Internet DRAFT - draft-ietf-teas-gmpls-scsi
draft-ietf-teas-gmpls-scsi
TEAS Working Group D. Ceccarelli
Internet-Draft Ericsson
Intended status: Standards Track L. Berger
Expires: March 3, 2018 LabN Consulting, L.L.C.
August 30, 2017
Generalized Interface Switching Capability Descriptor - Switching
Capability Specific Information
draft-ietf-teas-gmpls-scsi-04
Abstract
This document defines a generic information structure for information
carried in routing protocol Interface Switching Capability Descriptor
(ISCD) Switching Capability Specific Information (SCSI) fields. This
"Generalized SCSI" can be used with routing protocols that define
GMPLS ISCDs, and any specific technology. This document does not
modify any existing technology specific formats and is defined for
use in conjunction with new GMPLS Switching Capability types. The
context for this document is Generalized MPLS, and the reader is
expected to be familiar with the GMPLS architecture and associate
protocol standards.
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
Task Force (IETF). Note that other groups may also distribute
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This Internet-Draft will expire on March 3, 2018.
Copyright Notice
Copyright (c) 2017 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Generalized SCSI Formats . . . . . . . . . . . . . . . . . . 3
4. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 6
8.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
The context for this document is Generalized MPLS, and the reader is
expected to be familiar with the GMPLS architecture, associate
terminology and protocol standards. Notably, but not limited to,
[RFC3945], [RFC4202], [RFC4203] and [RFC5307].
The Interface Switching Capability Descriptor (ISCD) [RFC4202] allows
routing protocols such as OSPF and ISIS to carry technology specific
information in the the Switching Capability-specific information
(SCSI) field, see [RFC4203] and [RFC5307]. The format of an SCSI
field is dictated by the specific technology being represented as
indicated by the ISCD Switching Capability (SC) type field. Existing
Switching Capabilities are managed by IANA in the Switching Types
registry [1] and the related "IANA-GMPLS-TC-MIB" definitions.
[RFC7138] introduced a "sub-TLV" structure to its technology specific
SCSI field. The Sub-Type-Length-Value (TLV) based approach allows
for greater flexibility in the structure, ordering, and ability to
support extensions of the SC (technology) specific format. This Sub-
TLV approach is also used in [RFC7688].
This document generalizes this approach and defines a new generalized
SCSI field format for use by future specific technologies and
Switching Capability types. The generalized SCSI carries SCSI-TLVs
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that may be defined within the scope of a specific technology, or
shared across multiple technologies (e.g.,
[I-D.ietf-ccamp-ospf-availability-extension]). This document also
establishes a registry for SCSI-TLV definitions that may be shared
across multiple technologies.
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
[RFC2119].
The reader is expected to be familiar with GMPLS terminology, e.g. as
found in [RFC3945], as well as the terminology used in [RFC4202],
[RFC4203] and [RFC5307].
3. Generalized SCSI Formats
The Generalized SCSI is composed of zero or more variable length
type-length-value fields which are each called a SCSI-TLV. There are
no specific size restrictions on these SCSI-TLV. Size and other
formatting restrictions may be imposed by the routing protocol ISCD
field, refer to [RFC4203] and [RFC5307]. Please also refer to
[RFC3630] for the treatment of malformed Link TLVs.
The SCSI-TLV format is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... Value ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: TLV format
Type (2 octets):
This field indicates the type and structure of the information
contained in the Value field.
Length (2 octets):
This field MUST be set to the size, in octets (bytes), of the
Value field. The value of the field MUST be zero or divisible by
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4. Note that this implies that the Value field can be omitted or
contain padding.
Value (variable):
A variable length field, formatted according to the definition
indicated by value of the Type field. This field can be omitted
for certain types.
4. Procedures
The ISCD can include a Generalized SCSI when advertising technologies
whose Switching Capability definition references this document. The
corollary of this is that the Generalized SCSI MUST NOT be used for
ISCDs of technologies whose Switching Capability definition do not
reference this document.
