Source note · Early media and ringback behavior

CUBE's forked 18x consumption does not support Delayed-Offer to Delayed-Offer calls, SDP passthrough, SRTP passthrough, ANAT, media flow-around, media anti-trombone or early-dialog UPDATE block.

Checked 2026-09-24

Vendor: Cisco
Product: Cisco Unified Border Element
Subsystem: early dialog forking
Deployment: on-premises
Region: not restricted
Release range: IOS XE Denali 16.3.1 onwards
Checked: 2026-09-24

Sources

Cisco Unified Border Element Configuration Guide: Consumption of Forked 18x Responses with SDP During Early Dialog — Cisco Systems · tier 2 current vendor documentation · Restrictions section

Cite this note

APA

WarmTransfer. (2026, September 24). Early media and ringback behavior: source note early-media-ringback-cube-18x-restrictions. WarmTransfer. https://warmtransfer.net/knowledge/claims/early-media-ringback-cube-18x-restrictions

BibTeX

@misc{warmtransfer-claim-early-media-ringback-cube-18x-restrictions,
  title  = {Early media and ringback behavior: source note early-media-ringback-cube-18x-restrictions},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/early-media-ringback-cube-18x-restrictions},
  note   = {Source note early-media-ringback-cube-18x-restrictions, checked 2026-09-24}
}

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