I'm hoping to change out our T-1s for fiber in the next year and I'm trying to determine what router upgrades or replacements I'll need to make. The core router is a 7206 (VXR with NPE-400 and I/O controller w/2 FE/E ports). All my other sites connect to this one. Can this be upgraded to 1GB fiber? My sites have mostly 2651XM 10/100. I know these aren't fast enough. What would be a good replacement?