With resolution 2009-02-03-04, the ICANN Board asked the Root Server System Advisory Committee (RSSAC), the Security and Stability Advisory Committee (SSAC), and the ICANN staff to study the potential impact on the root zone stability that might arise when IPv6 address records, IDN top level names, other new TLDs, and new records to support DNS security are added to the root zone. The Board has expressed interest in hearing of the impact of the distinct changes, but also their aggregate effect on root zone operations. The Board also asks that the study address the technical and operational concerns regarding expanding the DNS root zone that have been expressed on this topic. A study team has been assembled and is composed of the following: Jaap Akkerhuis Lyman Chapin - Chair Patrik FC$ltstrC6m Glenn Kowack Lars-Johan Liman Bill Manning The goal of the study is to construct a complete, definitive, and authoritative model of the root server system (including all of its provisioning and query components) that shows how the different parts are related, and how changing the value of a variable in one part would affect each of the other parts. It will be as quantitative a model as possible given the relatively short time frame of the study. The idea is not to try to identify all of the bad things that might happen if (for example) the number of TLDs in the root zone were to increase by several orders of magnitude during the same time period in which new RRs were added for DNSSEC (b^@^\how many entries in the root zone is too many?b^@^]), but to construct a model that demonstrates what the effects would be throughout the system of changing the value of one or more variables either individually or in combination (e.g., the rate at which new TLDs are added to the root, or the frequency of key rollover events in a signed root). This model will provide an unbiased factual and analyticalb^@^Trather than anecdotalb^@^Tbasis for recognizing and evaluating concerns about root server system security and stability as the root grows. As a tool for policy makers, it will show the expected impact on the root server system of policy decisions that would change various root zone parameters. The study team has a couple of methods for collecting inputs and encourages interested parties to provide the study team with their concerns. There is a public mailing list: root-scaling(a)icann.org and There is a comment site: +http://www.icann.org/en/public-comment/public-comment-200907.html#root-scali... If there are others whom you think would be interested in this work or have opinions/ideas, please pass along this note. Thanks