Source note · SIP trunk redundancy and failover design
Without an OPTIONS keepalive marking a peer down in advance, an element that fails over only on transaction timeout can wait on the order of Timer B (32 s at default T1) before trying the next server, unless a platform-specific shorter timer applies.
inferred · Checked 2026-09-25
- Vendor
- IETF
- Product
- SIP
- Subsystem
- failover timing
- Deployment
- any
- Region
- not restricted
- Release range
- current as of 2026-09-25
- Status
- inferred
- Checked
- 2026-09-25
Sources
- RFC 3261 — SIP: Session Initiation Protocol — IETF / RFC Editor · tier 1 standards and regulators · Section 17.1.1.2 combined with RFC 3263 section 4.3
Cite this note
APA
WarmTransfer. (2026, September 25). SIP trunk redundancy and failover design: source note sip-trunk-redundancy-design-inf-timer-b-delay. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-redundancy-design-inf-timer-b-delay
BibTeX
@misc{warmtransfer-claim-sip-trunk-redundancy-design-inf-timer-b-delay,
title = {SIP trunk redundancy and failover design: source note sip-trunk-redundancy-design-inf-timer-b-delay},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-trunk-redundancy-design-inf-timer-b-delay},
note = {Source note sip-trunk-redundancy-design-inf-timer-b-delay, checked 2026-09-25}
}