Which Expressway node is internet-facing?

• A. Expressway-C
• B. MRA Server
• C. Expressway-E
• D. CUCM

Answer: (C)

In a Cisco Expressway deployment, the node that sits on the internet-facing side is Expressway-E. This role is placed in the DMZ or public-facing network so it can accept connections from remote users and external services. Expressway-E handles inbound TLS connections, authentication, and NAT traversal for traffic coming from outside your internal network. It then communicates with Expressway-C on the inside of the network to carry signaling and media to internal endpoints such as CUCM or IM&P.

Expressway-C, by contrast, lives inside the LAN and is not exposed directly to the internet. Its job is to handle the internal signaling/media traversal and to bridge connections between the external Expressway-E and internal systems. The MRA Server is a separate component used to enable remote access for Jabber/Mobile clients and works with Expressway-E, but it isn’t the internet-facing Expressway node itself.

So, the internet-facing edge is the Expressway-E.