I think at least for Java and .NET (and other Microsoft stuff), there are plenty of certification. Don't know, how important they are, though. I don't know about network engineering, but in programming, the majority of certification does not at all require enough skill to really be even a mediocre programmer.
In companies, where management hires new developers without asking existing ones, it might be a plus. But personally, I wouldn't wanna work in such a company.
In fact, you will find, many developers look down at certification: http://stackoverflow.com/questions/84556/whats-your-favorite-programmer-cartoon/954235#954235
greetz
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