This should be obvious, but security certifications are in HIGH demand, let me tell you. Just look at all the high profile hacks over the last several years…and all of that is just the tip of the iceberg. So if you have a strong understanding of networks and protocols, and enjoy the security side of things, then I would suggest you pursue some security certifications. And start getting some experience within the security field, perhaps even where you are currently working. The security field is already going strong, and will only get stronger in the years to come. And…did I mention the pay is excellent??!!
Take a look at this ComputerWorld article on the top 8 security certs that are in demand.
The CISSP and SANS certs probably pertain most to the network side of things. (Disclaimer: I attend SANS conferences on a some-what regular basis, and I hold a SANS GSEC certification.)
Summary: Security is vitally important in the network field, so do your career a favor and learn it!