What "mode cme-app" commands exactly means?

[xidasd]

I have ISR 4321 that has been upgraded to "Cisco IOS XE Software, Version 17.02.01r". 

When I configure a SIP, "mode cme" command in voice register global displays "% Ambiguous command: "mode cme"". So, I have to use "mode cme-app" command instead, which I have never seen before. But with that commands, it seems that the registering of IP phones is not properly completed.

Even google doesn't give me any information about that command. 

What "mode cme-app" commands exactly mean? 

[Nithin Eluvathingal · Accepted solution]

I have a CME run-in on Version 16.12.04 which I have mode cme. asper the comparability guide, both 17.1.1 and 16.12 run same CME versions and  the latest cme  configuration guide, the command mentioned is mode cme. Need to test this command on lab

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/requirements/guide/33matrix.html

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/admin/configuration/manual/cmeadm/cmebasic.html

[xidasd]

Thanks, I think that two options are exactly same.

[Nithin Eluvathingal]

Mode CME and Mode CME-APP are not the same.

Isr 4321 can run CME on two modes CME and CME  Appliance mode, by using CME-APP, ISR 4321 runs on appliance mode and it can support 400 pools (with CME14.1. its dependent on CME versions). But the same router on Mode CME it can support maximum 50 pools.