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- Document: FSC-0045
- Version: 001
- Date: 17-Apr-90
-
-
-
-
-
- A Proposal
- for
- A New Packet Header Format
- Thom Henderson
- 1:107/542.1@FidoNet
- April 17, 1990
-
-
-
-
-
- Status of this document:
-
- This FSC suggests a proposed protocol for the FidoNet(r) community,
- and requests discussion and suggestions for improvements.
- Distribution of this document is unlimited.
-
- Fido and FidoNet are registered marks of Tom Jennings and Fido
- Software.
-
-
-
-
- Provisions have been made for storing full five-dimensional addresses (i.e.
- zone, net, node, point, and domain) in a packed message such that it is
- possible (albeit somewhat clumsily) to extract a full five dimensional
- origin and destination for any message. This has not, however, been
- extended to packet headers. It would be useful for various reasons, such
- as mail pickpus and password protection of mail links, to be able to
- quickly and easily extract similar five dimensional addresses from a packet
- header. This is a proposal for a packet header structure that would make
- that possible.
-
-
- The proposed packet header structure is as follows:
-
- Offset Width Description
- ====== ===== ===========
- 0 2 Originating node number
- 2 2 Destination node number
- 4 2 * Originating point number
- 6 2 * Destination point number
- 8 8 Reserved, must be zero
- 16 2 Packet sub-version (2)
- 18 2 Packet version (2)
- 20 2 Originating network
- 22 2 Destination network
- 24 1 Product code
- 25 1 Product revision level
- 26 8 Password
- 34 2 * Originating zone
- 36 2 * Destination zone
- 38 8 * Originating domain
- 46 8 * Destination domain
- 54 4 Product specific data
- 58 --- Start of first packed message
-
- * Field only guaranteed accurate in a type 2.2 header
-
-
- All numbers are in decimal. The point of this proposed structure is that
- it is backwards compatible. All significant fields of a normal type 2
- packet header are preserved and are in the same places. The following data
- fields of a type 2 packet have been discarded and replaced with new
- informational content:
-
- Packet creation date (6 bytes)
- Packet creation time (6 bytes)
- Packet baud rate (2 bytes)
- Reserved for future use (16 bytes)
-
- The field formerly occupied by the packet baud rate has been replaced by
- the packet sub-version number. If this number is set to "2" (an impossible
- baud rate), then that indicates a type 2.2 packet header, and the fields
- marked above with an asterisk become valid. If this field contains
- anything other than a 2, then only the original type 2.0 data may be
- regarded as accurate.
-