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

[Dean Willis <[e-mail]>]

On Jul 22, 2011, at 4:51 AM, Dave Cridland wrote:
> 
> 
> 1) There are no SRV records.
> 
> 2) Therefore browsers do not support them.
> 
> 3) Therefore you'd need to allow for A-lookup as fallback for the forseeable future.
> 
> 4) Therefore there's no incentive for browsers to support SRV.


That's pretty much where we were when we grafted SRV onto SIP eleven and a half years ago, updating earlier SIP drafts (which lacked SRV support). There was no incentive for SRV support in SIP user agents at the time, either. 

See:

http://tools.ietf.org/html/draft-ietf-sip-srv-00


The first SIP RFC 2543 used SRV, but didn't work very well. RFC 2782 cleaned up the SRV process somewhat, but we required further documentation for SIP to make use of it effectively.  It eventually worked itself out as RFC 3263, which also involved NAPTR records and a slew of other DNS kludges. But barring the limitations of DNS (some people still want requester-variant answers), it works pretty well now.

But yes, there's more to effective target resolution than just saying "Use SRV records". Especially if you have multiple protocol choices, proxies,  aliases, and TLS in the mix.

--
Dean Willis