Hi,
- If one site PRI is down, can we add working site PRI in down site's Route Group from CUCM to allow outbound calls?
MB: Yes you can create two route-groups and assign them to route-list. They will always go sequentially. Route-Group two will never be used until route-group one is dead
- Is there any restrictions on carrier to carrier manner?
MB: Not I am aware off as long as you are in india
- Is there any restrictions at geographical level like within same city or state it's allowed?
MB: Not I am aware of as long as you are in india
- Do you have regulation reference document/ link?
Useful links:
http://trai.gov.in/consultation-paper-internet-telephony-voip
https://supportforums.cisco.com/blog/12539601/trai-india-regulations-voipip-telephony