Network Working Group A. Lindem (Editor)
Internet-Draft Redback Networks
Intended status: Standards Track S. Mirtorabi
Expires: April 4, 2009 A. Roy
M. Barnes
Cisco Systems
R. Aggarwal
Juniper Networks
Oct 30 2008
Support of address families in OSPFv3
draft-ietf-ospf-af-alt-07.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
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.
This Internet-Draft will expire on April 4, 2009.
Copyright Notice
Copyright (C) The IETF Trust (2008).
Lindem (Editor), et al. Expires April 4, 2009 [Page 1]
Internet-Draft OSPFv3 AF Oct 2008
Abstract
This document describes a mechanism for supporting multiple address
families in OSPFv3 using multiple instances. It maps an address
family (AF) to an OSPFv3 instance using the Instance ID field in the
OSPFv3 packet header. This approach is fairly simple and minimizes
extensions to OSPFv3 for supporting multiple AFs.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Design Considerations . . . . . . . . . . . . . . . . . . 3
1.2. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Instance ID values for new AFs . . . . . . . . . . . . . . 4
2.2. OSPFv3 Options and Prefix Options Changes . . . . . . . . 4
2.2.1. OSPFv3 Options . . . . . . . . . . . . . . . . . . . . 4
2.2.2. Prefix Options . . . . . . . . . . . . . . . . . . . . 5
2.3. Advertising Prefixes in new AFs . . . . . . . . . . . . . 5
2.4. Changes to the Hello processing . . . . . . . . . . . . . 6
2.5. Next hop for IPv4 unicast and multicast AFs . . . . . . . 6
2.6. AS External LSA Forwarding Address for IPv4 Unicast
and IPv4 Multicast AFs . . . . . . . . . . . . . . . . . 7
2.7. Database Description Maximum Transmissoin Unit (MTU)
Specification for Non-IPv6 AFs . . . . . . . . . . . . . . 7
2.8. Operation over Virtual Links . . . . . . . . . . . . . . . 9
3. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 10
4. Security Considerations . . . . . . . . . . . . . . . . . . . 11
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.1. Normative References . . . . . . . . . . . . . . . . . . . 14
6.2. Informative References . . . . . . . . . . . . . . . . . . 14
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
Intellectual Property and Copyright Statements . . . . . . . . . . 17
Lindem (Editor), et al. Expires April 4, 2009 [Page 2]
Internet-Draft OSPFv3 AF Oct 2008
1. Introduction
OSPFv3 [OSPFV3] has been defined to support the base IPv6 unicast
Address Family (AF). There are requirements to advertise other AFs
in OSPFv3 including multicast IPv6, unicast IPv4, and multicast IPv4.
This document supports these other AFs in OSPFv3 by mapping each AF
to a separate Instance ID and OSPFv3 instance.
1.1. Design Considerations
This section describes the rationale for using the multiple instance
ID approach to support multiple address families in OSPFv3. As
described earlier, OSPFv3 is designed to support multiple instances.
Hence mapping an instance to an address family doesn't introduce any
new mechanisms to the protocol. It minimizes the protocol extensions
required and it simplifies the implementation. The presence of a
separate link state database per address family is also easier to
debug and operate. Additionally, it doesn't change the existing
instance, area, and interface based configuration model in most
OSPFv3 implementations.
1.2. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC-KEYWORDS].
Lindem (Editor), et al. Expires April 4, 2009 [Page 3]
Internet-Draft OSPFv3 AF Oct 2008
2. Protocol Details
Currently the entire Instance ID number space is used for IPv6
unicast. This specification assigns different Instance ID ranges to
different AFs in order to support other AFs in OSPFv3. Each Instance
ID implies a separate OSPFv3 instance with its own neighbor
adjacencies, link state database, protocol data structures, and
shortest path first (SPF) computation. Additionally, the current
LSAs that are defined to advertise IPv6 unicast prefixes can be used
without any modifications to advertise prefixes from other AFs.
