This read-create value is the starting port number of a Layer 4 source port range this ACL rule matches against, used together with aclRuleSrcL4PortRangeEnd instead of the single-port aclRuleSrcL4Port. An admin uses a range when the rule needs to match traffic from an entire block of ephemeral or application-specific source ports rather than one exact port. For example, setting aclRuleSrcL4PortRangeStart to 1024 alongside a corresponding range end matches traffic sourced from the full block of non-privileged ephemeral ports.