# Local gateway toward Webex Calling

- The local gateway is how premises PSTN or a PBX meets Webex Calling.
- Signaling to Calling is SIP over TLS. Media is SRTP.
- Registration-based and certificate-based trunks are different models.
- Dial peers still decide the premises leg.
- Confirm call caps and ciphers in the current guide.

Cisco's Webex Calling local gateway documentation describes CUBE as the supported trunk on the premises side for this design. A registration trunk and a certificate trunk do not have the same limits. People quote a 250-call registration cap from older guides. Treat that number as something to confirm in the guide for your tenant before you design to it.

A location uses a local gateway. Inbound DID hits a Webex dial peer, and outbound PSTN hits a carrier peer. If you only debug one peer, you will explain the wrong leg.

## Sources and go deeper

Independent, free, learning-only student project.

Opened 2026-10. A row marked confirm has no link, because that page was not verified.

- Webex. [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway). last checked 2026-10
- Webex. [Configure Local Gateway on Cisco IOS XE for Webex Calling](https://help.webex.com/en-us/article/jr1i3r/Configure-local-gateway-on-IOS-XE-for-Webex-Calling). last checked 2026-10
- Webex. [Get started with Webex Calling](https://help.webex.com/en-us/article/8jda92/Webex-Calling). last checked 2026-10
- Protocol and ports. [Port reference for Webex Calling](https://help.webex.com/en-us/article/b2exve/Port-Reference-Information-for-Cisco-Webex-Calling). last checked 2026-10
- RFC. [RFC 3711, SRTP](https://www.rfc-editor.org/rfc/rfc3711). last checked 2026-10
- RFC. [RFC 3261, SIP](https://www.rfc-editor.org/rfc/rfc3261). last checked 2026-10
- Cisco. [Cisco Unified Border Element product support](https://www.cisco.com/c/en/us/support/unified-communications/unified-border-element/series.html). last checked 2026-10
- Community. [Cisco Community, Collaboration knowledge base](https://community.cisco.com/t5/collaboration-knowledge-base/tkb-p/4691-docs-collaboration-voice-video). last checked 2026-10
- Wikipedia. [Voice over IP (Wikipedia)](https://en.wikipedia.org/wiki/Voice_over_IP). last checked 2026-10

Room or sheet file: ../../rooms/sources/local-gateway/sources.json