I need some advice. we are carrently having a callmanager 6.1 at the head office and we need to have either a call manager express on the DR site or configure SRST at the remote DR site ISR. what will be the best practice? the plan is that should we have a disaster, we have to be able to recover or have telephone access on the DR site.
Any advice will be appreciated.
You don't need a second "dedicated" router (the 3800 series should be perfect) :)
Cisco Unified Survivable Remote Site Telephony Version 4.1
Cisco Router Using Cisco Unified Survivable Remote Site Telephony
Components of Centralized Call-Processing Architecture
The Cisco Unified Communications system uses Cisco Unified Communications Manager in combination with Cisco Unified Survivable Remote Site Telephony which is embedded within Cisco IOSÂ® Software, to help provide high-availability IP telephony to branch offices. When access to Cisco Unified Communications Manager from the branch office is impeded, for example, as a result of a WAN link failure, Cisco Unified Survivable Remote Site Telephony provides telephony backup services to help ensure that the branch office has continuous telephony service over the Cisco network infrastructure deployed in the branch. The enhanced reliability provided by Cisco Unified Survivable Remote Site Telephony makes the Cisco Unified Communications system a cost-effective solution to ensure telephony operation to all users in an organization, whether they are located in the headquarters or in a branch office.
Furthermore, in certain environments, the security of telephony communication is a critical requirement. The Cisco Unified Communications system supports secure telephony communication between any two phones in the network, whether those phones are in the headquarters facility or at a branch office. Cisco Unified Survivable Remote Site Telephony contributes to this secure telephony communication solution by supporting the same secure telephony protocols in the branch office when the branch loses communication with the centralized Cisco Unified Communications Manager.
How It Works
Cisco developed Cisco Unified Survivable Remote Site Telephony technology for all Cisco IOS Software platforms that support voice (refer to Table 3 for a complete list). The Cisco Unified Survivable Remote Site Telephony feature integrates network intelligence into Cisco IOS Software, which acts as the call-processing engine for IP phones located in the branch office during a WAN outage.
In a centralized call-processing model, the Cisco Unified Survivable Remote Site Telephony router facilitates automatic failover so that local calls and active calls from Cisco Unified IP phones to the public switched telephone network (PSTN) are maintained even if a WAN failure occurs. If the WAN link to a remote office fails and connection to the Cisco Unified CallManager for the domain is lost, the phones in that branch office automatically redirect to the Cisco Unified Survivable Remote Site Telephony router. The Cisco Unified Survivable Remote Site Telephony router automatically takes over and offers a rich set of telephony functions to help ensure business continuity with minimal impact. When the disrupted WAN link is restored, the phones automatically reregister with the original Cisco Unified CallManager-and again, no manual intervention is required. Cisco Unified Survivable Remote Site Telephony is accomplished through this integrated system with no additional hardware components
Hope this helps!