Internet protocol tunnelling using templates

A method and apparatus for processing IP packets is disclosed. The method comprises defining sets of packet fields referred to as templates (in method steps 1101-1102), storing the templates in a memory, determining (in a step 1104) if a current IP packet is intended to be processed, identifying (in the step 1104) the process to be applied to the current IP packet, selecting, depending on an attribute of the identified process, at least one of the stored templates, and operating (in a step 1107) upon the current IP packet, using the templates, to form a processed IP packet.