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<h1 id="header_h1">OID Repository</h1><br><br><br><br>
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<h1 id="header_h1">OID Repository</h1>
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<span class="page_title">Frequently Asked Questions</span>
<table>
<tr>
<td rowspan="2"><a href="/helper"><img src="images/helper.png" height="55" width="55" border="0" alt="OID helper" align="middle"></a></td>
<td>Please check the Q&A below or ask your question directly to <a href="/helper">OID helper</a>.</td>
</tr>
<tr><td>To search for a particular OID, please use the <a href="basic-search.htm">search feature</a>.</td></tr>
</table>
<br><span class="page_subtitle">Questions</span>
<ol>
<li><a href="#1">What are the standards that define OIDs and the OID tree?</a></li>
<li><a href="#2">Which kind of objects can be referenced by OIDs?</a></li>
<li><a href="#3">Where can I learn more about OIDs and their registration?</a></li>
<li><a href="#4">How to add information to the OID repository?</a></li>
<li><a href="#modify">How to modify the description of an OID?</a></li>
<li><a href="#6">How to delete an OID (or move it elsewhere in the OID tree)?</a></li>
<li><a href="#7">How does the OID repository provided on this website compare with Harald Alvestrand's repository?</a></li>
<li><a href="#8">How to reference an OID description from this repository?</a></li>
<li><a href="#9">How many OIDs are currently described in this repository?</a></li>
<li><a href="#10">How to get an OID assigned?</a></li>
<li><a href="#national-RA">What decision needs be taken if a country wants a national Registration Authority for OIDs?</a></li>
<li><a href="#12">Are there guidelines or standards regarding subsequent arcs of a country arc?</a></li>
<li><a href="#13">What is the Internet OID?</a></li>
<li><a href="#14">Where does the dot notation for OIDs come from?</a></li>
<li><a href="#15">Why are top-level arcs restricted to three arcs numbered <tt>0</tt> to <tt>2</tt>, and why are arcs beneath top-level arcs <tt>0</tt> and <tt>1</tt> restricted to fourty arcs numbered <tt>0</tt> to <tt>39</tt>?</a></li>
<li><a href="#16">What do we call a registration tree (or object identifier tree)?</a></li>
<li><a href="#17">What is the ASN.1 notation of an OID?</a></li>
<li><a href="#management">How is the entire registration tree managed?</a></li>
<li><a href="#features">Which features are offered by this repository?</a></li>
<li><a href="#syntax-rules">What are the syntax rules to enter information about OIDs through the web interface?</a></li>
<li><a href="#oid-info">Which information is necessary to apply for an OID?</a></li>
<li><a href="#example">Is there a particular OID that can be used for documenting examples of object identifiers?</a></li>
<li><a href="#registration-authorities">What is the difference between the first and current Registration Authorities that appear in the description of some OIDs? What is their duty?</a></li>
<li><a href="#mib">What constraints are imposed to OIDs used in SNMP MIBs (Management Information Bases)?</a></li>
<li><a href="#lookup">Is there a way to look up an OID in the OID repository from my web browser?</a></li>
<li><a href="#leaf">What is a leaf OID? What is a frozen OID?</a></li>
<li><a href="#orphan">What is an orphan OID?</a></li>
<li><a href="#iri">What is an OID-IRI (Internationalized Resource Identifier)?</a></li>
<li><a href="#29">What are the duties of a Registration Authority?</a></li>
<li><a href="#size-limitations">Are there size limitations for OID encoding?</a></li>
<li><a href="#31">Are there binary encoders/decoders for OIDs?</a></li>
<li><a href="#cookies">Does this web site use cookies?</a></li>
<li><a href="#privacy">How does this web site protect users' privacy?</a></li>
<li><a href="#guidelines">What are the guidelines to adequately describe an OID in this OID repository?</a></li>
</ol><br></td>
</tr>
</table>
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<div id="table_answers_in_faq">
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<span class="page_subtitle">Answers</span>
<ol>
<li>
<div class="question">
What are the standards that define OIDs and the OID tree?<a name="1"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
They are defined in the <a href="standards.htm">Recommendation ITU-T X.660 series | ISO/IEC 9834 multi-part standard</a>, and in particular in <a href="https://itu.int/ITU-T/X.660">Rec.
ITU-T X.660 | ISO/IEC 9834-1</a>.<br>Binary encodings of OIDs are specified in <a href="https://itu.int/ITU-T/X.690">Rec.
ITU-T X.690 | ISO/IEC 8825-1</a> for the Binary (BER) and Distinguished
(DER) Encoding rules, in <a href="https://itu.int/ITU-T/X.691">Rec.
ITU-T X.691 | ISO/IEC 8825-2</a> for the Packed Encoding rules (PER).
An XML encoding of OIDs is specified in <a href="https://itu.int/ITU-T/X.693">Rec.
ITU-T X.693 | ISO/IEC 8825-3</a>. (See also <a href="#31">question
31</a> about binary encoders/decoders for OIDs.)<br><br></div>
</li>
<li>
<div class="question">
Which kind of objects can be referenced by OIDs?<a name="2"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
Objects that can typically be identified by an object identifier are
(non exhaustively):
<ul>
<li>
an <a href="/cgi-bin/display?tree=0.0">ITU-T Recommendation</a>,
an <a href="/cgi-bin/display?tree=1.0&see=all">ISO International
Standard</a>;
</li>
<li>
a <a href="country_oids.htm">country</a>, a company, a
project;
</li>
<li>
a certificate policy specified according to <a href="https://itu.int/ITU-T/X.500">Rec.
