CN100337446C - Method for rapid access neighbor device - Google Patents

Abstract

The present invention discloses a method for rapidly accessing neighbor devices; a network device records the IP address of the neighbor devices. The method comprises the following steps: A. the network device obtains and records the corresponding relation of IP address, and the media access control address and an outlet port which correspond to the IP address, of each neighbor device. B. When the neighbor devices are needed to be accessed, the network device searches all the corresponding relation recorded in the step A and then obtains the media access control address and the outlet port which correspond to the accessed IP address to access to the neighbor devices according to the IP address of the neighbor device to be accessed. The method for rapidly accessing neighbor devices of the present invention directly reads the recorded media access control address and the outlet ports to fast access the neighbor devices according to the IP address, by recording the IP address of the neighbor devices in advance, the media access control address and the outlet port obtained by the recorded IP address when accessing the neighbor devices.

Description

A method of quickly accessing neighboring devices

technical field

The invention relates to a method for quickly accessing neighbor equipment.

Background technique

In an Ethernet broadcast domain, two devices with IP addresses in the same network segment are called neighbor devices. When a network device in the network needs to access its neighbor device, the network device first checks its own Address Resolution Protocol (ARP, Address Resolution Protocol) table according to the IP address of the neighbor device, and judges whether the address resolution protocol (ARP) exists in the ARP table. If the ARP entry corresponding to the IP address of the neighbor device exists, obtain the ARP entry corresponding to the IP address of the neighbor device to realize access to the neighbor device; if it does not exist, broadcast to the network segment where the neighbor device is located When the neighbor device receives the ARP request message and returns an ARP reply message, the network device obtains the ARP entry corresponding to the IP address of the neighbor device according to the ARP reply message returned by the neighbor device. In the description herein, in order to distinguish a network device from its neighbor devices, a network device accessing its neighbor devices is called a master device. Here, the ARP entry corresponding to the IP address of the neighbor device is obtained according to the ARP response message returned by the neighbor device: when the master device receives the ARP response message returned by the neighbor device, it will obtain the ARP entry from the ARP response message. The media access control (MAC) address corresponding to the IP address of the neighbor device, and the port that enters the master device according to the ARP reply message learns the outgoing port corresponding to the MAC address of the neighboring device; the learned IP and MAC address and the outgoing port The correspondence between them is recorded in the ARP table as an ARP entry.

In the prior art, some ARP tables do not record the correspondence between MAC addresses and outgoing ports, but only record the correspondence between IP addresses and MAC addresses as an entry in the ARP table. In this case, when the master device needs to access its neighbor device, it first searches its own storage ARP table according to the IP address of the neighbor device to obtain the MAC address corresponding to the IP address, and then according to the found MAC The outbound port corresponding to the MAC address is found in the stored Layer 2 forwarding table, and the neighbor device is accessed through the found MAC address and outbound port. When the master device needs to record the correspondence between the IP address and MAC address of the neighbor device and the outbound port, the master device obtains the MAC address and outbound port of the neighbor device according to the ARP reply packet returned by the neighbor The corresponding relationship between MAC addresses is recorded in the ARP table, and the corresponding relationship between MAC addresses and outgoing ports is recorded in the Layer 2 forwarding table. Wherein, the layer-2 forwarding table is stored in the network device, and is used to record the correspondence between the MAC address of the network device and the outgoing port.

Similarly, for backbone devices in the network, such as routers or layer-3 switches, when business data is to be transmitted, if the ARP entry of the neighbor device to be accessed cannot be found in its own ARP table, it will broadcast and send ARP request message. However, from sending the ARP request message to receiving the ARP reply message, the master device may wait hundreds of milliseconds or even several seconds due to the network transmission speed and the processing speed of the neighbor device for the ARP request message. Such a long wait may not have much impact on the traditional pure data transmission network, but for IP telephony, digital TV, e-commerce and other services in the existing IP network, the delay of several seconds will It affects the quality of service to a great extent, especially for the backbone equipment in the network, after a few seconds of traffic delay, several gigabytes or even dozens of gigabytes of packets will be discarded.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method for quickly accessing neighboring devices, and the method can be used to realize fast accessing to neighboring devices.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

A method for quickly accessing neighbor equipment, the network equipment records the IP address of its own neighbor equipment, the method comprises the following steps:

A. After the network device records the IP address of its own neighbor device, according to the recorded IP address of the neighbor device, obtain and record the media access control address corresponding to each neighbor device IP address in the recorded neighbor device and the IP address Correspondence between the port and the output port;

B. When it is necessary to access the neighbor device, according to the IP address of the neighbor device to be accessed, search in all the corresponding relationships recorded in step A, obtain the media access control address and the egress port corresponding to the IP address to be accessed, and access the neighbor device .

