Next level in my career

Hi
Currently Iam working as a Network engineer in Nortel networks Domain.
I had worked on switches of Nortel networks.
What I should do for career growth changes?
Should I need to do some certifications or higher studies to have a career growth?
Since I worked for 5 years,I dont want to waste them,If I change my platform.
Please suggest me to do so that my experinces will be considered to avoid wasting them.

Regards
Bala