In message <20110724183343.GY22405@xxxxxx>, Willy Tarreau writes: > On Sun, Jul 24, 2011 at 08:25:05PM +0200, I=F1aki Baz Castillo wrote: > > 2011/7/24 Willy Tarreau <w@xxxxxx>: > > >> > Making an additional DNS request and a connection come with a cost. > > >> > > >> http://tools.ietf.org/html/draft-ibc-websocket-dns-srv-02#section-5.2 > > > > > > You still need the DNS request : the client does an A/AAAA request for > > > the HTTP host, then if you ask it to use an SRV record for the WS conne= > ction, > > > it must perform that request too, even if it's to conclude that it can = > reuse > > > the idle connection. > > = > > > Ok, but I don't consider a xtra DNS query to be so hard. > > I had to perform sites analysis for a customer a few months ago. Many > web pages nowadays have between 100 and 200 objects to fetch, spread > over up to 25-30 host names. If you take even only 100ms for each of > them, you're at 3 additional seconds to display the page. Granted those > requests are not WS and only HTTP, but as I said, SRV for WS won't work > before it works with HTTP, at least due to proxies. No. It takes 100ms extra. Only if you serialise all the lookups does it take 3 extra seconds. If you are not doing the DNS lookups in parallel today you are already doing a dis-service to your customers. Adding a SRV lookup should add 0ms if it isn't there as you should be making A, AAAA and SRV lookups in parallel. Non-existance is as cachable as existance is. > But those 3 extra seconds will always be considered a good reason not > to make SRV mandatory for HTTP. The web is degrading very quickly due > to poor practices, and we should be careful not to suggest to make it > even worse. > > Regards, > Willy > > _______________________________________________ > Ietf mailing list > Ietf@xxxxxxxx > https://www.ietf.org/mailman/listinfo/ietf -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@xxxxxxx _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf