Internet DRAFT - draft-ietf-lamps-rfc7030est-clarify
draft-ietf-lamps-rfc7030est-clarify
LAMPS Working Group M. Richardson
Internet-Draft Sandelman Software Works
Updates: 7030 (if approved) T. Werner
Intended status: Standards Track Siemens
Expires: February 12, 2021 W. Pan
Huawei Technologies
August 11, 2020
Clarification of Enrollment over Secure Transport (EST): transfer
encodings and ASN.1
draft-ietf-lamps-rfc7030est-clarify-10
Abstract
This document updates RFC7030: Enrollment over Secure Transport (EST)
to resolve some errata that were reported, and which have proven to
cause interoperability issues when RFC7030 was extended.
This document deprecates the specification of "Content-Transfer-
Encoding" headers for EST endpoints. This document fixes some
syntactical errors in ASN.1 that were present.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 12, 2021.
Copyright Notice
Copyright (c) 2020 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
(https://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Changes to EST endpoint processing . . . . . . . . . . . . . 3
3.1. Whitespace processing . . . . . . . . . . . . . . . . . . 4
3.2. Changes sections 4 of RFC7030 . . . . . . . . . . . . . . 4
3.2.1. Section 4.1.3 . . . . . . . . . . . . . . . . . . . . 4
3.2.2. Section 4.3.1 . . . . . . . . . . . . . . . . . . . . 4
3.2.3. Section 4.3.2 . . . . . . . . . . . . . . . . . . . . 5
3.2.4. Section 4.4.2 . . . . . . . . . . . . . . . . . . . . 5
3.2.5. Section 4.5.2 . . . . . . . . . . . . . . . . . . . . 5
4. Clarification of ASN.1 for Certificate Attribute set. . . . . 6
5. Clarification of error messages for certificate enrollment
operations . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Updating section 4.2.3: Simple Enroll and Re-enroll
Response . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Updating section 4.4.2: Server-Side Key Generation
Response . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
Enrollment over Secure Transport (EST) is defined in [RFC7030]. The
EST specification defines a number of HTTP end points for certificate
enrollment and management. The details of the transaction were
defined in terms of MIME headers as defined in [RFC2045], rather than
in terms of the HTTP protocol as defined in [RFC7230] and [RFC7231].
[RFC2616] and later [RFC7231] Appendix A.5 has text specifically
deprecating Content-Transfer-Encoding. However, [RFC7030]
incorrectly uses this header.
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Any updates to [RFC7030] to bring it inline with HTTP processing risk
changing the on-wire protocol in a way that is not backwards
compatible. However, reports from implementers suggest that many
implementations do not send the Content-Transfer-Encoding, and many
of them ignore it. The consequence is that simply deprecating the
header would remain compatible with current implementations.
[I-D.ietf-anima-bootstrapping-keyinfra] extends [RFC7030], adding new
functionality, and interop testing of the protocol has revealed that
unusual processing called out in [RFC7030] causes confusion.
EST is currently specified as part of [IEC62351], and is widely used
in Government, Utilities and Financial markets today.
This document therefore revises [RFC7030] to reflect the field
reality, deprecating the extraneous field.
This document deals with errata numbers [errata4384], [errata5107],
[errata5108], and [errata5904].
This document deals with [errata5107] and [errata5904] in Section 3.
[errata5108] is dealt with in Section 5. [errata4384] is closed by
correcting the ASN.1 Module in Section 4.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Changes to EST endpoint processing
The [RFC7030] sections 4.1.3 (CA Certificates Response, /cacerts),
4.3.1/4.3.2 (Full CMC, /fullcmc), 4.4.2 (Server-Side Key Generation,
/serverkeygen), and 4.5.2 (CSR Attributes, /csrattrs) specify the use
of base64 encoding with a Content-Transfer-Encoding for requests and
response.
This document updates [RFC7030] to require the POST request and
payload response of all endpoints use Base64 encoding as specified in
Section 4 of [RFC4648]. In both cases, the Distinguished Encoding
Rules (DER) [X.690] are used to produce the input for the Base64
encoding routine. This format is to be used regardless of any
Content-Transfer-Encoding header, and any value in such a header MUST
be ignored.
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3.1. Whitespace processing
Note that "base64" as used in the HTTP [RFC2616] does not permit
CRLF, while the "base64" used in MIME [RFC2045] does. This
specification clarifies that despite [RFC2616], that white space
including CR, LF, spaces (ASCII 32) and, tabs (ASCII 9) SHOULD be
tolerated by receivers. Senders are not required to insert any kind
of white space.
