1) Can we create a Partition under Partition.
2) Can a Partition be part of multple CSS's. If yes, then can we define priorities for these partitions.
Yes, the CSS is made up from what you have in the line CSS + device CSS. However the order is of no importance unless there are patterns that are equally good matches, only then, the order matters.
3) Can we define a Partition from Site-A to CSS on Site-B and vice-versa.
You definde objects in partitions, then assign these to CSS to provide calling privileges. You can make it 1 way dialing or 2 way dialing.
4) Is there any limitation on number of Partitions per CSS.
Not in the number of partitions, but each CSS can only be 512 characters long. The whole CSS from what I explained above can be 1024 chars.
5) Can we have single DN assigned to two different lines on single phone. If yes, can we loopback the ring from line-1 to line-2.
Yes, but it needs to be in a different partitions and then you configure call forward settings for cascading.
If this helps, please rate
if this helps, please rate