[Standards-JIG] Re: What happened to the ACK proposal?

David Chisnall theraven at sucs.org
Tue Aug 16 11:09:55 UTC 2005

On 15 Aug 2005, at 23:39, Sander Devrieze wrote:

> I don't think so. There are 3 options (as far as I can see):
> * You will get a reply from the receiving server that says:
>    - Your message is stored offline.


>    - Your message is delivered to the sender (if he is online).

Right.  Except that the server has no way of knowing that you are  
online.  All the server knows is that you were online at some point  
within the last 60 seconds.  The server can then put the message into  
your socket and pray.  Meanwhile, it tells the sender that the  
message was delivered.  Unfortunately, your connection was  
interrupted 20 seconds ago, so the message is dropped. Silently.  The  
next time the server tries to write to your socket (or maybe the time  
after that, depending on how often you get messages), it will get a  
write error and fail.  The sender believes everything is fine, the  
receiver has no way of knowing the message was ever sent.

That's what you get for using a protocol designed for interconnecting  
networks over high-loss physical connections as your transport  
layer.  Ain't the Internet grand?

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