[openib-general] Re: [swg] Re: private data...

[Tom Tucker]

If TCP/IP addresses and port numbers are being used to identify hosts
and services then IMHO there should be no ambiguity (read overlap)
between these port numbers and IP addresses on different transports.
This means specifically, that if an IB application is listening on a
host on port number 600, then this port number/IP address pair are
CONSUMED. Having another application listening on the same port over the
"native" stack should not happen and if it does chaos will absolutely
ensue. This also applies to iWARP/IP applications. 

Note that the same port number on DIFFERENT IP addresses is absolutely
fine. In fact, with CMA it will be possible for a service (.e.g. NFS) to
listen on a given port on an IB, an iWARP, AND a "native" TCP interface
all at the same time. No problem because the IP addresses are different.

Note that without integration with the host stack the implementation
cannot enforce this, but we should assume that the management tools
and/or documentation will. Otherwise, we end down an incredibly deep
rathole -- and it's dark down there.

On Thu, 2005-10-20 at 12:00 -0700, Fab Tillier wrote:
> > From: James Lentini [mailto:jlentini at netapp.com]
> > Sent: Thursday, October 20, 2005 11:39 AM
> > 
> > I like Sean's idea better. Have a well know service id or range of
> > service ids on which this protocol is used. I think of it as a service
> > running on top of the CM protocol for using IP addresses on native IB.
> > I don't think it should be mandatory for every CM connection.
> 
> The well known service ID implies that a DAPL application *would* prevent a TCP
> application from using a particular port, which seems to conflict your statement
> that DAPL apps shouldn't prevent TCP apps from working.
> 
> That's not to say you couldn't have one range of service IDs for TCP
> applications, and another range for DAPL applications, and yet another range per
> protocol or application that wishes to use IP addressing during connection
> establishment.  However, this doesn't extend the CM protocol, but just creates
> an ad-hoc group of protocols that happen to define the first 32-bytes of their
> private data similarly.
> 
> Having a bit in the CM REQ indicate whether the first 32-bytes of private data
> contain the source and destination IP addresses allows any app using any service
> ID to use IP addresses as source and destination identifiers regardless of what
> protocol they actually use once the connection is established.
> 
> Defining service ID ranges for particular protocols then becomes the
> responsibility of the organizations defining such protocols and the owner of the
> OUI with which the service ID ranges are defined, and is outside the scope of
> the IBTA.
> 
> - Fab
> 
> 
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