ITU-T X.500</a>;
</li>
<li>an encryption algorithm (for example <a href="/get/1.3.14.3.2.26">SHA-1</a>);</li>
<li>
<a href="/get/2.27">identification schemes</a> for tag-based
applications (see <a href="https://itu.int/ITU-T/X.668">Recommendation
ITU-T X.668 | ISO/IEC 9834-9</a>);
</li>
<li>
e-health data (for example, data from the <a href="/get/2.16.840.1.113883">HL7
Consortium</a>);
</li>
<li>
Common Alerting Protocol (<a href="/get/0.0.24.1303">CAP</a>)
emergency messages;
</li>
<li>
an attribute of an ITU-T X.500- or LDAP-based directory to make
up a <code>DistinguishedName</code>;
</li>
<li>
an ASN.1 module (for example, for the <a href="/get/2.41.0.1">BioAPI
Interworking Protocol</a>), an ASN.1 type (or abstract syntax);
</li>
<li>
a <a href="/cgi-bin/display?tree=2.1(1,2,3,4,5">set of ASN.1
encoding rules</a>;
</li>
<li>a MIB for SNMP network management;</li>
<li>
a managed object class, one of its attributes, a notification
or even other templates used in the area of network management
and the GDMO standard (see <a href="https://www.itu.int/rec/T-REC-X.722/en">Recommendation
ITU-T X.722 | ISO/IEC 10165-4</a>);
</li>
<li>
an information object (see <a href="https://www.itu.int/rec/T-REC-X.681/en">Recommendation
ITU-T X.681 | ISO/IEC 8824-2</a>);
</li>
<li>the type of some part of an ITU-T X.400 electronic message body;</li>
<li>a file format;</li>
<li>etc.</li>
</ul>
Examples of OID uses are also listed on the <a href="https://www.itu.int/oth/T0B04000048/en">ITU-T flyer</a>.<br><br></div>
</li>
<li>
<div class="question">
Where can I learn more about OIDs and their registration?<a name="3"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
Apart from the <a href="standards.htm">official standards</a> (see
<a href="faq.htm#1">question 1</a>), OIDs are explained in:
<ul>
<li>
the <a href="https://www.itu.int/oth/T0B04000048/en">OID flyer</a>
from ITU-T Study Group 17;
</li>
<li>
the quick <a href="doc/introduction%20to%20object%20identifiers%20(OIDs).pdf">introduction
to OIDs</a>;
</li>
<li>the ITU handbook "<a href="https://www.itu.int/pub/T-HDB-LNG.4-2010">Object identifiers (OIDs) and their registration authorities</a>";</li>
<li>
section 10.8 of Olivier Dubuisson's <a href="https://www.oss.com/asn1/resources/books-whitepapers-pubs/asn1-books.html#dubuisson">book
"ASN.1 - Communication between heterogeneous systems"</a>;
</li>
<li>
John Larmouth's <a href="https://www.oss.com/asn1/resources/books-whitepapers-pubs/asn1-books.html#larmouth">book
"ASN.1 complete"</a>;
</li>
<li>
John Larmouth's tutorial "Registration authorities
for OID components" [<a href="doc/OID-tutorial.htm">html</a>]
[<a href="doc/OID-tutorial.ppt">ppt</a>];
</li>
<li>
the presentation "<a href="doc/MoU%20presentation%20on%20OIDs.pdf">Identifying
objects: The ASN.1 approach</a>";
</li>
<li>see also <a href="#16">question 16</a>.<br><br></li>
</ul>
</div>
</li>
<li>
<div class="question">
How to add information to the OID repository?<a name="4"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
This OID repository is not an official Registration Authority,
so any OID <a href="#guidelines">described</a> in this OID repository has to be officially allocated
by the Registration Authority of its parent OID. There are at least
4 ways of adding a new OID description to the repository: <br>a. Enter the OID value in the box under "Add a description for the
following OID to the database" on the <a href="index.htm">main page</a> and
click on the "Create" button; a new page will then be displayed with
some boxes to fill (see <a href="#guidelines">guidelines for describing an OID</a>). You can also enter the OID in the following box:<br><form method="post" action="/cgi-bin/manage" enctype="multipart/form-data">
<input type="hidden" name="a" value="create">     <strong>{</strong>
<input type="text" name="oid" size="30" value=""><strong>}</strong>
<input type="submit" name="submit" value="Create"></form>
b. Go to the parent OID of the OID that you want to add (i.e. the
OID at the immediate upper level in the OID tree) and click on the
"Create a child OID" link on the top right-hand side of the page;
a new page will then be displayed with some boxes to fill (see <a href="#guidelines">guidelines for describing an OID</a>).<br>c. Go to an OID at the same level as the OID that you want to add
(a.k.a. sibling OID) and click on the "Create a sibling OID" link
on the top right-hand side of the page; a new page will then be displayed
with some boxes to fill (see <a href="#guidelines">guidelines for describing an OID</a>).<br>d. If you have a lot of <a href="#guidelines">OID descriptions</a> to add, it is more convenient
to describe them in an XML document that conforms to our <a href="oid.xsd">XML
Schema for OIDs</a> and <a href="submit.htm">submit</a> this document
through the web interface. <br><em>
Note: In all 4 cases, the person (if any) you mention as <a href="#registration-authorities">registrant</a>
for the OID, and the person (if known) who is the <a href="#registration-authorities">registrant</a>
for the parent OID are automatically informed by email and can make
comments on your submission. The description of an OID will not be
visible until it is validated by the webmaster who is also automatically
informed by email.
</em><br><strong><br></strong>
</div>
</li>
<li>
<div class="question">
<a name="modify"></a>How to modify the description of an OID?<a name="5"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
If you want to update an OID that is described in the OID repository,
please click on the "Modify this OID" hyperlink at the top-right
of the web page that describes the OID or enter the OID in the following
box:
<form method="post" action="/cgi-bin/manage" enctype="multipart/form-data">
<input type="hidden" name="a" value="modify">     <strong>{</strong>
<input type="text" name="oid" size="30" value=""><strong>}</strong>
<input type="submit" name="submit" value="Suggest a modification"></form>
<em>
Note: Your <a href="#guidelines">proposed modifications</a> will have to be validated by
the <a href="#registration-authorities">registrant</a> of the OID
being modified (if known), the <a href="#registration-authorities">registrant</a>
of the parent OID (if known) and the OID repository administrator
(who will all be automatically informed by e-mail) before they get
published.
