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Network Working Group B. Manning (Rice University)
INTERNET DRAFT R. Colella (NIST)
August 2, 1993
DNS NSAP Resource Records
Status of This Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its Areas, and
its Working Groups. Note that other groups may also distribute working
documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months.
Internet-Drafts may be updated, replaced, or obsoleted by other
documents at any time. It is not appropriate to use Internet-Drafts as
reference material or to cite them other than as a "working draft" or
"work in progress."
To learn the status of any Internet-Draft, please check the 1id-
abstract.txt listing contained in the Internet-Drafts Shadow Directories
on nic.ddn.mil, nnsc.nsf.net, nic.nordu.net, ftp.nisc.sri.com, or
munnari.oz.au.
It is intended that this document will be submitted to the IESG for
consideration as a standards document. Distribution of this document is
unlimited.
Abstract
The Internet is moving towards the deployment of an OSI lower layers
infrastructure. This infrastructure comprises the connectionless network
protocol (CLNP) and supporting routing protocols. Also required as part
of this infrastructure is support in the Domain Name System (DNS) for
mapping between names and NSAP addresses.
This document defines the format of two new Resource Records (RRs) for
the DNS, replacing the earlier work in RFC 1348. The RRs defined in this
paper allow the DNS to support domain name-to-NSAP and NSAP-to-domain
name mappings. The RRs may be used with any NSAP address format.
Expiration Date February 2, 1994 [Page 1]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
1 Introduction
The Internet is moving towards the deployment of an OSI lower layers
infrastructure. This infrastructure comprises the connectionless network
protocol (CLNP) [ISO86b] and supporting routing protocols. Also required
as part of this infrastructure is support in the Domain Name System
(DNS) [Moc87a , Moc87b] for mapping between domain names and OSI Network
Service Access Point (NSAP) addresses [ISO88] [Note: NSAP and NSAP
address are used interchangeably throughout this memo].
This document defines the format of two new Resource Records (RRs) for
the DNS, replacing the earlier work in RFC 1348. The RRs defined in this
paper allow the DNS to support domain name-to-NSAP and NSAP-to-domain
name mappings. The RRs may be used with any NSAP address format.
This memo assumes that the reader is familiar with the DNS. Some
familiarity with NSAPs is useful; see [CGC91] or [ISO88] for additional
information.
2 Background
The reason for defining DNS mappings for NSAPs is to support CLNP
in the Internet. Debugging with CLNP ping and traceroute is becoming
more difficult with only numeric NSAPs as the scale of deployment
increases. Current debugging is supported by maintaining and exchanging
a configuration file with name/NSAP mappings similar in function to
hosts.txt. This suffers from the lack of a central coordinator for this
file and also from the perspective of scaling. The former is the most
serious short-term problem. Scaling of a hosts.txt-like solution has
well-known long-term scaling difficiencies.
A second reason for this work is the proposal to use CLNP as an
alternative to IP: "TCP and UDP with Bigger Addresses (TUBA), A Simple
Proposal for Internet Addressing and Routing" [Cal92]. For this to be
practical, the DNS must be capable of supporting CLNP addresses.
3 Scope
The RRs defined in this paper support all known NSAP formats. This
includes support for the notion of a custom-defined NSAP format based on
an AFI obtained by the IAB for use in the Internet.
B. Manning/R. Colella [Page 2]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
As a point of reference, there is a distinction between registration
and publication of addresses. For IP addresses, the IANA is the root
registration authority and the DNS a publication method. For NSAPs,
addendum two of the network service definition, ISO8348/Ad2 [ISO88] is
the root registration authority and this memo defines how the DNS is
used as a publication method.
4 Structure of NSAPs
NSAPs are hierarchically structured to allow distributed administration
and efficient routing. Distributed administration permits subdelegated
addressing authorities to, as allowed by the delegator, further
structure the portion of the NSAP space under their delegated control.
Accomodating this distributed authority requires that there be little or
no a priori knowledge of the structure of NSAPs built into DNS resolvers
and servers.
For the purposes of this memo, NSAPs can be thought of as a tree of
identifiers. The root of the tree is ISO8348/Ad2 [ISO88], and has as
its immediately registered subordinates the one-octet Authority and
Format Identifiers (AFIs) defined there. The size of subsequently-
defined fields depends on which branch of the tree is taken. The depth
of the tree varies according to the authority responsible for defining
subsequent fields.
