How many total registrations and total IP and analog phones can we have when in survivable mode.

In survivable mode, the 2 port gives you a 5 call license, the 4 port gives you a 10 call license, and the 8 port gives you a 15 call license. Avaya's recommendation is to allow 2 (combination of analog phones and/or IP phones) for every PSTN port. The 2/4/8 port -AV models allow 15 registered IP phones as the maximum number of registered IP phones, plus the Analog Phones and trunk.