| 摘要 |
<p>Methods, apparatus and computer programs for determining header data for and based on a plurality of messages. Each message comprises header data having a plurality of fields each of which has a value. A first message is received and data indicative of at least some of the header data of the first message is stored. A second message is received and a value for at least one given field associated with header data for the second message is determined based at least on the stored data and the header data of the second message. The determined value is other than a value of the given field of the second message.</p> |