3.2. Changes sections 4 of RFC7030
3.2.1. Section 4.1.3
Replace:
A successful response MUST be a certs-only CMC Simple PKI Response,
as defined in [RFC5272], containing the certificates described in the
following paragraph. The HTTP content-type of
"application/pkcs7-mime" is used. The Simple PKI Response is sent
with a Content-Transfer-Encoding of "base64" [RFC2045].
with: (RFCEDITOR: maybe artwork is the wrong choice here)
A successful response MUST be a certs-only CMC Simple PKI Response,
as defined in [RFC5272], containing the certificates described in the
following paragraph. The HTTP content-type of
"application/pkcs7-mime" is used. The CMC Simple PKI Response is
encoded in base64 [RFC4648].
3.2.2. Section 4.3.1
Replace:
If the HTTP POST to /fullcmc is not a valid Full PKI Request, the
server MUST reject the message. The HTTP content-type used is
"application/pkcs7-mime" with an smime-type parameter "CMC-request",
as specified in [RFC5273]. The body of the message is the binary
value of the encoding of the PKI Request with a
Content-Transfer-Encoding of "base64" [RFC2045].
with:
If the HTTP POST to /fullcmc is not a valid Full PKI Request, the
server MUST reject the message. The HTTP content-type used is
"application/pkcs7-mime" with an smime-type parameter "CMC-request",
as specified in [RFC5273]. The body of the message is encoded
in base64 [RFC4648].
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3.2.3. Section 4.3.2
Replace:
The body of the message is the binary value of the encoding of the
PKI Response with a Content-Transfer-Encoding of "base64" [RFC2045].
with:
The body of the message is the base64 [RFC4648] encoding of the
PKI Response.
3.2.4. Section 4.4.2
Replace:
An "application/pkcs8"
part consists of the base64-encoded DER-encoded [X.690]
PrivateKeyInfo with a Content-Transfer-Encoding of "base64"
[RFC4648].
with:
An "application/pkcs8" part consists of the base64-encoded
DER-encoded [X.690] PrivateKeyInfo.
Replace:
In all three additional encryption cases, the EnvelopedData is
returned in the response as an "application/pkcs7-mime" part with an
smime-type parameter of "server-generated-key" and a Content-
Transfer-Encoding of "base64".
with:
In all three additional encryption cases, the EnvelopedData is
returned in the response as an "application/pkcs7-mime" part
with an smime-type parameter of "server-generated-key". It is
base64 encoded [RFC4648].
3.2.5. Section 4.5.2
This section is updated in its entirety in Section 4.
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4. Clarification of ASN.1 for Certificate Attribute set.
Section 4.5.2 of [RFC7030] is to be replaced with the following text:
4.5.2 CSR Attributes Response
If locally configured policy for an authenticated EST client
indicates a CSR Attributes Response is to be provided, the server
response MUST include an HTTP 200 response code. An HTTP response
code of 204 or 404 indicates that a CSR Attributes Response is not
available. Regardless of the response code, the EST server and CA
MAY reject any subsequent enrollment requests for any reason, e.g.,
incomplete CSR attributes in the request.
Responses to attribute request messages MUST be encoded as the
content-type of "application/csrattrs", and are to be "base64"
[RFC4648] encoded. The syntax for application/csrattrs body is as
follows:
CsrAttrs ::= SEQUENCE SIZE (0..MAX) OF AttrOrOID
AttrOrOID ::= CHOICE {
oid OBJECT IDENTIFIER,
attribute Attribute {{AttrSet}} }
AttrSet ATTRIBUTE ::= { ... }
An EST server includes zero or more OIDs or attributes [RFC2986] that
it requests the client to use in the certification request. The
client MUST ignore any OID or attribute it does not recognize. When
the server encodes CSR Attributes as an empty SEQUENCE, it means that
the server has no specific additional information it desires in a
client certification request (this is functionally equivalent to an
HTTP response code of 204 or 404).
If the CA requires a particular cryptographic algorithm or use of a
particular signature scheme (e.g., certification of a public key
based on a certain elliptic curve, or signing using a certain hash
algorithm) it MUST provide that information in the CSR Attribute
Response. If an EST server requires the linking of identity and POP
information (see Section 3.5), it MUST include the challengePassword
OID in the CSR Attributes Response.
The structure of the CSR Attributes Response SHOULD, to the greatest
extent possible, reflect the structure of the CSR it is requesting.
Requests to use a particular signature scheme (e.g. using a
particular hash function) are represented as an OID to be reflected
in the SignatureAlgorithm of the CSR. Requests to use a particular
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cryptographic algorithm (e.g., certification of a public key based on
a certain elliptic curve) are represented as an attribute, to be
reflected as the AlgorithmIdentifier of the SubjectPublicKeyInfo,
with a type indicating the algorithm and the values indicating the
particular parameters specific to the algorithm. Requests for
descriptive information from the client are made by an attribute, to
be represented as Attributes of the CSR, with a type indicating the
[RFC2985] extensionRequest and the values indicating the particular
attributes desired to be included in the resulting certificate's
extensions.