Wherein, a neighbor table is set, and the recording of the IP address of the neighbor device is to record the IP address of the neighbor device in the neighbor table.

Wherein, the neighbor devices are part of all neighbor devices.

Wherein, in step A, the corresponding relationship between the obtained IP address of each neighbor device and the corresponding media access control address and outgoing port of the IP address is:

A1. Read the IP address of the neighbor device in the neighbor table, and send an address resolution protocol request message for the currently read IP address; judge whether all the IP addresses in the neighbor table have been read, and if so, perform step B; Otherwise, return to step A1.

Wherein, in step A, the correspondence between the IP address of the neighbor device and the media access control address corresponding to the IP address and the egress port is recorded as follows: the network device combines the IP address of the neighbor device with the obtained media access control address and The corresponding relationship between outgoing ports is recorded in its own address resolution protocol table;

In step B, said according to the IP address of the neighboring device to be accessed to obtain the media access control address and the outgoing port corresponding to the IP address is: according to the IP address of the neighboring device to be accessed, search in the address resolution protocol table to obtain The media access control address and egress port corresponding to the IP address.

Wherein, in step A, the correspondence between the IP address of the neighbor device and the media access control address corresponding to the IP address and the egress port is recorded as follows: the network device records the IP address of the neighbor device and the obtained media access control address Record the corresponding relationship between them in the address resolution protocol table of itself, and record the corresponding relationship between the media access control address of the neighboring device obtained corresponding to the IP address and the outgoing port in its own Layer 2 forwarding table;

In step B, said according to the IP address search of the neighbor equipment to be accessed to obtain the media access control address and the output port corresponding to the IP address is: according to the IP address of the neighbor equipment to be accessed, search and obtain in the address resolution protocol table and the media access control address; and then search the layer-2 forwarding table according to the obtained media access control address to obtain the corresponding egress port.

Wherein, in step A, the correspondence between the IP address of the neighbor device and the media access control address corresponding to the IP address and the egress port is recorded as follows: the network device combines the IP address of the neighbor device with the obtained media access control address and The corresponding relationship between outgoing ports is recorded in its own neighbor table;

In step B, according to the IP address of the neighbor device to be accessed, the media access control address and the output port corresponding to the IP address are obtained by searching the neighbor table according to the IP address of the neighbor device to be accessed. The media access control address and egress port corresponding to the IP address.

Wherein, setting the maintenance timer and the maintenance time, and starting the maintenance timer when the network is running, the method further includes the following steps:

C11, judging whether the maintenance timer reaches the maintenance time, if it arrives, then execute step C12; otherwise, return to step C11;

C12, read the IP address in the neighbor table, and judge whether there is a media access control address and an outgoing port corresponding to the IP address in the address resolution protocol table, if there is, then perform step C13; otherwise, for the currently read IP address After sending the address resolution protocol request message, execute step C13;

C13, judge whether all IP addresses in the neighbor table have been read, if yes, then return to step C11; otherwise, return to step C12;

While performing steps C11, C12 and C13, according to the ARP reply message returned by the neighbor equipment, obtain the media access control address and the outgoing port of the IP address of the returned ARP reply message, and enter the address resolution protocol The table records the correspondence between the IP address, the media access control address, and the outgoing port.

Wherein, setting the maintenance timer and the maintenance time, and starting the maintenance timer when the network is running, the method further includes the following steps:

C21, judging whether the maintenance timer reaches the maintenance time, if it arrives, then execute step C22; otherwise, return to step C21;

C22. Read the IP address in the neighbor table, and judge whether there is a media access control address corresponding to the IP address in the address resolution protocol table, and if so, perform step C23; otherwise, send address resolution for the currently read IP address After the protocol request message, execute step C23;

C23, judging whether all IP addresses in the neighbor table have been read, if yes, then return to step C21; otherwise, return to step C22;

While performing steps C21, C22 and C23, according to the ARP reply message returned by the neighbor equipment, obtain the media access control address and the outgoing port of the IP address of the returned ARP reply message, and in the address resolution protocol The corresponding relationship between the IP address and the media access control address is recorded in the table, and the corresponding relationship between the obtained media access control address and the egress port is recorded in the Layer 2 forwarding table.

