Slow directory browsing between winME and Linux/samba over DIALUP link

Kenny, Liam lkenny at accuris.ie
Thu Jun 7 14:35:05 GMT 2001


Hi,

Im experiencing slow performance when dialing up a samba/linux server
(28.8kbps) and accessing
samba shares using winME and win2000 as clients.

It takes more than twice as long to browse a directory with winME than when
I use Linux/smbclient
over the same dialup connection. (Its not just a case of GUI vs. command
line)

After capturing a packet trace of the browsing in both cases, I can see that
quite different interactions
are taking place when winME acts as the browsing client as opposed to
smbclient:


winME:
    With winME as the client, the predominant interaction is that the client
sends an 
    SMBtrans2 Request (TRANS2_OPEN) and the samba server responds with an
SMB
    response of size 576 bytes followed by an NBSS continuation packet of
198 bytes.
    This interaction repeats itself about 100 times or so. There were other
interactions
    but these were not so numerous (and each was also in the form of
request/response)
    It looks like the propagation delay generated by the client waiting for
each response
    before sending the next request might be the main cause of the slowness.

smbclient/linux:
    With smbclient as client, the picture is quite different. The main
interaction is that the client sends
    a TRANS2_FIND_FIRST2 request and the server responds with a a
TRANS_FIND_FIRST2 response
    indicating a data size to come of 54K.  The server proceeds to send
continuation messages
    until the whole 54K of response has been transmitted (only pausing for
acks when the TCP transmit 
    window is exhausted). 
    So in this case, really only one significant request/response
interaction took place.
    This would seem to be why it is MUCH faster (propagation delays cut
out).
    (I also noted that the messages sizes of the responses were over 1500
bytes
     which would also help to avoid too many TCP ack interactions and
possible cut out
     more propagation delay)

So my questions are:

-    Does anyone know if there is a way to tune winME to be more efficient
over a dialup link ?
-    Is there a way to make samba force this more efficient dialog for
dialup links ?
-    Any other thoughts ?

If you read this far, thanks for your time and any input you might have,
Liam.




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