It should be noted that OSPFv3 is running on top of IPv6 and uses
IPv6 link local addresses for OSPFv3 control packets. Therefore, it
is required that IPv6 be enabled on a link, although the link may not
be participating in any IPv6 AF.
2.1. Instance ID values for new AFs
Instance ID zero is already defined by default for the IPv6 unicast
AF. We define the following ranges for different AFs. The first
value of each range is considered as the default value for the
corresponding AF.
Instance ID # 0 - # 31 IPv6 unicast AF
Instance ID # 32 - # 63 IPv6 multicast AF
Instance ID # 64 - # 95 IPv4 unicast AF
Instance ID # 96 - # 127 IPv4 multicast AF
Instance ID # 128 - # 255 Unassigned
OSPFv3 Instance IDs
2.2. OSPFv3 Options and Prefix Options Changes
A new AF-bit is added to the OSPFv3 options field. V6-bit and MC-bit
are only applicable to the IPv6 unicast AF.
2.2.1. OSPFv3 Options
1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+-+-+--+--+--+
| | | | | | | | | | | | | | | |AF|*|*|DC|R|N|MC| E|V6|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+-+-+--+--+--+
The Options field
Lindem (Editor), et al. Expires April 4, 2009 [Page 4]
Internet-Draft OSPFv3 AF Oct 2008
OSPFv3 Options
V6-bit
The V6 bit is used in OSPFv3 to exclude a node from IPv6 unicast
route calculation but allow it in the SPF calculation for other
address families. Since Instance ID now denotes the AF
explicitly, this bit is ignored in AFs other than IPv6 unicast.
MC-bit
This bit is not used in other AFs introduced in this document.
AF-bit
When a router supports AF, it MUST set this new bit in the OSPFv3
Options field of Hello Packets, DD packets, and LSAs.
2.2.2. Prefix Options
0 1 2 3 4 5 6 7
+--+--+--+--+--+--+--+--+
| | | |DN| P|x |LA|NU|
+--+--+--+--+--+--+--+--+
Prefix Options
NU-bit
The "no unicast" capability bit. If set, the prefix should be
excluded from IPv6 unicast calculations. If not set, it should be
included. It SHOULD be cleared in advertised prefixes for
multicast AFs and MUST be ignored for received prefixes for
multicast AFs.
x-bit
This bit will be deprecated in a future version of [OSPFV3]. It
may be reassigned in the future.
The LA-bit, P-bit, and DN-bit are described in [OSPFV3]. Note that
all bits unused in a given AF MAY be redefined for AF specific
purposes in future specifications.
2.3. Advertising Prefixes in new AFs
Each Prefix defined in OSPFv3 has a prefix length field. This
facilitate advertising prefixes of different lengths in different
AFs. The existing LSAs defined in OSPFv3 are used for this purpose
Lindem (Editor), et al. Expires April 4, 2009 [Page 5]
Internet-Draft OSPFv3 AF Oct 2008
and there is no need to define new LSAs.
2.4. Changes to the Hello processing
When a router does not support an AF but it is configured with the
corresponding Instance ID packets could be black holed. This could
happen due to misconfiguration or a router software downgrade. Black
holing is possible because the router which doesn't support the AF
can still be included in the SPF calculated path as long as it
establishes adjacencies using the Instance ID corresponding to the
AF. Note that router and network LSAs are AF independent.
In order to avoid the above situation, hello processing is changed in
order to only establish adjacencies with routers that have the AF-bit
set in their Options field.
Receiving Hello Packets is specified in section 3.2.2.1 of [OSPFV3].
The following check is added to Hello reception:
o When a router participates in an AF (sets the AF-bit in Options
field) it MUST discard Hello packets having the AF-bit clear in
the Options field. The only exception is the Base IPv6 unicast
AF, where this check MUST NOT be done (for backward
compatibility).