</em><br>If the First or Current Registration Authorities requested privacy
protection, their postal address, email address and phone number are
not displayed (but you can receive them by email). In that case, please
use the "Comments" box at the bottom of the "Suggest
a modification" web page to describe the changes.<br>If an OID is misplaced in the OID tree and should be moved elsewhere
in the tree, please use the "Comments" box at the bottom
of the "Suggest a modification" web page to be displayed
to explain where (and why) the OID should be moved.<br>You can also mention in the "Comments" box that an OID is
a <a href="#leaf">leaf</a> in the OID tree (i.e. child OIDs cannot
be allocated) or is <a href="#leaf">frozen</a> (i.e. no more child
OIDs can be allocated).<br><br></div>
</li>
<li>
<div class="question">
How to delete an OID (or move it elsewhere in the OID tree)?<a name="6"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
According to <a href="https://www.itu.int/rec/T-REC-X.660/en">Recommendation
ITU-T X.660 | ISO 9834-1</a>, an OID shall not be deleted once it
has been allocated by a Registration Authority. However if an OID
that is described in this OID repository has never been officially
allocated by the Registration Authority for the parent OID (or is
misplaced in the OID tree), you can request its deletion from the
OID repository (or move elsewhere) by clicking on the "Modify
this OID" hyperlink at the top-right of the web page that describes
the OID or by entering the OID in the following box:
<form method="post" action="/cgi-bin/manage" enctype="multipart/form-data">
<input type="hidden" name="a" value="modify">     <strong>{</strong>
<input type="text" name="oid" size="30" value=""><strong>}</strong>
<input type="submit" name="submit" value="Suggest deletion"></form>
Use the "Comments" box at the bottom of the page to be displayed
to explain why the OID should be deleted (or moved elsewhere). Your
suggestion will have to be validated by the registrant of the OID
(if known), the registrant of the parent OID (if known) and the OID
repository administrator (who will all be automatically informed by
e-mail) before it get published.<br><br></div>
</li>
<li>
<div class="question">
How does the OID repository provided on this website compare with Harald Alvestrand's repository?<a name="7"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
We get Harald's agreement to dump his repository and merge the data
into our repository. This was done in June 2003 and our OID repository
now encompasses <a href="https://www.alvestrand.no/objectid/">Harald's
registry</a>.<br><br></div>
</li>
<li>
<div class="question">
How to reference an OID description in this repository?<a name="8"></a><a name="get"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The shortest and easiest means is to append the OID (whether it is
in <a href="#17">ASN.1 notation</a>, <a href="#14">dot notation</a>,
<a href="#iri">IRI notation</a> or <a href="https://datatracker.ietf.org/doc/html/rfc3061">URN
notation</a>) to the <a href="/get/">http://oid-info.com/get/</a>
URL, <em>e.g.</em>:
<ul>
<li> <a href="/get/2.999">http://oid-info.com/get/2.999</a> (recommended);</li>
<li>
<a href="/get/%7Bjoint-iso-itu-t%20example(999)%7D">http://oid-info.com/get/{joint
iso-itu-t example(999)}</a> (ASN.1 notation);
</li>
<li>
<a href="/get//Joint-ISO-ITU-T/Example">http://oid-info.com/get//Joint-ISO-ITU-T/Example</a>
or <a href="/get//2/999">http://oid-info.com/get//2/999</a> (OID-IRI
notation; with a '/' at the beginning of the OID notation, hence
two '/'s after 'get');
</li>
<li>
<a href="/get//Example">http://oid-info.com/get//Example</a>
(OID-IRI notation using a long arc; with a '/' at the beginning
of the OID notation, hence two '/'s after 'get');
</li>
<li>
<a href="/get/urn:oid:2.999">http://oid-info.com/get/urn:oid:2.999</a>
(URN notation).<br><br></li>
</ul>
</div>
</li>
<li>
<div class="question">
How many OIDs are currently described in this repository?<a name="9"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
There are close to 2 billion OID descriptions stored in this repository
(see <a href="/cgi-bin/display?a=count_nodes">exact number</a>). The
repository is well alive and updated as often as necessary; <a href="/cgi-bin/display?a=count_nodes">statistics</a>
are available about the number of OIDs added to the repository (or
updated) over the past 12 months. A (non-exhaustive) list of standards
(and other documents that define OIDs) which have been captured in
our repository is <a href="captured-standards.htm">available</a>.<br><br></div>
</li>
<li>
<div class="question">
How to get an OID assigned?<a name="10"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The original intention of the <a href="https://www.itu.int/rec/T-REC-X.660/en">Recommendation
ITU-T X.660 | ISO/IEC 9834</a> series was that anyone should be able
to get an OID if they needed one. There are registration authorities
from which it is easy and quite cheap (sometimes even free!) to have
an OID assigned, such as:
<ul>
<li>
If you only need an OID for an example in a document, use <code><a href="/get/2.999">{joint-iso-itu-t(2)
example(999)}</a></code> as explained in <a href="#example">question
22</a>.
</li>
<li>
<a href="country_oids.htm#agreements">Several countries</a>
assign OIDs (usually after paying a fee decided by the national
registration authority) under their country arc <a href="/get/2.16"><code>{joint-iso-itu-t(2)
country(16)}</code></a> and/or <a href="/get/1.2"><code>{iso(1)
member-body(2)}</code></a> (see <a href="country_codes.htm">correspondence
table between country codes and OIDs</a>). (Note: If you are representing
a country and want to nominate a registration authority for your
country arc under <a href="/get/1.2"><code>{iso(1) member-body(2)}</code></a>
or <a href="/get/2.16"><code>{joint-iso-itu-t(2) country(16)}</code></a>,
please see <a href="#11">question 11</a> below.)
</li>
<li>
<a href="https://pen.iana.org/pen/PenApplication.page">IANA</a>
(Internet Assigned Numbers Authority) hands out OIDs for free under
<a href="/get/1.3.6.1.4.1"><code>{iso(1) identified-organization(3)
dod(6) internet(1) private(4) enterprise(1)}</code></a>; these OIDs
are used a lot (but not only) to identify Management Information
Bases (MIBs) for network management (SNMP).
</li>
<li>
<a href="https://oidplus.viathinksoft.com/oidplus/?goto=oidplus:com.viathinksoft.freeoid">ViaThinkSoft</a>
freely assigns an OID to private persons and developers of freeware,
shareware or open-source software under <a href="/get/1.3.6.1.4.1.37476.9000"><code>{iso(1)
identified-organization(3) dod(6) internet(1) private(4) enterprise(1)
37476 freesub(9000)}</code></a>.
</li>
<li>
<a href="https://webapp.etsi.org/ASN1ObjectTree/ASN1.asp">ETSI</a>
(European Telecommunication Standards Institute) hands out OIDs
under <code><a href="/get/0.4.0.127.0">{itu-t(0) identified-organization(4)
etsi(0) reserved(127) etsi-identified-organization(0)}</a></code>
even for non-ETSI-members.
</li>
<li>
Network operators can have an OID assigned by ITU-T under <code><a href="/get/0.3">{itu-t(0)
network-operator(3)}</a></code>; telecom operators can have an OID
assigned by their national PTT administration under <code><a href="/get/0.2">{itu-t(0)
administration(2)}</a></code>.
</li>
<li>
For the health sector, see <a href="https://wiki.hl7.org/index.php?title=HL7_OID_Registry_Frequently_Asked_Questions#Somebody_told_me_I_need_an_OID_for_my_Organization._What_do_I_do.3F">HL7's
FAQ</a>.
</li>
<li>
Dave Harvey (UK) <a href="https://www.medicalconnections.co.uk/Free_UID">sub-delegate
ranges of his own OID</a> to anyone who uses a <a href="https://www.dicomstandard.org">DICOM</a>
toolkit (communication in medicine).
</li>
<li>
You can <a href="https://learn.microsoft.com/en-us/windows/win32/ad/obtaining-an-object-identifier-from-microsoft?redirectedfrom=MSDN">obtain
an OID from Microsoft</a> to extend the Active Directory schema.
</li>
<li>
You can <a href="https://www.itu.int/ITU-T/asn1/uuid.html#UUID%20Generation%20&%20Registration">generate
a UUID</a> (or use a UUID that you already hold) and append it as
a subsequent arc of <a href="/get/2.25"><code>{joint-iso-itu-t(2)
uuid(25)}</code></a> (without registering it, in particular in this
OID repository, because it is guaranteed to be globally unique with
a high probability) according to <a href="https://www.itu.int/rec/T-REC-X.667/en">Recommendation
ITU-T X.667 | ISO/IEC 9834-8</a> (but see <a href="#size-limitations">question
30 about size limitations of OID encodings</a>).
</li>
</ul>
<em>Important note</em>: OIDs have to be requested from those registrations authorities because this OID repository
is
<em>not</em> a registration authority.
