16-bit unsigned integer. Optional padding. Values in this field are ignored. The size in bytes of the Server Network Data structure MUST be a multiple of 4. If the channelCount field contains an odd value, then the size of the channelIdArray (and by implication the entire Server Network Data structure) will not be a multiple of 4. In this scenario, the Pad field MUST be present and it is used to add an additional 2 bytes to the size of the Server Network Data structure. If the channelCount field contains an even value, then the Pad field is not required and MUST not be present.