Comment 1 for bug 1446869

From the TNC IFMap document:

The first time a pollResult contains search results for a new subscription, the search results MUST consist of the complete set of identifiers, links, and metadata for the subscription as specified in section 3.7.2.1. The complete search results are sent to the MAP Client in a searchResult element. Subsequent pollResults (known as “delta pollResults”) MUST contain
updates in updateResult elements as metadata is added and deletes in deleteResult elements as metadata is removed. The update Result and deleteResult elements returned by the server MUST reflect ALL of the updates which have occurred since the last poll which affect the client’s subscriptions.

A metadata change may introduce or remove a link between two subgraphs that match a subscription. When this happens after an initial searchResult message has been sent, the MAP Server informs the MAP Client about the metadata that was added or removed to the subscription using updateResult and deleteResult elements.