The Generalized SCSI MAY contain a sequence of zero or more SCSI-
TLVs. Sub-TLV parsing (format) errors, such as an underrun or
overrun, MUST be treated as a malformed ISCD. SCSI-TLVs MUST be
processed in the order received and, if re-originated, ordering MUST
be preserved. Unknown SCSI-TLVs MUST be ignored and transparently
processed, i.e., re-originated when appropriate. Processing related
to multiple SCSI-TLVs of the same type may be further refined based
on the definition on the type.
5. Security Considerations
This document does not introduce any security issue beyond those
discussed in [RFC4203] and [RFC5307]. As discussed there, the
information carried in ISCDs are not used for SPF computation or
normal routing and the extensions here defined do not have direct
effect on IP routing. Tampering with GMPLS TE LSAs may have an
effect on the underlying transport network. Mechanisms such as
[RFC2154] and [RFC5304] to protect the transmission of this
information are suggested.
6. IANA Considerations
This document defines a new SCSI-TLV that is carried in the SCSI
field of the ISCDs defined in [RFC4203] and [RFC5307]. The SCSI-TLV
includes a 16-bit type identifier (the Type field). The same Type
field values are applicable to the new SCSI-TLV.
IANA is requested to create and maintain a new registry, the
"Generalized SCSI (Switching Capability Specific Information) TLVs
Types" registry under the the "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Parameters" registry.
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The definition of the new registry is as follows:
Value SCSI-TLV Switching Type Reference
--------- ----------------------- -------------- ---------
0 Reserved [This ID]
1-65535 Unassigned (value list) [This ID]
New allocation requests to this registry must indicate the value or
values to be used in the Switching Type column.
The registry should be established with registration policies of
"Specification Required", see [RFC5226].
REMOVE THIS AFTER PUBLICATION: The designated expert will be
appointed by the Routing AD. It is suggested to appoint any current
TEAS WG chair.
7. Acknowledgments
The authors would like to thank Adrian Farrel and Julien Meuric for
the careful review and suggestions. Thomas Heide Clausen provided
useful comments as part of the Routing Directorate review.
8. References
8.1. Normative References
[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>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003, <https://www.rfc-
editor.org/info/rfc3630>.
[RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005,
<https://www.rfc-editor.org/info/rfc4202>.
[RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
<https://www.rfc-editor.org/info/rfc4203>.
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[RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008,
<https://www.rfc-editor.org/info/rfc5307>.
8.2. Informative References
[I-D.ietf-ccamp-ospf-availability-extension]
Long, H., Ye, M., Mirsky, G., D'Alessandro, A., and H.
Shah, "OSPF-TE Link Availability Extension for Links with
Variable Discrete Bandwidth", draft-ietf-ccamp-ospf-
availability-extension-10 (work in progress), August 2017.
[RFC2154] Murphy, S., Badger, M., and B. Wellington, "OSPF with
Digital Signatures", RFC 2154, DOI 10.17487/RFC2154, June
1997, <https://www.rfc-editor.org/info/rfc2154>.
[RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945,
DOI 10.17487/RFC3945, October 2004, <https://www.rfc-
editor.org/info/rfc3945>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008, <https://www.rfc-
editor.org/info/rfc5226>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>.
[RFC7138] Ceccarelli, D., Ed., Zhang, F., Belotti, S., Rao, R., and
J. Drake, "Traffic Engineering Extensions to OSPF for
GMPLS Control of Evolving G.709 Optical Transport
Networks", RFC 7138, DOI 10.17487/RFC7138, March 2014,
<https://www.rfc-editor.org/info/rfc7138>.
[RFC7688] Lee, Y., Ed. and G. Bernstein, Ed., "GMPLS OSPF
Enhancement for Signal and Network Element Compatibility
for Wavelength Switched Optical Networks", RFC 7688,
DOI 10.17487/RFC7688, November 2015, <https://www.rfc-
editor.org/info/rfc7688>.
8.3. URIs
[1] http://www.iana.org/assignments/gmpls-sig-parameters/gmpls-sig-
parameters.xml#gmpls-sig-parameters-3
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Authors' Addresses
Daniele Ceccarelli
Ericsson
Torshamnsgatan 21
Kista - Stockholm
Sweden
Email: daniele.ceccarelli@ericsson.com
Lou Berger
LabN Consulting, L.L.C.
Email: lberger@labn.net
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