This 16-byte octet string captures the destination and source SMDS addresses of the last PDU that triggered the 'Dst Ia Not Found' violation, meaning the destination individual address simply doesn't exist in the switch's address table. An admin decoding the destination half of this pair can identify exactly which unreachable address a customer's device is mistakenly trying to send traffic to, often revealing a stale or mistyped destination configured at the customer premises. For example, a customer who recently changed ISPs but left an old destination address configured on their equipment would generate this violation repeatedly.