Network Working Group K. Kompella

Network Working Group K. Kompella
Request for Comments: 4940 Juniper Networks
BCP: 130 B. Fenner
Category: Best Current Practice AT&T Labs--Research
June 2007

IANA Considerations for OSPF

Status of This Memo

This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The IETF Trust (2007).

Abstract

This memo creates a number of OSPF registries and provides guidance
to IANA for assignment of code points within these registries.

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RFC 4940 IANA Considerations for OSPF June 2007

Table of Contents

1. Introduction ....................................................3
1.1. Conventions Used in This Document ..........................4
2. OSPF Registries .................................................4
2.1. OSPFv2 Options .............................................4
2.2. OSPFv3 Options .............................................4
2.3. OSPF Packet Type (Both v2 and v3) ..........................4
2.3.1. OSPF Authentication Type ............................5
2.4. OSPFv2 Link State (LS) Type ................................5
2.4.1. OSPFv2 Router LSA Link Type .........................5
2.4.2. OSPFv2 Router Properties ............................6
2.5. OSPFv3 LSA Function Code ...................................6
2.5.1. OSPFv3 Prefix Options ...............................6
2.5.2. OSPFv3 Router LSA Link Type .........................6
2.6. OSPFv2 Opaque LSA Type .....................................7
2.6.1. OSPFv2 Grace LSA Top Level TLVs .....................7
3. Acknowledgments .................................................8
4. Security Considerations .........................................8
5. IANA Considerations .............................................8
5.1. OSPFv2 Options Registry ....................................8
5.2. OSPFv3 Options Registry ....................................8
5.3. OSPF Packet Type Registry ..................................9
5.4. OSPF Authentication Type Registry ..........................9
5.5. OSPFv2 Link State Type Registry ............................9
5.6. OSPFv2 Router LSA Link Type Registry ......................10
5.7. OSPFv2 Router Properties Registry .........................10
5.8. OSPFv3 LSA Function Code Registry .........................11
5.9. OSPFv3 Prefix Options Registry ............................12
5.10. OSPFv3 Router LSA Link Type Registry .....................12
5.11. OSPFv2 Opaque LSA Type Registry ..........................13
5.12. OSPFv2 Grace LSA Top Level TLV Registry ..................13
6. References .....................................................13
6.1. Normative References ......................................13
6.2. Informative References ....................................14

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RFC 4940 IANA Considerations for OSPF June 2007

1. Introduction

This memo defines various OSPF registries for IANA to set up and
maintain for OSPF code points. In some cases, this memo defines
ranges of code point values within these registries; each such range
has a different assignment policy.

The terms used in describing the assignment policies are as follows:

o Standards Action

o Experimentation

o Vendor Private Use

o Reserved

Standards Action means that assignments in that range MUST only be
made for Standards Track RFCs (as defined in [RFC2434]).

Some of the registries defined below reserve a range of values for
Experimentation. For guidelines regarding the use of such values see
[RFC3692]. Values from this range MUST NOT be assigned by IANA.
Further guidance on the use of the Experimentation range may be found
in paragraphs 4, 5, and 6 of [RFC3692]. An implementation MAY choose
to not support values from the Experimentation range. In such a
case, the protocol data structure with a code point from the
Experimentation range is ignored, unless other protocol machinery
says how to deal with it. "Ignored" in this context means that the
associated data structure is removed from the received packet before
further processing, including flooding.

Values set aside as Vendor Private Use MUST NOT be assigned by IANA.
A protocol data structure whose code point falls in this range MUST
have a disambiguating field identifying the Vendor. This identifier
consists of four octets of the Vendor's SMI (Structure of Management
Information) enterprise code (see [ENTERPRISE-NUMBERS]) in network
byte order; the location of this code must be well-defined per data
structure. An implementation that encounters a Vendor Private code
point SHOULD check whether the enterprise code is one that it
recognizes; if so, the implementation MAY choose to interpret the
code point and data structure. Otherwise, it SHOULD ignore the code
point, unless the protocol machinery says how to deal with the data
structure (as defined in the previous paragraph). This allows
multiple vendor private extensions to coexist in a network.

Values in the Reserved range MUST NOT be assigned until a Standards
Track or Best Common Practices RFC is published defining the

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assignment policy for that range. This RFC MUST be the product of
the OSPF Working Group; if the OSPF WG is terminated, then it MUST be
reviewed by an Expert Reviewer designated by the IESG.

1.1. Conventions Used in This Document

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 2119 [RFC2119].

2. OSPF Registries

This section lists the various registries for OSPF protocol code
points. Note that some of these are for OSPF, and some are specific
to a particular version of OSPF; also, some registries predate this
memo.

