Re: [tram] IPv4 and IPv6 allocations

[Simon Perreault <[e-mail]>]

Le 2014-02-19 12:07, Mallinath Bareddy a écrit :
> Pal, I am not sure how a "pre call" setup will help in this case, as we
> will not know ahead of time about the peer address type.

You don't need to know the peer's address type (with ICE, does such a
concept exist anyway?). To properly support dual stack, you need to
unconditionally create IPv4 and IPv6 relayed candidates.

>From RFC 6157:

   When following the ICE procedures, in addition to local addresses,
   user agents may need to obtain addresses from relays; for example, an
   IPv6 user agent would obtain an IPv4 address from a relay.  The relay
   would forward the traffic received on this IPv4 address to the user
   agent using IPv6.  Such user agents MAY use any mechanism to obtain
   addresses in relays, but, following the recommendations in ICE, it is
   RECOMMENDED that user agents support STUN relay usage [6] [8] for
   this purpose.

   IPv4/IPv6 user agents SHOULD gather both IPv4 and IPv6 addresses
   using the ICE procedures to generate all their offers.  This way,
   both IPv4-only and IPv6-only answerers will be able to generate a
   mutually acceptable answer that establishes a session (having used
   ICE to gather both IPv4 and IPv6 addresses in the offer reduces the
   session establishment time because all answerers will find the offer
   valid.)

Simon
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