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Internet Engineering Task Force (IETF)
Request for Comments: 7153
Updates: 4360, 5701
Category: Standards Track
ISSN: 2070-1721
E. Rosen
Cisco Systems, Inc.
Y. Rekhter
Juniper Networks, Inc.
March 2014

IANA Registries for BGP Extended Communities

Abstract

This document reorganizes the IANA registries for the type values and sub-type values of the BGP Extended Communities attribute and the BGP IPv6-Address-Specific Extended Communities attribute. This is done in order to remove interdependencies among the registries, thus making it easier for IANA to determine which codepoints are available for assignment in which registries. This document also clarifies the information that must be provided to IANA when requesting an allocation from one or more of these registries. These changes are compatible with the existing allocations and thus do not affect protocol implementations. The changes will, however, impact the "IANA Considerations" sections of future protocol specifications. This document updates RFC 4360 and RFC 5701.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7153.

Copyright Notice

Copyright © 2014 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................3
   2. Types, Sub-Types, and Registries ................................4
   3. Applicability to IPv6-Address-Specific EC Attribute .............4
   4. How to Request EC Type and/or Sub-Type Codepoints ...............5
   5. IANA Considerations .............................................6
      5.1. Registries for the "Type" Field ............................7
           5.1.1. Transitive Types ....................................7
           5.1.2. Non-Transitive Types ................................8
      5.2. Registries for the "Sub-Type" Field ........................9
           5.2.1. EVPN Extended Community Sub-Types ...................9
           5.2.2. Transitive Two-Octet AS-Specific Extended Community
                  Sub-Types ..........................................10
           5.2.3. Non-Transitive Two-Octet AS-Specific Extended
                  Community Sub-Types ................................10
           5.2.4. Transitive Four-Octet AS-Specific Extended
                  Community Sub-Types ................................11
           5.2.5. Non-Transitive Four-Octet AS-Specific Extended
                  Community Sub-Types ................................11
           5.2.6. Transitive IPv4-Address-Specific Extended Community
                  Sub-Types ..........................................12
           5.2.7. Non-Transitive IPv4-Address-Specific Extended
                  Community Sub-Types ................................12
           5.2.8. Transitive Opaque Extended Community Sub-Types .....13
           5.2.9. Non-Transitive Opaque Extended Community
                  Sub-Types ..........................................13
           5.2.10. Generic Transitive Experimental Use Extended
                   Community Sub-Types ...............................14
           5.2.11. Registries for the "Value" Field ..................14
                  5.2.11.1. Traffic Action Fields ....................14
      5.3. Registries for IPv6-Address-Specific ECs ..................15
           5.3.1. Transitive Types ...................................15
           5.3.2. Non-Transitive Types ...............................15
   6. Security Considerations ........................................15
   7. Acknowledgments ................................................16
   8. Normative References ...........................................16

1. Introduction

RFC 4360 [RFC4360] defines the BGP "Extended Communities" (EC) attribute. This attribute consists of a sequence of eight-octet "extended communities". The high-order octet is defined to be the "Type" field. Each Type has a range of values for "Transitive Extended Community Types" and a range of values for "Non-transitive Extended Community Types". Some of these ranges are further subdivided into a sub-range of values to be assigned by IANA under the "Standards Action" policy, a sub-range of values to be assigned 

   by IANA under the "First Come First Served" policy, and a sub-range
   for "experimental use".  (See [RFC5226], [RFC7120], and [RFC3692] for
   an explanation of these policies.)

For some Extended Community Types, the second octet of the Extended Community is a "Sub-Type" field, and the remaining six octets are the "Value" field. These are referred to as "Extended Types". For other types, there is no "Sub-Type" field, and the "Value" field contains seven octets. These are referred to as "Regular Types".

RFC 4360 is not very specific about how the IANA registries for Extended Community Types and/or Sub-Types are to be organized, and this has led to some confusion. The purpose of this document is to reorganize the registries to make the IANA codepoint allocation task more straightforward.

2. Types, Sub-Types, and Registries

The high-order octet of an Extended Community will be known as the "Type" field.

