I've got just odd question. Why there is a requirement to have RDC for using Marketing Cloud ID Service ? I'm currently using 2o7.net domain and still can get Visitor ID when activated through DTM. Does RDC is to reduce latency and not to loss any data ? Or there are more implications when using 2o7.net domain for tracking server ?
It is always recommended to implement RDC for Marketing Cloud ID Service and thus use ***.sc.omtrdc.net domain for tracking server to reduce latency and data loss related issues.
Basically ,Regional data collection is a network of regional data collection centers (DCC) that aim to reduce latency and data loss associated with Adobe image requests. Data is collected at DCC sites throughout the world, then immediately forwarded to the Data Processing Center for processing. Please see the following link for more info : https://marketing.adobe.com/resources/help/en_US/whitepapers/rdc/