Re: [Sipping] Question on draft-ietf-sipping-v6-transition-07

["Elwell, John" <[e-mail]>]

 

> -----Original Message-----
> From: Vijay K. Gurbani [mailto:[e-mail]] 
> Sent: 28 January 2010 19:43
> To: Elwell, John
> Cc: [e-mail]
> Subject: Re: [Sipping] Question on draft-ietf-sipping-v6-transition-07
> 
> Elwell, John wrote:
> > " 1.  In some cases, especially those dealing with third party call 
> > control (see Section 4.2 of [12]), there arises a need to 
> specify the
> > IPv6 equivalent of the IPv4 unspecified address (0.0.0.0) in the SDP
> > offer.  For this, IPv6 implementations MUST use a domain name within
> > the .invalid DNS top-level domain instead of using the IPv6
> > unspecified address (i.e., ::)."
> > 
> > Can somebody recall the reason for this? Both "0.0.0.0" and 
> "::" mean
> > "unspecified" in their respective IP versions.
> 
> John: Right; so I went back to my email archives to when
> Gonzalo and I had a conversation about this (on April 27, 2006.)
> 
> We favored an .invalid over :: because the Application folks had
> indicated this to be their preference in the past.  For IPv4,
> 0.0.0.0 was supported for backwards compatibility, but it appears
> that a move to IPv6 can be handled cleanly with using only .invalid
> instead of having two alternative solutions.
[JRE] Thanks, Vijay. However, RFC 3264 specifies only 0.0.0.0 for the case where the address is not known in the initial offer (I am not talking about the deprecated use for hold). It does not specify .invalid, so I don't know what you mean by two alternative solutions.

John

> 
> Thanks,
> 
> - vijay
> -- 
> Vijay K. Gurbani, Bell Laboratories, Alcatel-Lucent
> 1960 Lucent Lane, Rm. 9C-533, Naperville, Illinois 60566 (USA)
> Email: vkg@{alcatel-lucent.com,bell-labs.com,acm.org}
> Web:   http://ect.bell-labs.com/who/vkg/
>