a9601b6a_PDML_Specification__Description
[Attribute] unmaskedvalue (optional) [Description] 
This attribute is used only if the length of the current field is not an integer number of bytes. For instance, a field which is 4-bit wide belongs to this category. In this case, the size attribute is misleading because this size refers to the 'parent' field defined into the NetPDL specification. For instance, this attribute is used for PDML fields that derive from a field of the NetPDL specification, which must always be included within a field (that is the 'parent' field). The unmaskedvalue attribute keeps the value of the field supposing that its length is equal to the parent field. For instance, a field with length equal to 1 byte, split in 2 fields of 4 bits each, will originate two in the PDML description that have the unmaskedvalue attribute equal to the value of the field as a whole. This attribute is required only for fields that derive from fields; in the other cases it can be omitted. This attribute is used to speed up the reassembling of the hexadecimal dump of the packet starting from the PDML file.
PDML Specification
Description