Anupam,
CUCM prevents you from using the same IP and port destination for a SIP trunk. So the question back to your provider is if they expect CUCM to communcate over the same IP and same port number for all 10 trunks. If the answer is yes, same IP and PORT, then you must use DNS name resolution to specify the 10 different trunks. If they allow incrementing of port to the same IP, then you should be able to define each trunk by IP and port. Most customers use the DNS trick to have 10 different DNS names resolve to the same IP.
As for the return 10 trunks, I am not sure how to answer that. What is their IP and port numbering requriements for the 10 trunks? If they can vary the IP and port number, then use DNS to resolve the IP and set the port number accordingly. If the IP must be unique or the port number cannot change from 5080, then you are going to be restricted to 5 trunks max.
Thanks,
Dan Keller
Technical Marketing Engineer.