[dat-discussions] RE: [openib-general] Re: iWARP emulationprotocol

[Caitlin Bestler]

> -----Original Message-----
> From: openib-general-bounces at openib.org 
> [mailto:openib-general-bounces at openib.org] On Behalf Of Sean Hefty
> Sent: Thursday, October 20, 2005 8:51 AM
> To: Kanevsky, Arkady
> Cc: swg at infinibandta.org; openib-general at openib.org; Lentini, 
> James; Davis, Arlin R
> Subject: Re: [dat-discussions] RE: [openib-general] Re: iWARP 
> emulationprotocol
> 
> Kanevsky, Arkady wrote:
> > I will update the proposal for IBTA based on this feedback and all 
> > other feedback posted.
> > I will still separate private data usage proposal and port mapping 
> > one.
> 
> Again, I think that these should be in the same proposal.  
> The CM REQ carries the IB transport layer address.  The goal 
> here is to map another transport layer address to the IB one. 
>  The source port is included in the private data.  By not 
> including the destination port, there's an assumption that 
> it's provided somewhere else in the CM REQ.  We should either 
> make this explicit, or put the destination port in the 
> private data as well.
> 

Under the general programming model for an IP-centric daemon,
the listener can assume that connection requests will be for
the TCP port that the listen was issued upon.

However, the daemon typically listens on *all* addresses that
the system supports. It is not uncommon for the application
to note which destination address was actually requested and
to vary the service provided based upon that. This is what makes
it possible for single machines to host vast numbers of web sites.

It is less common, but still requiring support, for the daemon
to differentiate service based upon the source address. It is
more common to simply refuse service based upon the source 
address, which can be handled by the CM or firewall itself
rather than by the application, but there are exceptions.
Some web-sites have intranet versus internet verions. Some
file servers control access lists based upon source address.
It is actually quite effective when combined with network
authentication of source addresses.