ALTO Working Group Q. Wu Internet-Draft Y. Lee Intended status: Standards Track D. Dhody Expires: April 24, 2014 Huawei S. Randriamasy Alcatel-Lucent October 21, 2013 ALTO Traffic Engineering Cost Metrics draft-wu-alto-te-metrics-00 Abstract Cost Metric is a basic concept in Application-Layer Traffic Optimization (ALTO). It is used in both the Cost Map Service and the Endpoint Cost Service. Future extensions to ALTO may also use Cost Metric. Different applications may benefit from different Cost Metrics. For example, a Resource Consumer may prefer Resource Providers that have low latency to the Resource Consumer. However the base ALTO protocol [ALTO] has defined only a single cost metric, i.e., the generic "routingcost" metric (Sec. 14.2 of ALTO base specification [ALTO]). In this document, we define XXX Cost Metrics, derived from OSPF-TE and ISIS-TE, to measure network delay, jitter, packet loss, hop count, and bandwidth. The metrics defined in this document provide a relatively comprehensive set of Cost Metrics for ALTO focusing on traffic engineering. Additional Cost Metrics such as financial cost metrics may be defined in other documents. 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 24, 2014. Wu, et al. Expires April 24, 2014 [Page 1] Internet-Draft ALTO TE Metrics October 2013 Copyright Notice Copyright (c) 2013 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. Conventions used in this document . . . . . . . . . . . . . . 4 3. Metric: delay . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Metric: delayjitter . . . . . . . . . . . . . . . . . . . . . 7 5. Metric: pktloss . . . . . . . . . . . . . . . . . . . . . . . 9 6. Cost Metric: hopcount . . . . . . . . . . . . . . . . . . . . 11 7. Metrics: bandwidth . . . . . . . . . . . . . . . . . . . . . . 12 8. Metric: maxbw . . . . . . . . . . . . . . . . . . . . . . . . 14 9. Maximum Reserved Bandwdith: maxreservbw . . . . . . . . . . . 15 10. Metric: unreservbw . . . . . . . . . . . . . . . . . . . . . . 16 11. Metric: residuebw . . . . . . . . . . . . . . . . . . . . . . 17 12. Metric: availbw . . . . . . . . . . . . . . . . . . . . . . . 18 13. Metric: utilbw . . . . . . . . . . . . . . . . . . . . . . . . 19 14. Security Considerations . . . . . . . . . . . . . . . . . . . 20 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22 16.1. Normative References . . . . . . . . . . . . . . . . . . 22 16.2. Informative References . . . . . . . . . . . . . . . . . 22 Appendix A. Filtering constraint Extensions . . . . . . . . . . . 23 Appendix B. Contributing Authors Addresses . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26 Wu, et al. Expires April 24, 2014 [Page 2] Internet-Draft ALTO TE Metrics October 2013 1. Introduction Cost Metric is a basic concept in Application-Layer Traffic Optimization (ALTO). It is used in both the Cost Map Service and the Endpoint Cost Service. In particular, applications may benefit from knowing network performance measured in several Cost Metrics. For example, a more delay sensitive application may focus on latency, and a more bandwidth-sensitive application may focus on available bandwidth. In this document, we define X Cost Metrics, extending the base ALTO protocol [ALTO], which has defined only a single Cost Metric, i.e., the generic "routingcost" metric (Sec. 14.2 of ALTO base specification [ALTO]). The Cost Metrics that we define in this document focus on traffic engineering. Additional metrics may be defined in other documents. In particular, the Cost Metrics that we define in this document can be gathered from routing systems; [OSPF-TE], [ISIS-TE], [BGP-LS] and [BGP-PM] define mechanisms that allow an ALTO Server to retrieve and derive the necessary information to provide the metrics that we define in this document. Note