Internet DRAFT - draft-ali-pce-additional-of-and-metric

draft-ali-pce-additional-of-and-metric










     CCAMP Working Group                                       Zafar Ali 
     Internet Draft                                       George Swallow 
     Intended status: Standard Track                   Clarence Filsfils 
     Expires: April 14, 2013                              Siva Sivabalan 
                                                         Stefano Previdi 
                                                           Cisco Systems 
                                                            Kenji Kumaki 
                                                        KDDI Corporation 
                                                        October 15, 2012  
                                                                             
                                         
      
            Additional Objective Functions and Metric Types in Path 
               Computation Element Communication Protocol (PCEP) 
                 draft-ali-pce-additional-of-and-metric-00.txt 


     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).  Note that other groups may also distribute 
     working documents as Internet-Drafts.  The list of current 
     Internet-Drafts is at http://datatracker.ietf.org/drafts/current/. 

     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." 

     This Internet-Draft will expire on April 14, 2013.  
         
     Copyright Notice 
         

     Copyright (c) 2012 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. 
      
      
      
     Ali, Swallow, Filsfils       Expires April 2013            [Page 1] 






     ID           draft-ali-pce-additional-of-and-metric-00.txt 
         

      

     This document may contain material from IETF Documents or IETF 
     Contributions published or made publicly available before November 
     10, 2008.  The person(s) controlling the copyright in some of this 
     material may not have granted the IETF Trust the right to allow 
     modifications of such material outside the IETF Standards Process. 
     Without obtaining an adequate license from the person(s) 
     controlling the copyright in such materials, this document may not 
     be modified outside the IETF Standards Process, and derivative 
     works of it may not be created outside the IETF Standards Process, 
     except to format it for publication as an RFC or to translate it
     into languages other than English. 

     Abstract 

     Network performance criteria such as latency and latency variation 
     are becoming critical to data path selection, especially for 
     networks used by financial institutions. This draft defines 
     additional objective functions and metrics types related to latency 
     and latency variation in Path Computation Element Communication 
     Protocol (PCEP).  

     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]. 

     Table of Contents 

      
     Copyright Notice..................................................1 
     1. Introduction...................................................3 
     2. PCEP extensions................................................3 
           2.1. New Metric Object Types................................3 
              2.1.1. P2P Latency Metric................................4 
              2.1.2. P2P Latency Variation Metric......................4 
              2.1.3. P2MP Latency Metric...............................4 
              2.1.4. P2MP Latency Variation Metric.....................5 
           2.2. Handling of New Metric Object Types....................5 
           2.3. New Objective Functions................................5 
              2.3.1. Minimum Latency Path Objective Function...........6 
              2.3.2. Minimum Latency Variation Path Objective Function.6 
           2.4. Handling of New Objective Functions....................6 
     3. Security Considerations........................................6 
      
      
     Ali, Swallow, Filsfils, et al     Expires April 2013       [Page 2] 
      






     ID           draft-ali-pce-additional-of-and-metric-00.txt 
         

     4. IANA Considerations............................................6 
     5. References.....................................................7 
           5.1. Normative References...................................7 
           5.2. Informative References.................................7 
      
     1. Introduction 

       As noted in [OSPF-TE-METRIC] and [ISIS-TE-METRIC], in certain 
       networks such as financial information networks (e.g. stock 
       market data providers), performance criteria (e.g. latency, 
       latency variation) are becoming critical to data path selection 
       along with other metrics. Such networks may require selection of 
       a path that minimizes end-to-end latency and/or end-to-end 
       latency variation. Or a path may need to be found that optimizes 
       some other metric, but is subjected to a latency and/or latency 
       variation bound(s).  

       The METRIC object defined in [RFC5440] allows a PCC to specify a 
       bounded acceptable path cost and/or optimization metric. While 
       [RFC5440], [RFC5541] and [RFC6006] define various Metric Types, 
       these RFCs do not address latency and latency variation metrics. 
       This document extends [RFC 5540] with four new Metric Types 
       namely Point-to-Point (P2P) latency metric, P2P latency variation 
       metric, Point-to-Multipoint (P2MP) latency metric and P2MP 
       latency variation metric.  