Registries that are specific to one version of OSPF reflect the
version number in the registry name (e.g., OSPFv2 Options). A
registry whose name does not mention a version number applies to both
OSPFv2 and OSPFv3 (e.g., OSPF Packet Type).

2.1. OSPFv2 Options

(Defined in Section A.2 of [RFC2328], updated in Section A.1 of
[RFC2370]. See also [RFC3101].)

Assignment policy: Standards Action.

2.2. OSPFv3 Options

(Defined in Section A.2 of [RFC2740])

Assignment policy: Standards Action.

2.3. OSPF Packet Type (Both v2 and v3)

(Defined in Section A.3.1 of [RFC2328])

+---------+--------------------+
| Range | Assignment Policy |
+---------+--------------------+
| 0 | Not to be assigned |
| 1-5 | Already assigned |
| 6-127 | Standards Action |
| 128-255 | Reserved |
+---------+--------------------+

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RFC 4940 IANA Considerations for OSPF June 2007

2.3.1. OSPF Authentication Type

(Defined in Section A.3.1 of [RFC2328])

(Note: this registry is called "OSPF AUTHENTICATION CODES" by IANA.)

+-------------+-------------------+
| Range | Assignment Policy |
+-------------+-------------------+
| 0-2 | Already assigned |
| 3-247 | Standards Action |
| 248-65519 | Reserved |
| 65520-65535 | Experimentation |
+-------------+-------------------+

2.4. OSPFv2 Link State (LS) Type

(Defined in Section A.4.1 of [RFC2328])

+---------+--------------------+
| Range | Assignment Policy |
+---------+--------------------+
| 0 | Not to be assigned |
| 1-11 | Already assigned |
| 12-127 | Standards Action |
| 128-255 | Reserved |
+---------+--------------------+

If a new LS Type is documented, the documentation MUST say how the
Link State ID is to be filled in, what the flooding scope of the LSA
(Link State Advertisement) is, and how backward compatibility is
maintained.

2.4.1. OSPFv2 Router LSA Link Type

(Defined in Section A.4.2 of [RFC2328])

+---------+--------------------+
| Range | Assignment Policy |
+---------+--------------------+
| 0 | Not to be assigned |
| 1-4 | Already assigned |
| 5-127 | Standards Action |
| 128-255 | Reserved |
+---------+--------------------+

There is no range for Vendor Private Use, as there is no space for an
enterprise code to identify the Vendor.

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No Experimental range is defined, due to possible backwards
compatibility issues.

If a new Router LSA Link Type is documented, the documentation SHOULD
say how the Link State ID, Link ID, and Link Data fields are to be
filled in, and how backward compatibility is maintained.

2.4.2. OSPFv2 Router Properties

(Defined in Section A.4.2 of [RFC2328], updated in [RFC3101])

This 8-bit field in the Router LSA is unnamed; it is the field
immediately following the Router LSA length.

Assignment policy: Standards Action.

2.5. OSPFv3 LSA Function Code

This registry is created by [OSPF-CAP]. This document provides the
values to be populated for values defined in Section A.4.2.1 of
[RFC2740].

2.5.1. OSPFv3 Prefix Options

(Defined in Section A.4.1.1 of [RFC2740])

Assignment policy: Standards Action.

2.5.2. OSPFv3 Router LSA Link Type

(Defined in Section A.4.3 of [RFC2740])

+---------+--------------------+
| Range | Assignment Policy |
+---------+--------------------+
| 0 | Not to be assigned |
| 1-4 | Already assigned |
| 5-127 | Standards Action |
| 128-255 | Reserved |
+---------+--------------------+

There is no range for Vendor Private Use, as there is no space for an
enterprise code to identify the Vendor.

No Experimental range is defined, due to possible backwards
compatibility issues.

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RFC 4940 IANA Considerations for OSPF June 2007

2.6. OSPFv2 Opaque LSA Type

(Defined in Section A.2 of [RFC2370])

(Note: this registry is called "OSPF Opaque LSA Option" by IANA. See
also [RFC3630].)

+---------+--------------------+
| Range | Assignment Policy |
+---------+--------------------+
| 0 | Not to be assigned |
| 1-3 | Already assigned |
| 4-127 | Standards Action |
| 128-247 | Reserved |
| 248-251 | Experimentation |
| 252-255 | Vendor Private Use |
+---------+--------------------+

In an OSPFv2 Opaque LSA with Opaque LSA Type in the Vendor Private
Use range, the first four octets of Opaque Information MUST be the
Vendor enterprise code.

A document defining a new Standards Track Opaque LSA with TLVs and
sub-TLVs MUST describe ranges and assignment policies for these TLVs.