2.5. Next hop for IPv4 unicast and multicast AFs
OSPFv3 runs on top of IPv6 and uses IPv6 link local addresses for
OSPFv3 control packets and next hop calculations. Although IPV6 link
local addresses could be used as next hops for IPv4 address families,
it is desirable to have IPv4 next hop addresses. For example, in
IPv4 multicast having the next hop address the same as the Protocol
Independent Multicast (PIM) [PIM] neighbor address (IPv4 address)
makes it easier to determine which upstream neighbor to send a PIM
join when doing a Reverse Path Forwarding (RPF) lookup. It is also
easier for troubleshooting to have a next hop with the same AF.
In order to achieve this, the link's IPv4 address will be advertised
in the "link local address" field of the IPv4 instance's Link-LSA.
This address is placed in the first 32 bit of "link local address"
field and used for IPv4 next hop calculations. The remaining bits
MUST be set to zero.
We call direct interface address (DIA) the address that is reachable
directly via the link provided that a layer 3 to layer 2 mapping is
available. Note that there is no explicit need for the IPv4 link
addresses to be on the same subnet. An implementation should resolve
layer 3 to layer 2 mappings via Address Resolution Protocol (ARP)
Lindem (Editor), et al. Expires April 4, 2009 [Page 6]
Internet-Draft OSPFv3 AF Oct 2008
[ARP] or Neighbor Discovery (ND) [ND] for a DIA even if the IPv4
address is not on the same subnet as the router's interface IP
address.
2.6. AS External LSA Forwarding Address for IPv4 Unicast and IPv4
Multicast AFs
For OSPFv3, this address is fully qualified IPv6 address (128 bits).
If included, data traffic for the advertised destination will be
forwarded to this address. For IPv4 unicast and IPv4 multicast AFs,
the Forwarding address in AS-external-LSAs MUST encode an IPv4
address. To achieve this, the IPv4 Forwarding address is advertised
by placing it in the first 32 bits of the Forwarding address field in
the AS-external-LSAs. The remaining bits MUST be set to zero.
2.7. Database Description Maximum Transmissoin Unit (MTU)
Specification for Non-IPv6 AFs
For address families other than IPv6, both the MTU for the address
family of the instance and IPv6 MTU used for OSPFv3 maximum packet
determination must be considered. The MTU in the Database
Description packet MUST always contain the MTU corresponding to the
advertised address family. For example, if the instance corresponds
to an IPv4 address family, the IPv4 MTU for the interface MUST be
specified in the interface MTU field. As specified section 10.6 of
[OSPFV2], the Database Description packet will be rejected if the MTU
is greater than the receiving interface's MTU for the address family
corresponding to the instance. This behavior will assure an
adjacency is not formed and address family specific routes are not
installed over a path with conflicting MTUs.
The value used for OSPFv3 maximum packet size determination must also
be compatible for an adjacency to be established. Since only a
single MTU field is specified, the M6-bit is defined by this
specification. If the M6-bit is clear, the specified MTU should also
be checked against the IPv6 MTU and the Database Description packet
should be rejected if the MTU is larger than the receiving
interface's IPv6 MTU. An OSPFv3 router SHOULD NOT set the M6-bit if
its IPv6 MTU and address family specific MTU are the same.
If the IPv6 and IPv4 MTUs differ, the M6-bit MUST be set for non-IPv6
address families. If the M6-bit is set, the IPv6 MTU is decided by
the presence or absense of IPv6 MTU TLV in the LLS [LLS] block. If
this TLV is present, it carries the IPv6 MTU which should be compared
with local IPv6 MTU. If this TLV is absent, the minimum IPv6 MTU of
1280 octets should be used for the comparison (refer to [IPV6]).
If the M6-bit is set in a received Database Description packet for a
Lindem (Editor), et al. Expires April 4, 2009 [Page 7]
Internet-Draft OSPFv3 AF Oct 2008
non-IPv6 address family, the receiving router MUST NOT check the
Interface MTU in the Database Exchange packet against the receiving
interface's IPv6 MTU.
