Packet trace records – format only headers

There are two ways of passing the formatter truncated records so that trace records contain only headers:

Use the ABBREV keyword of the PKTTRACE command to truncate traced records. No matter the value of ABBREV, the record always contains the IP header and protocol header.
Shorten the data that is passed to the formatter. Use these steps:
1. Determine whether the trace record is the first segment of packet. The sequence number field of the header (PTH_SeqNum) is 0. The record contains the IP header and protocol header if there is any. Otherwise, the record contains only data.
2. Set the CTELENP field, which is the first halfword of a trace record, to the smaller of CTELENP or the sum of the size of following fields:
  - The CTEFDATA field
  - The PTH_HDR field
  - The IP header
  - The protocol header
3. Set the PTO_SEGMENT flag to 0. The length also includes the 2-byte length field CTELENE.

Rule: Records that are passed to the formatter must always contain at least the ITTCTE, PTHDR_t, the IP header, and the protocol header.