<br><br></div>
</li>
<li>
<div class="question">
What decision needs be taken if a country wants a national Registration Authority for OIDs?<a name="11"></a><a name="national-RA"></a><a name="country"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
Country arcs are the subsequent arcs of <a href="/get/1.2"><code>{iso(1)
member-body(2)}</code></a> and <a href="/get/2.16"><code>{joint-iso-itu-t(2)
country(16)}</code></a>. The values assigned to country arcs are the
<a href="https://unstats.un.org/unsd/methods/m49/m49alpha.htm">numerical
codes</a> (without leading zeros) assigned by the United Nations Statistics
Division together with the corresponding and the <a href="https://www.iso.org/obp/ui/#search">ISO
3166-1-alpha-2 code</a>. <a href="/get/1.2"><code>{iso(1) member-body(2)}</code></a>
was deprecated in favour of <a href="/get/2.16"><code>{joint-iso-itu-t(2)
country(16)}</code></a>, thus countries which have never been operating
a national Registration Authority (RA) for OIDs are encouraged to
request an arc under <a href="/get/2.16"><code>{joint-iso-itu-t(2)
country(16)}</code></a>. Countries are discouraged to request an arc
under both <a href="/get/1.2"><code>{iso(1) member-body(2)}</code></a>
and <a href="/get/2.16"><code>{joint-iso-itu-t(2) country(16)}</code></a>.<br><a href="https://www.itu.int/rec/T-REC-X.660/en">Recommendation ITU-T
X.660 | ISO/IEC 9834-1</a>, clause A.4.5, specifies that the <a href="https://www.iso.org/members.html">ISO
National Body</a> of the country and the <a href="https://www.itu.int/hub/membership/our-members/">administration
representing the country in the ITU</a> shall agree together (as a
national decision) on the organization that will be the RA for their
country arc. In the case of a country arc under <a href="/get/1.2"><code>{iso(1)
member-body(2)}</code></a> the decision is only taken by the <a href="https://www.iso.org/members.html">ISO
National Body</a> of the country. For more detailed information, see
"<a href="country_oids.htm">Operation of a country Registration
Authority</a>".<br>One way to know if your country is already operating an RA for OIDs
is too check the <a href="country_oids.htm#agreements">known
country RAs</a>.<br><br></div>
</li>
<li>
<div class="question">
Are there guidelines or standards regarding subsequent arcs of a country arc?<a name="12"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
Country arcs are the subsequent arcs of <a href="/get/1.2"><code>{iso(1)
member-body(2)}</code></a> and <a href="/get/2.16"><code>{joint-iso-itu-t(2)
country(16)}</code></a>.<br>The structure underneath a country arc is a national decision. The
basic standard is of course <a href="https://www.itu.int/rec/T-REC-X.660/en">Recommendation
ITU-T X.660 | ISO/IEC 9834-1</a>. It might be worth having a look
at <a href="https://www.itu.int/rec/T-REC-X.670/en">Recommendation
ITU-T X.670</a> "<em>
Procedures for registration agents operating
on behalf of organizations to register organization names subordinate
to country names
</em>".<br>There is no guidelines besides the fact that any registration authority
needs to keep records according to the aforementioned standards. A
good idea is probably to look at <a href="country_oids.htm#agreements">how
other countries have organized subsequent arcs beneath their country
arc</a> as well as reading the ITU handbook on "<a href="https://www.itu.int/pub/T-HDB-LNG.4-2010"><em>
Object
identifiers (OIDs) and their registration authorities
</em></a>". You can also take benefit from the
<a href="#guidelines">guidelines to adequately describe an OID in this OID repository</a>.<br><br></div>
</li>
<li>
<div class="question">
What is the Internet OID?<a name="13"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The Internet OID is <code><a href="/get/1.3.6.1">{iso(1) identified-organization(3)
dod(6) internet(1)}</a></code> or equivalently in dot notation <code><a href="/get/1.3.6.1">1.3.6.1</a></code>.<br><br></div>
</li>
<li>
<div class="question">
Where does the dot notation for OIDs come from?<a name="14"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
(<em>from Harald Alvestrand's <a href="https://www.alvestrand.no/objectid/index.html">website</a></em>)<br>The dot notation is an IETF invention. The ASN.1 group thought it
better to have a notation using spaces and braces, with optional text
labels, so that <code>1.3.6.1</code> would become something like <code>{iso(1)
identified-organization(3) dod(6) internet(1)}</code> or <code>{1
3 6 1}</code> or variants thereof.<br>The IETF folks thought this was somewhat inconvenient, and decided
to use a space-free notation. This is, among other things, spelled
out in IETF <a href="https://datatracker.ietf.org/doc/html/rfc1778">RFC 1778,
section 2.15</a>, but was in use long before that time. IETF <a href="https://datatracker.ietf.org/doc/html/rfc2252">RFC
2252, section 4.1</a>, eliminates the "<code>ds.4.10</code>" form.<br><br></div>
</li>
<li>
<div class="question">
Why are top-level arcs restricted to three
arcs numbered <code>0</code> to <code>2</code>, and why are arcs beneath
top-level arcs <code>0</code> and <code>1</code> restricted to fourty
arcs numbered <code>0</code> to <code>39</code>?<a name="15"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
This enables optimized binary encodings in which all arcs beneath
top-level arcs <code>0</code> and <code>1</code>, and arcs <code>0</code>
to <code>47</code> beneath top-level arc <code>2</code> are encoded
on a single octet (see <a href="https://www.itu.int/rec/T-REC-X.690/en">Rec.
