As of July 2019 this router has been removed from service but it is still up and running!trans-sec1.Tampa1 uptime is 20 years, 4 days, 17 hours, 18 minutes
As far as we can tell, Level 3 holds the crown:
trans-sec1.Tampa1#show ver
Cisco Internetwork Operating System Software
IOS (tm) 2500 Software (C2500-I-L), Version 11.3(9), RELEASE SOFTWARE (fc1)
Copyright (c) 1986-1999 by cisco Systems, Inc.
Compil...