Pre-deployment Checklist and Tasks
appliance. Expressway-E is static-NATed to a public IP. All communication to the Expressway-E is based
on the NATed IP. This means that Cisco ASA allows traffic from inside to reach the DMZ by using the
NATed IP. This is also known as NAT reflection.
SIP and H.323 ALGs are disabled on the Cisco ASA appliance carrying network traffic to or from the Cisco
Expressway-E. When enabled, this is frequently found to negatively affect the built in traversal functionality
of the Cisco Expressway-E, because much of the SIP messaging is encrypted and Cisco ASA cannot
inspect the payload.
This design follows a single-cluster centralized call processing model. The endpoints use a seven-digit
phone number for dialing, which preserves the capability to receive calls from devices that only support
numeric dialing. The numbers are in the following pattern:
For URI dialing, the endpoints are assigned the URI in the following pattern:
For business-to-business calls, the example external domain used is:
Deploy MRA and B2B Collaboration