after reading this doc, I am still confused as to what Opt1stScan means. Is it an indication of a successful scan? Why is it on skipped list?

Thanks for the clarification

After reading Charles post here, It is difficult to understand the difference between notBestIP and Opt1stScan. sorry for being so thick…

Opt1stScan and OptNotBestIP are closely related.

Consider a host with a couple of interfaces with endpoints 1.1.1.1 and 2.2.2.2. On scanning 1.1.1.1 ADDM decides it is a new entity and creates a Host node. When the same host is scanned using 2.2.2.2 ADDM does not know if that endpoint is that found on the host. For example, NATing may mean that the second interface is not reachable and actually corresponds to a different device. Thus ADDM performs a few of the initial requests (for hosts this is getDeviceInfo, getHostInfo and getInterfaceList) to determine if the endpoint actually belongs to the same host. Should ADDM decide that it is the same host the DA is marked Opt1stScan and discovery is complete.

On rescanning 2.2.2.2 ADDM knows that the second endpoint belongs to a host which has been successfully scanned using 1.1.1.1 so it immediately stops without performing any discovery marking the DA as OptNotBestIP.

As time passes things change. Hence after a period of time (default 7 days, configurable as Scan optimization timeout) ADDM decides it better check if 2.2.2.2 still references the same host. If it does then that DA will be marked Opt1stScan and discovery stopped.

Overview is that:

• Opt1stScan is either an initial scan or scan after Scan optimization timeout when an endpoint is found to belong to a device which has successfully be scanned on another endpoint.
• OptNotBestIP is a scan where an endpoint is known to belong to a device which has successfully been scanned by another endpoint and Scan optimization timeout has not passed since last scanning the endpoint.

This is a great explanation Andrew. I think I understand it a little better now. what is the chance that this explanation can find its way to the doc?

So, Opt1stScan means that ADDM ‘thinks’ it is a host it already discovered but has done a little extra work to try to figure out if this is true. NotBestIP means that ADDM ‘knows’ it has scanned this host on a different IP. Both result in ‘skipped’ as a result.

Fundamentally yes.

With the ‘knows’ bit timing out based on the scan optimization timeout value.