The question is: does the same make/model router support a different number of phones if it is configured as simply a CUCME device versus configured as as SRST fallback device?
Different Cisco documents seem to give different supported numbers - indicating that there is a difference
The Cisco Unified CME 11.6 Supported Firmware, Platforms, Memory, and Voice document, located here:
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/requirements/guide/cme116spc.html
indicates that a 3945 will support 350 phones (450 is its a 3945E version).
However, the Cisco Unified Survivable Remote Site Telephony and Cisco Unified Enhanced Survivable Remote Site Telephony Version 11.0 Data Sheet, located here:
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/requirements/guide/cme116spc.html
indicates that a 3945 will support up to 1200 phones (up to 1500 if its a 3945E version).
In the end, the CUCME and the SRST router are essentially performing the same tasks: registering/deregistering devices, processing call control via dial peers, setting up and tearing down calls.
So, I have two questions:
1 - Is my interpretation correct? A 3945 router that is ONLY running CUCME (ie telephony-services) is limited to 350 phones while a 3945 router that is running SRST (ie call-manager-fallback) can support 1500?
2 - Since the router is running the same code base - what accounts for the drastic difference in supported numbers?
