please, i want to take my CCIE lab. i live in cameroon, so to obtain a visa for a country such as USA or other country for LAB, is very difficult. i want to know who give Invitation Letter (Entrance Visa) and if it can help me to easily obtain a visa .
in this case, what is the duration of this visa
3 month, 4 month ....
please help me, i want to take my CCIE LAB R&S in the next year.