Datasheet

Cisco Preferred Architecture for
Midmarket Collaboration PAGE 29
Collaboration Edge
Mobile and Remote Access
The mobile and remote access feature enables Jabber clients and Cisco EX, SX, C, and MX Series endpoints to register
securely to Cisco Unified CM through Expressway-E and Expressway-C without any VPN. A Jabber client can send and
receive several types of collaboration flows (audio, video, instant messaging, and presence), while a hardware endpoint
can send audio and video streams. When multiple edges are deployed, Cisco recommends using Geo-DNS services to
provide the best network option based on assigning the closest edge in the DNS response.
The mobile and remote access functionality also leverages Expressway-C and Expressway-E. Both business-to-business
and mobile and remote access services are supported on the same server.
PSTN Gateway
Because landlines and mobile phones use the PSTN for local and international calls, external connectivity to the PSTN
from an organization’s IP telephony network is a requirement (Figure 15).
Figure 15. PSTN Connectivity
Use Cisco ISR with a time-division multiplexing (TDM) module as the PSTN gateway at headquarters. This configuration
enables the gateway to implement media interworking for the organization’s incoming and outgoing PSTN calls.
At remote sites, deploy a Cisco ISR for local PSTN connectivity using voice modules. For more information about Cisco
ISR, see the data sheet.
Table 9. Recommended PSTN Gateways
Location PSTN Gateway
Headquarters ISR G2 3900 series
Remote Sites ISR G2 2900 series
If SIP trunks are used to connect to a service provider for voice calls, enable CUBE functionality on the Cisco ISR that is
deployed at headquarters. When deploying Cisco ISR with CUBE functionality, observe the following recommendations:
•
Deploy CUBE in the demilitarized zone (DMZ).
•
Enable the firewall for NAT to convert the external address to the address of CUBE.
•
Enable the firewall to inspect voice calls.
Cisco Unified CM routes calls through SIP trunks to gateways, CUBE, or Cisco Expressway based on the dial plan. For
dial plan recommendations, see the Dial Plan section.