OSPF-TE Link Availability Extension for Links with Variable Discrete Bandwidth
draft-ietf-ccamp-ospf-availability-extension-06
The information below is for an old version of the document.
draft-ietf-ccamp-ospf-availability-extension-06
Network Working Group H. Long, M.Ye
Internet Draft Huawei Technologies Co., Ltd
Intended status: Standards Track G. Mirsky
Ericsson
A.D'Alessandro
Telecom Italia S.p.A
H. Shah
Ciena
Expires: February 2017 August 19, 2016
OSPF-TE Link Availability Extension for Links with Variable Discrete
Bandwidth
draft-ietf-ccamp-ospf-availability-extension-06.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 introduces an optional ISCD
Availability sub-TLV to extend the Open Shortest Path First (OSPF)
Generalized Multi-Protocol Label Switching (GMPLS). This extension
can be used for route computation in a network that contains links
with variable discrete bandwidth.
Status of this Memo
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reference material or to cite them other than as "work in progress."
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Table of Contents
1. Introduction ................................................ 3
2. Overview .................................................... 4
3. Extension to OSPF Routing Protocol........................... 4
3.1. ISCD Availability sub-TLV............................... 4
3.2. Signaling Process....................................... 5
4. Security Considerations...................................... 5
5. IANA Considerations ......................................... 6
6. References .................................................. 6
6.1. Normative References.................................... 6
6.2. Informative References.................................. 6
7. Acknowledgments ............................................. 7
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].
The following acronyms are used in this draft:
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GMPLS Generalized Multi-Protocol Label Switching
LSA Link State Advertisement
ISCD Interface Switching Capacity Descriptor
LSP Label Switched Path
OSPF Open Shortest Path First
PSN Packet Switched Network
SNR Signal-to-noise Ratio
SONET-SDH Synchronous Optical Network - Synchronous Digital
Hierarchy
SPF Shortest Path First
1. Introduction
Some data communication technologies, e.g., microwave, and copper,
allow seamless change of maximum physical bandwidth through a set of
known discrete values. The parameter availability [G.827], [F.1703],
[P.530] is often used to describe the link capacity during network
planning. The availability is a time scale, which is a proportion of
the operating time that the requested bandwidth is ensured.
Assigning different availability classes to different types of
service over such kind of links provides more efficient planning of
link capacity. To set up an LSP across these links, availability
information is required for the nodes to verify bandwidth
satisfaction and make bandwidth reservation. The availability
information should be inherited 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. Since different service types may need different
availabilities guarantees, multiple <availability, bandwidth> pairs
may be required when signaling. The signaling extension for links
with discrete bandwidth is defined in [ETPAI].
For the route computation, the availability information should be
provided along with bandwidth resource information. In this document,
an extension on Interface Switching Capacity Descriptor (ISCD)
[RFC4202] for availability information is defined.
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2. Overview
A node which has link(s) with variable bandwidth attached should
include a <bandwidth, availability> information list in its OSPF 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 piece of information to be flooded in the network and
used by the nodes or the PCE for the path computation. The computed
path can then be provisioned via the signaling protocol.
For links with variable discrete bandwidth, Availability information
is needed to be carried by the signaling for a better link bandwidth
utilization. Extensions to RSVP-TE can be found in [ETPAI].
3. Extension to OSPF-TE
3.1. ISCD Availability sub-TLV
The ISCD sub-TLV is defined in Section 1.4 of [RFC4203]. The ISCD
Availability sub-TLV is defined in this document as a sub-TLV of
ISCD. The Switching Capability specific information field of ISCD
MAY include one or more ISCD Availability sub-TLV(s). The ISCD
Availability sub-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: TBA by IANA, suggested value is 0x01, 16 bits;
Length: A 16 bits field that expresses the length of the TLV in
bytes;
Availability level: 32 bits
This field is a 32-bit IEEE floating point number which
describes the decimal value of availability guarantee of the
switching capability in the ISCD object. The value MUST be
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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 which
describes the LSP Bandwidth at a certain Availability level
which was described in the Availability field. The units are
bytes per second.
3.2. Processing Procedures
A node which has link(s) with variable bandwidth attached SHOULD
contain one or more ISCD Availability sub-TLVs in its OSPF TE LSA
messages. Each ISCD Availability sub-TLV provides the information
about how much bandwidth a link can support for a specified
availability. This information SHOULD be used for path calculation
by the node(s).
A node that doesn't support ISCD Availability sub-TLV SHOULD ignore
ISCD Availability sub-TLV. If a node who supports ISCD Availability
sub-TLVs doesn't receive the TLV, it indicates that the link is with
fixed bandwidth, and the availability can be interpreted as the
highest availability value, e.g., five nines. It's legal to send
multiple ISCD Availability sub-TLVs for the same availability level.
4. Security Considerations
This document extends [RFC4203]. As with [RFC4203], it specifies
the contents of Opaque LSAs in OSPFv2. As Opaque LSAs are not used
for Shortest Path First (SPF) computation or normal routing, the
extensions specified here have no direct effect on IP routing.
Tampering with GMPLS TE LSAs may have an effect on the underlying
transport (optical and/or Synchronous Optical Network - Synchronous
Digital Hierarchy (SONET-SDH)) network. [RFC3630] notes that the
security mechanisms described in [RFC2328] apply to Opaque LSAs
carried in OSPFv2. 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.
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5. IANA Considerations
This document introduces an Availability sub-TLV of the ISCD sub-TLV
of the TE Link TLV in the TE Opaque LSA for OSPF v2. IANA will
created and maintain a new sub-registry, the "Types for sub-TLV of
Interface Switching Capability Descriptor" registry under the "Open
Shortest Path First (OSPF) Traffic Engineering TLVs" registry, see
http://www.iana.org/assignments/ospf-traffic-eng-tlvs.
This document proposes a suggested value for the Availability sub-
TLV; it is recommended that the suggested value be granted by IANA.
Type Description Reference
--- ------------------ -----------
0 Reserved [This ID]
0x01 Availability [This ID]
The registration procedure for this registry is Standards Action as
defined in [RFC5226].
6. References
6.1. Normative References
[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.
6.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.
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[RFC5226] Narten,T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226, May 2008.
[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
[ETPAI] H., Long, M., Ye, Mirsky, G., Alessandro, A., Shah, H.,
"Ethernet Traffic Parameters with Availability
Information", Work in Progress, June, 2015
7. 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
Ericsson
Email: gregory.mirsky@ericsson.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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