SNMP Objects

Hi,

Im just learning about snmp at the moment as I am using it in a college project to retrieve information about network devices.

Im a bit confused about objects though. Is there a set list of objects or do you create your own. When I say objects I mean things like sysUpTime, sysLocation etc.

The reason I ask is that I set up an ubuntu virtual machine at home and installed the net-snmp package. I can run all the command line applications to like snmpwalk etc to my router, my desktop and get back information like sysDecr, Location, up time etc. I tried running the following command to my laptop:

$snmpget -v 2c -c public 192.168.1.15 sysUpTime.0

Now it is communicating with the laptop as it comes back with something like snmpv2mib - sysUpTime not there. Not those words exactly but you know what I mean. I also ran an snmpwalk to my laptop and it worked but none of the things like

sysUpTime
sysLocation etc were returned.

These commands return this type of information when I send it to my router or desktop.

On my laptop I have the net-snmp agent running. Any ideas here??

Thanks