This is the display-duplicate prefix length accompanying cienaCesExtAclEntryNotifSrcInetAddr inside the same extended-ACL notification trap, telling the receiver exactly how broad the newly authorized source network is without needing to reference the live configuration table. An admin's audit tooling needs this paired with the address field to fully and unambiguously record what was authorized at that point in time, since scope materially changes the security implication of an authorization event. For example, a trap showing a source address duplicated here with this prefix length reported as 32 tells an auditor a single host was authorized, a meaningfully narrower and lower-risk change than the same address authorized with a /8 prefix.