that the metrics that the ALTO Server retrieves may be defined for only links, and hence, the server will need to compose the link metrics to obtain path metrics used in services such as the Cost Map Service. In this definition, we define the metrics to be independent of link or path, considering that future ALTO extensions may define link-based services, and hence the defined metrics should still be usable. One challenge in defining the metrics is that performance metrics often depend on configuration parameters. For example, the value of packet loss rate depends on the measurement interval. We handle this issue [YRY: IMPORTANT TO SOLVE] The definitions of a set Cost Metrics can allow us to extend the base protocol (e.g., allowing output and constraints use different Cost Metrics), but such extensions are not in the scope of this document. Wu, et al. Expires April 24, 2014 [Page 3] Internet-Draft ALTO TE Metrics October 2013 2. 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 RFC2119 [RFC2119]. Syntax specifications shown here use the augmented Backus-Naur Form (ABNF) as described in [RFC5234], and are specified as in the base JSON specification [RFC4627]. Wu, et al. Expires April 24, 2014 [Page 4] Internet-Draft ALTO TE Metrics October 2013 3. Metric: delay Cost Metric name: delay Metric Description: To specify spatial and temporal aggregated delay over the specified source and destination. The spatial aggregation unit is specified in the query context (e.g., PID to PID, or endhost to endhost); and the temporal unit is specified as the measurement interval. Metric Unit: The unit is microseconds. Metric Value Type: A single 'JSONNumber' type value containing a non-negative integer component that may be followed by a fraction part and/or an exponent part. Cost Mode: A Cost Mode is encoded as a US-ASCII string. The string MUST either have the value 'numerical' or 'ordinal'. Measurement details: YRY: SPECIFY MORE DETAILS. Example 1: POST /endpointcost/lookup HTTP/1.1 Host: alto.example.com Content-Length: TBA Content-Type: application/alto-endpointcostparams+json Accept: application/alto-endpointcost+json,application/alto-error+json { "cost-type": {"cost-mode" : "numerical", "cost-metric" : "delay"}, "endpoints" : { "srcs": [ "ipv4:192.0.2.2" ], "dsts": [ "ipv4:192.0.2.89", "ipv4:198.51.100.34", "ipv4:203.0.113.45" ] } } HTTP/1.1 200 OK Content-Length: TBA Content-Type: application/alto-endpointcost+json { "meta" :{ "cost-type": {"cost-mode" : "numerical", Wu, et al. Expires April 24, 2014 [Page 5] Internet-Draft ALTO TE Metrics October 2013 "cost-metric" : "delay" } }, "endpoint-cost-map" : { "ipv4:192.0.2.2": { "ipv4:192.0.2.89" : 10, "ipv4:198.51.100.34" : 20, "ipv4:203.0.113.45" : 30, } } } Wu, et al. Expires April 24, 2014 [Page 6] Internet-Draft ALTO TE Metrics October 2013 4. Metric: delayjitter Cost Metric name: delayjitter Metric Description: To specify the average delay variation over a configurable interval for each source/destination pair between two endpoints (network locations) in the network. It could be either end to end jitter or the jitter associated with a link (linkjitter). The unit is microseconds. Cost Metric Value type: A single 'JSONumber' type value containing an integer component that may be prefixed with an optional minus sign, which may be followed by a fraction part and/or an exponent part. Purpose: This is intended to be a constraint attribute value It could be used as a cost metric constraint attribute used together with cost metric attribute 'routingcost' or on its own or as a returned cost metric in the response. Cost mode: A Cost Mode is encoded as a US-ASCII string. The string MUST either have the value 'numerical' or 'ordinal'. Measurement timing: Gather and update at the configurable interval if