OSPF Routing Extension for Links with Variable Discrete Bandwidth
The information below is for an old version of the document.
This is an older version of an Internet-Draft that was ultimately published as RFC 8330.
|Authors||Hao Long , Min Ye , Greg Mirsky , Himanshu C. Shah , Alessandro D'Alessandro|
|Last updated||2014-10-24 (Latest revision 2014-10-08)|
|RFC stream||Internet Engineering Task Force (IETF)|
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Network Working Group H. Long, M.Ye Internet Draft Huawei Technologies Co., Ltd Intended status: Standards Track G. Mirsky Ericsson A. Alessandro Telecom Italia S.p.A H. Shah Ciena Expires: April 2015 October 8, 2014 OSPF Routing Extension for Links with Variable Discrete Bandwidth draft-ietf-ccamp-ospf-availability-extension-00.txt Abstract Packet switching network MAY contain links with variable discrete bandwidth, e.g., copper, radio, etc. The bandwidth of such link MAY change discretely in reaction to changing external environment. Availability is typically used for describing such links during network planning. This document describes an extension for OSPF routing for route computation in a Packet Switched Network (PSN) which contains links with variable discrete bandwidth by introducing an OPTIONAL Availability sub-TLV. 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. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on April 8, 2014. Long, et al. Expires April 8, 2015 [Page 1] Internet-Draft OSPF -- Availability extension October 2014 Copyright Notice Copyright (c) 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. Overview .................................................... 3 3. Extension to OSPF Routing Protocol........................... 4 3.1. Interface Switching Capacity Descriptor................. 4 3.2. ISCD Availability sub-TLV............................... 5 3.3. Signaling Process....................................... 6 4. Security Considerations...................................... 6 5. IANA Considerations ......................................... 6 6. References .................................................. 6 6.1. Normative References.................................... 6 6.2. Informative References.................................. 7 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: OSPF Open Shortest Path First PSN Packet Switched Network SNR Signal-to-noise Ratio LSP Label Switched Path ISCD Interface Switching Capacity Descriptor Long, et al. Expires April 8, 2015 [Page 2] Internet-Draft OSPF -- Availability extension October 2014 PE Provider Edge LSA Link State Advertisement 1. Introduction Some data communication technologies allow seamless change of maximum physical bandwidth through a set of known discrete values. For example, in mobile backhaul network, microwave links are very popular for providing connection of last hops. In case of heavy rain, to maintain the link connectivity, the microwave link MAY lower the modulation level since demodulating lower modulation level need lower signal-to-noise ratio (SNR). This is called adaptive modulation technology [EN 302 217]. However, lower modulation level also means lower link bandwidth. When link bandwidth reduced because of modulation down-shifting, high priority traffic can be maintained, while lower priority traffic is dropped. Similarly the cooper links MAY change their effective link bandwidth due to external interference. The parameter availability [G.827, F.1703, P.530] is often used to describe the link capacity during network planning. 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. 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 to support in routing signaling. The extension reuses the reserved field in the ISCD and also introduces an OPTIONAL Availability sub-TLV. If there is a hop that cannot support the Availability sub-TLV, the Availability sub-TLV SHOULD be ignored. 2. Overview A node which has link(s) with variable bandwidth attached SHOULD contain a <bandwidth, availability> information list in its OSPF TE LSA messages. The list provides the information that how much Long, et al. Expires April 8, 2015 [Page 3] Internet-Draft OSPF -- Availability extension October 2014 bandwidth a link can support for a specified availability. This information is used for path calculation by the PE node(s). To setup an label switching path (LSP), a PE node MAY collect link information which is spread in OSPF TE LSA messages by network nodes to get know about the network topology, calculate out an LSP route based on the network topology and send the calculated LSP route to signaling to initiate a PATH/RESV message for setting up the LSP. Availability information is required to carry in the signaling message to better utilize the link bandwidth. The signaling extension for availability can be found in [ASTE]. 3. Extension to OSPF Routing Protocol 3.1. Interface Switching Capacity Descriptor The Interface Switching Capacity Descriptor (ISCD) sub-TLV [RFC 4203] 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Cap | Encoding | AI | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 7 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Capacity-specific Information | | (variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Long, et al. Expires April 8, 2015 [Page 4] Internet-Draft OSPF -- Availability extension October 2014 A new AI field is defined in this document. AI: ISCD Availability sub-TLV index, 8 bits This new field is the index of Availability sub-TLV for this ISCD sub-TLV. 3.2. ISCD Availability sub-TLV When the Switching Capability field is PSC-1, PSC-2, PSC-3, PSC-4, the Switching Capability specific information field 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Index | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Availability level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP Bandwidth at Availability level n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 0x01, 16 bits; Length: 16 bits; Index: 8 bits This field is the index of this Availability sub-TLV, referred by the AI field of the ISCD sub-TLV. 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 capacity in the ISCD object which has the AI value equal to Index of this sub-TLV. The value MUST be less than 1. 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. Long, et al. Expires April 8, 2015 [Page 5] Internet-Draft OSPF -- Availability extension October 2014 3.3. Signaling Process 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 PE node(s). A node that doesn't support ISCD Availability sub-TLV SHOULD ignore ISCD Availability sub-TLV. 4. Security Considerations This document does not introduce new security considerations to the existing OSPF protocol. 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. This document proposes a suggested value for the Availability sub-TLV; it is recommended that the suggested value be granted by IANA. Initial values are as follows: Type Length Format Description --- ---- ------------------ ----------- 0 - Reserved Reserved value 0x01 8 see Section 3.2 Availability sub- TLV 6. References 6.1. Normative References [RFC2210] Wroclawski, J., ''The Use of RSVP with IETF Integrated Services'', RFC 2210, September 1997. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. Long, et al. Expires April 8, 2015 [Page 6] Internet-Draft OSPF -- Availability extension October 2014 [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [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. [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 [EN 302 217] ETSI standard, ''Fixed Radio Systems; Characteristics and requirements for point-to-point equipment and antennas'', April, 2009 [ASTE] H., Long, M., Ye, Mirsky, G., Alessandro, A., Shah, H., ''RSVP-TE Signaling Extension for Links with Variable Discrete Bandwidth'', Work in Progress, February, 2014 6.2. Informative References [MCOS] Minei, I., Gan, D., Kompella, K., and X. Li, "Extensions for Differentiated Services-aware Traffic Engineered LSPs", Work in Progress, June 2006. 7. Acknowledgments Authors' Addresses Long, et al. Expires April 8, 2015 [Page 7] Internet-Draft OSPF -- Availability extension October 2014 Hao Long Huawei Technologies Co., Ltd. No.1899, Xiyuan Avenue, Hi-tech Western District Chengdu 611731, P.R.China Phone: +86-18615778750 Email: firstname.lastname@example.org Min Ye Huawei Technologies Co., Ltd. No.1899, Xiyuan Avenue, Hi-tech Western District Chengdu 611731, P.R.China Email: email@example.com Greg Mirsky Ericsson Email: firstname.lastname@example.org Alessandro D'Alessandro Telecom Italia S.p.A Email: email@example.com Himanshu Shah Ciena Corp. 3939 North First Street San Jose, CA 95134 US Email: firstname.lastname@example.org Long, et al. Expires April 8, 2015 [Page 8]