[Dovecot] More effective mailbox fetching over high RTT link

[Andrzej Adam Filip]

Ed W <lists at wildgooses.com> wrote:

> Andrzej Adam Filip wrote:
>> Could you offer some suggestion how to fetch mailbox content over
>> high RTT link (with negligible packet loss)?
>>
>> Currently I use IMAP+IDLE *but* it fails to use full available bandwidth
>> due to high RTT and "send command wait for response" nature of POP3 and
>> IMAP4 protocols.
>>
>>   
>
> Is this a satellite phone question?
>
> I build a bunch of products to help with this, but for a fairly
> specialist market.  You can probably contact me offlist via this email
> address or any of them on the website below?
>
>    http://www.mailasail.com
>
> However, we use lots of compression, pipelining and some predictive
> fetches to wring every bit of performance out of a 2.4Kbit connection
> with 1.5s+ latency
>
> Good luck
>
> Ed W

It is not a a satellite phone question. :-)
It is "imap over (compressed) ssh" with "link merely one category above
modem speed" to access "shared mailbox". Fetchamil's IMAP+IDLE works 
"almost acceptable" except pretty long periods of pretty high loads on
the link.

It seems that significant part of problems is sufficiently similar to
sat-phone situation.

BTW Do you suffer sufficient packet loss to consider using UDP instead
of TCP based protocols?

-- 
[pl>en: Andrew] Andrzej Adam Filip : anfi at onet.eu
There is no likelihood man can ever tap the power of the atom.
  -- Robert Millikan, Nobel Prize in Physics, 1923