ITU-T X.690 | ISO/IEC 8825-1</a>, clause 8.19). Arcs greater to <code>47</code>
benath top-level arc <code>2</code> are hence encoded on more than
one octet.<br><br></div>
</li>
<li>
<div class="question">
What do we call a registration tree (or object identifier tree)?<a name="16"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
In an open and international world such as the one of telecommunications
and information technologies, you often need to be able to reference
an "object" (see <a href="#1">question 1</a>) in a unique and universal
way. The ASN.1 standard defines an object as being "<em>
a well-defined
piece of information, definition or specification which requires a
name in order to identify its use in an instance of communication
</em>".<br>In general, an object is a class of information (for example, a file
format), rather than an instance of such a class (for example, an
individual file). It is thus the class of information (defined by
some referenceable specification), rather than the piece of information
itself, that is assigned a place in the tree.<br>The naming structure that has been chosen is a tree structure that
allows to name objects in a local or international context, without
beeing limited either by the registration authority, nor by the number
of objects they can register.<br><br></div>
</li>
<li>
<div class="question">
What is the ASN.1 notation of an OID?<a name="17"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
Each OID arc is associated with a mandatory number (used for data
transfers) and an optional (but recommended) alphanumeric identifier
(for legibility).<br>An identifier begins with a lower-case letter (from '<code>a</code>'
to '<code>z</code>') and is followed by lower-case or upper-case letters
(from '<code>a</code>' to '<code>z</code>', or from '<code>A</code>'
to '<code>Z</code>'), digits (from '<code>0</code>' to '<code>9</code>')
or hyphens ('<code>-</code>'). See Rec. ITU-T X.680 | ISO/IEC 8824-1,
clause 32, for more details.<br>In <a href="name-forms.htm">some cases</a>, the identifier has been
standardized and can be used alone (without the associated number)
in the ASN.1 notation. The number can always be used alone. This web
site will issue an error message if you are trying to display an OID
using an invalid ASN.1 notation.<br>An OID is semantically an ordered list of OID components (number only,
or identifier followed by a number between parentheses, or identifier
alone in <a href="name-forms.htm">some cases</a>). Starting with the
root of the OID tree, each OID component identifies an arc in the
OID tree. The last OID component identifies an arc leading to a node
to which an object has been assigned. It is this object which is identified
by the OID.<br>Example: <a href="/get/2.5.4.49"><code>{joint-iso-itu-t ds(5) attributeType(4)
distinguishedName(49)}</code></a> where <a href="/get/2"><code>joint-iso-itu-t</code></a>
is a <a href="name-forms.htm">standardized identifier</a> which can
appear alone, <i>i.e.</i>, without its associated number.<br>(See also <a href="#14">question 14</a> for the dot notation and <a href="#iri">question
28</a> about the OID-IRI notation.) <br><br></div>
</li>
<li>
<div class="question">
How is the entire registration tree managed?<a name="18"></a><a name="management"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The management of the entire registration tree is accomplished by
a process of delegation of authority. In this process the registration
authority responsible for a given arc in the registration tree may
partition that naming-domain. In doing so, it may or may not delegate
the registration responsibility for the naming-domain formed by each
partition to a subordinate Registration Authority. The naming of a
partition does not necessarily imply authority to register objects
under that partition. This delegation of registration responsibility
can be applied repeatedly with a subordinate registration authority
partitioning further the naming domain for which it is responsible
and delegating responsibility for those partitions to registration
authorities subordinate to it.<br>The registration authority responsible for a given naming-domain must
assign a name to the partition of that naming-domain that a given
sub-authority will manage. The name assigned shall be globally unambiguous,
and shall be concatenated as a prefix to all names assigned by that
sub-authority. The repeated application of this process through a
hierarchy of registration agents ensures the generation of unambiguous
names.<br>An organization, a standard or an automated facility can be the registration
authority for more than one partition of a naming-domain (see also
<a href="#11">questions 11 and 12</a> for how country arcs are managed).<br><br></div>
</li>
<li>
<div class="question">
Which features are offered by this repository?<a name="19"></a><a name="features"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The <a href="display-example.htm">description page</a> for each OID
offers the following features:
<ul type="disc">
<li>
have a synthetic <a href="/cgi-bin/display?tree=">graphical
view</a> of the tree (click on the
<img src="images/mm.gif" width="19" height="18" alt="Folding the subtree">
and
<img src="images/pm.gif" width="19" height="18" alt="Unfolding the subtree">
icons to fold and unfold arcs);
</li>
<li>display the description of another OID (the "Go" button);</li>
<li>
use the "remote control" to display the description
of:
<ul>
<li>
the parent OID (i.e. the OID at the immediate upper level
in the OID tree),
</li>
<li>
the previous or next sibling OID (i.e. OID at the same
level in the OID tree),
</li>
<li>
the very first or very last sibling OID (i.e. OID with the
lowest or greatest number at the same level in the OID tree),
or
</li>
<li>
the first child OID (the OID with the lowest number at
the immediate lower level in the OID tree);
</li>
</ul>
</li>
<li>
submit a description of a child OID under the current OID (see
also <a href="#syntax-rules">question 20</a>): After putting down
some information (description of the OID, its registrant...),
the registrant of the OID (if known), the registrant of the parent
OID (if known) and the OID repository administrator will be automatically
asked by email to review and validate your submission. Note that
the description page of the newly created OID will only be available
after validation;
</li>
<li>
submit a description of a sibling OID, i.e. an OID at the same
level as the current OID (see also <a href="#syntax-rules">question
20</a>);
</li>
<li>
propose modifications of the description of the current OID:
these modifications will have to be validated by the registrant
of the OID (if known), the registrant of the parent OID (if known)
and the OID repository administrator (who will all be automatically
informed by e-mail) before they get published;
</li>
<li>
do a <a href="basic-search.htm">quick search</a> of the entire
OID repository by searching for a particular string in all attributes;
</li>
<li>
do an <a href="search.htm">advanced search</a> of the entire
OID repository by searching for a particular value for each description
attribute or even by using regular expressions.
</li>
</ul>
Other features are available from the <a href="index.htm">main page</a> of
the OID repository:
<ul>
<li>
display an <a href="/cgi-bin/display?a=random">OID description
randomly</a>;
</li>
<li>
display the <a href="/cgi-bin/display?a=count_nodes">number
of OIDs</a> in the repository as well as statistics about how
many OID descriptions were added or modified over the past 12
months;
</li>
<li>
add the description of a given OID (see also <a href="#syntax-rules">question
20</a>);
</li>
<li>
<a href="submit.htm">submit</a> many OIDs to the database by
describing them in an XML file.<br><br></li>
</ul>
</div>
</li>
<li>
<div class="question">
What are the syntax rules to enter information about OIDs through the web interface?<a name="20"></a><a name="syntax-rules"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
When adding information about an OID into the OID repository, non-ASCII
characters such as accentuated letters are allowed in most fields
("Description", "Information", registrant "First
name", "Last name" and "Address"). The software
will replace them by their equivalent <a href="https://www.w3.org/MarkUp/html-spec/html-spec_13.html#SEC106">HTML
code</a>.<br>The following HTML tags are allowed in the "Description",
"Information" and "Address" fields: <code><a></code>,
<code><br/></code>, <code><code></code>, <code><em></code>,
<code><img></code>, <code><li></code>, <code><ol></code>,
<code><strong></code>, <code><sub></code>, <code><sup></code>
and <code><ul></code>. Use of <code><br></code> or <code><br/></code>
is not mandatory to break lines because any newline character will
