rfc1480.txt
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| US | +-------+ | +----------------------------------+ | | | | | +-----+ +-----+ +-----+ +-----+ +-----+ | FED | | DNI | | TX | | SD | | CA | +-----+ +-----+ +-----+ +-----+ +-----+ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++Cooper & Postel [Page 6] RFC 1480 The US Domain June 1993 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ SCHOOL AND LIBRARY VIEW +-----+ | CA | +-----+ | +------------------------------------------------+ | | | | | +-----+ +-----+ +-----+ +-------------+ +-----+ | K12 | | CC | | TEC | | LOS ANGELES | | LIB | +-----+ +-----+ +-----+ +-------------+ +-----+ / \ /|\ /|\ /|\ /|\ +--------+ +---+ +---+ +--------+ +----------+ +------+ |sch dist| |PVT| |SJC| |WM TRADE| |pvt school| |MALIBU| +--------+ +---+ +---+ +--------+ +----------+ +------+ /|\ /|\ +--------+ +--------+ |sch name| |sch name| +--------+ +--------+ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ VIEW OF STATE, REGIONAL, and GENERAL AGENCIES +-----+ | CA | +-----+ | +-------------------------+ | | | +-------+ +--------+ +-----+ | STATE | |DISTRICT| | GEN | +-------+ +--------+ +-----+ /|\ /|\ /|\ +--------+ +------+ +---------+ |CALTRANS| |SCAQMD| |domain pk| ---------+ +------+ +---------+ | +--------+ |TCEW100E| +--------+ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++Cooper & Postel [Page 7] RFC 1480 The US Domain June 1993 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ VIEW OF LOCALITY +-----+ | CA | +-----+ | +-----------------------------------+ | | +-------------------------+ +----------------+ | LOS ANGELES | | SANTA MONICA | +-------------------------+ +----------------+ / | | /|\ | /|\ / | | | | | +---+ +--+ +--+ +-----------+ +--+ +---+ |bus| |CI| |CO| | pvt school| |CI| |bus| +---+ +--+ +--+ +-----------+ +--+ +---+ /\ | | / \ | +------------+ / \ | |HARBOR GUARD| / \ | +------------+ +-----+ +-----+ +-----+ +----+ |FIRE | |ADMIN| |PARKS| |FIRE| +-----+ +-----+ +-----+ +----+ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2.1 State Codes The state codes are the two letter US Postal abbreviations. For example: "CA" California. 2.2 Locality Names Within the state name space there are "locality" names, some may be cities, some may be counties, some may be local names, but not incorporated entities. Registered names under "locality" could be like: <hostname>.CI.<locality>.<state>.US ==> city gov't agency <hostname>.CO.<locality>.<state>.US, ==> county gov't agency <hostname>.<locality>.<state>.US ==> businesses In the cases where the locality name is a county, there is a branch under the locality name, called "county" or "CO", that is used by the county government. Businesses are registered directly under the locality name.Cooper & Postel [Page 8] RFC 1480 The US Domain June 1993 Under the city locality name space there is a "city" or "CI" branch for city government agencies. As usual, businesses and private schools may register directly under the city name. In the case where there is both a county and a city with the same locality name there is no problem, since the names will be unique with the "CO" or "CI" keyword. In our area the county has a fire department and the city has its own fire department. They could have names like: Fire-Dept.CI.Los-Angeles.CA.US Fire-Dept.CO.Los-Angeles.CA.US Cities may be named (designated) by their full name (spelled out with hyphens replacing spaces (e.g., Los-Angeles or Fort-Collins), or by a city code. The first choice is the full city name. In some cases it may be appropriate to use the well-known city abbreviation known throughout a locality. However, it is very desirable that all users in the same city use the same designator for the city. That is, any particular locality should have just one DNS name. Some users would like names associated with a greater metropolitan area or region like the "Bay Area" or "Tri-Cities". One problem with this is that these names are not necessarily unique within a state. The best thing to do in this case is to use the larger metropolitan city in your hostname. Cities and counties are used. Should all the names be obvious? Trying to do this is desirable and also impossible. There will come a point when the obviously right name for an organization is already taken. As the system grows this will happen with increasing frequency. While ease of use to the end user is desirable, a higher priority must be placed on having a system that operates. This means that the manageability of the system must have high consideration. The reason the DNS was created was to subdivide the problem of maintaining a list of hosts in the Internet into manageable portions. The happy result is that this subdivision makes name uniqueness easier and promotes logical grouping. What is a "logical grouping" though, always depends on the viewer. Many levels of delegation are needed to