Re: [dccp] Re: dccp_service in sockaddr_dccp{}

[Yoshifumi Nishida <nishida at csl.sony.co.jp>]

From: Arnaldo Carvalho de Melo <acme at conectiva.com.br>
Subject: Re: [dccp] Re: dccp_service in sockaddr_dccp{}
Date: Fri, 9 Sep 2005 14:31:33 -0300
Message-ID: <20050909173132.GV19109 at mandriva.com>

 > Em Fri, Sep 09, 2005 at 08:34:17AM -0700, Eddie Kohler escreveu:
 > > Hi,
 >  
 > > Although we can't be sure yet, we do imagine that almost every DCCP
 > > connection will specify a service code.  If the server specifies a
 > > service code, and the client does not, then the client's connection
 > > attempt will be rejected.
 > 
 > This is as well my understanding of the draft authors intention (pun) for
 > the service code in the REQUEST packet, hence the field in sockaddr_dccp,
 > think of it as something like scope_id (RFC 2553) in sockaddr_in6 if you
 > will, different reasons, but one could use the same arguments of those
 > against having service in sockaddr_{in_}_dccp to say that scope_id should
 > really have been implemented as a setsockopt and not be present in
 > sockaddr_in6 :-)
 
Hmm, A good point. :-)  But, I still prefer using a setsockopt..

I think that I understand the draft authors's intention that service code
can be used as an extention to port number. 
My little concern (which may not be correct) is that one of the key deployment 
issues of DCCP is smooth transition from UDP. If we can modify UDP applications 
(especially client side) with minimum costs (ex: just replace SOCK_DGRAM 
to SOCK_DCCP or SOCK_CONN_DGRAM), the benefit might be not small. 
Besides that, we don't have to increase the number of sockaddr struct as 
some folks pointed out, so the implementation would be simpler. 

Thanks,
--
Yoshifumi Nishida
nishida at csl.sony.co.jp