Network Working Group S. Poretsky Internet Draft Allot Communications Expires: September 08, 2009 Intended Status: Informational Brent Imhoff Juniper Networks March 08, 2009 Terminology for Benchmarking Link-State IGP Data Plane Route Convergence <draft-ietf-bmwg-igp-dataplane-conv-term-17.txt> Status of this Memo This Internet-Draft is submitted to IETF 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. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on September 8, 2009. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. ABSTRACT This document describes the terminology for benchmarking Interior Gateway Protocol (IGP) Route Convergence. The terminology is to be used for benchmarking IGP convergence time through externally observable (black box) data plane measurements. The terminology can be applied to any link-state IGP, such as ISIS and OSPF. Poretsky, Imhoff [Page 1]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence Table of Contents 1. Introduction and Scope........................................3 2. Existing Definitions .........................................4 3. Term Definitions..............................................4 3.1 States 3.1.1 Route Convergence....................................4 3.1.2 Full Convergence.....................................5 3.1.3 Network Convergence..................................5 3.1.4 Route-Specific Convergence...........................6 3.1.5 Stale Forwarding.....................................6 3.2 Events 3.2.1 Convergence Event....................................7 3.2.2 Convergence Event Trigger............................7 3.2.3 Convergence Event Instant............................8 3.2.4 Convergence Recovery Instant.........................8 3.2.5 First Route Convergence Instant......................9 3.2.6 Convergence Event Transition.........................9 3.2.7 Convergence Recovery Transition......................10 3.2.8 Nested Convergence Events............................10 3.3 Interfaces 3.3.1 Local Interface......................................11 3.3.2 Neighbor Interface...................................11 3.3.3 Remote Interface.....................................11 3.3.4 Preferred Egress Interface...........................12 3.3.5 Next-Best Egress Interface...........................12 3.4 Benchmarking Method 3.4.1 Packet Loss..........................................13 3.4.2 Convergence Packet Loss..............................13 3.4.3 Rate-Derived Convergence Method......................14 3.4.4 Loss-Derived Convergence Method......................14 3.4.5 Packet Sampling Interval.............................15 3.5 Benchmarks 3.5.1 Full Convergence Time................................17 3.5.2 First Route Convergence Time.........................17 3.5.3 Route-Specific Convergence Time......................17 3.5.4 Sustained Convergence Validation Time................18 3.5.5 Reversion Convergence Time...........................19 4. IANA Considerations...........................................19 5. Security Considerations.......................................19 6. Acknowledgements..............................................20 7. References....................................................20 8. Author's Address..............................................21 Poretsky, Imhoff [Page 2]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 1. Introduction and Scope This draft describes the terminology for benchmarking Interior Gateway Protocol (IGP) Route Convergence. The motivation and applicability for this benchmarking is provided in [Po07a]. The methodology to be used for this benchmarking is described in [Po07m]. The purpose of this document is to introduce new terms required to complete execution of the IGP Route Convergence Methodology [Po07m]. These terms apply to IPv4 and IPv6 traffic and IGPs. Convergence times are measured at the Tester on the data plane by observing packet loss through the DUT. The methodology and terminology to be used for benchmarking Route Convergence can be applied to any link-state IGP such as ISIS [Ca90] and OSPF [Mo98]. The data plane is measured to obtain black-box (externally observable) convergence benchmarking metrics. When there is no packer loss observed in the data plane, the convergence time SHALL be reported as zero. An example of Route Convergence as observed and measured from the data plane is shown in Figure 1. The graph in Figure 1 shows Forwarding Rate versus Time. Time 0 on the X-axis is on the far right of the graph. The Offered Load to the ingress interface of the DUT SHOULD equal the measured Throughput [Ba99][Ma98] of the DUT and the Forwarding Rate [Ma98] and Convergence Packet Loss is measured at the Preferred and Next-Best Egress interfaces of the DUT befire, during, and after a Convergence Event Trigger. These components of the graph are defined in the Term Definitions section. Full Convergence-> Convergence Convergence Recovery Event Event Time= Instant Instant Trigger 0sec Forwarding Rate= ^ ^ ^ ^ Offered Load= Offered Load --> ------\ Packet /----------- <--Max Throughput \ Loss /<----Convergence Convergence------->\ / Event Transition Recovery Transition \ / \_____/<------Maximum Packet Loss ^ First Route Convergence Instant Y-axis = Forwarding Rate X-axis = Time (increases right to left to match commercial test equipment displays) Figure 1. Convergence Graph Poretsky, Imhoff [Page 3]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 2. Existing Definitions This document uses existing terminology defined in other BMWG work. Examples include, but are not limited to: Latency [Ref.[Ba91], section 3.8] Frame Loss Rate [Ref.