Cisco Unified Border Element Configuration Guide - Cisco IOS XE 17.6 Onwards - DTMF Relay

Publisher

Cisco Systems

URL

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/ios-xe/config/ios-xe-book/dtmf-relay.html

Published

2026-04-25

Updated

unknown

Accessed

2026-09-24

HTTP status

200

License

Cisco documentation terms; no-redistribution; short excerpts and locators only

Source notes citing this source

• Cisco's proprietary cisco-rtp DTMF relay (payload type 121) has been discontinued on CUBE. in context
• CUBE uses payload types 96 and 97 for fax by default, and Cisco advises the asymmetric payload dtmf command when a third-party device's DTMF payload type conflicts. in context
• H.323 (and with it the H.245 alphanumeric and signal DTMF methods) is not supported on CUBE from IOS XE Bengaluru 17.6.1a onwards. in context
• On CUBE (IOS XE 17.6 onwards), SIP DTMF relay methods are rtp-nte (RFC 2833), sip-notify (Cisco proprietary), sip-kpml (RFC 4730) and sip-info, plus G.711 in-band audio, which needs no configuration. in context
• If an endpoint supports none of the DTMF relay methods configured on CUBE, an MTP or transcoder is required. in context
• When more than one out-of-band DTMF method is configured on a CUBE dial-peer, preference runs from highest to lowest in the order the methods were configured. in context
• CUBE prefers sip-notify or sip-kpml over rtp-nte, and rtp-nte over in-band, when selecting a DTMF method. in context
• On CUBE, sip-info DTMF handling is always enabled for SIP dial-peers and is invoked when a SIP INFO with DTMF relay content is received. in context
• The CUBE dtmf-relay command accepts up to six methods on a VoIP dial-peer. in context
• Cisco documentation classifies RFC 2833 NTE as an in-band DTMF method because the events travel in the RTP stream. disputed in context
• On CUBE (IOS XE 17.6 onwards) the documented DTMF relay methods for SIP are rtp-nte (RFC 2833 NTE), sip-kpml (RFC 4730), sip-notify (Cisco proprietary), sip-info and cisco-rtp (discontinued); in-band DTMF in G.711 audio needs no configuration. in context
• When more than one DTMF relay method is configured on a CUBE dial-peer, preference runs from highest to lowest in the order the methods were configured. in context
• CUBE's rtp-nte method, which Cisco labels RFC 2833, is the same named-telephone-event mechanism now specified by RFC 4733, so a carrier that asks for RFC 4733 DTMF is normally met by rtp-nte. inferred in context

Cite this source record

APA

WarmTransfer. (2026, April 25). Cisco Unified Border Element Configuration Guide - Cisco IOS XE 17.6 Onwards - DTMF Relay. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-cube-xe-dtmf-relay

BibTeX

@misc{warmtransfer-cisco-cube-xe-dtmf-relay,
  title  = {Cisco Unified Border Element Configuration Guide - Cisco IOS XE 17.6 Onwards - DTMF Relay},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-cube-xe-dtmf-relay},
  note   = {Cisco Systems, accessed 2026-09-24}
}