Security & Network Management

Hi everyone,
I am looking for security and/or Network Manegement solution in and NT ethernet, cisco PIX 4.4 environment. My questions are:
1) Is it recommended to have security and network mangement (monitoring) done by one software/hardware?
2) Does it exist such a product? if yes can you tell me few name
3) if not advicable to have this done by one product can you give me few names of each product.
Thanks.