[openib-general] [ANNOUNCE] Contribute RDS (ReliableDatagramSockets) to OpenIB

[Rick Frank]

Folks, I just realized that the RDS proposal doc I posted was not the 
latest - I have attached a newer doc.

BTW - Our goal at Oracle is to eventually replace our use of UDP with RDS - 
we want to get out of the business of making UDP work for us (from user 
mode) - each time we create new internal database clients with corresponding 
new IPC requirements.

I'm not proposing that we change our use of the connectionless datagram 
model - we have to many dependencies on this.  For example, very shortly we 
will need to support reliably (and efficiently) moving 1meg msgs in our 
IPC - which will further complicate the UDP implementation - and further 
reduce its performance compared to RDP - which can support the 1meg MTU 
naturally for some interconnects - and or rely on a driver level 
implementation RDS / transport for those that do not.  Basically it is very 
hard to do this stuff from user mode.

Note that we will still be using our existing IPC module for RDS - just 
removing the remaining UDP vestages.

Of course for this to work - we will need RDS to be ubiquitous - supported 
on all interconnects - to include simple Ethernet NICs.

----- Original Message ----- 
From: "Rimmer, Todd" <trimmer at silverstorm.com>
To: "Bob Woodruff" <robert.j.woodruff at intel.com>; "Caitlin Bestler" 
<caitlinb at broadcom.com>; "Rick Frank" <Richard.Frank at oracle.com>; "Pandit, 
Ranjit" <rpandit at silverstorm.com>; "Grant Grundler" <iod00d at hp.com>
Cc: <openib-general at openib.org>
Sent: Friday, November 04, 2005 6:02 PM
Subject: RE: [openib-general] [ANNOUNCE] Contribute RDS 
(ReliableDatagramSockets) to OpenIB


> Bob wrote,
> Perhaps if tunneling udp packets over RC connections rather than
> UD connections provides better performance, as was seen in the RDS
> experiment, then why not just convert
> IPoIB to use a connected model (rather than datagrams)
> and then all existing IP upper level
> protocols would could benefit, TCP, UDP, SCTP, ....

This would miss the second major improvement of RDS, namely removing the 
need for the application to perform timeouts and retries on datagram 
packets.  If Oracle ran over UDP/IP/IPoIB it would not be guaranteed a 
loss-less reliable interface.  If UDP/IP/IPoIB provided a loss-less reliable 
interface it would likely break or affect other UDP applications which are 
expecting a flow controlled interface.

Todd Rimmer
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