       [RFC5541] defines a framework to extend the PCEP to allow a PCE 
       to indicate the set of objective functions it supports. [RFC5541] 
       also define procedure so that a PCC can indicate in a path 
       computation request the required objective function, and a PCE   
       can report in a path computation reply the objective function 
       that was used for path computation. While [RFC5541] and [RFC6006] 
       define various objective functions, these documents do not define 
       objective functions for optimizing network performance criteria 
       such as latency and latency variation. This document extends the 
       [RFC5541] with two new objective functions namely Minimum Latency 
       Path (MLP) OF and Minimum Latency Variation Path (MLVP) OF. 

     2. PCEP extensions 

        This section defines PCEP extensions for requirements outlined 
        in Section 1.  

     2.1. New Metric Object Types  

           This document defines the following four additional types for 
        the <METRIC> object defined in [RFC5440}. For explanation of 

      
      
     Ali, Swallow, Filsfils, et al     Expires April 2013       [Page 3] 
      






     ID           draft-ali-pce-additional-of-and-metric-00.txt 
         

        these metrics, the following terminology is used and expanded 
        along the way.  

          - A network comprises of a set of N links {Li, (i=1...N)}. 

          - A path P of a P2P LSP is a list of K links {Lpi,(i=1...K)}. 

     2.1.1. P2P Latency Metric 

        Link delay metric is defined in [OSPF-TE-METRIC] and [ISIS-TE-
        METRIC]. P2P latency metric type of <METRIC> object in PCEP 
        encodes the sum of the link delay metric of all links along a 
        P2P Path. Specifically, extending on the above mentioned 
        terminology:  

          -  Link delay metric of link L is denoted D(L). 

          -  P2P latency metric for the Path P = Sum {D(Lpi), 
            (i=1...K)}. 

        Value for P2P latency metric type is to be assigned by IANA 
        (suggested value: 11).  

     2.1.2. P2P Latency Variation Metric 

        Link delay variation metric is defined in [OSPF-TE-METRIC] and 
        [ISIS-TE-METRIC]. P2P latency variation metric type of <METRIC> 
        object in PCEP encodes a function of the link delay variation 
        metric of all links along a P2P Path. Specifically, extending on 
        the above mentioned terminology:  

          -  Latency variation of link L is denoted DV(L). 

          -  P2P latency variation metric for the Path P = Function 
            {DV(Lpi), (i=1...K)}. 

        Specification of the "Function" used to drive latency variation 
        metric of a path from latency variation metrics of individual 
        links along the path is beyond the scope of this document.  

        Value for P2P latency variation metric is to be assigned by IANA 
        (suggested value: 12).  

     2.1.3. P2MP Latency Metric 

       P2MP latency metric type of <METRIC> object in PCEP encodes the 
       path latency metric for destination that observes the worst 

      
      
     Ali, Swallow, Filsfils, et al     Expires April 2013       [Page 4] 
      






     ID           draft-ali-pce-additional-of-and-metric-00.txt 
         

       latency metric among all destination of the P2MP tree. 
       Specifically, extending on the above mentioned terminology: 

         - A P2MP Tree T comprises of a set of M destinations {Dest_j, 
           (j=1...M)} 

         - P2P latency metric of the Path to destination Dest_j is 
           denoted by LM(Dest_j). 

         - P2MP latency metric for the P2MP tree T = Maximum 
           {LM(Dest_j), (j=1...M)}.   

       Value for P2MP latency metric is to be assigned by IANA 
       (suggested value: 13).  

     2.1.4. P2MP Latency Variation Metric 

       P2MP latency variation metric type of <METRIC> object in PCEP 
       encodes the path latency variation metric for destination that 
       observes the worst latency variation metric among all destination 
       of the P2MP tree. Specifically, extending on the above mentioned 
       terminology: 

         - A P2MP Tree T comprises of a set of M destinations {Dest_j, 
           (j=1...M)} 

         - P2P latency variation metric of the Path to destination 
           Dest_j is denoted by LVM(Dest_j). 

         - P2MP latency variation metric for the P2MP tree T = Maximum 
           {LVM(Dest_j), (j=1...M)}.   

       Value for P2MP latency variation metric is to be assigned by IANA 
       (suggested value: 14).  

     2.2. Handling of New Metric Object Types  

        This document does not propose any changes to handling of Metric 
        object. Specifically, the new metric types defined in this 
        document are handled in the same fashion as metric types defined 
        in [RFC5440].  

     2.3. New Objective Functions 

        This document extends the [RFC 5541] with two new objective 
        functions namely Minimum Latency Path (MLP) OF and Minimum 
        Latency Variation Path (MLVP) OF. The objective function code 
        for each of the new objective function is also defined.  
      