keep the zone files manageable. Many sections of the name space are needed to allow unique names to be easily added.Cooper & Postel [Page 9] RFC 1480 The US Domain June 1993 Way back in the olden days, when the Internet was invented, some thought that an 8-bit network number would be more than enough to number all the networks that would ever exist. Today, there are over 10,000 networks operating in the Internet, and arguments are made about the doubling time being 2 years versus 4 years. One concern is that things will continue to grow dramatically, and this will require more subdivision of the domain name management. Maybe the plan for the US Domain is overkill on growth planning, but there has never been overplanning for growth yet. When things are bigger, names have to be longer. There is an argument that with only 8-character names, and in each position allow a-z, 0-9, and -, you get 37**8 = 3,512,479,453,921 or 3.5 trillion possible names. It is a great argument, but how many of us want names like "xs4gp-7q". It is like license plate numbers, sure some people get the name they want on a vanity plate, but a lot more people who want something specific on a vanity plate can't get it because someone else got it first. Structure and longer names also let more people get their "obviously right" name. 2.3 Schools K12 schools are connecting to the Internet and registering in the Internet DNS. A decision has been made by the IANA (after consultation with the new InterNIC Internet Registry and the Federal Networking Council (FNC)) to direct these school registrations to the US domain using the naming structure described here. There is a need for competent, experienced, volunteers to come forward to act as third and perhaps fourth level registries and to operate delegated portions of the DNS. There are two reasons for registering schools in the US Domain. (1) uniqueness of names, and (2) management of the database. 1. Name Uniqueness: There are many "Washington" high schools, only one can be "Washington.EDU" (actually none can be, since that name is used by a University. There will be many name conflicts if all schools attempt to register directly under EDU. In addition, in some districts, the same school name is used at different levels, for example, Washington Elementary School and Washington High School. We suggest that when necessary, the keywords "Elementary", "Middle", and "High" be used to distinguish these schools. These keywords would only be usedCooper & Postel [Page 10] RFC 1480 The US Domain June 1993 when they are needed, if the school's name is unique without such keywords, don't use them. 2. Database Management: One goal of the DNS is to divide up the management of the name database in to small pieces. Each piece (or "zone" in DNS terminology) could be managed by a distinct administrator. Adding all the high schools to the EDU domain will make the already large zone file for EDU even larger, possibly to the point of being unmanageable. For both these reasons it is necessary to introduce structure into names. Structure provides a basis for making common names unique in context, and for dividing the management responsibility. The US Domain has a framework established and has registered many schools already in this structured scheme. The general form is: <school>.<district>.K12.<state>.US. For example: Hamilton.LA-Unified.K12.CA.US Public schools are usually organized by districts which can be larger or smaller than a city or county. For example, the Portland school district in Oregon, is in three or four counties. Each of those counties also has non-Portland districts. It makes sense to name schools within districts. However districts often have the same name as a city or county so there has to be a way to distinguish a public school district name from some other type of locality name. The keyword "K12" is used for this. For example, typical K12 school names currently used are: IVY.PRS.K12.NJ.US DMHS.JCPS.K12.KY.US OHS.EUNION.K12.CA.US BOHS.BREA.K12.CA.US These names are generally longer than the old alternative of shorter names in the EDU domain, but that would not have lasted long without a significant number of schools finding that their "obviously correct" name has already been used by some other school.Cooper & Postel [Page 11] RFC 1480 The US Domain June 1993 When there are many things to name some of the names will be long. In some cases there may be appropriate abbreviations that can be used. For example Hamilton High School in Los Angeles could be: Hami.Hi.LA.K12.CA.US If a school has a number of PCs, then each PC should have a name. Suppose they are named "alpha", "beta", ... then if they belong to a school named "Lincoln.High.Lakewood.K12.CA.US" their names would be: alpha.Lincoln.High.Lakewood.K12.CA.US. beta.Lincoln.High.Lakewood.K12.CA.US⌨️ 快捷键说明
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