In addition to other answers given by others, loop detection is found when the same request comes at same sip node again without getting final answer (then we check whether its loop or not). The case you are talking about First request is already answered, so as per my understanding, in any case request will not be responded with 482 response code by the server who has already created final answer for earlier request (although SIP node may ignore the request if you try to send request with same parameter in new request, which will never be the case I think).
,Regards Vijay Badola [Description: stock-photo-young-man-looking-at-go-green-logo-42539080] Note:We have responsibility to the environment. Before printing this e-mail or any other document, let's ask ourselves whether we need a hard copy. From: [email protected] [mailto:[email protected]] On Behalf Of Keerthi Srinivasan Sent: Tuesday, October 30, 2012 4:48 PM To: [email protected]; [email protected] Subject: [SIPForum-discussion] To-Tag in REGISTER message All, When UA sends REGISTER request to the server it does not contain the To-Tag and Server is accepts the Registration (200 OK) will have the To-Tag. If the Refresh or Deregister does not have the To-Tag in the REGISTER message. Is the server will accept the Refresh or Deregister REGISTER message or will send 482 Loop Detected as per the RFC3261 (8.2.2.2 Merged Requests) Here is the RFC3261 content: 8.2.2.2 Merged Requests If the request has no tag in the To header field, the UAS core MUST check the request against ongoing transactions. If the From tag, Call-ID, and CSeq exactly match those associated with an ongoing transaction, but the request does not match that transaction (based on the matching rules in Section 17.2.3), the UAS core SHOULD generate a 482 (Loop Detected) response and pass it to the server transaction. The same request has arrived at the UAS more than once, following different paths, most likely due to forking. The UAS processes the first such request received and responds with a 482 (Loop Detected) to the rest of them. Is the Server MUST reject or Accept the Refresh / Deregister REGISTER request? -- Regards, Keerthi ________________________________ DISCLAIMER: The information in this message is confidential and may be legally privileged. It is intended solely for the addressee. Access to this message by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, or distribution of the message, or any action or omission taken by you in reliance on it, is prohibited and may be unlawful. Please immediately contact the sender if you have received this message in error. Further, this e-mail may contain viruses and all reasonable precaution to minimize the risk arising there from is taken by OnMobile. OnMobile is not liable for any damage sustained by you as a result of any virus in this e-mail. All applicable virus checks should be carried out by you before opening this e-mail or any attachment thereto. Thank you - OnMobile Global Limited.
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