Hi Kano,
After taking another look at my dictionary, I see what you mean. Yes, it does stop at 1.3.6.1.4.1.11.2.3.7.11.17. I have one of these switches in my lab and will see what happens if I walk that branch. I would expect that 1.3.6.1.4.1.11.2.3.7.11.17.0 is the SysObjectID, but I'll check it to be sure.
What firmware version are you running and in what context did this OID come to you if your NNM can walk it?
It may take me a little while to get access to my switch, so I'll try to respond as soon as possible.