it is link attribute. See [OSPF-TE] for configurable interval. The configurable interval for end to end jitter could be same as link. Measurement points with Potential Measurement Domain: The measurement point could be at any endpoint between source and destination in the network. Examples: POST /endpointcost/lookup HTTP/1.1 Host: alto.example.com Content-Length: TBA Content-Type: application/alto-endpointcostparams+json Accept: application/alto-endpointcost+json,application/alto-error+json { "cost-type": {"cost-mode" : "numerical", "cost-metric" : "delayjitter"}, "endpoints" : { "srcs": [ "ipv4:192.0.2.2" ], "dsts": [ "ipv4:192.0.2.89", Wu, et al. Expires April 24, 2014 [Page 7] Internet-Draft ALTO TE Metrics October 2013 "ipv4:198.51.100.34", "ipv4:203.0.113.45" ] } } HTTP/1.1 200 OK Content-Length: TBA Content-Type: application/alto-endpointcost+json { "meta": { "cost type": { "cost-mode": "numerical", "cost-metric":"delayjitter" } }, "endpoint-cost-map": { "ipv4:192.0.2.2": { "ipv4:192.0.2.89" : 0 "ipv4:198.51.100.34" : 1 "ipv4:203.0.113.45" : 5 } } } Wu, et al. Expires April 24, 2014 [Page 8] Internet-Draft ALTO TE Metrics October 2013 5. Metric: pktloss Cost Metric name: pktloss Metric Description: To specify a percentage of the total traffic sent over a configurable interval for each source/destination pair between two endpoints(network locations) in the network. It could be either end to end packet loss or the packet loss associated with a link (linkloss). Cost Metric Value type: A single number value containing an integer component that may be prefixed with an optional minus sign, which may be followed by a fraction part and/or an exponent part. Purpose: This is intended to be a constraint attribute value It could be used as a cost metric constraint attribute used together with cost metric attribute 'routingcost' or on its own or as a returned cost metric in the response. Cost mode: A Cost Mode is encoded as a US-ASCII string. The string MUST either have the value 'numerical' or 'ordinal'. Measurement timing: Gather and update at the configurable interval if it is link attribute. See [OSPF-TE] for configurable interval. The configurable interval for end to end packet loss could be same as link. Measurement points with Potential Measurement Domain: The measurement point could be at any endpoint between source and destination in the network. Examples: POST /endpointcost/lookup HTTP/1.1 Host: alto.example.com Content-Length: TBA Content-Type: application/alto-endpointcostparams+json Accept: application/alto-endpointcost+json,application/alto-error+json { "cost-type": {"cost-mode" : "numerical", "cost-metric" : "pktloss"}, "endpoints" : { "srcs": [ "ipv4:192.0.2.2" ], "dsts": [ "ipv4:192.0.2.89", "ipv4:198.51.100.34", Wu, et al. Expires April 24, 2014 [Page 9] Internet-Draft ALTO TE Metrics October 2013 "ipv4:203.0.113.45" ] } } HTTP/1.1 200 OK Content-Length: TBA Content-Type: application/alto-endpointcost+json { "meta": { "cost type": { "cost-mode": "numerical", "cost-metric":"pktloss"} } }, "endpoint-cost-map": { "ipv4:192.0.2.2": { "ipv4:192.0.2.89" : 0, "ipv4:198.51.100.34": 1, "ipv4:203.0.113.45" : 0, } } } Wu, et al. Expires April 24, 2014 [Page 10] Internet-Draft ALTO TE Metrics October 2013 6. Cost Metric: hopcount Cost Metric name: hopcount Metric Description: To specify the number of hops in the path between the source endpoint and the destination endpoint. Editor Note: Need to specify which layer (IP perhaps), details TBD for multiple-layer aspect. Cost Metric Value type: A single 'JSONNumber' type value containing an integer component that may be prefixed with an optional minus sign. Purpose: This is intended to be a constraint attribute value It could be used as a cost metric constraint attribute used together with