RFC 3261 permits Retry-After with 500, 503 or 600 responses to tell the caller how long to wait before retrying.

Checked 2026-10-02

Vendor
not restricted
Product
not restricted
Subsystem
SIP headers
Deployment
any
Region
not restricted
Release range
RFC 3261
Checked
2026-10-02

Sources

Cite this note

APA

WarmTransfer. (2026, October 2). Calls-per-second limits on SIP trunks and dialers: source note sip-trunk-cps-limits-rfc3261-retry-after. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-cps-limits-rfc3261-retry-after

BibTeX

@misc{warmtransfer-claim-sip-trunk-cps-limits-rfc3261-retry-after,
  title  = {Calls-per-second limits on SIP trunks and dialers: source note sip-trunk-cps-limits-rfc3261-retry-after},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-trunk-cps-limits-rfc3261-retry-after},
  note   = {Source note sip-trunk-cps-limits-rfc3261-retry-after, checked 2026-10-02}
}

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