This holds the upper bound of a destination port range, active only when cienaCesAclRuleMatchL4DstPort is set to range, mirroring the source-side cienaCesAclRuleL4SrcPortUpper field's behavior. An admin uses this alongside cienaCesAclRuleL4DstPort to define a contiguous block of destination ports a single rule should govern, useful for services that span a known port range rather than a single fixed port. For example, an admin restricting access to a range of ports used by a passive-FTP data-connection range might set the lower bound to 50000 and this upper-bound field to 51000, covering that entire block in one rule instead of a thousand individual-port rules.