Re: [MMUSIC] (Rough) Consensus Call - No FQDN support in ice-sip-sdp

[Roman Shpount <[e-mail]>]

On Tue, May 21, 2019 at 10:36 AM Christer Holmberg <
[e-mail]> wrote:

> Roman suggested text yesterday, and with my change suggestion it would
> look like:
>
>
>
> <connection-address>: :: is taken from RFC 4566 <<RFC4566>>. It is the IP
> address of the candidate, allowing for IPv4 addresses, IPv6 addresses,
>
> and fully qualified domain names (FQDNs).  When parsing this field, an
> agent can differentiate  an IPv4 address and an IPv6 address by presence
>
> of a colon in its value - the presence of a colon indicates IPv6.  *An
> agent processing remote candidates MUST ignore candidate lines that include
> *
>
> *candidates with FQDN or IP address versions that are not supported or
> recognized.  The procedures for handling FQDN candidates, and for agents *
>
> *to indicate support of such procedures, need to be specified in an
> extension specification.* If candidate with FQDN <connection-address> is
> the
>
> default destination/candidate, the "c=" address type MUST be set the IP
> address family for the FQDN DNS resolution result and the "c=" connection
>
> address MUST be set to FQDN. Differences in the "c=" line address family
> and type with FQDN resolution result MUST not cause ICE support
> verification failure.
>
> The text in bold covers the
> must-ignore-FQDN-and-will-be-specified-in-an-extension-specification part.
>
>
>
> Now, I have some difficulties to understand the last sentence. It seems to
> indicate that some FQDN DNS resolution is performed, and that the IP family
> is set according to the result. But, what if the result contains both IPv6
> and IPv4?
>
>
>
> Also, I assume that the procedures in the last sentence is related to the
> provider of the candidates. If so, it needs to be more clear.
>
>
>
The last portion definitely needs to be clarified. I am trying to provide
procedures for Verifying ICE support when FQDN is used in default ICE
candidate. In this case, agent which receives such offer must verify ICE
support without the need for FQDN resolution. My suggestion is to use
literal FQDN value from default candidate in c= line and do not validate
address family and type (do not detect m= line mismatch if address family
and type are not what is result of some unspecified resolution procedure).
_____________
Roman Shpount