OSPF-TE Link Availability Extension for Links with Variable Discrete Bandwidth
draft-ietf-ccamp-ospf-availability-extension-09

Network Working Group                                     H. Long, M.Ye 
Internet Draft                             Huawei Technologies Co., Ltd         
Intended status: Standards Track                              G. Mirsky 
                                                             Individual   
                                                         A.D'Alessandro 
                                                   Telecom Italia S.p.A 
                                                                H. Shah 
                                                                  Ciena         
Expires: August 2017                                  February 15, 2017
                                   
                                      
    OSPF-TE Link Availability Extension for Links with Variable Discrete 
                                Bandwidth 
            draft-ietf-ccamp-ospf-availability-extension-09.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. Overview .................................................... 4 
   3. TE Metric Extension to OSPF-TE............................... 4 
      3.1. Availability SCSI-TLV................................... 4 
      3.2. Processing Procedures................................... 5 
   4. Security Considerations...................................... 6 
   5. IANA Considerations ......................................... 6 
   6. References .................................................. 7 
      6.1. Normative References.................................... 7 
      6.2. Informative References.................................. 7 
   7. 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", "MAY", and "OPTIONAL" in this 
   document are to be interpreted as described in RFC-2119 [RFC2119]. 

   The following acronyms are used in this draft: 

   GMPLS     Generalized Multi-Protocol Label Switching 

   LSA       Link State Advertisement 

   ISCD      Interface Switching Capability Descriptor 

   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 

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 
 
 
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   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 [ETPAI]. 

2. 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 [ETPAI]. 

   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. 

3. TE Metric Extension to OSPF-TE 

3.1. Availability SCSI-TLV 

   The Generalized SCSI is defined in [GSCSI]. The Availability TLV 
   defined in this document is a new type of Generalized SCSI-TLV. The 
   Availability SCSI-TLV can be included for one or more times. The 
   Availability SCSI-TLV has the following format: 

 
 
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       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: 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 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 which describes 
   the LSP Bandwidth for the Availability level represented in the 
   Availability field. The units are bytes per second.  

3.2. Processing Procedures  

   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 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 
 
 
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   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, only the first Availability 
   SCSI-TLV for an availability level carried in the same ISCD SHALL be 
   processed. 

4. Security Considerations 

   This document does not introduce security issues beyond those 
   discussed in [RFC4203].  As with [RFC4203], it specifies the content 
   of an 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 impact on the ability to 
   set up connections in the underlying data plane network. As the 
   additional availability information may represent information that 
   an operator may wish to keep private, consideration should be given 
   to securing this information. [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. 

5. 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 
   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.  

   Type             Description                    Reference 
 
 
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   ---              ------------------             ----------- 

   0x01             Availability                   [This ID]  

   The registration procedure for this registry is Standards Action as 
   defined in [RFC5226]. 

6. References 

6.1. Normative References 

   [GSCSI]   Ceccarelli, D. and Berger, L., "Generalized Routing 
             Interface Switching Capability Descriptor Switching 
             Capability Specific Information", Work in Progress, 
             January, 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. 

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. 

   [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. 

 
 
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   [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, August, 2016 

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 
   Individual 
    
   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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