Alright, I'm being driven crazy by this. Even though I definitely know more than enough about IS-IS operation to be comfy on the BSCI exam, I'm vexed trying to get a better understanding anyway of the OSI protocols.
Which I notice are sometimes also called the ISO protocols.
Which one is an actual layer 3 protocol? And, how would you classify the other one?
One BSCI textbook tells me IS-IS uses CLNS to transmit routing data, even if it's IP routes it's transmitting.
Another textbook tells me IS-IS itself is a Layer 3 specification; that it sits right on top of the data-link layer and uses neither IP nor CLNS to send info, but rather its own Layer 3 format.
I know I don't need to know these things inside and out to pass the exam, but I like knowing things anyway.
I tried looking at the official ISO documents on CLNS and CLNP but it seems you have to pay money to look at those (not likely in my case).
Please shed the light for me....