Internet DRAFT - draft-bhatla-dnsext-murr
draft-bhatla-dnsext-murr
INTERNET DRAFT Mukesh Bhatla
8 November 2002 Motorola Inc.
DNS RR type for Multiple Unicast
draft-bhatla-dnsext-murr-00.txt
Status of This Memo
Distribution of this memo is unlimited.
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. 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
and may be updated, replaced, or obsoleted by other documents at
any time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at:
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at:
http://www.ietf.org/shadow.html.
Abstract
To date, the scenario of multiple IP addresses for same domain name
arises for the case where either we have multihomed IP hosts or we
have multiple servers having the same domain name and application
on the client needs to approach only one of those IP hosts. However,
the penetration of mobile hosts and personal devices identified, on
the internet, by the user's Network Access Identifier (NAI) may
create a scenario where multiple devices may have same domain name
but different IP addresses and all of those devices may need to get
the service or data from the application which only identifies them
by their host name.
This document proposes to add a new Resource Record called the
Multiple Unicast Resource Record (MURR) to the DNS system. This
resource record is added for a domain name where the applications
retrieving the IP address for the domain name have to provide the
service (like PUSH data) to all the IP addresses retrieved in the
multiple MURRs for the domain name.
Bhatla Expires April 2003 [Page 1]
Internet Draft November 2002
1. Introduction
The use of mobile Internet is projected to increase manifolds, each
Individual is foreseen to use multiple mobile devices. Each of
these devices may be identified by the Network Access Identifier
(NAI-RFC2486)[3]. This will create the scenario where multiple
devices have the same domain name but different IP addresses. The
DNS which maps the domain name to IP address may have multiple
Resource records for each domain name. Each of these RRs will map
the domain name to an IP address.
This document proposes to add a new Resource Record called the
Multiple Unicast Resource Record (MURR) to the DNS system. This
resource record is added for a domain name where the applications
retrieving the IP address for the domain name have to provide the
service (like PUSH data) to all the IP addresses retrieved in
the multiple MURRs for the domain name.
2. Applicability Statement
Currently DNS stores the Resource records corresponding to
each domain name. These Resource Records include the A and
AAAA resource records, which map a host name to an IPv4 and
IPv6 address respectively. A domain name may have multiple
IP addresses corresponding to it, each of this IP address is
represented by an A record. Applications query the DNS server
for these resource records to map the domain name to the
IP address. These A records are retrieved by the client
application through the Resolver, which resides on client
itself. Its not well defined whether the resolver will convey
the multiple IP addresses retrieved for a domain name or will
convey only one of them to the application. Application
normally communicates with only one of the IP address, which
is retrieved by the application by the domain name query.
The scenario where all the hosts, who have the same domain name,
and have to be sent the same data is a possibility. (It is
possible in the case where same NAI is used on various mobile
hosts and the domain name of these mobile hosts is derived from
the NAI,and all these mobile hosts have to be sent PUSH DATA).
Multiple Unicast resource record is added for a domain name
where the application retrieving the IP address for the domain
name has to provide the service (e.g. PUSH data) to all the IP
addresses retrieved in the multiple MURRs for the domain name.
A domain name can have multiple MURRs, if multiple hosts having
different IP addresses but the same domain name are present.
The application can either do a MURR DNS query or all the MURR
records could be sent as a part of the additional part of the
DNS A resource record query.
Bhatla Expires April 2003 [Page 2]
Internet Draft November 2002
The main goal of MURR is to convey to the application that
all the hosts having the same domain name desire Multiple
Unicast. The application can easily distinguish between the
need for Multiple unicast to all the IP addresses provided
by MURR or to provide/get the service to/from a single host
in the case IP addresses are provided by the A records.
This enables host whose domain name is being resolved to have
control over how it wants to get/provide a service. Resolver
MUST forward all the RRs of the type MURR to the application.
MURR is especially useful for the IP Reachability service for the
wireless mobile stations. For the IP Reachability service the
host name of the mobile station is derived from the NAI (user@domain)
of the user on the mobile. The NAI is converted from user@domain to
user.domain to derive the domain name for the mobile. This derived
domain is updated along with the IP address of the domain name
(A resource records) to the DNS server by the home AAA or
the Home Agent (HA) for the mobile station. An application on
the network can resolve this domain name to the IP address to
provide a service (like PUSH data) to the subscriber. It's a
possibility that same NAI could be used on multiple mobiles;
this will create a scenario where same domain name will be mapped
to multiple IP addresses. This will result in multiple A resource
records being returned to the resolver on the client where
application is resolving the domain name to the IP address.
Most of the current applications/resolver will pick up one of
the IP addresses and unicast the data to it.
If MURR is used instead of the A Resource Record to map the domain
name to the IP address. The application will have to unicast
the data to all the hosts having the same domain name but different
IP addresses as specified in the MURRs for that domain name.
MURR's use is not limited to the wireless scenario; it could be
used in any access method.
A domain name can have multiple MURRs in master file of DNS server.
The dynamic DNS server update procedures are as specified in the
RFC 2136.
Bhatla Expires April 2003 [Page 3]
Internet Draft 4 January 2002
3. NAI RR Type
The MURR record has the DNS RR type of "?", hence has the same QTYPE
number of "?". Note: MURR RR requires IANA number assignment.
The class of MURR RR is defined in the IN class only.
4. MURR RDATA format
The RDATA of MURR is same as A RDATA format, 32 bit Internet Address.
4. Examples
An example MURR can be:
Mbhatla1.Motorola.com 10000 IN MURR 165.213.221.4
Mbhatla1.Motorola.com 10000 IN MURR 165.213.179.2
5. Security Considerations
Any information obtained from the DNS should be regarded as unsafe
unless techniques specified in [RFC2535] or [RFC2845] were used. The
definition of a new RR type does not introduce security problems into
the DNS.
6. IANA Considerations
It requires new RR type number from IANA.
Bhatla Expires April 2003 [Page 4]
Internet Draft November 2002
References
[1] Mockapetris, P., "Domain names - Concepts and Facilities", RFC
1034, Nov 1987.
[2] Mockapetris, P., "Domain names - Implementation and
Specification", RFC 1035, Nov 1987.
[3] Bernard Aboba and Mark A. Beadles "The Network Access
Identifier". RFC 2486. January 1999.
[4] 3GPP2 P.S0001-B work in progress.
Addresses
Questions about this memo can be directed to the authors:
Mukesh Bhatla
Motorola Inc.
1501 West Shure Drive,
Arlington Heights, IL 60074
Mbhatla1@email.mot.com
(847)435-0732
Bhatla Expires April 2003 [Page 5]
Internet Draft November 2002
Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC editor function is currently provided by the
Internet Society.
Bhatla Expires April 2003 [Page 6]