There will be one IANA registry for "Transitive Extended Community Types" (see Section 5.1.1) and one for "Non-transitive Extended Community Types" (Section 5.1.2). Each registry specifies three ranges, and each range is associated with a particular IANA allocation policy.

There will be a set of IANA registries for Extended Community Sub-Types (see Section 5.2). Each such registry will have a range of 0x00-0xFF. Values in the range 0x00-0xBF are assignable by IANA according to the "First Come First Served" allocation policy of [RFC5226]. Values in the range 0xC0-0xFF are assignable by IANA according to the "IETF Review" allocation policy of [RFC5226].

If a particular Type has Sub-Types, that Type's entry in its Type registry identifies its Sub-Type registry. Note that some Types do not have Sub-Types. When the request is made to establish a new Type registry, the request must specify whether or not there is to be a Sub-Type registry associated with that Type.

Whether a given Type has Sub-Types is determined when the Type is initially defined; this cannot be changed later.

3. Applicability to IPv6-Address-Specific EC Attribute

RFC 5701 [RFC5701] defines the IPv6-Address-Specific Extended Community to be a 20-octet quantity whose high-order two octets may be considered to be the "Type" field. The high-order octet is either

0x00, indicating a transitive Extended Community; or 0x40, indicating a Non-transitive Extended Community. The second octet is said to be a "Sub-Type", and it is suggested that the Sub-Types are the same as the Sub-Types for the IPv4-Address-Specific Extended Community. However, the existing IANA codepoint allocations for this octet do not always match the corresponding allocations for the IPv4-Address-Specific Extended Community Sub-Types.

This document modifies RFC 5701 by removing any requirement for the values of the second octet of the IPv6-Address-Specific Extended Community Type codepoints to match the codepoints in either of the IPv4-Address-Specific Sub-Types registries.

This document requests IANA to create two IPv6-Address-Specific Extended Community registries -- one for transitive communities and one for non-transitive communities. See Section 5.3.

4. How to Request EC Type and/or Sub-Type Codepoints

When a codepoint is needed for a new Extended Community, the requester should first determine whether an existing Type can be used. If so, IANA should be asked to allocate a codepoint from the corresponding Sub-Type registry, if there is one.

If a new Extended Community Type is needed, the requester should ask IANA to allocate a new type from the "BGP Transitive Extended Community Types" registry, the "BGP Non-Transitive Extended Community Types" registry, or both. It is up to the requester to state whether an allocation is needed from one or both of these registries. When an allocation from both registries is requested, the requester may find it desirable for both allocations to share the same low-order six bits. If so, it is the responsibility of the requester to explicitly request this of IANA.

Of course, any request for a codepoint from a particular registry must follow the defined registration procedures for that registry.

If a new Extended Community Type is needed and the new Type is to have Sub-Types, the requester should specify whether an existing Sub-Type registry can be used for the new Type or a new Sub-Type registry is needed. (At the current time, every Type that has Sub-Types is associated with a unique Sub-Type registry. It is possible that in the future a new Type registry may be created that is associated with a pre-existing Sub-Type registry.) In either case, if a new Sub-Type value needs to be allocated from a particular Sub-Type registry, the request should explicitly identify the registry.

If the creation of a new Sub-Type registry is requested, the range of values is always 0x00-0xFF. It is recommended that the allocation policy described in Section 2 be used, i.e., 0x00-0xBF to be allocated by IANA under the "First Come First Served" policy and 0xC0-0xFF to be allocated by IANA under the "IETF Review" policy.

Commonly, a new Extended Community is defined such that it can be of several Types. For example, one may want to define a new Extended Community so that it can be either transitive or non-transitive, either the two-octet AS Number Type or the four-octet AS Number Type, etc. The requester is responsible for explicitly asking IANA to allocate codepoints in all the necessary Type and/or Sub-Type registries.

When a new Extended Community is defined, it may be necessary to ask IANA to allocate codepoints in several Sub-Type registries. In this case, it is a common practice to ask IANA to allocate the same codepoint value in each registry. If this is desired, it is the responsibility of the requester to explicitly ask IANA to allocate the same value in each registry.

