RE: [dccp] SOCK_DCCP

[vladimir.moltchanov at nokia.com]

> -----Original Message-----
> From: dccp-bounces at ietf.org [mailto:dccp-bounces at ietf.org]On Behalf Of
> ext Ian McDonald
> Sent: 08 August, 2005 04:48
> To: Arnaldo Carvalho de Melo
> Cc: Yoshifumi Nishida; dccp at ietf.org
> Subject: Re: [dccp] SOCK_DCCP
> 
> 
> 
> Arnaldo Carvalho de Melo wrote:
> > Em Fri, Aug 05, 2005 at 08:35:44PM +0900, Yoshifumi Nishida 
> escreveu:
> > 
> >>Hello,
> >>I have one minor question.
> >>Some or most? DCCP implementations use SOCK_DCCP for dccp sockets.
> >>However, I found that some implementations already have another 
> >>socket type which has similar concept: SOCK_CONN_DGRAM, although 
> >>it has been used for ATM only and it is very rare to be seen.
> >>Do we need two similar socket types?
> > 
> > 
> > Further info about SOCK_CONN_DGRAM:
> > 
> > 
> http://publib.boulder.ibm.com/infocenter/pseries/index.jsp?top
ic=/com.ibm.aix.doc/aixprggd/progcomc/skt_types.htm
> 
> SOCK_CONN_DGRAM:
> 
> Provides connection-oriented datagram service.  This type of socket
> supports the bidirectional flow of data, which is sequenced and
> unduplicated, but is not reliable. Because this is a connection-oriented

This is the reason we would need to be different I would suspect. DCCP
is sequenced, unduplicated and not reliable BUT it is two half
connections if data needs to flow both ways which is different to this.

Regards,

Ian
=============================================================================

Hello.

I've got two questions concerning this discussion. 

1) Does it realy makes a difference, what is the exact socket type used for identifying DCCP? It is implementation specific anyhow and as long as it translates into the correct bits in the frame it should be fine. 

2) Following chapter 3.2 in draft document, separation on half-connection is purelly logical. Even on the protocol level they overlap with DataAck packets. Socket API's are much higher and I see no need to expose the logical separation to the application. Or, am I missing the point here?

B.R.
Vladimir.