A method for quickly accessing neighbor equipment provided by the present invention, by pre-recording the IP address of the neighbor equipment and obtaining the MAC address and the outgoing port according to the pre-recorded IP address, when the network equipment needs to access its neighbor equipment, it does not need to broadcast After receiving an ARP request message and waiting for the neighbor device to return an ARP response message, you can directly read the recorded corresponding MAC address and outgoing port according to the IP address, thereby realizing the purpose of quickly accessing the neighbor device. The method proposed by the invention greatly improves the access efficiency of the network equipment, reduces the packet loss rate of the network, and ensures the service quality of the network.

Description of drawings

Fig. 1 is the flowchart of fast access neighbor equipment among the present invention;

FIG. 2 is a flow chart of maintaining an ARP table in Embodiment 1 of the present invention.

Detailed ways

The core idea of the present invention is: before the network starts to operate, record the IP addresses of its neighbors in the network equipment; Address, obtain and record the MAC address and outgoing port corresponding to the IP address; when the network device needs to access the neighboring device, directly access its neighboring device according to the recorded MAC address and outgoing port, rather than when the network device needs to visit its neighbor The device obtains the corresponding MAC address and outgoing port according to the IP address of its neighbor device. In the description of specific embodiments, in order to distinguish a network device from its neighbor devices, the network device that accesses its neighbor devices is also referred to as a master device.

The technical solution of the present invention will be described in more detail through two examples below.

Embodiment one

Before the network starts running, set up a neighbor table in the master device, and record the IP addresses of the neighbor devices of the master device in the neighbor table according to the network topology during network planning. After the network starts running, execute the process shown in Figure 1, and the specific steps are as follows:

Steps 101-102: The master device sequentially reads the IP addresses in the neighbor table, and sends an ARP request message for the read IP addresses. Since it takes some time for the master device to receive the ARP reply message returned from the neighbor device, after sending the ARP request message read this time, it executes step 103 without waiting for the ARP reply message returned by the neighbor device.

During the execution of the process, when the master device receives the ARP reply packet returned by its neighbor device, it obtains the MAC address and outbound port corresponding to the IP address of the neighbor device according to the returned ARP reply packet, and the master device compares the IP address and The correspondence between MAC addresses and outgoing ports is recorded in the ARP table as an ARP entry.

The method of sequentially reading the neighbor table can be any method, as long as all the IP addresses in the neighbor table are read. For example: read from the first IP address to the last IP address in the neighbor table; or read in any order and set the read flag for the read IP address in the neighbor table or similar methods, To ensure that all IP addresses in the neighbor table will be read by the master device.

Step 103: Determine whether all the IP addresses in the neighbor table have been read, and if yes, execute step 104; otherwise, return to step 101.

Here, the method for judging whether all the IP addresses in the neighbor table have been read is determined according to the method for reading the IP addresses in step 101 . If it is read in order from the first IP address to the last IP address in the neighbor table, the method for judging whether all the IP addresses in the neighbor table have been read is to judge whether the currently read IP address is in the neighbor table The last IP address in , if yes, execute step 104; otherwise, return to step 101. If it is ensured that all the IP addresses in the neighbor list will be read by the master device by setting the read flag to the read IP addresses, then the judgment method in step 103 can be to judge whether there are any IP addresses that have not been set in the neighbor table. Read the identified IP address, if it does not exist, execute step 104; otherwise, return to step 101.

Step 104: When the master device needs to access the neighbor device, it only needs to directly look up the corresponding ARP entry in the ARP table according to the IP address of the neighbor device to realize the access to the neighbor device.

Usually, after the network has been running for a period of time, the master device will age the ARP table stored by itself, that is, delete some infrequently used ARP entries. Therefore, in order to prevent the master device from being unable to quickly access the neighbor device because it deletes the ARP entry of the neighbor device that needs to be accessed, the master device also needs to periodically maintain the ARP table according to the IP address recorded in the neighbor table. The period for periodic maintenance may be comprehensively determined according to the period for the master device to perform aging processing on the ARP table, the performance of the master device, and the network environment where the master device is located.