When a new Extended Community Sub-Type codepoint is allocated, it may also be desirable to allocate a corresponding value in one or both of the IPv6-Address-Specific Extended Community registries. The requester is responsible for requesting this allocation explicitly. If the requester would like the same numerical value to be allocated in an IPv6-Address-Specific Extended Community registry that is allocated in some other registry, it is the responsibility of the requester to explicitly ask this of IANA.

5. IANA Considerations

IANA has replaced the pre-existing BGP Extended Communities registries with the registries described in this section.

The registries reproduced below do not include the "references" or "date" fields for the individual codepoints in the registries, because it is difficult to incorporate those within the 72-character line limitation of RFCs. The references and associated dates have been copied from the existing registries when creating the new registries; the authors have worked with IANA to ensure that this information has been carried over correctly to the reorganized registry. As this document does not change the usage or semantics of any of the codepoints, the references associated with the individual codepoints do not change.

On the other hand, the references for each of the registries defined in this section have been changed to refer to this document.

5.1. Registries for the "Type" Field

5.1.1. Transitive Types

The following note has been added to the "BGP Transitive Extended Community Types" registry.

This registry contains values of the high-order octet (the "Type" field) of a Transitive Extended Community.

Registry Name: BGP Transitive Extended Community Types 

      RANGE            REGISTRATION PROCEDURES
      
      0x00-0x3F        First Come First Served
      0x80-0x8F        Experimental Use (see RFC 3692)
      0x90-0xBF        Standards Action
      
      TYPE VALUE       NAME
      
      0x00             Transitive Two-Octet AS-Specific Extended
                       Community (Sub-Types are defined in the
                       "Transitive Two-Octet AS-Specific Extended
                       Community Sub-Types" registry)
      
      0x01             Transitive IPv4-Address-Specific Extended
                       Community (Sub-Types are defined in the
                       "Transitive IPv4-Address-Specific Extended
                       Community Sub-Types" registry)
      
      0x02             Transitive Four-Octet AS-Specific Extended
                       Community (Sub-Types are defined in the
                       "Transitive Four-Octet AS-Specific Extended
                       Community Sub-Types" registry)
      
      0x03             Transitive Opaque Extended Community
                       (Sub-Types are defined in the "Transitive
                       Opaque Extended Community Sub-Types"
                       registry)
      
      0x04             QoS Marking
      
      0x05             CoS Capability
      
      0x06             EVPN (Sub-Types are defined in the "EVPN
                       Extended Community Sub-Types" registry)
      
      0x08             Flow spec redirect/mirror to IP next-hop
      0x80             Generic Transitive Experimental Use Extended
                       Community (Sub-Types are defined in the
                       "Generic Transitive Experimental Use Extended
                       Community Sub-Types" registry)

5.1.2. Non-Transitive Types

The following note has been added to the "BGP Non-Transitive Extended Community Types" registry.

This registry contains values of the high-order octet (the "Type" field) of a Non-transitive Extended Community.

Registry Name: BGP Non-Transitive Extended Community Types 

      RANGE            REGISTRATION PROCEDURES
      
      0x40-0x7F        First Come First Served
      0xC0-0xCF        Experimental Use (see RFC 3692)
      0xD0-0xFF        Standards Action
      
      TYPE VALUE       NAME
      
      0x40             Non-Transitive Two-Octet AS-Specific Extended
                       Community (Sub-Types are defined in the
                       "Non-Transitive Two-Octet AS-Specific Extended
                       Community Sub-Types" registry)
      
      0x41             Non-Transitive IPv4-Address-Specific Extended
                       Community (Sub-Types are defined in the
                       "Non-Transitive IPv4-Address-Specific Extended
                       Community Sub-Types" registry)
      
      0x42             Non-Transitive Four-Octet AS-Specific Extended
                       Community (Sub-Types are defined in the
                       "Non-Transitive Four-Octet AS-Specific Extended
                       Community Sub-Types" registry)
      
      0x43             Non-Transitive Opaque Extended Community
                       (Sub-Types are defined in the "Non-Transitive
                       Opaque Extended Community Sub-Types" registry)
      
      0x44             QoS Marking

5.2. Registries for the "Sub-Type" Field

5.2.1. EVPN Extended Community Sub-Types

The following note has been added to the "EVPN Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x06.

