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. 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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 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 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 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 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 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 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 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 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]