As per Relevance of the word implementation, we have this rfc below:
Network Working Group Jon
Request for Comments: 921
October 1984
Updates: RFC 897, RFC 881
Domain Name System Implementation Schedule -
Status of this
This memo is a policy statement on the implementation of the
Style Naming System in the Internet. This memo is an update
RFC-881, and RFC-897. This is an official policy statement of
IAB and the DARPA. Distribution of this memo is unlimited
The intent of this memo is to detail the schedule for
implementation for the Domain Style Naming System. The
of how this system works is to be found in the references
The Current
There are three aspects to the domain style naming system, (1)
names themselves, (2) the method of translating names to addresses
and (3) the relationship between the Internet and the rest of
world
The names are being changed from simple names, or globally
strings, to structured names, where each component name is
only with respect to the superior component name
Simple
Until recently, hosts in the DARPA research and DDN
communities were assigned names in a flat or global name
of character strings. There are some limits on these names
They must start with a letter, end with a letter or digit
have only letters or digits or hyphen as interior characters
Case is not significant
For example: USC-
Hierarchical
Because of the growth of the Internet, structured names (
domain style names) have been introduced. Each element of
structured name will be a character string (with the
constraints that previously applied to the simple names).
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RFC 921 October 1984
Domain Implementation Schedule -
elements (or components) of the structured names are
with periods, and the elements are written from the
specific on the left to the most general on the right
For example: USC-ISIF.
The Initial and Temporary
The introduction of these hierarchical names has been
limited. Every current name in this new system has the
"old-simple-name.ARPA". That is, the all the hosts are in
domain called "ARPA". This is a temporary situation.
current intention is for the ARPA domain to cease to exist
This means that all hosts will change their names as the
style names come into full use
Name to Address
Every host in the Internet is expected to have a way
translating the name of any other host into its Internet address
By and large, the name to address translation is done by
up the information in a table of all hosts
The maintenance of this table is centralized at the
Information Center (NIC). Each host is expected to obtain
current copy of the table on a timely basis. This table is
"HOSTS.TXT" [8] and is normally accessed via the
Server [9].
Interface to the
A great deal of mail moves between the Internet and
"systems" that somehow transport mail among computers. This
currently done by hiding some sort of "other-system"
information in the local-part of the mail address and using
mail-relay host in the host-part of the mailbox
For example
OBERST%EDUCOM.MAILNET@MIT-MULTICS.
EDMISTON.CIC@CSNET-RELAY.
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Domain Implementation Schedule -
The Future
Hierarchical
The use of the hierarchical names will be greatly
according to the rules established in the "Domain Requirements
memo (RFC-920) [5].
For example: F.ISI.USC.
There are several levels of development for use of the
style names
First, there is the current simple substitution of the
style names for the old style host names. At this stage
domain style names directly translate to host addresses (using
NIC tables) and all domain style names have two components.
mail system uses addresses of the form "local-part@host",
host is a domain style host name
For example: USC-ISIF.ARPA and Postel@USC-ISIF.
Here we expect that "USC-ISIF.ARPA" is the name of an
host and that we can send mail for "Postel" to the SMTP port
that host. It may be that some backward host can still fake
by ignoring the ".ARPA" and looking up an address
"USC-ISIF" in some old style file
Second, there is an extension to more name components and more
level domains. The mail system still uses addresses of the
"local-part@host", where host is a domain style host name
For example: F.ISI.USC.EDU and Postel@F.ISI.USC.
Here we expect that "F.ISI.USC.EDU" is the name of an
host and that we can send mail for "Postel" to the SMTP port
that host. It is likely that the NIC will enter these
domain style names in the centrally maintained table (i.e.,
HOSTS.TXT) during the transition period. It is unlikely that
backward host can hack this at all
Third, there is an extension to domain style names that
represent only organizations or administrative entities.
a host that acts for such entities may require a level
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Domain Implementation Schedule -
indirection in the search. The mail system may
"local-part@domain-name", where the "domain-name" identifies
host (as before) or an organization
For example: USC-ISI.EDU and Postel@USC-ISI.
Here we don't count on "USC-ISI. EDU" being the name of
Internet host. When we want to send mail to "Postel" we
the domain name server about sending mail to "USC-ISI.EDU".
The server will tell us the name (and address) of a
Internet host that handles mail on this organizations behalf
for example, "F.ISI.USC.EDU = 10.2.0.52". We then send
for "Postel@USC-ISI.EDU" to the SMTP port on F.ISI.USC.EDU
Name to Address
Every host in the Internet will be expected to have a way
translating the name of any other host into its Internet address
By and large, the name to address translation will be done
interacting with a lookup server. There will be a number
servers that each hold a portion of the name to
information
The maintenance of the translation data base will be
and distributed
The design and implementation details for this service are
in RFC-882 [2] and RFC-883 [3].
