OSPF-TE Link Availability Extension for Links with Variable Discrete Bandwidth
draft-ietf-ccamp-ospf-availability-extension-07

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: April 2017                                     October 8, 2016  
                                      
    OSPF-TE Link Availability Extension for Links with Variable Discrete 
                                Bandwidth 
            draft-ietf-ccamp-ospf-availability-extension-07.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 Generalized Multi-Protocol Label 
   Switching (GMPLS) Open Shortest Path First (OSPF) routing protocol. 
   This 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. 

    

Status of this Memo 

   This Internet-Draft is submitted in full conformance with the 
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   at any time.  It is inappropriate to use Internet-Drafts as 
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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.................................. 7 
   7. Acknowledgments ............................................. 8 
 
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]. 
 
 
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   The following acronyms are used in this draft: 

   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 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.  

 
 
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   In this document, an extension on Interface Switching Capacity 
   Descriptor (ISCD) [RFC4202] for availability information is defined. 
   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 a < availability, bandwidth> 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 information to be flooded in the network and used by 
   the nodes or the PCE for the path computation. In this document, an 
   extension to Interface Switching Capacity Descriptor (ISCD) [RFC4202] 
   for availability information 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. ISCD Availability sub-TLV 

   The ISCD sub-TLV is defined in Section 1.4 of [RFC4203]. The ISCD 
   Availability sub-TLV defined in this document is 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; 

 
 
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      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 
           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 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 does not support the ISCD Availability sub-TLV SHOULD 
   ignore ISCD Availability sub-TLV but it SHOULD be included in LSAs 
   sent to OSPF neighbors [RFC3630]. If a node who supports ISCD 
   Availability sub-TLVs does not receive the TLV, it SHOULD assume 
   that the link is with fixed bandwidth, and the availability can be 
   interpreted as the highest availability value, e.g., five nines. 
   It's not allowed to send multiple ISCD Availability sub-TLVs for the 
   same availability level. 

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 
 
 
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   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 an Availability sub-TLV of the ISCD sub-TLV 
   of the TE Link TLV in the TE Opaque LSA for OSPF v2. IANA is 
   requested to create 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 requested 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. 

 
 
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   [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. 

   [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 

 
 
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7. Acknowledgments 

   The authors would like to thank Acee Lindem, Daniele Ceccarelli, Lou 
   Berger for their comments on the document. 

    

   Authors' Addresses 

   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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