Because Best Effort (no MTP inserted) never adds an MTP, a Unified CM trunk set that way cannot guarantee an Early Offer when the call arrives from a Delayed Offer source, so a peer that rejects Delayed Offer needs either the Mandatory (insert MTP if needed) option or DO-EO conversion downstream.

inferred · Checked 2026-09-25

Vendor
Cisco
Product
Unified CM
Subsystem
sip-profile
Deployment
on-premises
Region
not restricted
Release range
unverified for current releases
Status
inferred
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP early offer and delayed offer: source note sip-early-delayed-offer-inf-best-effort-not-guaranteed. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-early-delayed-offer-inf-best-effort-not-guaranteed

BibTeX

@misc{warmtransfer-claim-sip-early-delayed-offer-inf-best-effort-not-guaranteed,
  title  = {SIP early offer and delayed offer: source note sip-early-delayed-offer-inf-best-effort-not-guaranteed},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-early-delayed-offer-inf-best-effort-not-guaranteed},
  note   = {Source note sip-early-delayed-offer-inf-best-effort-not-guaranteed, checked 2026-09-25}
}

Read in context