The general process of maintaining the ARP table in this embodiment is as follows: first, a maintenance timer is set in the master device, and the corresponding maintenance time is set, when the network starts to run, the maintenance timer in the master device is triggered, and the timer starts counting; When the timer reaches the maintenance time, it triggers the main device to maintain the ARP table. The specific process of maintaining the ARP table in this embodiment is shown in Figure 2:

Step 201: Judging whether the maintenance timer has reached the maintenance time, if so, the master device triggers the maintenance of its own ARP table, and performs step 202; otherwise, returns to step 201, and continues to judge whether the maintenance timer has reached the maintenance time.

Steps 202-203: The master device sequentially reads the IP addresses in the neighbor table, searches the ARP table for the corresponding ARP entry according to the read IP address, and if so, executes step 205; otherwise, executes step 204.

Step 204: Send an ARP request message for the currently read IP address. Since it takes some time for the master device to receive the ARP reply message returned from the neighbor device, after sending the ARP request message, it executes step 205 without waiting for the neighbor device to return the ARP reply message.

During the execution of the process, when the neighbor device returns an ARP reply message, the MAC address and outbound port corresponding to the IP address of the neighbor device are obtained according to the returned ARP reply message, and the IP address, MAC address and outbound port are used as An ARP entry is recorded in the ARP table.

Step 205: Judging whether all the IP addresses in the neighbor table have been read, if yes, return to step 201; otherwise, return to step 202.

Wherein, the method of reading the IP addresses in the neighbor table sequentially in step 202, and judging whether all IP addresses in the neighbor table have been read in step 205 is the same as the method described in Embodiment 1, and will not be described in detail here .

For some ARP tables that only record the correspondence between IP addresses and MAC addresses, but do not record the correspondence between IP addresses, MAC addresses and outgoing ports, the process of quickly accessing neighboring devices can also be completed according to the process shown in Figure The process shown in Figure 2 completes the operation of maintaining the neighbor table. Only in the process of Figure 1, the corresponding relationship between the outgoing port and the MAC address obtained through the ARP response message returned by the neighbor device is recorded in the two-layer forwarding table; in step 203 of the process of Figure 2, in addition to the need to The IP address of the device looks up the corresponding MAC address in the ARP table, and it is also necessary to look up the corresponding outbound port in the Layer 2 forwarding table of the master device according to the found MAC address. If the corresponding outbound port cannot be found in the Layer 2 forwarding table, Then perform step 204 to send an ARP request message for this IP address, and record the egress port obtained according to the ARP response message returned by the neighbor device in the Layer 2 forwarding table.

In the neighbor table of this embodiment, it is also possible not to record the IP addresses of all neighbor devices of the master device, but only to record the IP addresses of important neighbor devices. More details. Here, important neighbor devices refer to network devices that the master device needs to visit frequently and backbone devices in the network.

Embodiment two

Different from the first embodiment, in the second embodiment, the correspondence between the IP address, the MAC address and the egress port of the neighbor device is recorded in the neighbor table set by the master device. The specific process of embodiment two is the same as the process shown in Figure 1, just when the neighbor equipment returns the ARP response message, the MAC address and the outgoing port corresponding to the neighbor equipment IP address will be recorded in the neighbor table and the ARP table, or in the neighbor table, ARP table, and Layer 2 forwarding table, or only recorded in the neighbor table. Then, when the master device accesses the neighbor device, it can directly go to the neighbor table to find the corresponding MAC address and outgoing port according to the IP address of the neighbor device, so as to achieve the purpose of quickly accessing the neighbor device.

Since the neighbor device is a device that the master device may need to access frequently, the master device does not need to delete the ARP entries recorded in the neighbor table. And because the master device obtains the corresponding MAC address and outgoing port by looking up the neighbor table, it does not need to maintain the ARP table.

In the neighbor table of this embodiment, it is also possible not to record the IP addresses of all neighbor devices of the main device, but only to record the IP addresses of important neighbor devices. The specific implementation method is the same as that described in Embodiment 2, and will not More details.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (9)

