Cisco Cisco TelePresence Video Communication Server Expressway

Introduction 

An example remote endpoint, which is registering to the Cisco VCS Expressway via the internet. 

The DNS owned by service provider which hosts the external domain example.com. 

The DNS used by the Cisco VCS Expressway to perform DNS lookups. 

An NTP server pool which provides the clock source used to synchronize both internal and external 
devices. 

The example deployment includes: 

 

NAT (PAT) device performing port address translation functions for network traffic routed from the 
internal network to addresses in the DMZ (and beyond — towards remote destinations on the 
internet). 

 

Firewall device on the public-facing side of the DMZ. This device allows all outbound connections 
and inbound connections on specific ports. See Appendix 3 – NAT & firewall configuration. 

 

Home firewall NAT (PAT) device which performs port address and firewall functions for network 
traffic originating from the MXP1000 device. 

The example deployment is configured to route SIP (and H.323) signaling messages for calls made to 
URIs which use the domain example.com. 

 

DNS SRV records are configured in the public (external) and local (internal) network DNS server 
to enable routing of signaling request message to the relevant infrastructure elements (for 
example, before an external endpoint registers, it will query the external DNS servers to 
determine the IP address of the Cisco VCS Expressway). 

 

The internal SIP domain (example.com) is the same as the public DNS name. This enables both 
registered and non-registered devices in the public internet to call endpoint registered to the 
internal and external infrastructure (Cisco VCS Control and Cisco VCS Expressway). 

The DNS SRV configurations are described in Appendix 2: DNS records configuration. 

Cisco VCS Deployment Guide: Basic Cisco VCS configuration – Cisco VCS Control with 
Cisco VCS Expressway 

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