Registry Name: EVPN Extended Community Sub-Types 

      RANGE              REGISTRATION PROCEDURE
      
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
      
      SUB-TYPE VALUE     NAME
      
      0x00               MAC Mobility
      0x01               ESI MPLS Label
      0x02               ES Import

5.2.2. Transitive Two-Octet AS-Specific Extended Community Sub-Types

The following note has been added to the "Transitive Two-Octet AS-Specific Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x00. 

   Registry Name: Transitive Two-Octet AS-Specific Extended
                  Community Sub-Types
   
      RANGE              REGISTRATION PROCEDURE
   
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
   
      SUB-TYPE VALUE     NAME
   
      0x02               Route Target
      0x03               Route Origin
      0x05               OSPF Domain Identifier
      0x08               BGP Data Collection
      0x09               Source AS
      0x0A               L2VPN Identifier
      0x10               Cisco VPN-Distinguisher

5.2.3. Non-Transitive Two-Octet AS-Specific Extended Community

Sub-Types

The following note has been added to the "Non-Transitive Two-Octet AS-Specific Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x40. 

   Registry Name: Non-Transitive Two-Octet AS-Specific Extended
                  Community Sub-Types
   
      RANGE              REGISTRATION PROCEDURE
   
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
   
      SUB-TYPE VALUE     NAME
   
      0x04               Link Bandwidth Extended Community

5.2.4. Transitive Four-Octet AS-Specific Extended Community Sub-Types

The following note has been added to the "Transitive Four-Octet AS-Specific Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x02. 

   Registry Name: Transitive Four-Octet AS-Specific Extended
                  Community Sub-Types
   
      RANGE              REGISTRATION PROCEDURE
   
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
   
      SUB-TYPE VALUE     NAME
   
      0x02               Route Target
      0x03               Route Origin
      0x04               Generic
      0x05               OSPF Domain Identifier
      0x08               BGP Data Collection
      0x09               Source AS
      0x10               Cisco VPN Identifier

5.2.5. Non-Transitive Four-Octet AS-Specific Extended Community

Sub-Types

The following note has been added to the "Non-Transitive Four-Octet AS-Specific Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x42. 

   Registry Name: Non-Transitive Four-Octet AS-Specific
                  Extended Community Sub-Types
   
      RANGE              REGISTRATION PROCEDURE
   
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
   
      SUB-TYPE VALUE     NAME
   
      0x04               Generic

5.2.6. Transitive IPv4-Address-Specific Extended Community Sub-Types

The following note has been added to the "Transitive IPv4-Address-Specific Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x01. 

   Registry Name: Transitive IPv4-Address-Specific Extended
                  Community Sub-Types
   
      RANGE              REGISTRATION PROCEDURE
   
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
   
      SUB-TYPE VALUE     NAME
   
      0x02               Route Target
      0x03               Route Origin
      0x05               OSPF Domain Identifier
      0x07               OSPF Route ID
      0x0A               L2VPN Identifier
      0x0B               VRF Route Import
      0x10               Cisco VPN-Distinguisher

5.2.7. Non-Transitive IPv4-Address-Specific Extended Community

Sub-Types

The following note has been added to the "Non-Transitive IPv4-Address-Specific Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x41. 

   Registry Name: Non-Transitive IPv4-Address-Specific Extended
                  Community Sub-Types
   
      RANGE            REGISTRATION PROCEDURE
   
      0x00-0xBF        First Come First Served
      0xC0-0xFF        IETF Review
   
      None Assigned

5.2.8. Transitive Opaque Extended Community Sub-Types

The following note has been added to the "Transitive Opaque Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x03.

Registry Name:

Transitive Opaque Extended Community
Sub-Types 

       RANGE             REGISTRATION PROCEDURE
       
       0x00-0xBF         First Come First Served
       0xC0-0xFF         IETF Review
       
       SUB-TYPE VALUE    NAME
       
       0x06              OSPF Route Type
       0x0B              Color Extended Community
       0x0C              Encapsulation Extended Community
       0x0D              Default Gateway

5.2.9. Non-Transitive Opaque Extended Community Sub-Types

The following note has been added to the "Non-Transitive Opaque Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x43.