automatically be replaced with <code><br/></code> by the software.<br>The description should be as short as possible (usually, not more
than one line), limited to what is identified by the OID (hence no
need to use expressions like "OID for", "OID identifying", "Root OID
for", "Arc for", "This OID describes", etc.) and written in such a
way that is easily understandable by any user of the OID repository.<br><br></div>
</li>
<li>
<div class="question">
Which information is necessary to apply for an OID?<a name="21"></a><a name="oid-info"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
According to clause 8.2 f of <a href="https://www.itu.int/rec/T-REC-X.660/en">Recommendation
ITU-T X.660 | ISO/IEC 9834-1</a>, the registration record for an OID
shall include at least:<br>a) the <a href="#guidelines">definition</a> of the object (when the registration authority of
the parent OID performs a technical role, it checks that the objet
can be registered under the parent OID);<br>b) when applicable, the identifier (beginning with a lowercase letter)
assigned to the object (in addition to the unique number);<br>c) the name and contact information of the organization that proposed
the entry (usually it is the "<a href="#registration-authorities">First
registration authority</a>" for the requested OID);<br>d) the dates of submission/registration.<br><br></div>
</li>
<li>
<div class="question">
Is there a particular OID that can be used for documenting
examples of object identifiers?<a name="22"></a><a name="example"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
<a href="/get/2.999">{joint-iso-itu-t(2) example(999)}</a> (or <a href="/get/2.999">2.999</a>)
can be used by anyone, without any permission, for the purpose of
documenting examples of object identifiers (in the same way as "example.com"
is defined in <a href="https://datatracker.ietf.org/doc/html/rfc2606">IETF RFC
2606</a> as an example for web sites). <br><br></div>
</li>
<li>
<div class="question">
What is the difference between the first and current Registration Authorities
that appear in the description of some OIDs? What is their duty?<a name="23"></a><a name="registration-authorities"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
A <em>Registration Authority</em> (RA) is responsible for allocating
child arcs to the OID for which it manages. It ensures that an integer
is used once among the subsequent arcs (child OIDs). As much as possible,
it avoids the same identifier (beginning with a lowercase letter)
being used for multiple sub-arcs. It also keeps a record of information
(name of a contact person, postal address, telephone and fax numbers,
email address, etc.) about the RA for each child OID and delegates
its duty to each 'child' RA. Such information can be stored in the
OID repository but it is important to understand that an OID first
need to be <em>officially</em> allocated by an RA before it can be
described on this website which is not an official RA, but a <em>repository</em>
of information about existing OIDs.<br>The <em>first Registration Authority</em> of an OID is the very first
person or company to whom the OID was allocated by the RA of the superior
OID. According to <a href="https://www.itu.int/rec/T-REC-X.660/en">Recommendation
ITU-T X.660 | ISO/IEC 9834-1</a>, the first
RA can't be changed (if the responsibility is transfered to someone
else, the information is recorded in the "Current Registration
Authority" section, without changing the "First Registration
Authority" section).<br>By default, if the OID has recently been allocated, the Current RA
is the First RA. So, if you are <a href="#4">entering information
in the OID repository</a>, please fill only the "First Registration
Authority" section, and don't copy the same information in the
"Current Registration Authority" section).<br>When someone or an organization takes over the duty from the First
RA, the relevant information is indicated in the "Current Registration
Authority" section without changing the "First Registration
Authority" section.<br><br></div>
</li>
<li>
<div class="question">
What constraints are imposed to OIDs used in SNMP MIBs (Management Information Bases)?<a name="24"></a><a name="mib"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The constraints are gathered in sections 4.6.5, 4.6.6, and Appendix
D of IETF <a href="https://datatracker.ietf.org/doc/html/rfc4181">RFC 4181</a>
(updated by <a href="https://datatracker.ietf.org/doc/html/rfc4841">RFC 4841</a>)
which makes references to IETF <a href="https://datatracker.ietf.org/doc/html/rfc2578">RFC
2578</a>, sections 3.5, 3.6, 5.6, 7.10, and <a href="https://datatracker.ietf.org/doc/html/rfc3416">RFC
3416</a>, section 4.1.<br>
- According to IETF <a href="https://datatracker.ietf.org/doc/html/rfc2578">RFC 2578</a>, section 3.5, all OIDs are limited to 128 child OIDs and each OID has a maximum (integer) value of 2<sup>32</sup>-1 (<code>4294967295</code>).<br>
- The last arc of an OID assigned to any object (be it table, row, column, or scalar) must not be equal to 0.<br>- In some cases, a final arc 0 is used to translate between SNMPv1 and SNMPv2 notification parameters as explained in IETF <a href="https://datatracker.ietf.org/doc/html/rfc2576">RFC 2576</a>, section 3.<br>One example of a MIB module whose OID assignments follow the recommended scheme is the <code>POWER-ETHERNET-MIB</code> defined in <a href="https://datatracker.ietf.org/doc/html/rfc3621">RFC 3621</a>.<br>MIBs use a notation like "<code>.2.999</code>" where the leading dot shows that this OID is absolute while "<code>2.999</code>" might be considered as a relative OID by some tools which would then add a root OID in front of it.<br><br></div>
</li>
<li>
<div class="question">
Is there a way to look up an OID in the OID repository from my web browser?<a name="25"></a><a name="lookup"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
- If you're using <img src="images/firefox-icon.png" width="16" height="16" alt="[Firefox Icon]"><a href="https://www.mozilla.org/firefox/">Mozilla Firefox</a> or <img src="images/mozilla-icon.png" width="16" height="16" alt="[Mozilla Icon]"><a href="https://www.seamonkey-project.org">Mozilla SeaMonkey</a>
or <img src="images/google-chrome.ico" width="16" height="16" alt="[Chrome Icon]" border="0"><a href="https://www.google.com/chrome/">Google Chrome</a>, an <a href="https://mycroft.mozdev.org/search-engines.html?name=oid+resolver&skipcache=yes">OpenSearch
Plugin</a> (a.k.a. search engine) allows to display information about
an OID when an ASN.1 notation, dot notation, <a href="https://datatracker.ietf.org/doc/html/rfc3061">URN</a> notation
or <a href="#iri">OID-IRI</a> notation is entered in the search bar
at the top-right.<br><!-- - If you're using <a href="https://www.mozilla.org/products/thunderbird/">Mozilla
Thunderbird</a>, <img src="images/firefox-icon.png" width="16" height="16" alt="[Firefox Icon]"><a href="https://www.mozilla.org/products/firefox/">Mozilla Firefox</a>
or <img src="images/mozilla-icon.png" width="16" height="16" alt="[Mozilla Icon]"><a href="https://www.mozilla.org/projects/seamonkey/">Mozilla SeaMonkey</a>
(formerly known as Mozilla Application Suite), the <a href="https://dictionarysearch.mozdev.org">DictionarySearch
add-on</a> is easy to configure so that you can display information
about an OID by right-clicking on its selection:<br><ul>
<li>install the DictionarySearch extension corresponding to your
tool from <a href="https://dictionarysearch.mozdev.org">https://dictionarysearch.mozdev.org</a>;</li>
<li>in the "Tools" menu of your tool, select the "Extensions"
item;</li>
<li>highlight the line for DictionarySearch, then click on the "Options"
button;</li>
<li>add a new Dictionary with the following information (this will
display the description of the selected OID in dot notation; it
doesn't work well for a selected OID in ASN.1 notation because
the closing parentheses are removed for whatever reason):<br><em>Text</em>: <code>Search for OID "$"</code><br><em>Access key</em>: <code>O</code><br><em>URL</em>: <code>http://oid-info.com/cgi-bin/display?oid=$&a=display</code></li>
<li>This other new "Dictionary" may also be useful (it
will display a tree for the selected OID in dot notation):<br><em>Text</em>: <code>Display tree for OID "$"</code><br><em>Access key</em>: <code>T</code><br><em>URL</em>: <code>http://oid-info.com/cgi-bin/display?oid=$&a=tree</code>
</li>
</ul> --> - See also <a href="#8">question 8</a>.<br><br></div>
</li>
<li>
<div class="question">
What is a leaf OID? What is a frozen OID?<a name="26"></a><a name="leaf"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
These are not standardized concepts. In case an OID is a <em>leaf</em>
in the OID repository, no child OIDs can be allocated under that OID.
