Level one is our NOC. They monitor the network, provide onhand support for colo customers in the datacenter, perform our routine datacenter maintenance, handle incoming phone calls, reboot requests, outage reports, and answer tickets when they're not doing anything else. They're the front line for our support group.
We have a special subset of the NOC whose job is solely answering tickets. This group is comprised of our more experienced techs and is a recent addition to our support system. We've noticed a
very large improvement in ticket response times since putting this new group together. Since these guys aren't answering phones and handling customers in person and the like they can take the proper time research issues on your tickets.
Level 2 is our support escalation group. If our NOC gets stumped they'll escalate your support ticket to these guys. This group is comprised of our most senior and experienced technicians. These guys can afford to take even more time to research a particularly troublesome issue.
I suppose level three can be considered our managed services group. This group administers all of the Planet's local servers. Generally they don't do support unless theres that rare case where we need their expert help. If you purchase a high enough service level where you have your own personal technician it is mot likely someone from this group.
HTH