Interface to the
Mail will continue to move between the Internet and
"systems". This may be done by designating some sort
"other-system" representative organization in the domain
data bases that can indirect mail to a mail-relay host
For example
Oberst@EDUCOM.
When we want to send mail to "Oberst" we ask the domain
server about sending mail to "EDUCOM.MAILNET". The server
tell us the name (and address) of a real Internet host
handles mail on this organizations behalf, for example
"MIT-MULTICS.ARPA = 10.0.0.6". We then send mail
"Oberst@EDUCOM.MAILNET" to the SMTP port on MIT-MULTICS.ARPA
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For example
Edmiston@CIC.
When we want to send mail to "Edmiston" we ask the domain
server about sending mail to "CIC.CSNET". The server will
us the name (and address) of a real Internet host that
mail on this organizations behalf, for example
"CSNET-RELAY.ARPA = 10.4.0.5". We then send mail
"Edmiston@CIC.CSNET" to the SMTP port on CSNET-RELAY.ARPA
The Transition
Actually, the situation is a bit more complicated, of course.
are already using domain style names under the constraint that
domain style name is exactly their old style name with the
".ARPA" appended. The first transition step is to ensure that
hosts do this, and then to eliminate the use of old style
altogether
Please note carefully that two types of changes are being made
One is a change in the support mechanism for translating a
name to an internet address
that is from using local copies of a full centrally
table to dynamically accessing a distributed set of
each posesing a portion of a data base maintained in
distributed fashion
The other is a change in the host names themselves
from a flat global space of unstructured strings to
hierarchical structure of names
There are two steps to the transition plan
First, change from old names to domain style names
Second, change from using central tables to using name servers
There are two communities that are taking slightly different
in this transition. The DARPA research community is making the
transition. The DDN operational community is making the change
naming on the same schedule, but is not requiring hosts in the
operational community make the change to using servers at the
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Domain Implementation Schedule -
time (they can if they want to). The DDN PMO will establish
schedule for that change at a later time. The NIC will maintain
central table of all DDN operational hosts
Interface to the
The interchange of mail with "other-systems" will have to
pretty much as it has (except that RELAY-HOST is RELAY-HOST.ARPA
until organization names can be used. Then
organizations can be designated for each "other-system" in
domain server data bases that will then specify a mail-relay host
All Hosts Change
The impact of introducing the domain style names is that all
change their names at least once. Hosts that move to new domains
subdomains may change their names several times
Hosts have an official (or primary) name and possibly
nicknames. When mail is sent from a host, the official name is
in the mail header address fields
Suppose, that in the old days before domains were thought of, a
changed its name. What is the impact on users of changing the
of a host
Mail that was sent before the name was changed can not be
using mail program commands that automatically fill in the
address. While it may be possible to use special tricks to fix
the "From" or the "To" users addresses, the "Cc" addresses
very difficult to correct
Suppose one host changed its name from FOO to BAR. Mail
was sent from FRED@FOO to JOE@ABC can not be answered
the change of name is known to the user or the mail program
ABC and the host name BAR substituted for FOO. Mail that
sent to JOE@ABC from SAM@DEF with a cc to FRED@FOO can not
answered easily
Any mailing lists that have mailboxes with the host that
names will now have incorrect entries
The point is that while the host that changed names may be able
use special tricks for a while to fix things up for the users, it
difficult for other hosts to do this
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A general trick is to make the old name a nickname for the host
some period of time
The introduction of domain style names means that all hosts
their names essentially at the same time
To lessen the havoc, there will be a period of time when both the
and the new names are allowed. That is, the old names will
nicknames for a while
Primary
Currently, host have an official or primary names and may
several nicknames. For example
Primary Name
USC-ISIF.ARPA USC-ISIF
ADA-VAX.ARPA ADA-VAX ISI-VAXB AJPO
The data base is such than given any of the names for a host one
find the address, and given the address one can find the
name
In the new domain style name system this property must be maintained
That is, given the Internet address of a host one must be able
find the primary name of that host. This calls for
management of the distributed database by those in charge of
domains and zones
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Domain Implementation Schedule -
The Revised Time
There are three major phases to the implementation of the
names system: (1) putting the machinery in place (servers
resolvers), (2) getting the data base installed, (3) changing
user programs (mailers, etc.).
The machinery is now (at last) well along, there is a server
TOPS-20, and two different servers for Unix. The data base
contains the ARPA domain and is initialized for the other
level domains. Little has been done to change user programs
use the new procedures
Service Design and Specification: The design and
for the protocol and data base were published (RFC-882, RFC-883).
Domain Requirements Specification: The requirements
establishing a new domain are published as an RFC (RFC-920).