An example is the authority under which U.S. GOSIP defines NSAPs
[Gro91]. Under the AFI of 47, NIST (National Institute of Standards
and Technology) obtained a value of 0005 (the AFI of 47 defines
the next field as being two octets consisting of four BCD digits
from the International Code Designator space [ISO84]). NIST defined
the subsequent fields in [Gro91], as shown in Figure 1. The field
immediately following 0005 is a format identifier for the rest of the
U.S. GOSIP NSAP structure, with a hex value of 80. Following this is the
three-octet field, values for which are allocated to network operators;
the registration authority for this field is delegated to GSA (General
Services Administration).
The last octet of the NSAP is the NSelector (NSel). In practice, the
NSAP minus the NSel identifies the CLNP protocol machine on a given
system, and the NSel identifies the CLNP user. Since there can be more
than one CLNP user (meaning multiple NSel values for a given "base"
NSAP), the representation of the NSAP should be CLNP-user independent.
To achieve this, an NSel value of zero will be used with all NSAP values
stored in the DNS. An NSAP with NSel=0 identifies the network layer
itself. It is left to the application retrieving the NSAP to determine
the appropriate value to use in that instance of communication.
B. Manning/R. Colella [Page 3]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
________________
|_<--_IDP_-->__|_____________________________________
|_AFI_|__IDI___|____________<--_DSP_-->______________|
|_47__|__0005__|DFI_|_AA_|_Rsvd_|_RD_|Area_|_ID_|Sel_|
octets |__1__|___2____|_1__|_3__|__2___|_2__|__2__|_6__|_1__|
IDP Initial Domain Part
AFI Authority and Format Identifier
IDI Initial Domain Identifier
DSP Domain Specific Part
DFI DSP Format Identifier
AA Administrative Authority
Rsvd Reserved
RD Routing Domain Identifier
Area Area Identifier
ID System Identifier
SEL NSAP Selector
Figure 1: GOSIP Version 2 NSAP structure.
When CLNP is used to support TCP and UDP services, the NSel value used
will be the appropriate IP PROTO value as registered with the IANA.
For "standard" OSI, the selection of NSel values is left as a matter of
local administration. Administrators of systems that support the OSI
transport protocol [ISO86a] in addition to TCP/UDP must select NSels for
use by OSI Transport that do not conflict with the IP PROTO values.
In the NSAP RRs in Master Files and in the printed text in this memo,
NSAPs are often represented as a string of "."-separated hex values. The
values correspond to convenient divisions of the NSAP to make it more
readable. For example, the "."-separated fields might correspond to the
NSAP fields as defined by the appropriate authority (ISoc, GOSIP, ANSI,
etc.). The use of this notation is strictly for readability. The "."s do
not appear in DNS packets and DNS servers can ignore them when reading
Master Files. For example, a printable representation of the first four
fields of a U.S. GOSIP NSAP might look like
47.0005.80.005a00
B. Manning/R. Colella [Page 4]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
and a full U.S. GOSIP NSAP might appear as
47.0005.80.005a00.0000.1000.0020.00800a123456.00.
For more information on U.S. GOSIP NSAPs, see RFC1237 [CGC91]. Other
NSAP formats have different fields and field widths (see [Bry92]).
5 The NSAP RR
The NSAP RR is defined with mnemonic "NSAP" and TYPE code 22 (decimal)
and is used to map from domain names to NSAPs. Name-to-NSAP mapping in
the DNS using the NSAP RR operates analogously to IP address lookup. A
query is generated by the resolver requesting an NSAP RR for a provided
domain name.
NSAP RRs conform to the top level RR format and semantics as defined in
Section 3.2.1 of RFC 1035.
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |
/ /
/ NAME /
| |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TYPE = NSAP |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| CLASS = IN |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TTL |
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RDLENGTH |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
/ RDATA /
/ /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
B. Manning/R. Colella [Page 5]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
where:
* NAME: an owner name, i.e., the name of the node to which this
resource record pertains.
* TYPE: two octets containing the NSAP RR TYPE code of 22 (decimal).
* CLASS: two octets containing the RR IN CLASS code of 1.
* TTL: a 32 bit signed integer that specifies the time interval
that the resource record may be cached before the source of the
information should again be consulted. Zero values are interpreted
to mean that the RR can only be used for the transaction in
progress, and should not be cached. For example, SOA records are
always distributed with a zero TTL to prohibit caching. Zero values
can also be used for extremely volatile data.
