Hi,
you cannot monitor a link directly, but you can monitor the interfaces that are corresponding to that link. Each link gets terminated somewhere on a network device of some kind. You can get that device monitored with SCOM and then you will know when the link is up or down, depenmding on the interface status.
That is the closest what you can get to link monitoring with SCOM.
In order to get any netwoork device monitopred with SCOM, you first need to get your hands on a .MIB file from that device (vendor site, installation media, etc.) and then using the .MIB file and the following tool:
System Center Operations Manager - Extensible Network Monitoring Management Pack Generator tool
Here a couple of additional useful references:
SCOM 2016 – Network Monitoring MP Generator Tool
#OpsMgr: SNMP Management Pack Generator
The download link to the tools contains also the guide, which can also help you out.
Hope this helps.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Stoyan Chalakov