[Ba91], section 3.6] Throughput [Ref.[Ba91], section 3.17] Device Under Test (DUT) [Ref.[Ma98], section 3.1.1] System Under Test (SUT) [Ref.[Ma98], section 3.1.2] Out-of-order Packet [Ref.[Po06], section 3.3.2] Duplicate Packet [Ref.[Po06], section 3.3.3] Packet Reordering [Ref.[Mo06], section 3.3] 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 BCP 14, RFC 2119 [Br97]. RFC 2119 defines the use of these key words to help make the intent of standards track documents as clear as possible. While this document uses these keywords, this document is not a standards track document. 3. Term Definitions 3.1 States 3.1.1 Route Convergence Definition: The action to update all components of the router with the most recent route change(s) including the Routing Information Base (RIB) and Forwarding Information Base (FIB), along with software and hardware tables, such that forwarding is successful for one or more route entries. Discussion: Route Convergence MUST occur after a Convergence Event. Route Convergence can be observed externally by the rerouting of data traffic to the Next-best Egress Interface. Also, completion of Route Convergence may or may not be sustained over time. Measurement Units: N/A Issues: None See Also: Network Convergence Full Convergence Convergence Event Poretsky, Imhoff [Page 4]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 3.1.2 Full Convergence Definition: Route Convergence for an entire FIB in which complete recovery from the Convergence Event is indicated by the DUT throughput equal to the offered load. Discussion: When benchmarking convergence, it is useful to measure the time to converge an entire FIB. For example, a Convergence Event can be produced for an OSPF table of 5000 routes so that the time to converge routes 1 through 5000 is measured. Completion of Full Convergence is externally observable from the data plane when the Throughput of the data plane traffic on the Next-Best Egress Interface equals the offered load. Full Convergence MAY be measured using Rate-Derived Convergence Method or calculated using Loss-Derived Convergence Method. Full Convergence may or may not be sustained over time. The Sustained Convergence Validation Time MUST be applied. Measurement Units: N/A Issues: None See Also: Network Convergence Route Convergence Convergence Event 3.1.3 Network Convergence Definition: The process of updating of all routing tables, including distributed FIBs, in all routers throughout the network. Discussion: Network Convergence requires completion of all Route Convergence operations for all routers in the network following a Convergence Event. Completion of Network Convergence can be observed by recovery of System Under Test (SUT) Throughput to equal the offered load, with no Stale Forwarding, and no Blenders [Ca01][Ci03]. Measurement Units: N/A Issues: None Poretsky, Imhoff [Page 5]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence See Also: Route Convergence Stale Forwarding 3.1.4 Route-Specific Convergence Definition: Route Convergence for one or more specific route entries in the FIB in which recovery from the Convergence Event is indicated when data-plane traffic for the flow [Po06] matching that route entry(ies) is routed to the Next-Best Egress Interface. Discussion: When benchmarking convergence, it is sometimes useful to measure the time to converge a single flow [Po06] or group of flows to benchmark convergence time for one or a few route entries in the FIB instead of the entire FIB. Route-Specific Convergence of a flow is externally observable from the data plane when the data plane traffic for that flow is routed to the Next-Best Egress Interface. Measurement Units: N/A Issues: None See Also: Full Convergence Route Convergence Convergence Event 3.1.5 Stale Forwarding Definition: Forwarding of traffic to route entries that no longer exist or to route entries with next-hops that are no longer preferred. Discussion: Stale Forwarding can be caused by a Convergence Event and can manifest as a "black-hole" or microloop that produces packet loss. Stale Forwarding can exist until Network Convergence is completed. Stale Forwarding cannot be observed with a single DUT. Measurement Units: N/A Issues: None See Also: Network Convergence Poretsky, Imhoff [Page 6]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 3.2 Events 3.2.1 Convergence Event Definition: The occurrence of a planned or unplanned event in the network that results in a change in the egress interface of the Device Under Test (DUT) for routed packets. Discussion: Convergence Events include link loss, routing protocol session loss, router failure, configuration change, and better next-hop learned via a routing protocol. Measurement Units: N/A Issues: None See Also: Convergence Packet Loss Convergence Event Instant 3.2.2 Convergence Event Trigger Definition: An action taken by the Tester to produce a Convergence Event. Discussion: The Convergence Event Trigger is introduced by the Tester and may be indicated by link loss, routing protocol session loss, router failure, configuration change, or a better next-hop learned via a routing protocol introduced by the Tester. Measurement Units: N/A Issues: None See Also: Convergence Event Convergence Packet Loss Convergence Recovery Instant Poretsky, Imhoff [Page 7]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 3.2.3 Convergence Event Instant Definition: The time instant that a Convergence Event becomes observable in the data plane. Discussion: Convergence Event Instant is observable from the data plane as the precise time that the device under test begins to exhibit packet loss. The Convergence Event Instant is produced by the Convergence Event