[OTR-dev] OTR, Pidgin & Guaranteed message delivery

[Ian Goldberg]

On Sun, Sep 15, 2013 at 08:02:58PM -0700, Gregory Maxwell wrote:
> On Sun, Sep 15, 2013 at 2:43 PM, Peter Saint-Andre <stpeter at stpeter.im> wrote:
> > Ian is right that there's really no such thing as guaranteed delivery
> > in IM systems
> 
> At the level of an OTR protocol it could, however, be guaranteed that
> all messages are delivered or that service is completely denied. (e.g.
> by including the hash of the oldest unacknowledged prior message in
> every message, and the far end requesting any missing messages, then
> only displaying messages in order).

The network model for OTR is that the underlying IM system may drop
messages, but any messages it delivers will be delivered in order.  It
would make for a really weird conversation if messages on an IM network
were delivered out of order.  That said, we've had reports that
SecondLife's messaging system reorders messages.  If OTR sees a old
message delivered after a new one, the old one is dropped.

So yes, we could add a reliability layer on top of whatever IM network
we have, but I personally think that's out of scope.  If you really want
a reliable IM network, you can just use one, no?

   - Ian