DNS-based RR mechanisms
Abdullah Rayhan <[email protected]> Wed, 10 Apr 2002 14:40:27 -0400 (EDT)
| Newsgroups | gmane.ietf.cdi |
|---|---|
| Message-ID | <Pine.GSO.4.33.0204101326160.22972-100000@cardinal> |
I find the discussing in the request-routing known mechanisms not very accurate when describing the possible approaches in which RR is implemented to start with. Also the title is supposed to reflect the content but it goes as "known" while the content presents possible cases. The discussion is interesting in itself but does not reference how things are really implemented, For example, sec 2.3 talks about how multiple specialized RR-DNS servers are to be used to distribute complex decisions from single server. The motivation behind this, I believe, is load balancing but this is poorly said and primitive in application. RR-DNS server will perform the same functionality as a DNS server. The difference is being authorative over what domain which is the CN or the content provider if you like. Another difference might be is how load balancing is achieved through more elaborate mechanisms than being presented. Load balancing between surrogates or multiple RR-DNS servers? That needs to be said clearly as well. In the same section it goes on to mix NS and CNAME records without any refs. As a matter of fact, this is not allowed in DNS. You need an A record to go with NS record; DNS experts correct me if I am wrong. The example mentioned does make sense but the discussion should be around load balancing and not RR mechanisms. The discussion goes on in sec 2.3.1. The NS redirection is part of the DNS hierarchy and not RR. What this means is that the CN zone file can be a subdomain of the original provider domain. For example, news.soandso.com, news is resolved by CN RR-DNS server via DNS redirection rather than soandso.com. The same argument applies to section 2.3.2 when requests are redirect via DNS to the CN domain but CNAME are not returned, NS and A records are. The discussion of Anycast is theoretical and I doubt if there is any DNS implementation that makes use of it. It is not even documented and we dont know how it works. It is better if is dropped from the draft. I hope that the authors would take these comments into consideration to clarify the presentation of Section 2. Comments for other sections will follow at a latter time so not to have long emails. my 2 cents. regards Abdallah Rayhan