Internet DRAFT - draft-ietf-ccamp-ospf-availability-extension
draft-ietf-ccamp-ospf-availability-extension
Network Working Group H. Long, M.Ye
Internet Draft Huawei Technologies Co., Ltd
Intended status: Standards Track G. Mirsky
ZTE
A.D'Alessandro
Telecom Italia S.p.A
H. Shah
Ciena
Expires: June 2018 December 5, 2017
OSPF-Traffic Engineering Link Availability Extension for Links with
Variable Discrete Bandwidth
draft-ietf-ccamp-ospf-availability-extension-13.txt
Abstract
A network may contain links with variable discrete bandwidth, e.g.,
copper, radio, etc. The bandwidth of such links may change
discretely in reaction to changing external environment.
Availability is typically used for describing such links during
network planning. This document defines a new type of the
Generalized Switching Capability-specific information (SCSI) TLV to
extend the Generalized Multi-Protocol Label Switching (GMPLS) Open
Shortest Path First (OSPF) routing protocol. The extension can be
used for route computation in a network that contains links with
variable discrete bandwidth. Note, this document only covers the
mechanisms by which the availability information is distributed. The
mechanisms by which availability information of a link is determined
and the use of the distributed information for route computation are
outside the scope of this document. It is intended that technology-
specific documents will reference this document to describe specific
uses.
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), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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Table of Contents
1. Introduction ................................................ 3
2. Acronyms .................................................... 3
3. Overview .................................................... 4
4. TE Metric Extension to OSPF-TE............................... 4
4.1. Availability SCSI-TLV................................... 4
4.2. Processing Procedures................................... 5
5. Security Considerations...................................... 6
6. IANA Considerations ......................................... 6
7. References .................................................. 7
7.1. Normative References.................................... 7
7.2. Informative References.................................. 7
8. Acknowledgments ............................................. 8
Conventions used in this document
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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.
1. Introduction
Some data plane technologies, e.g., microwave, and copper, allow
seamless change of maximum physical bandwidth through a set of known
discrete values. The parameter, availability, as described in
[G.827], [F.1703] and [P.530] is often used to describe the link
capacity. The availability is a time scale, representing a proportion
of the operating time that the requested bandwidth is ensured. To
set up an LSP across these links, availability information is
required by the nodes to verify the bandwidth before making a
bandwidth reservation. Assigning different availability classes
over such links provides for a more efficient planning of link
capacity to support different types of services. The link
availability information will be determined by the operator and
statically configured. It will usually be determined from the
availability requirements of the services expected to be carried on
the LSP. For example, voice service usually needs "five nines"
availability, while non-real time services may adequately perform at
four or three nines availability. For the route computation, both
the availability information and the bandwidth resource information
are needed. Since different service types may need different
availability guarantees, multiple <availability, bandwidth> pairs
may be required to be associated with a link.
In this document, a new type of the Generalized SCSI TLV,
Availability TLV is defined. It is intended that technology-specific
documents will reference this document to describe specific uses.
The signaling extension to support links with discrete bandwidth is
defined in [I-D. ietf-ccamp-rsvp-te-bandwidth-availability].
2. Acronyms
The following acronyms are used in this draft:
GMPLS Generalized Multi-Protocol Label Switching
LSA Link State Advertisement
ISCD Interface Switching Capability Descriptor
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LSP Label Switched Path
OSPF Open Shortest Path First
PSN Packet Switched Network
SCSI Switching Capability-specific information
SNR Signal-to-noise Ratio
SONET-SDH Synchronous Optical Network - Synchronous Digital
Hierarchy
SPF Shortest Path First
TE Traffic Engineering
TLV Type Length Value
3. Overview
A node which has link(s) with variable bandwidth attached should
include < availability, bandwidth> information list in its OSPF
Traffic Engineering (TE) LSA messages. The list provides the mapping
between the link nominal bandwidth and its availability level. This
information is used for path calculation by the node(s). The setup
of a Label Switched Path requires this information to be flooded in
the network and used by the nodes or the PCE for the path
computation. In this document, a new type of the Generalized SCSI
TLV, Availability TLV is defined. The computed path can then be
provisioned via the signaling protocol [I-D. ietf-ccamp-rsvp-te-
bandwidth-availability].
Note, the mechanisms described in this document only distribute
availability information. The methods for measuring the information
or using the information for route computation are outside the scope
of this document.
4. TE Metric Extension to OSPF-TE
4.1. Availability SCSI-TLV
The Generalized SCSI is defined in [RFC8258]. The Availability TLV
defined in this document is a new type of Generalized SCSI-TLV. The
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Availability SCSI-TLV can be included for one or more times. The
Availability SCSI-TLV has the following format:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Availability level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP Bandwidth at Availability level n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 0x0001, 16 bits.
Length: 2 octets, 16 bits.
Availability level: 32 bits
This field is a binary32-format floating point number as defined by
[IEEE754-2008]. The bytes are transmitted in network order; that is,
the byte containing the sign bit is transmitted first. This field
describes the decimal value of availability guarantee of the
switching capability in the Interface Switching Capability
Descriptor (ISCD) [RFC4202] object. The value MUST be less than 1.
The Availability level is usually expressed in the value of
0.99/0.999/0.9999/0.99999.
LSP Bandwidth at Availability level n: 32 bits
This field is a 32-bit IEEE floating point number as defined by
[IEEE754-2008]. The bytes are transmitted in network order; that is,
the byte containing the sign bit is transmitted first. This field
describes the LSP Bandwidth for the Availability level represented
in the Availability field. The units are bytes per second.
