Re: [hybi] Last Call: <draft-ietf-hybi-thewebsocketprotocol-10.txt> (The WebSocket protocol) to Proposed Standard

Dave Cridland <> Thu, 21 July 2011 22:21 UTC

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Date: Thu, 21 Jul 2011 23:21:07 +0100
From: Dave Cridland <>
To: Bruce Atherton <>, Server-Initiated HTTP <>, IETF-Discussion <>, David Endicott <>
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Subject: Re: [hybi] Last Call: <draft-ietf-hybi-thewebsocketprotocol-10.txt> (The WebSocket protocol) to Proposed Standard
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On Thu Jul 21 23:15:59 2011, Bruce Atherton wrote:
> So if you have no control over the DNS, it is not a problem. The  
> host will be resolved exactly the same way as it is now, using a  
> hosts file or A record or whatever. The only change is that the  
> client is required to try to use the more advanced mechanism if it  
> is available.

> I admit that I find it a little troubling to use MUST for the  
> client to follow this procedure as there is a burden on  
> implementers to understand how to code this since it isn't done by  
> default in the standard libraries the way that ordinary name  
> resolution is. Making it the recognized best practice with a SHOULD  
> would be preferable all else being equal.
SRV lookup is pretty commonplace now in libraries. XMPP and SIP  
clients have no difficulty finding this functionality in a wide  
variety of environments. For the web, where there are substantially  
fewer web browsers than there are XMPP clients, I don't think this  
would pose any kind of problem.

> It can be argued that not using a MUST may well open up  
> interoperability problems because some Websockets clients contact  
> the wrong host. However, keep in mind that in the older SIP RFC2543  
> it provided two resolution mechanisms. It specified that clients  
> SHOULD look up address records, but MAY use the DNS SRV mechanism.  
> SIP survived that without too much of a hassle. And specifying that  
> Websockets clients SHOULD use DNS SRV, but MAY use address records  
> alone looks like an improvement.
SIP survived because it was very small. I don't see WS making a  
transition, in the same way that repeated attempts have failed to  
move HTTP to SRV.

Dave Cridland - -
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