This read-write field toggles whether the switch performs detailed SIP Level 3 PDU error checking, validating fields like address types, BA sizes, and header extensions, the kinds of checks reflected in the many lportSmdsCnt Invalids counters, on this SMDS interface. An admin might disable detailed checking temporarily on a trusted or performance-critical path to reduce processing overhead, while normally leaving it on to catch malformed SIP3 traffic early. For example, turning lportSmdsPduCheck off would stop the switch from incrementing counters like lportSmdsCntSip3BetagMismatchs even if malformed cells were arriving, since the underlying validation itself is disabled.