cost metric attribute 'routingcost' or on its own or as a returned cost metric in the response. Cost mode: A Cost Mode is encoded as a US-ASCII string. string MUST either have the value 'numerical' or 'ordinal'. Wu, et al. Expires April 24, 2014 [Page 11] Internet-Draft ALTO TE Metrics October 2013 7. Metrics: bandwidth Cost Metric name: bandwidth Metric Description: To specify Bandwidth over a configurable interval for each source/destination pair between two endpoints (network locations)in the network. It could be either aggregated bandwidth for end to end path or the bandwidth associated with a link. The units are bytes per second. Cost Metric Value type: A single 'JSONNumber' type value containing an integer component that may be prefixed with an optional minus sign, which may be followed by a fraction part and/or an exponent part. Purpose: This is intended to be a constraint attribute value It could be used as a cost metric constraint attribute used together with cost metric attribute 'routingcost' or on its own or as a returned cost metric in the response. Cost mode: A Cost Mode is encoded as a US-ASCII string. The string MUST either have the value 'numerical' or 'ordinal'. This is just a definition of the costtype 'bandwidth'. The use of this cost is always in conjunction with what it represents, which could be Max Bandwidth (maxbw), Residual Bandwidth (residuebw) etc. Examples: (based on Residual Bandwidth (residuebw)) POST /endpointcost/lookup HTTP/1.1 Host: alto.example.com Content-Length: TBA Content-Type: application/alto-endpointcostparams+json Accept: application/alto-endpointcost+json,application/alto-error+json { "cost-type": {"cost-mode" : "numerical", "cost-metric" : "residubw"}, "endpoints" : { "srcs": [ "ipv4:192.0.2.2" ], "dsts": [ "ipv4:192.0.2.89", "ipv4:198.51.100.34", "ipv4:203.0.113.45" ] Wu, et al. Expires April 24, 2014 [Page 12] Internet-Draft ALTO TE Metrics October 2013 } } HTTP/1.1 200 OK Content-Length: TBA Content-Type: application/alto-endpointcost+json { "meta": { "cost type": { "cost-mode": "numerical", "cost-metric":"residubw" } }, "endpoint-cost-map": { "ipv4:192.0.2.2": { "ipv4:192.0.2.89" : 0, "ipv4:198.51.100.34": 2000, "ipv4:203.0.113.45" : 5000, } } } Wu, et al. Expires April 24, 2014 [Page 13] Internet-Draft ALTO TE Metrics October 2013 8. Metric: maxbw A maxbw is gathered using [RFC3630], [RFC3784] or [BGP-LS]. It could be either maximum bandwidth for end to end path or the bandwidth associated with a link. It is extended from Bandwidth Cost metric and defined as: Object { BWType max; [PIDName srcPID;] [PIDName dstPID;] [JSONBool state;] //TRUE = not steady for src/dst pair; FALSE = steady; Bandwidth bw; }maxbw; Wu, et al. Expires April 24, 2014 [Page 14] Internet-Draft ALTO TE Metrics October 2013 9. Maximum Reserved Bandwdith: maxreservbw A maxreservbw is gathered using [RFC3630], [RFC3784] or [BGP-LS]. It could be either maximum reserved bandwidth for end to end path or the bandwidth associated with a link. It is extended from Bandwidth Cost metric and defined as: Object { BWType maxreserved; [PIDName srcPID;] [PIDName dstPID;] [JSONBool state;] //TRUE = not steady for src/dst pair; FALSE = steady; Bandwidth bw; }maxreservbw; Wu, et al. Expires April 24, 2014 [Page 15] Internet-Draft ALTO TE Metrics October 2013 10. Metric: unreservbw A unreservbw is gathered using [RFC3630], [RFC3784] or [BGP-LS]. It could be either unreserved bandwidth for end to end path or the bandwidth associated with a link. It is extended from Bandwidth Cost metric and defined as: Object { BWType unreserved; [PIDName srcPID;] [PIDName dstPID;] [JSONBool state;] //TRUE = not steady for src/dst pair; FALSE = steady; Bandwidth bw<1,8> }unreservbw; //This bandwidth is per priority [TBD]. Wu, et al. Expires April 24, 2014 [Page 16] Internet-Draft ALTO TE Metrics October 2013 11. Metric: residuebw A residuebw is gathered using [OSPF-TE], [ISIS-TE] or [BGP-PM]. It could be either residual bandwidth for end to end path or the bandwidth associated with a link. It is extended from Bandwidth Cost metric and defined as: Object { BWType Residue; [PIDName srcPID;] [PIDName dstPID;] [JSONBool state;] //TRUE = not steady for src/dst pair; FALSE = steady; Bandwidth bw; }rediduebw; Wu, et al. Expires April 24, 2014 [Page 17] Internet-Draft ALTO TE Metrics October 2013 12. Metric: availbw A availbw is gathered using [OSPF-TE], [ISIS-TE] or [BGP-PM]. It could be either available bandwidth for end to end path or the bandwidth associated with a link. It is extended from Bandwidth Cost metric and defined as: Object { BWType Available; [PIDName srcPID;] [PIDName dstPID;] [JSONBool state;] //TRUE = not steady for src/dst pair; FALSE = steady; Bandwidth bw; }availbw; Wu, et al. Expires April 24, 2014 [Page 18] Internet-Draft ALTO TE Metrics October 2013 13. Metric: utilbw A utilbw is gathered using [OSPF-TE], [ISIS-TE] or [BGP-PM]. It could be either utilized bandwidth for end to end path or the bandwidth associated with a link. It is extended from Bandwidth Cost metric and defined as: Object { BWType Utilized; [PIDName srcPID;] [PIDName dstPID;] [JSONBool state;] //TRUE = not steady for src/dst pair; FALSE = steady; Bandwidth bw; }utilbw; Wu, et al. Expires April 24, 2014 [Page 19] Internet-Draft ALTO TE Metrics October 2013 14. Security Considerations The properties defined in this document present no security considerations beyond those in Section 14 of the base ALTO specification [ALTO]. Wu, et al. Expires April 24, 2014 [Page 20] Internet-Draft ALTO TE Metrics October 2013 15. IANA Considerations IANA has added the following entries to the ALTO cost map Properties registry, defined in Section 3 of [RFCXXX]. +-----------+--------------+------------------------+ | Namespace | Property | Reference | +-----------+--------------+------------------------+ | | delay | [RFCxxxx], Section 3.1 | | | jitter | [RFCxxxx], Section 3.2 | | | pktloss | [RFCxxxx], Section 3.3 | | | bandwidth | [RFCxxxx], Section 3.4 | | | hopcount | [RFCxxxx], Section 3.5 | | | maxbw |[RFCxxxx], Section 3.6 | | | maxresbw |[RFCxxxx], Section 3.7 | | | unresdbw |[RFCxxxx], Section 3.8 | | | residbw |[RFCxxxx], Section 3.9 | | | availbw |[RFCxxxx], Section 3.10 | | | utilbw |[RFCxxxx], Section 3.11 | +-----------+--------------+------------------------+ Wu, et al. Expires April 24, 2014 [Page 21] Internet-Draft ALTO TE Metrics October 2013 16. References 16.1. Normative References [ALTO] Alimi, R., "ALTO Protocol", ID draft-ietf-alto-protocol-16, May 2013. [BGP-LS] Gredler, H., "North-Bound Distribution of Link-State and TE Information using BGP", ID draft-ietf-idr-ls-distribution-03, May 2013. [BGP-PM] Wu, Q., "BGP attribute for North-Bound Distribution of Traffic Engineering (TE) performance Metrics", ID draft-wu-idr-te-pm-bgp-02, October 2013. [ISIS-TE] Giacalone, S., "ISIS Traffic Engineering (TE) Metric Extensions", ID draft-ietf-isis-te-metric-extensions-01, October 2013. [OSPF-TE] Giacalone, S., "OSPF Traffic Engineering (TE) Metric Extensions", ID draft-ietf-ospf-te-metric-extensions-04, June 2013. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997. [RFC4627] Crockford, D., "The application/json Media Type for JavaScript Object Notation (JSON)", RFC 4627, July 2006. [RFC5234] Crocker, D., "Augmented BNF for Syntax Specifications: ABNF", RFC 5234, January 2008. 16.2. Informative References [RFC6390] Clark, A. and B. Claise, "Framework for Performance Metric Development", RFC 6390, July 2011. Wu, et al. Expires April 24, 2014 [Page 22] Internet-Draft ALTO TE Metrics October 2013 Appendix A. Filtering constraint Extensions Section 10.2.2.3 of "ALTO: Application Layer Traffic Optimization Protocol" [I.D-ietf-alto-protocol] states: " object { CostType cost-type; [JSONString constraints<0..