Domain Style Names in Table: Hosts are using their domain
names as their official and primary names. The standard table
host names contains domain style names as the official and
name
Servers for ARPA Domain: Several domain name servers are
operation to supply host name to internet address translations
one of these servers is at the NIC
15 Dec 84 Domain
A master table of top level domain names and their
servers is established at the NIC. Probably this information
be added to the HOSTS.TXT file as a new entry type
15 Jan 85 Begin New Domain
New domains may register according to the procedures
restrictions described in RFC-920 [5].
15 Feb 85 Major Machinery
The principal servers are up and running, there are
programmed and tested for the most popular systems (Unix 4.2bsd
TOPS-20).
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15 May 85 Significant Use of Resolvers and
Programs (e.g., Mailers, Telnet, FTP) begin regular use of the
mechanisms (resolvers and servers). This may be done by
the programs to act as resolvers themselves and call on
directly, or to provide system calls that include the
function to replace old system calls that accessed the host table
15 Jul 85 Implementation of the Domain Naming System
The goal is to complete the switch over to the domain style
and the use of the servers by this date. All programs
translate host name to Internet addresses should now
procedures based on the use of the domain style names system
resolvers and servers and the distributed data base
15 Sep 85 Decommission Host
At this point the master host table maintained by the NIC need
longer be complete for the DARPA research community. A full
of the DDN operational hosts will be maintained by the NIC
15 Oct 85 DDN Plan for Domains Name
The DDN PMO may establish a plan for the future support of name
address translations in the DDN community
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Domain Implementation Schedule -
Appendix : The Old Time
Here we present the time table from the previous schedule (RFC-897)
with some comments on what was and was not accomplished
-- Nov 83 Plan and
At this point the overall plan for the implementation of
style names and name servers, and a schedule of events
published (RFC-881). Also the design and specification for
protocol and data base were published (RFC-882, RFC-883).
schedule did not work.>
-- Nov 83 Initial Domain Style Host Name
At this point a version of the host table which includes
domain style names is made available (DHOSTS.TXT).
schedule.>
-- Feb 84 Domain Requirements
At this point the requirements for establishing a new domain
published as an RFC
list, but no RFC was published until Oct84 [5].>
14 Mar 84 Begin using Domain Style
At this point all hosts should start using their domain
names as their official and primary names. The standard table
host names contains domain style names as the official and
name (DHOSTS.TXT becomes HOSTS.TXT).
schedule.>
04 Apr 84 Server for ARPA
At this point several domain name servers are in operation
supply host name to internet address translations, one of
servers is at the NIC
schedule, but by Sep84.>
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Domain Implementation Schedule -
04 Apr 84 Domain
At this point a master table of top level domain names and
associated servers is established at the NIC
02 May 84 Stop using old style
At this point the use of old style names must be completely
out
OHOSTS.TXT file.>
02 May 84 Certain New
At this point a few new domains may be established, in
the DDN domain
according to the new rules (see [5]).>
06 Jun 84 General & Multilevel
At this point additional new domains may be established, if
meet the requirements. Domain style names may have more than
segments
18 Jul 84 Organizational
Domain style names may identify organizations. Finding an
for a host may involve a level of indirection
05 Sep 84 Decommission Host
At this point the master host table maintained by the NIC need
longer be complete for the DARPA research community. A full
of the DDN operational hosts will be maintained by the NIC
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03 Oct 84 DDN Plan for Domains Name
At this point the DDN PMO will establish a plan for the
support of name to address translations in the DDN community
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Domain Implementation Schedule -
[1] Postel, J., "The Domain Names Plan and Schedule", RFC-881,
Information Sciences Institute, November 1983.
[2] Mockapetris, P., "Domain Names - Concepts and Facilities",
RFC-882, USC Information Sciences Institute, November 1983.
[3] Mockapetris, P., "Domain Names - Implementation
Specification", RFC-883, USC Information Sciences Institute
November 1983.
[4] Postel, J., "Domain Name System Implementation Schedule",
RFC-897, USC Information Sciences Institute, February 1984.
[5] Postel, J., and J. Reynolds, "Domain Requirements", RFC-920,
Information Sciences Institute, October 1984.
[6] Mockapetris, P., "The Domain Name System", Proceedings of
IFIP 6.5 Working Conference on Computer Message Services
Nottingham, England, May 1984. Also as ISI/RS-84-133,
June 1984.
[7] Mockapetris, P., J. Postel, and P. Kirton, "Name Server
for Distributed Systems", Proceedings of the
International Conference on Computer Communication, Sidney
Australia, October 1984. Also as ISI/RS-84-132, June 1984.
[8] Feinler, E., K. Harrenstien, Z. Su, and V. White, "DoD
Host Table Specification", RFC-810, Network Information Center
SRI International, March 1982.
[9] Harrenstien, K., V. White, and E. Feinler, "Hostnames Server",
RFC-811, Network Information Center, SRI International
March 1982.
Postel [Page 13]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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