Which two functionalities does Cisco Expressway provide in the Cisco Collaboration architecture? (Choose two.) MGCP gateway registration

Cisco Expressway is a key component for edge and remote collaboration services. Its two primary functionalities are enabling secure firewall traversal and facilitating business-to-business (B2B) communications. The firewall traversal, known as Mobile and Remote Access (MRA), allows endpoints like Cisco Jabber and IP phones to securely connect to on-premises Unified Communications Manager (CUCM) from the public internet without a VPN. The B2B functionality enables secure standards-based (SIP/H.323) video and voice calls between an organization and its partners, customers, or suppliers over the internet, acting as a secure gateway.

A. customer interaction management services: This is a function of contact center applications like Cisco Unified Contact Center Express (UCCX), not Expressway.
D. Survivable Remote Site Telephony functionality: SRST is a feature of Cisco IOS gateways (routers) that provides call processing redundancy for remote sites during a WAN failure.
E. MGCP gateway registration: Media Gateway Control Protocol (MGCP) gateways register directly with Cisco Unified Communications Manager (CUCM), not with Expressway.

1. Cisco Collaboration System 12.x Solution Reference Network Designs (SRND), Chapter: Cisco Expressway Deployment. The introduction explicitly states, "Cisco Expressway provides two main collaboration services: Mobile and Remote Access (MRA) and Business-to-Business (B2B) audio and video calls." This directly supports options B and C.

2. Cisco Expressway Series Data Sheet. Under the "Key features and benefits" section, the document lists "Comprehensive collaboration for remote workers" (describing MRA for secure firewall traversal) and "Business-to-business collaboration" as core functionalities.

3. Cisco Unified Communications Manager Administration Guide, Release 12.5(1)SU1, Chapter: Gateways. This guide details the configuration of gateways, stating, "Cisco Unified Communications Manager supports several protocols for gateway control, including... MGCP," confirming that MGCP gateways are managed by CUCM, not Expressway.

4. System Configuration Guide for Cisco Unified SRST, Cisco IOS XE Release 17.2, Chapter: Overview of Cisco Unified SRST. This document defines SRST as a feature that "provides Cisco Unified Communications Manager with fallback support for Cisco IP phones that are attached to a Cisco router on your local network," confirming it is a router-based feature.