Registry Name: 

                  Non-Transitive Opaque Extended Community
                  Sub-Types
      
      RANGE              REGISTRATION PROCEDURE
      
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
      
      SUB-TYPE VALUE     NAME
      
      0x00               BGP Origin Validation State

5.2.10. Generic Transitive Experimental Use Extended Community

Sub-Types

The following note has been added to the "Generic Transitive Experimental Use Extended Community Sub-Types" registry:

This registry contains values of the second octet (the "Sub-Type" field) of an extended community when the value of the first octet (the "Type" field) is 0x80.

Registry Name: Generic Transitive Experimental Use Extended Community Sub-Types 

      RANGE              REGISTRATION PROCEDURE
      
      0x00-0xBF          First Come First Served
      0xC0-0xFF          IETF Review
      
      SUB-TYPE VALUE     NAME
      
      0x06               Flow spec traffic-rate
      0x07               Flow spec traffic-action (Use of the
                         "Value" field is defined in the
                         "Traffic Action Fields" registry)
      0x08               Flow spec redirect
      0x09               Flow spec traffic-remarking
      0x0A               Layer2 Info Extended Community

Note: RFC 5575 contains narrative text that declares the "Flow spec traffic-rate" to be non-transitive but then assigns it a codepoint that indicates that it is transitive. Addressing this error in RFC 5575 is not within the scope of this document.

5.2.11. Registries for the "Value" Field

At the time of the writing of this document, there is only one registry containing codepoints for the "Value" field of an Extended Community.

5.2.11.1. Traffic Action Fields

This registry has not been modified.

5.3. Registries for IPv6-Address-Specific ECs

5.3.1. Transitive Types

The following note has been added to the "Transitive IPv6-Address-Specific Extended Community Types" registry:

This registry contains values of the two high-order octets of an IPv6-Address-Specific Extended Community. 

   Registry Name: Transitive IPv6-Address-Specific Extended
                  Community Types
   
      RANGE              REGISTRATION PROCEDURE
   
      0x0000-0x00FF      First Come First Served
   
      TYPE VALUE         NAME
   
      0x0002             Route Target
      0x0003             Route Origin
      0x0004             OSPFv3 Route Attributes (deprecated)
      0x000B             VRF Route Import
      0x0010             Cisco VPN-Distinguisher
      0x0011             UUID-based Route Target

5.3.2. Non-Transitive Types

The following note has been added to the "Non-Transitive IPv6-Address-Specific Extended Community Types" registry:

This registry contains values of the two high-order octets of an IPv6-Address-Specific Extended Community. 

   Registry Name: Non-Transitive IPv6-Address-Specific Extended
                  Community Types
   
      RANGE              REGISTRATION PROCEDURE
   
      0x4000-0x40FF      First Come First Served
   
      None assigned

6. Security Considerations

No security considerations are raised by this document.

7. Acknowledgments

The authors wish to thank Jon Mitchell, Hyojeong Kim, and Pearl Liang for their review and comments.

The authors wish to thank Amanda Baber of IANA for educating us on some of the problems faced by IANA staff when responding to requests for BGP Extended Community Type and Sub-Type codepoint allocations.

8. Normative References

   [RFC3692]  Narten, T., "Assigning Experimental and Testing Numbers
              Considered Useful", BCP 82, RFC 3692, January 2004.
   
   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, February 2006.
   
   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.
   
   [RFC5701]  Rekhter, Y., "IPv6 Address Specific BGP Extended Community
              Attribute", RFC 5701, November 2009.
   
   [RFC7120]  Cotton, M., "Early IANA Allocation of Standards Track Code
              Points", BCP 100, RFC 7120, January 2014.

Authors' Addresses

   Yakov Rekhter
   Juniper Networks
   1194 North Mathilda Ave.
   Sunnyvale, CA  94089

EMail: 

          yakov@juniper.net
   
   Eric C. Rosen
   Cisco Systems, Inc.
   1414 Massachusetts Avenue
   Boxborough, MA  01719

EMail: 

          erosen@cisco.com