In case an OID is <em>frozen</em> in the OID repository, no more child
OIDs can be created in addition to the existing ones. In both cases,
the system does not accept the creation of child OIDs. The status
is also mentioned on the web page that describes an OID (see example
for a <a href="/get/0.0.2">leaf OID</a> and for a <a href="/get/0">frozen
OID</a>).<br>To report that an OID is a leaf or is frozen, please <a href="#modify">suggest
a modification</a> for this OID and use the "Comments" box
at the bottom.<br><br></div>
</li>
<li>
<div class="question">
What is an orphan OID?<a name="27"></a><a name="orphan"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
This is not a standardized concept but this term is used to qualify
an OID that is described in the OID repository, but some of its parent
OIDs are not described in the OID repository. This does not mean that
these unknown parent OIDs do not exist (actually they do exist because
an OID can only be allocated by the Registration Authority of its
parent OID). However the user who submitted the description of this
OID has no knowledge of how to describe these parent OIDs.<br><!-- This is useful in cases such as:<br>- you have found the description of an OID somewhere on the web or
in a document, but you don't know how to describe all arcs along the
path;<br>- you have a bunch of OIDs to submit to the OID repository, so you
can submit them in any order because there is no obligation to submit
the father OID first.<br>-->
Orphan OIDs are not visible when one
<a href="/cgi-bin/display?tree=">walks down the OID tree</a>. However,
they are <a href="display-example.htm">displayed</a> when one asks
for the description of a particular OID. <em>Orphan grandchild OIDs</em>
(<em>i.e.</em>, OIDs for which we have a description as well as a
description of their grandparent OID, but no description of their
parent OID) are accessible from the <a href="display-example.htm">description
page</a> of their grandparent OID.<br><br></div>
</li>
<li>
<div class="question">
What is an OID-IRI (Internationalized Resource Identifier)?<a name="28"></a><a name="iri"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
Historically, OIDs could only be denoted in <a href="#14">dot notation</a>
(<em>e.g.</em>, <code>2.27</code>) or in <a href="#17">ASN.1 notation</a>
(<em>e.g.</em>, <code>{joint-iso-itu-t(2) tag-based(27)}</code>) where
only ASCII identifiers are allowed. The need was identified for a
human-friendly notation which would not be limited to latin alphabets
and would encompass the diversity of <a href="https://www.unicode.org">Unicode
alphabets</a>.<br>An OID-IRI (a.k.a. international OID) is a string of slash-separated
Unicode labels from the root of the OID tree, which unambiguously
identifies a node in the OID tree (e.g., "<a href="/get//Joint-ISO-ITU-T/Example"><code>/Joint-ISO-ITU-T/Example</code></a>").<br>A Unicode label is a case-sensitive string of Unicode characters (except
the <code>SPACE</code> character). Just as an OID node can have multiple
identifiers in ASN.1 notation, it can have multiple Unicode labels
(this allows backwards-compatibility when a company changes its name,
for example). Each OID node has a default Unicode label which is its
number (<em>e.g.</em>, "<a href="/get//2/999"><code>/2/999</code></a>").<br>In order to support names of OIDs in multiple languages, an OID can
have multiple Unicode labels, giving rise to a need to transform a
path using Unicode labels into a canonical form of purely numerical
labels to identify the OID. This is handled by the <a href="introduction.htm#ors">OID
Resolution System</a>.<br>A <em>long arc</em> is a particular kind of Unicode label which identifies
an OID that is not immediately beneath the root of the OID tree. For
example, OID <code>{joint-iso-itu-t(2) example(999)}</code> has a
long arc named "<code>Example</code>" allowing OID-IRI "<code><a href="/get//Example">/Example</a></code>"
which is shorter than OID-IRI "<code><a href="/get//Joint-ISO-ITU-T/Example">/Joint-ISO-ITU-T/Example</a></code>".
Long arcs are only allowed for OIDs under the <code>joint-iso-itu-t(2)</code>
top-level arc (see the <a href="https://www.itu.int/go/X660">register of
long arcs)</a>.<br>The <a href="https://www.itu.int/rec/T-REC-X.680/en">ASN.1 standard</a>
specifies an <code>OID-IRI</code> type for exchanging OID-IRI values
between machines.<br><br></div>
</li>
<li>
<div class="question">
What are the duties of a Registration Authority?<a name="29"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
Guidance is given in sections 8.2 (Operation), 9 (registration procedures)
and 11 (recommended fee structure) of <a href="https://www.itu.int/rec/T-REC-X.660/en">Recommendation
ITU-T X.660 | ISO/IEC 9834-1</a>.<br>The open-source database system <a href="https://oidplus.viathinksoft.com/oidplus/">OIDplus</a>
from ViaThinkSoft can be used by Registration Authorities to manage
their OIDs. It includes a feature to export data into an <a href="submit.htm">XML
document that can then be uploaded to this OID repository</a>.<br><br></div>
</li>
<li>
<div class="question">
Are there size limitations for OID encoding?<a name="30"></a><a name="size-limitations"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The <a href="standards.htm">OID standards</a> have no limit whatsoever about the depth of an OID in the OID tree (i.e., number of arcs) and the size of the integer associated to each OID arc. At the moment, the <a href="/get/1.3.6.1.4.1.1248.1.1.2.1.3.21.69.112.115.111.110.32.83.116.121.108.117.115.32.80.114.111.32.52.57.48.48">longest OID</a> described in the OID repository has 171 chars and 34 arcs. The <a href="/get/2.25.336702412625001560652410773774433371419">greatest number</a> for an OID arc has 39 digits. However, there are constraints for OIDs used in SNMP Management Information Bases (<a href="#mib">see question 24</a>) and some tools may have size limitations (or bugs):<br>- The <a href="https://lapo.it/asn1js/">ASN.1 JavaScript decoder at
lapo.it</a>, <a href="https://www.bouncycastle.org">Bouncy Castle Crypto
APIs</a>, OpenSSL (version 0.9.8o, 1 Jun 2010) and the built-in Java
class "<code>org.ietf.jgss.Oid</code>" can handle <a href="/get/2.25">UUIDs
used as OIDs</a>.<br>- Windows CryptoAPI Shell Extension (tested with Windows XP and Windows
7) cannot handle <a href="/get/2.25">UUIDs used as OIDs</a>: The maximum
useable OID value in Windows is 2<sup>64</sup>-1 (e.g., <code>2.999.18446744073709551615</code>).
Windows will show whitespace when any higher value occurs.<br>- Mozilla software cannot handle <a href="/get/2.25">UUIDs used as
OIDs</a>: The maximum useable OID value in Mozilla software is 2<sup>32</sup>-1
(e.g., <code>2.999.4294967295</code>). The program will show "Unknown"
when an arc contains a higher value (e.g., <code>{2 999 Unknown 0}</code>).
