"Monitor and support" what exactly do you require ? Most any snmp management system like Orion, Whats up gold, Openview NNM can do that.
Its when you get into the details that things get differentiated very quickly.
How many devices, how many different models, OS versions, configuration management, OS management, Modular IOS support, Monitoring, thresholding, alerting and alerting actions, integration with other systems, etc. Its lots more than just a couple of things you need to watch.