4.2. Processing Procedures
The ISCD allows routing protocols such as OSPF to carry technology
specific information in the Switching Capability-specific
information (SCSI) field, see [RFC4203]. A node advertising an
interface with a Switching Capability which supports variable
bandwidth attached SHOULD contain one or more Availability SCSI-TLVs
in its OSPF TE LSA messages. Each Availability SCSI-TLV provides the
information about how much bandwidth a link can support for a
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specified availability. This information may be used for path
calculation by the node(s).
The Availability SCSI-TLV MUST NOT be sent in ISCDs with Switching
Capability field values that have not been defined to support the
Availability SCSI-TLV. Non-supporting nodes would see such as a
malformed ISCD/LSA.
Absence of the Availability SCSI-TLV in an ISCD containing Switching
Capability field values that have been defined to support the
Availability SCSI-TLV, SHALL be interpreted as representing fixed-
bandwidth link with the highest availability value.
Only one Availability SCSI-TLV for the specific availability level
SHOULD be sent. If multiple are present, the Availability SCSI-TLV
with the lowest bandwidth value SHALL be processed. If an
Availability SCSI-TLV with an invalid value (e.g., large than 1) is
received, the Availability SCSI-TLV will be ignored.
5. Security Considerations
This document specifies the contents of Opaque LSAs in OSPFv2.
Tampering with GMPLS TE LSAs may have an effect on traffic
engineering computations. [RFC3630] suggests mechanisms such as
[RFC2154] to protect the transmission of this information, and those
or other mechanisms should be used to secure and/or authenticate the
information carried in the Opaque LSAs. An analysis of the security
of OSPF is provided in [RFC6863] and applies to the extensions to
OSPF as described in this document. Any new mechanisms developed to
protect the transmission of information carried in Opaque LSAs will
also automatically protect the extensions defined in this document.
Please refer to [RFC5920] for details on security threats; defensive
techniques; monitoring, detection, and reporting of security
attacks; and requirements.
6. IANA Considerations
This document introduces a new type for availability of the
Generalized SCSI-TLV of the TE Link TLV in the TE Opaque LSA for
OSPF v2. Technology-specific documents will reference this document
to describe specific use of this Availability SCSI-TLV.
IANA has created a registry called the "Generalized SCSI (Switching
Capability Specific Information) TLVs Types" registry. The registry
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is needed to be updated to include the Availability SCSI-TLV. This
document proposes a suggested value for the Availability SCSI-TLV;
it is requested that the suggested value be granted by IANA.
Note (Please REMOVE this note before publication): the registry will
be created by [RFC8258]. The requested value should be added to it
when it is created.
Type Description Reference
--- ------------------ -----------
0x01 Availability [This ID]
7. References
7.1. Normative References
[RFC8258] Ceccarelli, D. and Berger, L., "Generalized Routing
Interface Switching Capability Descriptor Switching
Capability Specific Information", RFC 8258, October, 2017.
[RFC4202] Kompella, K. and Rekhter, Y. (Editors), "Routing
Extensions in Support of Generalized Multi-Protocol Label
Switching (GMPLS)", RFC 4202, October 2005.
[RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, October 2005.
[IEEE754-2008] IEEE standards, "IEEE Standard for Floating-Point
Arithmetic", IEEE Standard 754, August 2008
7.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC2154] Murphy, S., Badger, M., Wellington, B., "OSPF with Digital
Signatures", RFC2154, June 1997.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.
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[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
[RFC6863] Hartman, S. and D. Zhang, "Analysis of OSPF Security
According to the Keying and Authentication for Routing
Protocols (KARP) Design Guide", RFC 6863, March 2013.
[G.827] ITU-T Recommendation, "Availability performance parameters
and objectives for end-to-end international constant bit-
rate digital paths", September, 2003.
[F.1703] ITU-R Recommendation, "Availability objectives for real
digital fixed wireless links used in 27 500 km
hypothetical reference paths and connections", January,
2005.
[P.530] ITU-R Recommendation," Propagation data and prediction
methods required for the design of terrestrial line-of-
sight systems", February, 2012
[I-D. ietf-ccamp-rsvp-te-bandwidth-availability] H., Long, M., Ye,
Mirsky, G., Alessandro, A., Shah, H., "Ethernet Traffic
Parameters with Availability Information", Work in
Progress, August, 2017
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", RFC 8174, May 2017.
8. Acknowledgments
The authors would like to thank Acee Lindem, Daniele Ceccarelli, Lou
Berger for their comments on the document.
Authors' Addresses
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Hao Long
Huawei Technologies Co., Ltd.
No.1899, Xiyuan Avenue, Hi-tech Western District
Chengdu 611731, P.R.China
Phone: +86-18615778750
Email: longhao@huawei.com
Min Ye
Huawei Technologies Co., Ltd.
No.1899, Xiyuan Avenue, Hi-tech Western District
Chengdu 611731, P.R.China
Email: amy.yemin@huawei.com
Greg Mirsky
ZTE
Email: gregimirsky@gmail.com
Alessandro D'Alessandro
Telecom Italia S.p.A
Email: alessandro.dalessandro@telecomitalia.it
Himanshu Shah
Ciena Corp.
3939 North First Street
San Jose, CA 95134
US
Email: hshah@ciena.com
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