Network address translator (NAT) mapping keep-alive method and system based on session initiation protocol (SIP)

A technology of mapping relationship and keep-alive messages, which is applied in the field of SIP technology and NAT mapping keep-alive, can solve the problems of server update, heavy terminal pressure, and large SIP messages, etc., and achieve the goal of reducing downtime, small data volume, and small impact Effect

Active Publication Date: 2011-04-13
MAIPU COMM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, under normal circumstances, the mapping relationship generated on the NAT device is temporary, and the time of this mapping may be very short, only a few seconds
If this address mapping is not used for a period of time, the mapping will be deleted over time, causing the server to no longer be able to call the end user
So in order to ensure that the SIP server can call the SIP terminal at any time, the SIP server needs to keep this mapping alive. The existing implementation method is usually that the SIP server regularly sends SIP messages such as notify and option to the public network port of the NAT device to keep the mapping. Keep alive this mapping, but the SIP message is relatively large, and the terminal needs complex decoding. If the mapping is short-lived, then it is necessary to send keep-alive messages frequently. At this time, the pressure on the terminal, network, and server is all is big
[0004] In addition, when the NAT device is restarted and the NAT address mapping is manually cleared or abnormally deleted, the server can no longer call the SIP terminal. For the existing implementation, see Chinese patent application "200610119375.5 A method for maintaining NAT address binding in a SIP network system and its device", usually the terminal also sends a keep-alive message, such as an option message, but the option message can only keep alive the existing NAT mapping, and cannot make the server update its saved terminal mapping relationship, unless the terminal re-initiates registration, but the terminal does not It cannot perceive the abnormality of the NAT device, so the registration will only be initiated when the registration times out, and this time may be very long (RFC3261 recommends one hour), then the terminal user may not receive the call request from the server within an hour, yes VOIP business has a big impact

Method used

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  • Network address translator (NAT) mapping keep-alive method and system based on session initiation protocol (SIP)
  • Network address translator (NAT) mapping keep-alive method and system based on session initiation protocol (SIP)
  • Network address translator (NAT) mapping keep-alive method and system based on session initiation protocol (SIP)

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Embodiment Construction

[0022] Such as figure 1 As shown, the system includes a SIP terminal, a NAT device, and a SIP server, and the SIP terminal and the SIP server communicate through the NAT device. Such as figure 2 As shown, the SIP terminal in the private network needs to communicate with the SIP server in the public network, and a temporary [private network address: private network port] to [public network address: public network port] will be generated on the NAT device. If the SIP server wants to call the SIP terminal, it must access the [public network address: public network port] of the NAT device, and the NAT device will automatically forward the call to the SIP terminal through the corresponding [private network address: private network port].

[0023] The NAT mapping keep-alive method in this embodiment is as follows image 3 Shown:

[0024] First, the SIP terminal sends a REGISTER message to the SIP server to register. After receiving the REGISTER message, the SIP server not only n...

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Abstract

The invention provides a network address translator (NAT) mapping keep-alive method and a system for realizing the method, and in the method, the mapping relationship can be timely reconstructed after being eliminated and can be mapped on NAT with less network consumption. The NAT mapping keep-alive method based on SIP comprises the following steps: a. an SIP terminal launches registration to an SIP server via an NAT device, and when the SIP terminal launches registration, the NAT device stores the mapping relationship between the SIP terminal and the NAT device; b. after the SIP server receives the registration of SIP terminal, the SIP server sends a keep-alive message of the user datagram protocol (UDP) style to the SIP terminal via the NAT device periodically; c. the SIP terminal starts a timer after receiving the keep-alive message; and d. the SIP terminal judges whether the keep-alive message is received or not in overtime of the timer, if so, resetting the timer and returning tothe step; and if not, triggering the SIP terminal for registration again, eliminating the timer and returning to step a.

Description

technical field [0001] The technical solution relates to SIP (Session Initiation Protocol, Session Initiation Protocol) technology and NAT (Network Address Translator, Network Address Translation) mapping keep-alive technology. Background technique [0002] Although it is an inevitable trend for IPv6 to replace IPv4, IPv4 will still exist for a long time, and the existence of IPv4 must be accompanied by a large number of NATs. With the increasing popularity of VOIP (Voice over IP, Voice over IP) services, the impact of NAT on P2P media services is increasing. significantly. [0003] In a network environment with NAT devices, if the SIP terminal is on the private network and the SIP server is on the public network, when the SIP terminal registers with the server, a mapping relationship between the private network address and the public network address will be generated on the NAT. The relationship can ensure that when the SIP server sends a SIP call request, it can be delive...

Claims

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Application Information

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IPC IPC(8): H04L29/12H04L29/06
Inventor 张华洪
Owner MAIPU COMM TECH CO LTD
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