Source note · Calls that drop after about 30 seconds
A UAS core passes its 2xx response to the transport repeatedly, at an interval that starts at T1 seconds and doubles on each retransmission until it reaches T2 seconds.
Checked 2026-09-25
The 2xx response is passed to the transport with an interval that starts at T1 seconds and doubles for each retransmission until it reaches T2 seconds.
- Vendor
- IETF
- Product
- SIP
- Subsystem
- INVITE transaction / UAS core
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 3261 as updated by RFC 6026
- Checked
- 2026-09-25
Sources
- RFC 6026: Correct Transaction Handling for 2xx Responses to Session Initiation Protocol (SIP) INVITE Requests — IETF / RFC Editor · tier 1 standards and regulators · Section 8 (Exact Changes to RFC 3261), entry for RFC 3261 page 85, section 13.3.1.4
Cite this note
APA
WarmTransfer. (2026, September 25). Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-2xx-retransmit-interval. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-2xx-retransmit-interval
BibTeX
@misc{warmtransfer-claim-sip-calls-drop-30-seconds-2xx-retransmit-interval,
title = {Calls that drop after about 30 seconds: source note sip-calls-drop-30-seconds-2xx-retransmit-interval},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-calls-drop-30-seconds-2xx-retransmit-interval},
note = {Source note sip-calls-drop-30-seconds-2xx-retransmit-interval, checked 2026-09-25}
}