Date   : Tue, 27 Jul 2010 13:28:03 +0100
From   : jgh@... (J.G.Harston)
Subject: FileStore emulator 2010/07/24

Rick Murray wrote:
> J.G.Harston wrote:
>>>> Is there a doc anywhere describing the interfacing protocol? I'm trying to
>>>> unpick the AUN stuff,
>> http://mdfs.net/Docs/Comp/Econet/
>
> I meant, more specifically, BeebEm. How does it stuff the network
> address, port, etc into a TCP/IP packet?

In the same way that any other Econet-Over-IP stuffs an Econet packet
into a TCP/IP packet. I posted this to the list a couple of years ago,
see http://mdfs.net/Archive/BBCMicro/2007/08/09/013023.htm

An Econet packet looks like this:
   +------+------+-----+-----+---------+------+-----------------------------+
   | Dest | Dest | Src | Src | Control | Port |         Data                |
   | Stn  | Net  | Stn | Net |  Byte   |      |                             |
   +------+------+-----+-----+---------+------+-----------------------------+
    <-------- - - Packet Header - - ---------> <--- - - Packet Data - - --->

which is parcelled up into a UDP/IP packet like this:
     +-------------------+
     | IP Header:        |
     |  Version          |
     |  Header Length    |
     |  Type             |
     |  Total Length     |
     |  ID               |
     |  Fragment         |
     |  Protocol         |
     |  Header CRC       |
     |  Source Address   | - site.network.net.stn
     |  Dest Address     | - site.network.net.stn
     |  Options          |
     | ----------------- |
     | IP Data:          |
     |  UDP packet       |
     | +---------------+ |
     | | UDP Header:   | |
     | |  Source Port  | |
     | |  Dest Port    | | - &8000 for Econet-Over-IP
     | |  Length       | |
     | |  Checksum     | |
     | | ------------- | |
     | | UDP Data:     | |
     | | +-----------+ | |
     | | | Tr.Type   | | |
     | | | Eco Port  | | | From Econet packet header
     | | | Eco Ctrl  | | | From Econet packet header
     | | | Padding   | | |
     | | | Sequence  | | |
     | | | --------- | | |
     | | |  Econet   | | |
     | | |  Packet   | | |
     | | |   Data    | | |
     | | +-----------+ | |
     | +---------------+ |
     +-------------------+

as described in more detail in http://mdfs.net/Docs/Comp/Econet/OverIPsrc

-- 
J.G.Harston - jgh@...