Datasheet

Cisco Preferred Architecture for
Midmarket Collaboration PAGE 30
Collaboration Edge
PSTN Connectivity for Voice
Enable PSTN connectivity for voice calls by using either an analog or ISDN interface. A Cisco ISR with analog or ISDN
cards provides these interfaces. Connectivity is usually local, and a site with PSTN interfaces uses its local ISR as a voice
gateway. Follow these recommendations for deploying an ISR for PSTN connectivity:
•
PSTN interface (analog or ISDN)
◦ The device providing these interfaces is a Cisco ISR with analog or ISDN cards.
◦ Connectivity is usually local; a site with PSTN interfaces uses its local ISR as a voice gateway.
◦ Redundancy is achieved by deploying multiple ISRs. Cisco Unified CM has the ability to route traffic to the
closest available router.
•
SIP trunks to the service provider, and ISR or CUBE as a border element
◦ This deployment is typically used in a centralized architecture. Remote sites either do not have local connectivity,
or they have local connectivity but use it only for backup voice services. In this case the WAN connectivity has to
be sized to accommodate PSTN calls traversing the WAN to the central site where CUBE is deployed.
◦ Redundancy can be achieved by deploying multiple ISRs, sometimes to different voice carriers. Cisco Unified
CM has the ability to route traffic to the closest available router.
ISDN Connectivity for Video
Although many organizations now use the Internet for business-to-business video connectivity, legacy interoperability with
ISDN networks might still be required if the called party is not reachable through the Internet. To provide ISDN
connectivity for video, use the Cisco TelePresence ISDN GW 3241 as a standalone unit.
Virtual Private Network
A virtual private network (VPN) enables an organization’s network to be extended to remote and teleworker sites,
providing those sites with full access to corporate services. Use the organization’s existing VPN to extend collaboration
services to teleworkers, or use Cisco IP Phones with VPN clients.