Dear Eastlake, You are absoutly right, but if considering about the end-to-end SIP call, this lookup time will make some influence with the calling establish time, as Michael mentioned, "The performance of lookups scales linearly (worst case) with the number of zone cuts ". So that's the reason why I want to know the real-data about the lookup time in current DNS system. :-) It may be a problem for real-time applications. Yours Felix. ----- Original Message ----- From: "Donald Eastlake 3rd" <dee3@xxxxxxxxxxxxxxxxxx> To: "Felix, Zhang" <lionking@xxxxxxxxxx> Cc: <ietf@xxxxxxxx> Sent: Thursday, March 11, 2004 6:30 AM Subject: Re: Question for the DNS system. > Deep (many label) DNS names work fine. But for some reason the DNS > system has long suffered from lust for the root where people scramble > for DNS names with the minimum number of labels. This, coupled with the > marketing efforts of some TLD owners resulting in very wide zones that > require huge servers, are harder to deploy DNSSEC on, etc. It's wide > zones that are a potential problem, not deep names. > > (There is some logic in going for short domain names interms of total > number of characters or ease of memorization. But based on that, > 1.2.3.example would be superior to onetwothree.example. Yet people lust > after the second...) > > Thanks, > Donald > ====================================================================== > Donald E. Eastlake 3rd dee3@xxxxxxxxxxxxxxxxxx > 155 Beaver Street +1-508-634-2066(h) +1-508-786-7554(w) > Milford, MA 01757 USA Donald.Eastlake@xxxxxxxxxxxx > > On Wed, 10 Mar 2004, Felix, Zhang wrote: > > > Date: Wed, 10 Mar 2004 13:02:36 +0800 > > From: "Felix, Zhang" <lionking@xxxxxxxxxx> > > To: ietf@xxxxxxxx > > Subject: Question for the DNS system. > > > > Dear all, > > > > According to the current Internet, in most cases, the > > allocation/design of DNS is not more than 3-5 levels, such as > > us.ibm.com etc. What's my problems is that "when using lots of DNS > > names with more than 5 levels, Is there some problem with the whole > > DNS system, such as some performance problem for searching, > > dificulities to operate etc.....? Could the current DNS tree > > architecure bear large traffic or not?" Is there somebody can provide > > some real data about the current Internet, such as average search time > > etc. > > > > As everyone knows, IPv6 is coming .......... :-) > > > > Best regards. > > > > Yours Felix. Zhang.