Local Gateway Requirements for Webex Calling

General prerequisites

Before you configure a local gateway for Webex Calling, ensure that you:

  • Have a basic knowledge of VoIP principles

  • Have a basic working knowledge of Cisco IOS-XE and IOS-XE voice concepts

  • Have a basic understanding of the Session Initiation Protocol (SIP)

  • Have a basic understanding of Cisco Unified Communications Manager (Unified CM) if your deployment model includes Unified CM

See the Cisco Unified Border Element (CUBE) Enterprise Configuration Guide for details.

Hardware and Software Requirements for Local Gateway

Make sure your deployment has one or more of the local gateways (Cisco CUBE (for IP-based connectivity) or Cisco IOS Gateway (for TDM-based connectivity)) that are in Table 1 of the Local Gateway for Webex Calling Ordering Guide. Additionally, make sure the platform is running a supported IOS-XE release as per the Local Gateway Configuration Guide.

Certificate and Security Requirements for Local Gateway

Webex Calling requires secure signaling and media. The local gateway performs the encryption, and a TLS connection must be established outbound to the cloud with the following steps:

  • The LGW must be updated with the CA root bundle from Cisco PKI

  • A set of SIP digest credentials from Control Hub’s Trunk configuration page are used to configure the LGW (the steps are part of the configuration that follows)

  • CA root bundle validates presented certificate

  • Prompted for credentials (SIP digest provided)

  • The cloud identifies which local gateway is securely registered

Firewall, NAT Traversal, and Media Path Optimization Requirements for Local Gateway

In most cases, the local gateway and endpoints can reside in the internal customer network, using private IP addresses with NAT. The enterprise firewall must allow outbound traffic (SIP, RTP/UDP, HTTP) to specific IP addresses/ports, covered in Port Reference Information.

If you want to utilize Media Path Optimization with ICE, the local gateway’s Webex Calling facing interface must have a direct network path to and from the Webex Calling endpoints. If the endpoints are in a different location and there is no direct network path between the endpoints and the local gateway’s Webex Calling facing interface, then the local gateway must have a public IP address assigned to the interface facing Webex Calling for calls between the local gateway and the endpoints to utilize media path optimization. Additionally, it must be running IOS-XE version 16.12.5.