Source note · SIP trunk redundancy and failover design
RFC 3261 sets INVITE client transaction Timer B to 64*T1, and with the default T1 of 500 ms that is 32 seconds.
Checked 2026-09-25
- Vendor
- IETF
- Product
- SIP
- Subsystem
- transaction layer
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 3261, current as of 2026-09-25
- Checked
- 2026-09-25
Sources
- RFC 3261 — SIP: Session Initiation Protocol — IETF / RFC Editor · tier 1 standards and regulators · Section 17.1.1.2 Formal Description; Table 4 timer values
Cite this note
APA
WarmTransfer. (2026, September 25). SIP trunk redundancy and failover design: source note sip-trunk-redundancy-design-rfc3261-timer-b. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-redundancy-design-rfc3261-timer-b
BibTeX
@misc{warmtransfer-claim-sip-trunk-redundancy-design-rfc3261-timer-b,
title = {SIP trunk redundancy and failover design: source note sip-trunk-redundancy-design-rfc3261-timer-b},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-trunk-redundancy-design-rfc3261-timer-b},
note = {Source note sip-trunk-redundancy-design-rfc3261-timer-b, checked 2026-09-25}
}