Never worked for any of those companies but I worked for AT&T which is a huge Cisco shop. Depending on what you do it can range from $20/hr up to probably well over $200+/hr. Troubleshooting routers is a very generic phrase. Are you trouble shooting hardware? Configuration? Performance? Architecture? Security? Fiber runs?
It can run from as basic as making sure all of the line cards and route processors on a router are functional to troubleshooting OC768 peering issues in their backbone, or mitigating a global DDOS attack against a key infrastructure client (IE trying to take someone like Colonial Pipeline down).
Regardless of what you do, learn TCP/IP very well. Be familiar with network architecture, how routers, switches, load balancers, firewalls, vpns, and proxies work. Understand the various features that all of those devices have, understand the pros and cons of the various hardware platforms (why would you pick an ISR over a nexus 7k), and make sure you understand the impact of a change down stream (what will happen to your frame relay network if you migrate from EIGRP to OSPF. How would the architecture need to change to ensure the IGP performs well with the knew routing protocol).
But like I always say, don't listen to me. I'm just another lost nikka :nonikkas:
assuming he makes it