CODEWITHSUNDEEP
sipvoip
Kousalya
Kousalya

Reputation: 760

SIP registration process

To make calls through voip user need to register first. So registration is mandatory one. I have some basic knowledge of registration process. User sends REGISTER request to server with expires header value 30 seconds. Server upon receiving request from user it sends responses with expires header value 120 seconds. User need to register again before expires header time period ends or before 60 seconds. Once registration is done registrar server will sends the user's uri and location in location server. So user's location will be present in location server. If location server has user's location, then why user need to register again before time period ends. And user needs to re-register only once before the time period or multiple times?? how long the users ip will be present in location server??

Upvotes: 1

Views: 5020

Answers (1)

Nick
Nick

Reputation: 535

When a valid REGISTER is sent the SIP Registrar creates a binding for that user and stores it as an "Address of Record",

At a minimum this typically contains the SIP URI, the public IP and the time at which it expires, which is equal to the current time + the time in the SIP Expires header. This is referred to as "Adding a Binding" in the RFC.

After the time it expires has been reached the Address of Record is no longer valid and is generally dropped / deleted. Registrations are soft state and expire unless refreshed.

If another valid REGISTER is received before the expiry time is reached the Address of Record on the SIP Registrar is refreshed to reflect the new expiry time. This is called "Refreshing a Binding" in the RFC.

So in answer to your question:

how long the users ip will be present in location server??

Until the time the last valid REGISTER was received + the expiry time of the REGISTER is reached.

And user needs to re-register only once before the time period or multiple times?? A user only needs to send another valid REGISTER once before the binding expires to keep the binding in there as an Address of Record.

Further reading:

Upvotes: 5

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