Which component pair handles firewall traversal and media traversal for remote collaboration endpoints accessing cloud services?

Which component pair handles firewall traversal and media traversal for remote collaboration endpoints accessing cloud services?

• A. Expressway-C/Expressway-E pair.
• B. CUCM Publisher.
• C. Cisco Unity Connection.
• D. ASA Firewall Module.

Answer: (A)

When remote collaboration endpoints need to reach cloud services, crossing firewalls and NATs for both signaling and media is essential. The Cisco Expressway pair—one component placed inside the network (Expressway-C) and the other at the perimeter (Expressway-E)—is built exactly for that role. They act as traversal gateways: signaling between endpoints and cloud services flows through them, and media can be relayed or routed via ICE/STUN/TURN paths when direct peer-to-peer communication isn’t possible due to NAT or firewall restrictions. Expressway-C connects to internal systems (like IM&P and, if needed, CUCM) and to Expressway-E, while Expressway-E sits at the edge facing the Internet and cloud services. This setup enables remote endpoints to register, sign in, and establish calls with cloud-hosted services without exposing the internal network directly. The other options don’t provide this specialized traversal capability. A CUCM Publisher handles on-prem call control, Cisco Unity Connection is a voicemail platform, and an ASA Firewall Module is a general firewall product rather than the dedicated collaboration traversal solution.

When remote collaboration endpoints need to reach cloud services, crossing firewalls and NATs for both signaling and media is essential. The Cisco Expressway pair—one component placed inside the network (Expressway-C) and the other at the perimeter (Expressway-E)—is built exactly for that role. They act as traversal gateways: signaling between endpoints and cloud services flows through them, and media can be relayed or routed via ICE/STUN/TURN paths when direct peer-to-peer communication isn’t possible due to NAT or firewall restrictions. Expressway-C connects to internal systems (like IM&P and, if needed, CUCM) and to Expressway-E, while Expressway-E sits at the edge facing the Internet and cloud services. This setup enables remote endpoints to register, sign in, and establish calls with cloud-hosted services without exposing the internal network directly.

The other options don’t provide this specialized traversal capability. A CUCM Publisher handles on-prem call control, Cisco Unity Connection is a voicemail platform, and an ASA Firewall Module is a general firewall product rather than the dedicated collaboration traversal solution.