ATM data service unit

Data Service Unit

data service unit， DSU

MAC Service Data Unit MSDU

NSDU Network Service Data Unit

SDU Service data unit

Service Data Unit

service data unit integrity

Service Data Unit SDU

SMDA data service unit

Transport Service Data Unit

TSDU Transport Service Data Unit

XUDTS eXtended Unit Data Service

session service data unit

presentation service data unit

network service data unit

actual data application

Application Data

Application Data Base