Source note · SIP registration failures
Under RFC 3261 a non-INVITE client transaction such as REGISTER over UDP retransmits on Timer E, which starts at T1 (500 ms default) and doubles up to T2 (4 s), and gives up when Timer F fires at 64*T1 (32 s by default).
Checked 2026-09-25
- Vendor
- not restricted
- Product
- SIP
- Subsystem
- transactions
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 3261 as updated by RFC 4320
- Checked
- 2026-09-25
Sources
- RFC 3261 — SIP: Session Initiation Protocol — IETF / RFC Editor · tier 1 standards and regulators · Section 17.1.2.2 Formal Description (non-INVITE client transaction) and Table 4
Cite this note
APA
WarmTransfer. (2026, September 25). SIP registration failures: source note sip-registration-failures-timer-f-32s. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-registration-failures-timer-f-32s
BibTeX
@misc{warmtransfer-claim-sip-registration-failures-timer-f-32s,
title = {SIP registration failures: source note sip-registration-failures-timer-f-32s},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-registration-failures-timer-f-32s},
note = {Source note sip-registration-failures-timer-f-32s, checked 2026-09-25}
}