The figure below graphically depicts the OSPFv3 Database Description
Packet:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| 3 | 2 | Packet Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| Area ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| Checksum | Instance ID | 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| 0 | Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| Interface MTU | 0 |0|0|0|M6|0|I|M|MS|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| DD sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| |
+- -+
| |
+- An LSA Header -+
| |
+- -+
| |
+- -+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
| ... |
The OSPFv3 Database Description Packet
The changed fields in the Database Description packet are described
below. The remaining fields are unchanged from [OSPFV3].
Interface MTU
The size in octets of the largest address-family specific datagram
that can be sent out the associated interface without
fragmentation. The MTUs of common Internet link types can be
found in Table 7-1 of [MTUDISC]. Interface MTU should be set to 0
in Database Description packets sent over virtual links.
Lindem (Editor), et al. Expires April 4, 2009 [Page 8]
Internet-Draft OSPFv3 AF Oct 2008
M6-bit
The IPv6 MTU bit - this bit indicates the sender is using a
different IPv6 MTU than the MTU for the address family.
IPv6 MTU TLV can be optionally carried in LLS block as described
above. This TLV carries the IPv6 MTU on the interface. The length
field of of TLV is set to 4 bytes.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 3 (TBD) | 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Format of IPv6 MTU TLV
The IPv6 MTU TLV may appear in the LLS block only once.
2.8. Operation over Virtual Links
OSPFv3 control packets sent over a virtual link are IPv6 packets and
may traverse multiples hops. Therefore, there must be a global IPv6
address associated with the virtual link so that the control packet
is forwarded correctly by the intermediate hops between virtual link
endpoints. Although this requirement can be satisfied in IPv6
unicast AFs, it will not function in other AFs as there will not be a
routable global IPv6 address or forwarding path. Therefore, virtual
links are not supported in AFs other than IPv6 Unicast.
Lindem (Editor), et al. Expires April 4, 2009 [Page 9]
Internet-Draft OSPFv3 AF Oct 2008
3. Backward Compatibility
In this section, we will define a non-capable OSPFv3 router as one
not supporting this specification. Each new AF will have a
corresponding Instance ID and can interoperate with the existing non-
capable OSPFv3 routers in an IPv6 unicast topology. Furthermore,
when a non-capable OSPFv3 router uses an Instance ID which is
reserved for a given AF, no adjacency will be formed with this router
since the AF-bit in the Options field will not be set in Hello
packets. Therefore, there are no backward compatibility issues. AFs
can be gradually deployed without disturbing networks with non-
capable OSPFv3 routers.
Lindem (Editor), et al. Expires April 4, 2009 [Page 10]
Internet-Draft OSPFv3 AF Oct 2008
4. Security Considerations
IPsec [IPsec]. can be used for OSPFv3 authentication and
confidentiality as described in [OSPFV3-AUTH]. When multiple OSPFv3
instances use the same interface, they all must use the same Security
Association (SA), since the SA selectors do not provide selection
based on OSPFv3 header fields such as the instance ID. This
restriction is documented in section 8 of [OSPFV3-AUTH].
Security considerations for the OSPFv3 are covered in [OSPFV3].
Lindem (Editor), et al. Expires April 4, 2009 [Page 11]
Internet-Draft OSPFv3 AF Oct 2008
5. IANA Considerations
The following IANA assignments are to be made from existing
registries:
AF-bit is assigned from OSPFv3 Options field as defined in
Section 2.2.1.
IANA is requested to create a new registry, "OSPFv3 Instance ID
Address Family Values". for assignment of address families IDs. Note
that the Instance ID MAY be used for applications other than the
support of multiple address families. However, if it is being used
for address families the assignments herein should be honored.