      
     Ali, Swallow, Filsfils, et al     Expires April 2013       [Page 5] 
      






     ID           draft-ali-pce-additional-of-and-metric-00.txt 
         

     2.3.1. Minimum Latency Path Objective Function 

        Minimum Latency Path (MLP) OF is defined as an objective 
        function where a path is computed such that latency of the path 
        is minimized.  

        Objective function code for MLP OF is to be assigned by IANA 
        (suggested value: 9).  

     2.3.2. Minimum Latency Variation Path Objective Function 

         Minimum Latency Variation Path (MLVP) OF is defined as an 
        objective function where a path is computed such that latency 
        variation in the path is minimized.  

        Objective function code for MLVP OF is to be assigned by IANA 
        (suggested value: 10).  

     2.4. Handling of New Objective Functions 

        This document does not propose any changes to handling of <OF> 
        object. Specifically, the new OF types defined in this document 
        are handled in the same fashion as OF types defined in 
        [RFC5541].  

     3. Security Considerations 

        This document does not introduce any additional security issues 
        beyond those identified in [RFC5440], [RFC5541] and [RFC6006]. 

     4. IANA Considerations 

        This document defines the following four additional types for 
        the <METRIC> object defined in [RFC5440].  

        Value                         Description 

        -----                         ------------ 

        TBA (suggest value: 11)       P2P latency metric 

        TBA (suggest value: 12)       P2P latency variation metric 

        TBA (suggest value: 13)       P2MP latency metric 

        TBA (suggest value: 14)       P2MP latency variation metric 


      
      
     Ali, Swallow, Filsfils, et al     Expires April 2013       [Page 6] 
      






     ID           draft-ali-pce-additional-of-and-metric-00.txt 
         

        This document defines the following two objective functions 
        codes for the <OF> object defined in [RFC5541].   

        Value                   Description 

        -----                   ------------ 

        TBA (suggest value: 9)  Minimum Latency Path (MLP) OF 

        TBA (suggest value: 10) Minimum Latency Variation Path (MLVP) OF 

      
     5. References 

     5.1. Normative References 

        [RFC5440] Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path 
                  Computation Element (PCE) Communication Protocol 
                  (PCEP)", RFC 5440, March 2009. 

        [RFC5541] Le Roux, JL., Vasseur, JP., and Y. Lee, "Encoding of 
                  Objective Functions in the Path Computation Element 
                  Communication Protocol (PCEP)", RFC 5541, June 2009. 

        [DRAFT-OSPF-TE-METRIC] S. Giacalone, D. Ward, J. Drake, A. 
                  Atlas, S. Previdi, "OSPF Traffic Engineering (TE) 
                  Metric Extensions", draft-ietf-ospf-te-metric-
                  extensions, work in progress. 

        [DRAFT-ISIS-TE-METRIC] S. Previdi, S. Giacalone, D. Ward, J. 
                  Drake, A. Atlas, C. Filsfils, "IS-IS Traffic 
                  Engineering (TE) Metric Extensions", draft-previdi-
                  isis-te-metric-extensions, work in progress. 

      
     5.2. Informative References 

        [RFC6006] Zhao, Q., Ed., King, D., Ed., Verhaeghe, F., Takeda, 
                  T., Ali, Z., and J. Meuric, "Extensions to the Path 
                  Computation Element Communication Protocol (PCEP) for 
                  Point-to-Multipoint Traffic Engineering Label Switched 
                  Paths", RFC 6006, September 2010. 

     Authors' Addresses 




      
      
     Ali, Swallow, Filsfils, et al     Expires April 2013       [Page 7] 
      






     ID           draft-ali-pce-additional-of-and-metric-00.txt 
         

         
        Zafar Ali 
        Cisco Systems 
        Email: zali@cisco.com 
      
        George Swallow 
        Cisco Systems 
        swallow@cisco.com 
         
        Clarence Filsfils  
        Cisco Systems 
        cfilsfil@cisco.com 
         
        Siva Sivabalan 
        Cisco Systems 
        msiva@cisco.com 
         
        Stefano Previdi 
        Cisco Systems 
        sprevidi@cisco.com  
         
        Kenji Kumaki 
        KDDI Corporation 
        Email: ke-kumaki@kddi.com  
         
      

         

         

















      
      
     Ali, Swallow, Filsfils, et al     Expires April 2013       [Page 8]