2.6.1. OSPFv2 Grace LSA Top Level TLVs

(Defined in Appendix A of [RFC3623])

+-------------+--------------------+
| Range | Assignment Policy |
+-------------+--------------------+
| 0 | Not to be assigned |
| 1-3 | Already assigned |
| 4-255 | Standards Action |
| 256-65519 | Reserved |
| 65520-65527 | Experimentation |
| 65528-65535 | Vendor Private Use |
+-------------+--------------------+

In a Grace LSA, if a top-level TLV has a Type from the Vendor Private
Use range, the Length MUST be at least four, and the first four
octets of the Value field MUST be the Vendor enterprise code.

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RFC 4940 IANA Considerations for OSPF June 2007

3. Acknowledgments

Many thanks to Adrian Farrel and Acee Lindem for their review and
comments.

4. Security Considerations

The lack of adequate IANA guidelines may be viewed as an avenue for
Denial of Service attacks on IETF protocols (in this case, OSPFv2 and
OSPFv3), and on the IETF Standards Process in general. This memo
attempts to close this loophole for OSPFv2 and OSPFv3.

Authors contemplating extensions to OSPF SHOULD examine such
extensions carefully, and consider whether new registries are needed,
and if so, allocation policies within each registry.

5. IANA Considerations

This document specifies assignment policy for several existing IANA
registries and creates several more.

5.1. OSPFv2 Options Registry

Section 2.1 defines the policy for allocation of bits from this
registry as "Standards Action". There are only 8 bits in this field,
and 6 are already assigned. The initial registry contents are given
below.

OSPFv2 Options Registry (Section 2.1)

Value Description Reference
----- ----------- ---------
0x02 E-bit [RFC2328]
0x04 MC-bit [RFC1584]
0x08 N/P-bit [RFC3101]
0x10 Reserved
0x20 DC-bit [RFC1793]
0x40 O-bit [RFC2370]

5.2. OSPFv3 Options Registry

Section 2.2 defines the policy for allocation of bits from this
registry as "Standards Action". There are 24 bits in this field, and
6 are assigned. The initial registry contents are given below.

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OSPFv3 Options Registry (Section 2.2)

Value Description Reference
-------- ----------- ---------
0x000001 V6-bit [RFC2740]
0x000002 E-bit [RFC2328]
0x000004 MC-bit [RFC1584]
0x000008 N-bit [RFC3101]
0x000010 R-Bit [RFC2740]
0x000020 DC-bit [RFC1793]

5.3. OSPF Packet Type Registry

Section 2.3 defines the policy for allocation of values from this
registry for different ranges. The initial registry contents are
given below.

OSPF Packet Type (Section 2.3)

Value Description Reference
----- -------------------- ---------
1 Hello [RFC2328]
2 Database Description [RFC2328]
3 Link State Request [RFC2328]
4 Link State Update [RFC2328]
5 Link State Ack [RFC2328]

5.4. OSPF Authentication Type Registry

This registry already exists at IANA, called "ospf-authentication-
codes". Section 2.3.1 defines the policy for allocation from this
registry for different ranges.

5.5. OSPFv2 Link State Type Registry

Section 2.4 defines the policy for allocations from this registry for
different ranges. The initial registry contents are given below.

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OSPFv2 Link State (LS) Type (Section 2.4)

Value Description Reference
----- ------------------------ ---------
1 Router-LSA [RFC2328]
2 Network-LSA [RFC2328]
3 Summary-LSA (IP network) [RFC2328]
4 Summary-LSA (ASBR) [RFC2328]
5 AS-external-LSA [RFC2328]
6 Group-membership-LSA [RFC1584]
7 NSSA AS-external LSA [RFC3101]
8 Reserved
9 Link-local Opaque LSA [RFC2370]
10 Area-local Opaque LSA [RFC2370]
11 Opaque LSA [RFC2370]

5.6. OSPFv2 Router LSA Link Type Registry

Section 2.4.1 defines the policy for allocations from this registry
for different ranges. The initial registry contents are given below.

OSPFv2 Router LSA Link Type (Section 2.4.1)

Value Description Reference
----- ------------------------------------------- ---------
1 Point-to-Point connection to another router [RFC2328]
2 Transit Network [RFC2328]
3 Stub Network [RFC2328]
4 Virtual Link [RFC2328]

5.7. OSPFv2 Router Properties Registry

Section 2.4.2 defines the policy for allocation of bits from this
registry as "Standards Action". There are only 8 bits in this field,
and 5 are already assigned. The initial registry contents are given
below.

OSPFv2 Options Registry (Section 2.1)

Value Description Reference
----- ----------- ---------
0x01 B-bit [RFC2328]
0x02 W-bit [RFC2328]
0x04 V-bit [RFC2328]
0x08 W-bit [RFC1584]
0x10 Nt-bit [RFC3101]

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5.8. OSPFv3 LSA Function Code Registry

This registry is created by [OSPF-CAP], which also defines the
registration policy. This section contains values that belong in
this registry that were defined by [RFC2740].