+-------------+----------------------+--------------------+
| Value/Range | Designation | Assignment Policy |
+-------------+----------------------+--------------------+
| 0 | Base IPv6 Unicast AF | Already assigned |
| | | |
| 1-31 | IPv6 Unicast AFs | Already assigned |
| | dependent on local | |
| | policy | |
| | | |
| 32 | Base IPv6 Multicast | Already assigned |
| | | |
| 33-63 | IPv6 Multicast AFs | Already assigned |
| | dependent on local | |
| | policy | |
| | | |
| 64 | Base IPv4 Unicast AF | Already assigned |
| | | |
| 65-95 | IPv4 Unicast AFs | Already assigned |
| | dependent on local | |
| | policy | |
| | | |
| 96 | Base IPv4 Multicast | Already assigned |
| | | |
| 97-127 | IPv4 Multicast AFs | Already assigned |
| | dependent on local | |
| | policy | |
| | | |
| 128-255 | Unassigned | Standards Action |
+-------------+----------------------+--------------------+
OSPFv3 Address Family Use of Instance IDs
Lindem (Editor), et al. Expires April 4, 2009 [Page 12]
Internet-Draft OSPFv3 AF Oct 2008
o Instancs IDs 0-127 are assigned by this specification.
o Instance IDs in the range 128-255 are not assigned at this time.
Before any assignments can be made in this range, there MUST be a
Standards Track RFC including IANA Considerations explicitely
specifying the AF Instance IDs being assigned.
M6-Bit is assigned as defined in Section 2.7.
A TLV type for IPv6 MTU TLV is assigned from OSPF LLS TLVs registry.
Lindem (Editor), et al. Expires April 4, 2009 [Page 13]
Internet-Draft OSPFv3 AF Oct 2008
6. References
6.1. Normative References
[IPV6] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[IPsec] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.
[OSPFV2] Moy, J., "OSPF Version 2", RFC 2328, April 1998.
[OSPFV3] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, July 2008.
[OSPFV3-AUTH]
Gupta, M. and S. Melam, "Authentication/Confidentiality
for OSPFv3", RFC 4552, June 2006.
[RFC-KEYWORDS]
Bradner, S., "Key words for use in RFC's to Indicate
Requirement Levels", RFC 2119, March 1997.
6.2. Informative References
[ARP] Plummer, D., "An Ethernet Address Resolution Protocol",
RFC 826, November 1982.
[LLS] Zinin, A., Roy, A., Nguyen, L., Friedman, B., and D.
Young, "OSPF Link-local Signaling",
draft-ietf-ospf-lls-05.txt, Work in progress.
[MTUDISC] Mogul, J. and S. Deering, "Path MTU Discovery", RFC 1191,
November 1990.
[ND] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861,
September 2007.
[PIM] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006.
Lindem (Editor), et al. Expires April 4, 2009 [Page 14]
Internet-Draft OSPFv3 AF Oct 2008
Appendix A. Acknowledgments
The RFC text was produced using Marshall Rose's xml2rfc tool.
Thanks to Tom Henderson and the folks at Boeing for implementing in
quagga.
Thanks to Nischal Seth for review and comments.
Lindem (Editor), et al. Expires April 4, 2009 [Page 15]
Internet-Draft OSPFv3 AF Oct 2008
Authors' Addresses
Acee Lindem
Redback Networks
102 Carric Bend Court
Cary, NC 27519
USA
Email: acee@redback.com
Sina Mirtorabi
Cisco Systems
3 West Plumeria Drive
San Jose, CA 95134
USA
Email: smirtora@cisco.com
Abhay Roy
Cisco Systems
225 West Tasman Drive
San Jose, CA 95134
USA
Email: akr@cisco.com
Michael Barnes
Cisco Systems
225 West Tasman Drive
San Jose, CA 95134
USA
Email: mjbarnes@cisco.com
Rahul Aggarwal
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
USA
Email: rahul@juniper.net
Lindem (Editor), et al. Expires April 4, 2009 [Page 16]
Internet-Draft OSPFv3 AF Oct 2008
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
Lindem (Editor), et al. Expires April 4, 2009 [Page 17]