The sequence is Distinguished Encoding Rules (DER) encoded [X.690]
and then base64 encoded (Section 4 of [RFC4648]). The resulting text
forms the application/csrattr body, without headers.
For example, if a CA requests a client to submit a certification
request containing the challengePassword (indicating that linking of
identity and POP information is requested; see Section 3.5), an
extensionRequest with the Media Access Control (MAC) address
([RFC2307]) of the client, and to use the secp384r1 elliptic curve
and to sign with the SHA384 hash function. Then, it takes the
following:
OID: challengePassword (1.2.840.113549.1.9.7)
Attribute: type = extensionRequest (1.2.840.113549.1.9.14)
value = macAddress (1.3.6.1.1.1.1.22)
Attribute: type = id-ecPublicKey (1.2.840.10045.2.1)
value = secp384r1 (1.3.132.0.34)
OID: ecdsaWithSHA384 (1.2.840.10045.4.3.3)
and encodes them into an ASN.1 SEQUENCE to produce:
30 41 06 09 2a 86 48 86 f7 0d 01 09 07 30 12 06 07 2a 86 48 ce 3d
02 01 31 07 06 05 2b 81 04 00 22 30 16 06 09 2a 86 48 86 f7 0d 01
09 0e 31 09 06 07 2b 06 01 01 01 01 16 06 08 2a 86 48 ce 3d 04 03
03
and then base64 encodes the resulting ASN.1 SEQUENCE to produce:
MEEGCSqGSIb3DQEJBzASBgcqhkjOPQIBMQcGBSuBBAAiMBYGCSqGSIb3DQEJDjEJ
BgcrBgEBAQEWBggqhkjOPQQDAw==
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5. Clarification of error messages for certificate enrollment
operations
[errata5108] clarifies what format the error messages are to be in.
Previously a client might be confused into believing that an error
returned with type text/plain was not intended to be an error.
5.1. Updating section 4.2.3: Simple Enroll and Re-enroll Response
Replace:
If the content-type is not set, the response data MUST be a
plaintext human-readable error message containing explanatory
information describing why the request was rejected (for
example, indicating that CSR attributes are incomplete).
with:
If the content-type is not set, the response data MUST be a
plaintext human-readable error message containing explanatory
information describing why the request was rejected (for
example, indicating that CSR attributes are incomplete).
Servers MAY use the "text/plain" content-type [RFC2046]
for human-readable errors.
5.2. Updating section 4.4.2: Server-Side Key Generation Response
Replace:
If the content-type is not set, the response data MUST be a
plaintext human-readable error message.
with:
If the content-type is not set, the response data MUST be a
plaintext human-readable error message.
Servers MAY use the "text/plain" content-type [RFC2046]
for human-readable errors.
6. Privacy Considerations
This document does not disclose any additional identities to either
active or passive observer would see with [RFC7030].
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7. Security Considerations
This document clarifies an existing security mechanism. It does not
create any new protocol mechanism.
All security considerations from [RFC7030] also apply for the
clarifications described in this document.
8. IANA Considerations
The ASN.1 module in Appendix A of this document makes use of object
identifiers (OIDs). This document requests that IANA register an OID
in the SMI Security for PKIX Arc in the Module identifiers subarc
(1.3.6.1.5.5.7.0) for the ASN.1 module. The OID for the Asymmetric
Decryption Key Identifier (1.2.840.113549.1.9.16.2.54) was previously
defined in [RFC7030].
IANA is requested to update the "Reference" column for the Asymmetric
Decryption Key Identifier attribute to also include a reference to
this document.
9. Acknowledgements
This work was supported by Huawei Technologies.
The ASN.1 Module was assembled by Russ Housley and formatted by Sean
Turner. Russ Housley provided editorial review.
10. References
10.1. Normative References
[errata4384]
"EST errata 4384: ASN.1 encoding error", n.d.,
<https://www.rfc-editor.org/errata/eid4384>.
[errata5107]
"EST errata 5107: use Content-Transfer-Encoding", n.d.,
<https://www.rfc-editor.org/errata/eid5107>.
[errata5108]
"EST errata 5108: use of Content-Type for error message",
n.d., <https://www.rfc-editor.org/errata/eid5108>.
[errata5904]
"EST errata 5904: use Content-Transfer-Encoding", n.d.,
<https://www.rfc-editor.org/errata/eid5904>.
