Frequency capping works in capping intervals and applies to the actual delivery times. The values you define impact each user separately within the target group of your campaign.
For example, if frequency capping is set for "once per 24 hours", each user who received a message at 10:00 am will not receive any further messages until 10:00 am on the next day.
CrossEngage supports two levels of frequency capping:
Campaign level (Campaigns -> Edit -> Cappings -> Frequency cappings): applies to users in the segment assigned to a specific campaign
Global level (More -> Cappings): sets frequency limitations across all campaigns in all channels