<br>- Mac OS X cannot handle OIDs of the form <code>2.<em>n</em></code>
where <code><em>n</em></code> > 47 (i.e., it wrongly decodes OIDs
which need more than one octet in the first two arcs). <br>More details can be found in <a href="https://misc.daniel-marschall.de/asn.1/oid_facts.html">Daniel
Marschall's study about OID encoding and size limitations</a>. Daniel's
<a href="https://misc.daniel-marschall.de/asn.1/oid-converter/online.php">DER
encoder</a> can also help in your testing.<br><br></div>
</li>
<li>
<div class="question">
Are there binary encoders/decoders for OIDs?<a name="31"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
See for example (non-exhaustive list):<strong><br></strong>- OSS Nokalva's online <a href="https://asn1.io">ASN.1
playground</a> encodes/decodes OIDs in any encoding rule (BER, DER,
PER, UPER, XER) with the following schema:<br><code>     OID-Module DEFINITIONS ::= BEGIN<br>       OID ::= OBJECT IDENTIFIER<br>     END</code><br>  The OID is provided in ASN.1 notation in the "Data:
Encode" box as follows:<br><code>     oid OID ::= {2 999}</code><br>- Daniel Marschall's online <a href="https://misc.daniel-marschall.de/asn.1/oid-converter/online.php">DER
encoder/decoder</a> (for PHP and C);<br>- <a href="https://bouncycastle.org">The Legion of the Bouncy Castle</a>'s
API for Java and C#;<br>- <a href="https://www.wireshark.org">Wireshark</a>'s subtool for ASN.1.<br>See also <a href="https://misc.daniel-marschall.de/asn.1/oid_facts.html#chap4">Daniel
Marschall's software compatibility analysis for large OIDs</a>.<br><br></div>
</li>
<li>
<div class="question">
Does this web site use cookies?<a name="32"></a><a name="cookies"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
You can set up your browser to reject cookies: Disabling their use
will not materially impact on your interaction with this website.<br>Only users who have submitted information on OIDs (description of
a new OID or proposed modifications to an existing OID) have a unique
cookie placed on their machine with their first name, last name and
email address, so that the "submitter" section is automatically
filled the next time they submit information. This cookie is not used
to track your use of the OID repository.<br>The <a href="/helper">OID helper</a> chatbot is (externally) hosted
by <a href="https://pandorabots.com/botmaster/en/~121e02c2b4d4270afe6afac6~/faq">Pandorabots</a>
which normally tracks individual conversations by placing a cookie
on your browser, in order to offer contextual answers to your questions
(please check <a href="https://home.pandorabots.com/policies.html#privacy-policy">Pandorabots'
privacy policy</a>). However, if your browser is not setup to accept
cookies, an alternative mechanism is used through a hidden variable
in the HTML form.<br><br></div>
</li>
<li>
<div class="question">
How does this web site protect users' privacy?<a name="33"></a><a name="privacy"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The purpose of this section (updated on 24 Jan 2019) is to inform
you about the way your personal data is handled on this web site.
By providing your personal data to this web site, you acknowledge
and consent to the collection, use and disclosure of your personal
data for a legitimate interest as explained hereunder. This web site
never sells, leases or rents your personal data.<br>Only users who have submitted information on OIDs (description of
a new OID or proposed modifications to an existing OID) have personal
data stored in the OID repository database. The only reason to keep
such information is to inform them when the OID description is validated
or modified by the OID repository administrator, or when modifications
are suggested by another user (see also <a href="#cookies">question
32 about cookies</a>). This information is not publicly disclosed
on the web site. (Note, however, that it may be sent by email to the
<a href="#registration-authorities">(current or first) registration
authority</a> of the OID and of its parent OID, when they are known).<br>Only those users who are the contact of a <a href="#registration-authorities">(current
or first) registration authority</a> for an OID and have not ticked
the box "<i>Protect the privacy of the Registration Authority
by not displaying the contact information on the web site</i>"
have their personal data (email address, postal address, phone number)
publicly visible on the web site. (Note, however, that even when the
"privacy" box is ticked, any user of this web site can <a href="/cgi-bin/manage?a=get-info">receive
by email a copy of such data</a> so as to be able to contact the registration
authority of an OID; such requests are recorded). These users are
automatically notified by email when information about them is entered
and can request deletion of such data.<br>In some cases, your personal data appears in the OID repository because
it is publicly available on another web site (e.g., <a href="https://www.iana.org/assignments/enterprise-numbers/enterprise-numbers">IANA
enterprise numbers</a>).<br>To check if personal data related to you appears in the OID repository,
please use the <a href="search.htm">advanced search</a>. You can
also <a href="/cgi-bin/manage?a=get-personal-data">get a copy</a>
of all personal data appearing in the OID repository. In any case,
your personal data is never used for sending any kind of publicity
to you.<br>A log of all modifications made to an OID is also kept (hence your
personal data may appear in that log) but it is not public and would
only be used by the OID repository administrator to explain or undo
changes if needed.<br>For any other question related to data protection or to request the
rectification or erasure of your personal data, you can <a href="/helper">contact
the webmaster</a>. Repetitive, disproportionate or impracticable requests
may be rejected.
<br><br></div>
</li>
<li>
<div class="question">
What are the guidelines to adequately describe an OID in this OID repository?<a name="34"></a><a name="guidelines"></a>
<a href="#top"><img src="images/page_top_fleche.png" width="27" height="17" border="0"></a>
</div>
<div class="answer">
The following rules are followed by the OID repository administrator to validate OID descriptions:
<ul>
<li>The description shall be as short as possible (usually, not more than one line) and focus on <em>what</em> (i.e., which object) is identified by the OID. The description shall not be a sentence (with a verb). Consequently, the description does not end up with a full stop "." (except when the full stop is part of an abbreviation). See also the <a href="#syntax-rules">syntax rules</a>.</li>
<li>The description should be easily understandable by any user of the OID repository. Substantives should not be put one after the other without inserting small words like "for", "of", etc. This helps understanding the description and avoids ambiguities when translating to other languages.</li>
<li>Useless expressions like "OID for", "OID identifying", "Root OID for", "Top arc for", "Arc for", "This OID describes", "This arc describes", etc., are forbidden.</li>
<li>Words are not capitalized (contrarily to what is usually done for paper or book titles in English) except for an abbreviation or acronym which is put between parentheses after the expression that defines it (with each letter of the abbreviation being capitalized in its definition), e.g., Meaning of My Abbreviation (MMA).</li>
<li>Any text (e.g., how it is used, how child OIDs are allocated, etc.) which is not related to <em>what</em> is identified by the OID shall be moved to the "Information" part. Any text which can be assimilated to a publicity or a company description shall be avoided (a URL can be associated to the company name).</li>
</ul>
</div>
</li>
</ol>
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Subversion Repositories oidinfo_new_design

oidinfo_new_design/trunk/faq.htm – Rev 38