What is the identity range SQL Server providing, is it unlimited?

What is the identity range SQL Server 2008 R2 providing, is it unlimited?
I got one escalation from application saying the data loading from excel is fialing with some error. The Table which should get the data is in replication. User is trying to load 132k records but the publisher identity range is 50000 and Subscribers is 45000. I beleive SQL server will increase the number when we try to insert more than the identity range. But anyway I increased it to 250k.Is the error about the identity range? error message was not clear. It might be time out error from UI also.

Thanks

Swapna