Cisco 2951 router can support up to 250 ephones and 500 dns in srst as per the chart here:
https://supportforums.cisco.com/discussion/11670501/error-exceed-limit-while-adding-ephone-cme-2921
However, I am only able to configure 20 dns even though I see that I should be able to configure 500 after doing " max-dn ? "
I will like to know what actually determines the number of dn's that can be configured on the router
will it be memory, dsp, license etc?
Thanks