John,
This is definitely one of those "Chicken vs. Egg issue" or "Foundation vs. House Issues"
If you are venturing into the IP camera world, both knowledge bases are important.
Networking Knowledge
In my opinion, you need to have a solid fundemental knowledge and understanding of how any robust IP network works before you slap devices onto it and expect it to perform or continue to perform as expected.
To be able to manage and support that network you must be able to understand the underlying communications and functionality.
From a simplistic perspective, a camera is just another 'IP device' that needs to communicate and be managed on that network.
More importantly, if you are coming into an organization that arleady has an existing IP network, you need to know and understand how to asses the current system(s) so that you can integrate properly without impacting the current performance. What is the IP schema used?, Are there any VLANs present? Does the organization use Level 1, 2, 3 & 4 level strategy for their infrastructure from Enterprise level to control levels?
These are just the start of assessing an existing system.
Camera Knowledge
On the other hand, a camera is of course more than just a network printer, desktop or VOIP phone etc.. (case in point, why your organization exists)
Your knowledge of how to properly select, where to place into an IP network and configure the a camera 'system' is very important as it impacts its overall performance and suitablity for use.
Unlike the old coaxial analog camera days where you have dedicated, single lines of communications between camera in the field to your monitoring/recording system you now have a shared communications resource , which when failing can be impacted by even the simplest of changes to the overall IP network. i.e adding cameras.