Re: [rtcweb] Dual stack RTCweb

Bernard Aboba <bernard_aboba@hotmail.com> Mon, 15 August 2011 09:23 UTC

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Subject: Re: [rtcweb] Dual stack RTCweb
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ICE is designed to handle dual stack operation.  It can even deal with NAT64, if correctly implemented. 

Since ICE tests pairs before using them, there is no "happy eyeballs" problem with ICE (e.g. if an IPv6 route doesn't exist, the test will fail). 

That said, IPv6/IPv4 priorities may need some adjustment in some situations (e.g. if the IPv6 routes are more circuitous than IPv4, it may not make sense to prefer IPv6 over IPv4).  

That is one of the reasons that I am not enthusiastic about treating the SDP JSON blob as "opaque" (e.g. not subject to adjustment). Doing so without the ability
to adjust IPv6/IPv4 priorities will result in poor performance in dual stack operation in some cases.