As defined in [RFC2740], the first 3 bits of the LSA Function
Code are the U, S1, and S2 bits. A given function code implies a
specific setting for the U, S1, and S2 bits as shown in the "LS Type"
column.
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|U |S2|S1| LSA Function Code |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

The U bit indicates how the LSA should be handled by a router which
does not recognize the LSA's function code. Its values are:

U-bit LSA Handling
----- ----------------------------------------------------
0 Treat the LSA as if it had link-local flooding scope
1 Store and flood the LSA, as if type understood

The S1 and S2 bits indicate the flooding scope of the LSA. The
values are:

S1 S2 Flooding Scope
-- -- --------------------------------------------------------------
0 0 Link-Local Scoping. Flooded only on link it is originated on
0 1 Area Scoping. Flooded to all routers in the originating area
1 0 AS Scoping. Flooded to all routers in the AS
1 1 Reserved

The initial registry contents are given below.

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OSPFv3 LSA Function Code (Section 2.5)

LSA Function Code LS Type Description Reference
----------------- ------- --------------------- ---------
1 0x2001 Router-LSA [RFC2740]
2 0x2002 Network-LSA [RFC2740]
3 0x2003 Inter-Area-Prefix-LSA [RFC2740]
4 0x2004 Inter-Area-Router-LSA [RFC2740]
5 0x4005 AS-External-LSA [RFC2740]
6 0x2006 Group-membership-LSA [RFC2740]
7 0x2007 Type-7-LSA [RFC2740]
8 0x0008 Link-LSA [RFC2740]
9 0x2009 Intra-Area-Prefix-LSA [RFC2740]

5.9. OSPFv3 Prefix Options Registry

Section 2.5.1 defines the policy for allocation of bits from this
registry as "Standards Action". There are only 8 bits in this field,
and 4 are already assigned. The initial registry contents are given
below.

OSPFv3 Prefix Options Registry (Section 2.5.1)

Value Description Reference
----- ----------- ---------
0x01 NU-bit [RFC2740]
0x02 LA-bit [RFC2740]
0x04 MC-bit [RFC2740]
0x08 P-bit [RFC2740]

5.10. OSPFv3 Router LSA Link Type Registry

Section 2.5.2 defines the policy for allocations from this registry
for different ranges. The initial registry contents are given below.

OSPFv3 Router LSA Link Type (Section 2.5.2)

Value Description Reference
----- ------------------------------------------- ---------
1 Point-to-Point connection to another router [RFC2740]
2 Transit Network [RFC2740]
3 Reserved [RFC2740]
4 Virtual Link [RFC2740]

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RFC 4940 IANA Considerations for OSPF June 2007

5.11. OSPFv2 Opaque LSA Type Registry

This registry already exists at IANA, called "ospf-opaque-types".
Section 2.6 defines the policy for allocation from this registry for
different ranges.

5.12. OSPFv2 Grace LSA Top Level TLV Registry

Section 2.6.1 defines the policy for allocations from this registry
for different ranges. The initial registry contents are given below.

OSPFv2 Grace LSA Top Level TLV (Section 2.6.1)

Value Description Reference
----- ----------------------- ---------
1 Grace Period [RFC3623]
2 Graceful Restart reason [RFC3623]
3 IP Interface Address [RFC3623]

6. References

6.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC1584] Moy, J., "Multicast Extensions to OSPF", RFC 1584, March
1994.

[RFC1793] Moy, J., "Extending OSPF to Support Demand Circuits", RFC
1793, April 1995.

[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

[RFC2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, July
1998.

[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.

[RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", RFC
2740, December 1999.

[RFC3101] Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option",
RFC 3101, January 2003.

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RFC 4940 IANA Considerations for OSPF June 2007

[RFC3623] Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful OSPF
Restart", RFC 3623, November 2003.

[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.

[RFC3692] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692, January 2004.

6.2. Informative References

[ENTERPRISE-NUMBERS]
"PRIVATE ENTERPRISE NUMBERS",
http://www.iana.org/assignments/enterprise-numbers.

[OSPF-CAP] Lindem, A., "Extensions to OSPF for Advertising Optional
Router Capabilities", Work in Progress, May 2007.

Authors' Addresses

Kireeti Kompella
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
US

EMail: [email protected]

Bill Fenner
AT&T Labs--Research
1 River Oaks Place
San Jose, CA 95134
US

Phone: +1 (408) 493-8505
EMail: [email protected]

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RFC 4940 IANA Considerations for OSPF June 2007

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