The originating user agent must generate an acknowledgement for each 2xx it receives with the same sequence number as the INVITE and the method set to acknowledge.

fact · verified 2026-09-15

Vendor
IETF
Product
Session Initiation Protocol
Subsystem
transactions
Deployment
not restricted
Region
not restricted
Release range
current as of 2026-09-15
Status
fact
Confidence
0.90
Verified
2026-09-15

Sources

Cite this claim

APA

WarmTransfer. (2026, September 15). SIP transactions dialogs and call setup: claim siptx-uac-sends-an-ack-for-every-2xx. WarmTransfer. https://warmtransfer.net/knowledge/claims/siptx-uac-sends-an-ack-for-every-2xx

BibTeX

@misc{warmtransfer-claim-siptx-uac-sends-an-ack-for-every-2xx,
  title  = {SIP transactions dialogs and call setup: claim siptx-uac-sends-an-ack-for-every-2xx},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/siptx-uac-sends-an-ack-for-every-2xx},
  note   = {Claim siptx-uac-sends-an-ack-for-every-2xx, verified 2026-09-15}
}

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