The basic assumption for these header layouts is that the data layout in the published messages is static. This implies the following:

Note:These assumptions have to be fulfilled by appropriate configuration of the Publisher.

Subscribershave to know the static message layout in advance. This means all fields in the headers which would be required for ad-hoc parsing of messages with dynamic layout can be omitted (e.g. PayloadHeaderor Sizes).

Finally, a Subscriberneeds an easy way to verify that a received message matches the expected message layout. Fields of the NetworkMessage header and the GroupHeaderwill be used for this purpose.

PublisherIdand WriterGroupIdidentify the WriterGroup. The NetworkMessageNumberis important for WriterGroupswhich distribute their DataSets over more than one NetworkMessage, and the GroupVersionallows the Subscriberto verify the expected layout of the DataSetMessagesand their DataSet fields.