1, a kind of method of fast access neighbor equipment, it is characterized in that, network equipment records the IP address of self neighbor equipment, and this method comprises the following steps: A. After the network device records the IP address of its own neighbor device, according to the recorded IP address of the neighbor device, obtain and record the media access control address corresponding to each neighbor device IP address in the recorded neighbor device and the IP address Correspondence between the port and the output port; B. When it is necessary to access the neighbor device, according to the IP address of the neighbor device to be accessed, search in all the corresponding relationships recorded in step A, obtain the media access control address and the egress port corresponding to the IP address to be accessed, and access the neighbor device . 2. The method according to claim 1, characterized in that a neighbor table is set, and said recording the IP address of the neighbor device is recording the IP address of the neighbor device in the neighbor table. 3. The method according to claim 2, wherein the neighbor devices are some of all neighbor devices. 4. The method according to claim 2 or 3, characterized in that, in step A, the correspondence between the IP address of each neighbor device obtained and the corresponding media access control address and outgoing port of the IP address is : A1. Read the IP address of the neighbor device in the neighbor table, and send an address resolution protocol request message for the currently read IP address; judge whether all the IP addresses in the neighbor table have been read, and if so, perform step B; Otherwise, return to step A1. 5. A method according to claim 1, 2 or 3, characterized in that, In step A, the corresponding relationship between the IP address of the neighbor device and the media access control address and the egress port corresponding to the IP address is recorded as follows: the network device combines the IP address of the neighbor device with the obtained media access control address and egress port The corresponding relationship between is recorded in its own address resolution protocol table; In step B, said according to the IP address of the neighboring device to be accessed to obtain the media access control address and the outgoing port corresponding to the IP address is: according to the IP address of the neighboring device to be accessed, search in the address resolution protocol table to obtain The media access control address and egress port corresponding to the IP address. 6. A method according to claim 1, 2 or 3, characterized in that, In step A, the correspondence between the IP address of the neighbor device and the media access control address corresponding to the IP address and the outgoing port is recorded as follows: the network device records the IP address of the neighbor device and the obtained media access control address The corresponding relationship is recorded in its own address resolution protocol table, and the corresponding relationship between the obtained neighbor device media access control address and the outgoing port corresponding to the IP address is recorded in its own Layer 2 forwarding table; In step B, said according to the IP address search of the neighbor equipment to be accessed to obtain the media access control address and the output port corresponding to the IP address is: according to the IP address of the neighbor equipment to be accessed, search and obtain in the address resolution protocol table and the media access control address; and then search the layer-2 forwarding table according to the obtained media access control address to obtain the corresponding egress port. 7. A method according to claim 2 or 3, characterized in that, In step A, the corresponding relationship between the IP address of the neighbor device and the media access control address and the egress port corresponding to the IP address is recorded as follows: the network device combines the IP address of the neighbor device with the obtained media access control address and egress port The corresponding relationship between is recorded in its own neighbor table; In step B, according to the IP address of the neighbor device to be accessed, the media access control address and the output port corresponding to the IP address are obtained by searching the neighbor table according to the IP address of the neighbor device to be accessed. The media access control address and egress port corresponding to the IP address. 8. The method according to claim 5, characterized in that the maintenance timer and maintenance time are set, and the maintenance timer is started when the network is running, the method further comprises the following steps: C11, judging whether the maintenance timer reaches the maintenance time, if it arrives, then execute step C12; otherwise, return to step C11; C12, read the IP address in the neighbor table, and judge whether there is a media access control address and an outgoing port corresponding to the IP address in the address resolution protocol table, if there is, then perform step C13; otherwise, for the currently read IP address After sending the address resolution protocol request message, execute step C13; C13, judge whether all IP addresses in the neighbor table have been read, if yes, then return to step C11; otherwise, return to step C12; While performing steps C11, C12 and C13, according to the ARP reply message returned by the neighbor equipment, obtain the media access control address and the outgoing port of the IP address of the returned ARP reply message, and enter the address resolution protocol The table records the correspondence between the IP address, the media access control address, and the outgoing port. 9. The method according to claim 6, characterized in that, setting the maintenance timer and maintenance time, and starting the maintenance timer when the network is running, the method further comprises the following steps: C21, judging whether the maintenance timer reaches the maintenance time, if it arrives, then execute step C22; otherwise, return to step C21; C22. Read the IP address in the neighbor table, and judge whether there is a media access control address corresponding to the IP address in the address resolution protocol table, and if so, perform step C23; otherwise, send address resolution for the currently read IP address After the protocol request message, execute step C23; C23, judging whether all IP addresses in the neighbor table have been read, if yes, then return to step C21; otherwise, return to step C22; While performing steps C21, C22 and C23, according to the ARP reply message returned by the neighbor equipment, obtain the media access control address and the outgoing port of the IP address of the returned ARP reply message, and in the address resolution protocol The corresponding relationship between the IP address and the media access control address is recorded in the table, and the corresponding relationship between the obtained media access control address and the egress port is recorded in the Layer 2 forwarding table.

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