*>;] [PIDFilter pids;] } ReqFilteredCostMap; object { PIDName srcs<0..*>; PIDName dsts<0..*>; } PIDFilter; with members: cost-type The CostType (Section 9.7) for the returned costs. The cost-metric and cost-mode fields MUST match one of the supported Cost Types indicated in this resource's capabilities (Section 10.2.2.4). The ALTO Client SHOULD omit the description field, and if present, the ALTO Server MUST ignore the description field. constraints Defines a list of additional constraints on which elements of the Cost Map are returned. This parameter MUST NOT be specified if this resource's capabilities ( Section 10.2.2.4) indicate that constraint support is not available. A constraint contains two entities separated by whitespace: (1) an operator, 'gt' for greater than, 'lt' for less than, 'ge' for greater than or equal to, 'le' for less than or equal to, or 'eq' for equal to; (2) a target cost value. The cost value is a number that MUST be defined in the same units as the Cost Metric indicated by the cost-metric parameter. ALTO Servers SHOULD use at least IEEE 754 double-precision floating point [IEEE.754.2008] to store the cost value, and SHOULD perform internal computations using double- precision floating-point arithmetic. If multiple 'constraint' parameters are specified, they are interpreted as being related to each other with a logical AND. " In the JSON Object of type ReqFilteredCostMap, the constraint attribute is expressed as: " [gt | lt | ge | le | eq ] " Wu, et al. Expires April 24, 2014 [Page 23] Internet-Draft ALTO TE Metrics October 2013 In this specification, the constraint attribute is changed to " [gt | lt | ge | le | eq ] " Accordingly, the constraints definition is changed to: " constraints Defines a list of additional constraints on which elements of the Cost Map are returned. This parameter MUST NOT be specified if this resource's capabilities ( Section 10.2.2.4) indicate that constraint support is not available. A constraint contains three entities separated by whitespace: (1)an cost type is by default cost-type in the JSON Object of type ReqFilteredCostMap. In addition, it could be another cost-type used for the returned cost (2) an operator, 'gt' for greater than, 'lt' for less than, 'ge' for greater than or equal to, 'le' for less than or equal to, or 'eq' for equal to; (3) a target cost value. The cost value is a number that MUST be defined in the same units as the Cost Metric indicated by the cost-metric parameter. ALTO Servers SHOULD use at least IEEE 754 double-precision floating point [IEEE.754.2008] to store the cost value, and SHOULD perform internal computations using double- precision floating-point arithmetic. If multiple 'constraint' parameters are specified, they are interpreted as being related to each other with a logical AND. " Editor-Notes: Filtering constraint extension should move to another document defining multi-metrics filtering in the future. Wu, et al. Expires April 24, 2014 [Page 24] Internet-Draft ALTO TE Metrics October 2013 Appendix B. Contributing Authors Addresses Y. Richard Yang Yale University 51 Prospect St New Haven CT USA Email: yry@cs.yale.edu Wu, et al. Expires April 24, 2014 [Page 25] Internet-Draft ALTO TE Metrics October 2013 Authors' Addresses Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: sunseawq@huawei.com Young Lee Huawei 1700 Alma Drive, Suite 500 Plano, TX 75075 USA Email: leeyoung@huawei.com Dhruv Dhody Huawei Leela Palace Bangalore, Karnataka 560008 INDIA Email: dhruv.ietf@gmail.com Sabine Randriamasy Alcatel-Lucent Wu, et al. Expires April 24, 2014 [Page 26]