There are several ways to do remote tape creation, and all are in use 
somewhere. Here are the most common.
 
    1. Backup to a remote TSM server over IP and then create the tape "locally".
    2. Server to server via normal IP.
    3. Tape extension works using IP, T3, DS3, OC3, WDM, etc. Many hardware 
vendors make such equipment.
 
Options 1 and 2 require a TSM Server running at the remote site with a tape 
dirve (library).
Option 3 just requires the tape drive (library) to be remote- although to 
restore remotely, you would still require the TSM server to be there.  Some use 
Option 1 and Option 3 bi-directionally, when they have two data centers serving 
as D/R sites to each other.
 
For more information you can contact me at richard_cowen AT cnt DOT com.