Re: [MMUSIC] ICE candidate address selection update draft
Jonathan Lennox <jonathan@vidyo.com> Sat, 04 August 2012 08:09 UTC
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From: Jonathan Lennox <jonathan@vidyo.com>
To: Ari Keranen <ari.keranen@nomadiclab.com>
Date: Sat, 04 Aug 2012 04:09:55 -0400
Thread-Topic: [MMUSIC] ICE candidate address selection update draft
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Cc: "mmusic@ietf.org" <mmusic@ietf.org>
Subject: Re: [MMUSIC] ICE candidate address selection update draft
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On Aug 3, 2012, at 12:27 PM, Ari Keranen wrote: > On 8/3/12 12:03 PM, Simon Perreault wrote: >> Le 2012-08-03 11:58, Ari Keranen a écrit : >>> Yes, you should not get ULAs from the STUN server as long as the STUN >>> server is properly located (on the Internet, outside of the organization >>> perimeter and on the other side of any NATs). And the peer reflexive >>> candidate (which would be global address) can be then matched with >>> peer's globals. >> >> But reflexive candidates don't always work. I know I said NPTv6, but we >> shouldn't prevent ICE from working behind evil NAT66. And an ICE client >> may not be able to reach a STUN server so you can't rely on having >> reflexive candidates. So you should still try to match ULAs with globals. > > OK, this is quite a corner case, but I'm afraid you're right. However, > if you have a global address on the interface (i.e., you're not behind > an evil NAT66), matching ULAs with globals doesn't make sense. So, I'd > suggest text along the lines of: > > o Candidate addresses from Unique Local Addresses (ULAs) SHOULD NOT > be combined with any other candidates except other ULA candidates. > However, if an interface does not have any global addresses, the > ULA SHOULD be used. > > (changed MUST to SHOULD and added the second sentence) Remembering that the two ICE endpoints need to agree on which candidates match, does this mean that I need to know whether my peer's ULA and my peer's global address are on its same interface? As a more general comment, one of the virtues of ICE is that by matching everything to everything, you're guaranteed to find a route, if one's possible, no matter how stupid or evil your network architects have been. I don't think we want to break that property for IPv6, except in cases where it's absolutely impossible (e.g., due to host behavior) for a route to work. If there's any circumstance where a network admin being "helpful" could make a connectivity check on a candidate pair succeed, I think we want to try that pair. Even if the IETF says that the network MUST NOT be configured so as to make such a route work. That said, if there were a well-defined algorithm to prioritize sensible checks over absurd ones, that'd be fine. I'm afraid I don't understand v6 addressing well enough to make concrete text suggestions based on this principle, though. -- Jonathan Lennox jonathan@vidyo.com
- [MMUSIC] ICE candidate address selection update d… Ari Keranen
- Re: [MMUSIC] ICE candidate address selection upda… Simon Perreault
- Re: [MMUSIC] ICE candidate address selection upda… Ari Keranen
- Re: [MMUSIC] ICE candidate address selection upda… Simon Perreault
- Re: [MMUSIC] ICE candidate address selection upda… Pal Martinsen (palmarti)
- Re: [MMUSIC] ICE candidate address selection upda… Ari Keranen
- Re: [MMUSIC] ICE candidate address selection upda… Ari Keranen
- Re: [MMUSIC] ICE candidate address selection upda… Simon Perreault
- Re: [MMUSIC] ICE candidate address selection upda… Ari Keranen
- Re: [MMUSIC] ICE candidate address selection upda… Jonathan Lennox
- Re: [MMUSIC] ICE candidate address selection upda… Pal Martinsen (palmarti)
- Re: [MMUSIC] ICE candidate address selection upda… Ari Keranen
- Re: [MMUSIC] ICE candidate address selection upda… Jonathan Lennox
- Re: [MMUSIC] ICE candidate address selection upda… Dan Wing
- Re: [MMUSIC] ICE candidate address selection upda… Jonathan Lennox
- Re: [MMUSIC] ICE candidate address selection upda… Pal Martinsen (palmarti)
- Re: [MMUSIC] ICE candidate address selection upda… Tom Taylor
- Re: [MMUSIC] ICE candidate address selection upda… Dan Wing
- Re: [MMUSIC] ICE candidate address selection upda… Pal Martinsen (palmarti)
- Re: [MMUSIC] ICE candidate address selection upda… Dan Wing
- Re: [MMUSIC] ICE candidate address selection upda… Dan Wing
- Re: [MMUSIC] ICE candidate address selection upda… Jonathan Lennox
- Re: [MMUSIC] ICE candidate address selection upda… Pal Martinsen (palmarti)