@miwashi
I tend to agree with undiscern that you should be getting your promotion in the next couple of years, unless you have been getting a string of Cs for your appraisals, or your CEP is MX12. I can't imagine that you would be given an entry grade for your CEP though. But maybe you know better. Why don't you ask your boss about your chances for promotion, and register your unhappiness? Since you have been an asset to him, he may have an incentive to put you up, to pre-empt your resignation.