* RDLENGTH: an unsigned 16 bit integer that specifies the length in
octets of the RDATA field.
* RDATA: a variable length string of octets containing the NSAP.
The value is the binary encoding of the NSAP as it would appear in
the CLNP source or destination address field. A typical example of
such an NSAP (in hex) is shown below. For this NSAP, RDLENGTH is
20 (decimal); "."s have been omitted to emphasize that they don't
appear in the DNS packets.
39840f80005a0000000001e13708002010726e00
NSAP RRs cause no additional section processing.
6 The NSAP-PTR RR
The NSAP-PTR RR is defined with mnemonic "NSAP-PTR" and TYPE code
23 (decimal). This RR is used to map from NSAPs to domain names.
NSAP-to-domain name mapping in the DNS using the NSAP-PTR RR operates
analogously to IP address-to-domain name lookup. A domain name is
generated from the NSAP according to the rules described below. A query
is sent by the resolver requesting an NSAP-PTR RR for the provided
domain name.
A domain name is generated from an NSAP by reversing the hex nibbles of
the NSAP, treating each nibble as a separate subdomain, and appending
the top-level subdomain name ".NSAP" to it. For example, the domain name
used in the reverse lookup for the NSAP
47.0005.80.005a00.0000.0001.e137.ffffff000065.00
B. Manning/R. Colella [Page 6]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
would appear as
0.0.5.6.0.0.0.0.f.f.f.f.f.f.7.3.1.e.1.0.0.0.0.0.0.0.0.0.a.5.0.0.\
0.8.5.0.0.0.7.4.NSAP.
[Implementation note: For sanity's sake user interfaces should be
designed to allow users to enter NSAPs using their natural order, i.e.,
as they are typically written on paper. Also, arbitrary "."s should be
allowed (and ignored).]
NSAP-PTR RRs conform to the top level RR format and semantics as defined
in Section 3.2.1 of RFC 1035.
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |
/ /
/ NAME /
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TYPE = NSAP-PTR |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| CLASS = IN |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TTL |
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RDLENGTH |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
/ RDATA /
/ /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
where:
* NAME: the domain name of the node to which this resource record
pertains. This name is derived from the NSAP as described above.
* TYPE: two octets containing the NSAP-PTR RR TYPE code of 23
(decimal).
* CLASS: two octets containing the RR IN CLASS code of 1.
B. Manning/R. Colella [Page 7]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
* TTL: a 32 bit signed integer that specifies the time interval
that the resource record may be cached before the source of the
information should again be consulted. Zero values are interpreted
to mean that the RR can only be used for the transaction in
progress, and should not be cached. For example, SOA records are
always distributed with a zero TTL to prohibit caching. Zero values
can also be used for extremely volatile data.
* RDLENGTH: an unsigned 16 bit integer that specifies the length in
octets of the RDATA field.
* RDATA: a variable length string of octets containing the domain name
associated with the NSAP.
NSAP RRs cause no additional section processing.
7 Master File Format
The format of NSAP and NSAP-PTR RRs in Master Files conforms to Section 5,
"Master Files," of RFC 1035. Below are examples of the use of these RRs
in Master Files.
;;;;;;
;;;;;; Master File for domain tuba.ncsl.nist.gov.
;;;;;;
@ IN SOA emu.ncsl.nist.gov. root.emu.ncsl.nist.gov. (
900831 ; Serial - date
1800 ; Refresh - 30 minutes
300 ; Retry - 5 minutes
604800 ; Expire - 7 days
3600 ) ; Minimum - 1 hour
IN NS emu.ncsl.nist.gov.
;
;
$ORIGIN tuba.ncsl.nist.gov.
;
emu IN NSAP 47.0005.80.005a00.0000.0001.e137.08002010726e.00
IN A 129.6.55.32
IN HINFO Sun_Sparc SunOS_4.1.3
;
osi IN NSAP 47.0005.80.005a00.0000.0001.e137.080020079efc.00
IN A 129.6.55.1
B. Manning/R. Colella [Page 8]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
;
cursive IN NSAP 47.0005.80.005a00.0000.0001.e137.eeeeee000085.00
IN A 129.6.224.85
IN HINFO PC_386 DOS_5.0/NCSA_Telnet(TUBA)
;
cisco1 IN NSAP 47.0005.80.005a00.0000.0001.e137.888888000181.00
IN A 129.6.224.181
;
3com1 IN NSAP 47.0005.80.005a00.0000.0001.e137.111111000111.00
IN A 129.6.225.111
;
infidel IN NSAP 47.0005.80.005a00.0000.0001.e137.ffffff000065.00
IN A 129.6.55.128
IN HINFO PC/486 BSDi1.0/TUBA
;;;;;;
;;;;;; Master File for reverse mapping of NSAPs under
;;;;;; 47.0005.80.005a00.0000.0001.e137
;;;;;;
@ IN SOA emu.ncsl.nist.gov. root.emu.ncsl.nist.gov. (
900831 ; Serial - date
1800 ; Refresh - 30 minutes
300 ; Retry - 5 minutes
604800 ; Expire - 7 days
3600 ) ; Minimum - 1 hour
IN NS emu.ncsl.nist.gov.
