of broadcasting the first DHCP request message, the terminal also includes: After the terminal accesses the first DHCP server, it broadcasts a DISCOVER message; After receiving the DISCOVER message, the first DHCP server returns a DHCPOFFER message to the terminal; After receiving the DHCPOFFER message, the terminal sends a second DHCP request message to the first DHCP server to confirm selection of the first DHCP server; The first DHCP server returns a DHCPACK message to the terminal. 5. A dynamic host configuration protocol reconnection method, characterized in that, comprising: The DHCP server receives the first DHCP request message broadcast by the terminal; According to the first DHCP request message, determine whether the related device information of the terminal is maintained; If the relevant device information of the terminal is not maintained, a DHCPNAK message is returned to the terminal to inform the terminal to start a new reconnection process. 6. The method according to claim 5, further comprising: receiving a second DHCP request message sent by the terminal, where the second DHCP request message confirms selection of the DHCP server; Return a DHCPACK message to the terminal. 7. The method according to claim 5, further comprising: receiving a DISCOVER message broadcast by the terminal; Returning a DHCPOFFER message to the terminal according to the DISCOVER message; receiving a second DHCP request message sent by the terminal, where the second DHCP request message confirms selection of the DHCP server; Return a DHCPACK message to the terminal. 8. A DHCP server for dynamic host configuration protocol reconnection, characterized in that, comprising: A receiving module, configured to receive the first DHCP request message broadcast by the terminal; A judging module, configured to judge whether relevant device information of the terminal is maintained according to the first DHCP request message; The sending module is configured to return a DHCPNAK message to the terminal when the judging module judges that the relevant device information of the terminal is not maintained, so as to inform the terminal to start a new reconnection process. 9. DHCP server according to claim 8, is characterized in that, The receiving module is further configured to receive a second DHCP request message sent by the terminal, and the second DHCP request message confirms selection of the DHCP server; The sending module is further configured to return a DHCPACK message to the terminal. 10. DHCP server according to claim 8, is characterized in that, The receiving module is further configured to receive a DISCOVER message broadcast by the terminal; The sending module is further configured to return a DHCPOFFER message to the terminal according to the DISCOVER message; The receiving module is further configured to receive a second DHCP request message sent by the terminal, and the second DHCP request message confirms selection of the DHCP server; The sending module is further configured to return a DHCPACK message to the terminal. 11. A system for dynamic host configuration protocol reconnection, characterized in that it includes a first DHCP server, a second DHCP server, and terminals respectively connected in communication with the first DHCP server and the second DHCP server; wherein: The second DHCP server is the DHCP server according to any one of claims 8-10; The terminal is configured to broadcast the first DHCP request message when switching from the first DHCP server to the second DHCP server; and receive the DHCPNAK message returned by the second DHCP server, and according to the DHCPNAK message The text starts a new reconnection process.