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[IEC62351]
International Electrotechnical Commission, "Power systems
management and associated information exchange - Data and
communications security - Part 9: Cyber security key
management for power system equipment", ISO/
IEC 62351-9:2017, 2017.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996,
<https://www.rfc-editor.org/info/rfc2045>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986,
DOI 10.17487/RFC2986, November 2000,
<https://www.rfc-editor.org/info/rfc2986>.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>.
[RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS
(CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008,
<https://www.rfc-editor.org/info/rfc5272>.
[RFC5273] Schaad, J. and M. Myers, "Certificate Management over CMS
(CMC): Transport Protocols", RFC 5273,
DOI 10.17487/RFC5273, June 2008,
<https://www.rfc-editor.org/info/rfc5273>.
[RFC5912] Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
DOI 10.17487/RFC5912, June 2010,
<https://www.rfc-editor.org/info/rfc5912>.
[RFC6268] Schaad, J. and S. Turner, "Additional New ASN.1 Modules
for the Cryptographic Message Syntax (CMS) and the Public
Key Infrastructure Using X.509 (PKIX)", RFC 6268,
DOI 10.17487/RFC6268, July 2011,
<https://www.rfc-editor.org/info/rfc6268>.
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[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[X.680] ITU-T, "Information technology - Abstract Syntax Notation
One.", ISO/IEC 8824-1:2002, 2002.
[X.681] ITU-T, "Information technology - Abstract Syntax Notation
One: Information Object Specification.", ISO/
IEC 8824-2:2002, 2002.
[X.682] ITU-T, "Information technology - Abstract Syntax Notation
One: Constraint Specification.", ISO/IEC 8824-2:2002,
2002.
[X.683] ITU-T, "Information technology - Abstract Syntax Notation
One: Parameterization of ASN.1 Specifications.", ISO/
IEC 8824-2:2002, 2002.
[X.690] ITU-T, "Information technology - ASN.1 encoding Rules:
Specification of Basic Encoding Rules (BER), Canonical
Encoding Rules (CER) and Distinguished Encoding Rules
(DER).", ISO/IEC 8825-1:2002, 2002.
10.2. Informative References
[I-D.ietf-anima-bootstrapping-keyinfra]
Pritikin, M., Richardson, M., Eckert, T., Behringer, M.,
and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping-
keyinfra-43 (work in progress), August 2020.
[RFC2307] Howard, L., "An Approach for Using LDAP as a Network
Information Service", RFC 2307, DOI 10.17487/RFC2307,
March 1998, <https://www.rfc-editor.org/info/rfc2307>.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616,
DOI 10.17487/RFC2616, June 1999,
<https://www.rfc-editor.org/info/rfc2616>.
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[RFC2985] Nystrom, M. and B. Kaliski, "PKCS #9: Selected Object
Classes and Attribute Types Version 2.0", RFC 2985,
DOI 10.17487/RFC2985, November 2000,
<https://www.rfc-editor.org/info/rfc2985>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
Appendix A. ASN.1 Module
This annex provides the normative ASN.1 definitions for the
structures described in this specification using ASN.1 as defined in
[X.680], [X.681], [X.682] and [X.683].
The ASN.1 modules makes imports from the ASN.1 modules in [RFC5912]
and [RFC6268].
There is no ASN.1 Module in RFC 7030. This module has been created
by combining the lines that are contained in the document body.
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PKIXEST-2019
{ iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-est-2019(TBD) }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
-- EXPORTS ALL --
IMPORTS
Attribute
FROM CryptographicMessageSyntax-2010 -- [RFC6268]
{ iso(1) member-body(2) us(840) rsadsi(113549)
pkcs(1) pkcs-9(9) smime(16) modules(0)
id-mod-cms-2009(58) }
ATTRIBUTE
FROM PKIX-CommonTypes-2009 -- [RFC5912]
{ iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkixCommon-02(57) } ;
-- CSR Attributes
CsrAttrs ::= SEQUENCE SIZE (0..MAX) OF AttrOrOID
AttrOrOID ::= CHOICE {
oid OBJECT IDENTIFIER,
attribute Attribute {{AttrSet}} }
AttrSet ATTRIBUTE ::= { ... }
-- Asymmetric Decrypt Key Identifier Attribute
aa-asymmDecryptKeyID ATTRIBUTE ::=
{ TYPE AsymmetricDecryptKeyIdentifier
IDENTIFIED BY id-aa-asymmDecryptKeyID }
id-aa-asymmDecryptKeyID OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) aa(2) 54 }
AsymmetricDecryptKeyIdentifier ::= OCTET STRING
END
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Authors' Addresses
Michael Richardson
Sandelman Software Works
Email: mcr+ietf@sandelman.ca
Thomas Werner
Siemens
Email: thomas-werner@siemens.com
Wei Pan
Huawei Technologies
Email: william.panwei@huawei.com
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