;
;
$ORIGIN 7.3.1.e.1.0.0.0.0.0.0.0.0.0.a.5.0.0.0.8.5.0.0.0.7.4.NSAP.
;
0.0.e.6.2.7.0.1.0.2.0.0.8.0 IN NSAP-PTR emu.tuba.ncsl.nist.gov.
;
0.0.c.f.e.9.7.0.0.2.0.0.8.0 IN NSAP-PTR osi.tuba.ncsl.nist.gov.
;
0.0.5.8.0.0.0.0.e.e.e.e.e.e IN NSAP-PTR cursive.tuba.ncsl.nist.gov.
;
0.0.1.8.1.0.0.0.8.8.8.8.8.8 IN NSAP-PTR cisco1.tuba.ncsl.nist.gov.
;
0.0.1.1.1.0.0.0.1.1.1.1.1.1 IN NSAP-PTR 3com1.tuba.ncsl.nist.gov.
;
0.0.5.6.0.0.0.0.f.f.f.f.f.f IN NSAP-PTR infidel.tuba.ncsl.nist.gov.
8 Security
Security issues are not addressed in this memo.
B. Manning/R. Colella [Page 9]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
9 Authors' Addresses
Bill Manning
Rice University -- ONCS
P.O. Box 1892
6100 South Main
Houston, Texas 77251-1892
USA
Phone: +1.713.285.5415
EMail: bmanning@rice.edu
Richard Colella
National Institute of Standards and Technology
Technology/B217
Gaithersburg, MD 20899
USA
Phone: +1 301-975-3627 (voice); +1 301 590-0932 (fax)
EMail: colella@nist.gov
A Issues
It may be useful to associate an X.500 distinguished name with an NSAP.
Some thought should be given to whether this is useful and how it could
be done.
References
[Bry92] P. Bryant. Nsaps. IPTAG/92/23 PB660, Science and Engineering
Research Council, Rutherford Appleton Laboratory, May 1992.
[Cal92] R. Callon. Tcp and udp with bigger addresses (tuba), a simple
proposal for internet addressing and routing. RFC 1347, Network
Working Group, June 1992.
[CGC91] R. Colella, E. Gardner, and R. Callon. Guidelines for osi
nsap allocation in the internet. RFC 1237, IETF OSI NSAP
Administration Working Group, July 1991.
B. Manning/R. Colella [Page 10]
INTERNET-DRAFT DNS NSAP Resource Records August 2, 1993
[Gro91] GOSIP Advanced Requirements Group. Government open systems
interconnection profile (gosip) version 2. Federal Information
Processing Standard 146-1, U.S. Department of Commerce,
National Institute of Standards and Technology, Gaithersburg,
MD, April 1991.
[ISO84] ISO/IEC. Data interchange - structures for the identification
of organization. International Standard 6523, ISO/IEC JTC 1,
Switzerland, 1984.
[ISO86a] ISO/IEC. Connection oriented transport protocol specification.
International Standard 8073, ISO/IEC JTC 1, Switzerland, 1986.
[ISO86b] ISO/IEC. Protocol for providing the connectionless-mode
network service. International Standard 8473, ISO/IEC JTC 1,
Switzerland, 1986.
[ISO88] ISO/IEC. Information processing systems -- data communications
-- network service definition addendum 2: Network layer
addressing. International Standard 8348/Addendum 2, ISO/IEC JTC
1, Switzerland, 1988.
[Moc87a] P. Mockapetris. Domain name -- concepts and facilities. RFC
1034, Network Working Group, November 1987.
[Moc87b] P. Mockapetris. Domain name -- implementation and specifica-
tion. RFC 1035, Network Working Group, November 1987.
Expiration Date February 2, 1994 [Page 11]