Trigger. The Convergence Event Instant always occurs concurrent or subsequent to the Tester introducing the Convergence Event Trigger. Measurement Units: hh:mm:ss:nnn:uuu, where 'nnn' is milliseconds and 'uuu' is microseconds. Issues: None See Also: Convergence Event Convergence Packet Loss Convergence Recovery Instant 3.2.4 Convergence Recovery Instant Definition: The time instant that Full Convergence completion is observed. Discussion: Convergence Recovery Instant is measurable from the data plane as the precise time that the device under test completes Full Convergence. The Convergence Recovery Instant MUST be maintained for an interval of duration equal to the Sustained Convergence Validation Time. Measurement Units: hh:mm:ss:nnn:uuu, where 'nnn' is milliseconds and 'uuu' is microseconds. Issues: None See Also: Sustained Convergence Validation Time Convergence Packet Loss Convergence Event Instant Poretsky, Imhoff [Page 8]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 3.2.5 First Route Convergence Instant Definition: The time instant a first route entry has converged following a Convergence Event, as observed by receipt of the first packet from the Next-Best Egress Interface. Discussion: The First Route Convergence Instant is an indication that the process to achieve Full Convergence has begun. Any route may be the first to converge for First Route Convergence Instant. Measurement on the data-plane enables the First Route Convergence Instant to be observed without any white-box information from the DUT. Measurement Units: hh:mm:ss:nnn:uuu, where 'nnn' is milliseconds and 'uuu' is microseconds. Issues: None See Also: Route Convergence Full Convergence Stale Forwarding 3.2.6 Convergence Event Transition Definition: A time interval observed following a Convergence Event in which Throughput gradually reduces to a minimum value. Discussion: The Convergence Event Transition is best observed for Full Convergence. The egress packet rate observed during a Convergence Event Transition may not decrease linearly and may not decrease to zero. Both the offered load and the Packet Sampling Interval influence the observations of the Convergence Event Transition. For example, it is possible that if the Convergence Event were to cause the Throughput [Ba91] to drop to zero then this may not be observed if the Packet Sampling Interval is set too high. This is further discussed with the term "Packet Sampling Interval". Measurement Units: seconds Issues: None Poretsky, Imhoff [Page 9]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence See Also: Convergence Event Full Convergence Packet Sampling Interval 3.2.7 Convergence Recovery Transition Definition: The characteristic of the DUT in which Throughput gradually increases to equal the offered load. Discussion: The Convergence Recovery Transition is best observed for Full Convergence. The egress packet rate observed during a Convergence Recovery Transition may not increase linearly. Both the offered load and the Packet Sampling Interval influence the observations of the Convergence Recovery Transition. This is further discussed with the term "Packet Sampling Interval". Measurement Units: seconds Issues: None See Also: Full Convergence Packet Sampling Interval 3.2.8 Nested Convergence Events Definition: The occurrence of a Convergence Event while the route table is converging from a prior Convergence Event. Discussion: The Convergence Events for a Nested Convergence Event MUST occur with different neighbors. A common observation from a Nested Convergence Event will be the withdrawal of routes from one neighbor while the routes of another neighbor are being installed. Measurement Units: N/A Issues: None See Also: Convergence Event Poretsky, Imhoff [Page 10]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 3.3 Interfaces 3.3.1 Local Interface Definition: An interface on the DUT. Discussion: A failure of the Local Interface indicates that the failure occurred directly on the DUT. Measurement Units: N/A Issues: None See Also: Neighbor Interface Remote Interface 3.3.2 Neighbor Interface Definition: The interface on the neighbor router or tester that is directly linked to the DUT's Local Interface. Discussion: A failure of a Neighbor Interface indicates that a failure occurred on a neighbor router's interface that directly links the neighbor router to the DUT. Measurement Units: N/A Issues: None See Also: Local Interface Remote Interface 3.3.3 Remote Interface Definition: An interface on a neighboring router that is not directly connected to any interface on the DUT. Discussion: A failure of a Remote Interface indicates that the failure occurred on a neighbor router's interface that is not directly connected to the DUT. Poretsky, Imhoff [Page 11]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence Measurement Units: N/A Issues: None See Also: Local Interface Neighbor Interface 3.3.4 Preferred Egress Interface Definition: The outbound interface from the DUT for traffic routed to the preferred next-hop. Discussion: The Preferred Egress Interface is the egress interface prior to a Convergence Event. Measurement Units: N/A Issues: None See Also: Next-Best Egress Interface 3.3.5 Next-Best Egress Interface Definition: The outbound interface from the DUT for traffic routed to the second-best next-hop. It is the same media type and link speed as the Preferred Egress Interface Discussion: The Next-Best Egress Interface becomes the egress interface after a Convergence Event. Measurement Units: N/A Issues: None See Also: Preferred Egress Interface Poretsky, Imhoff [Page 12]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 3.4 Benchmarking Methods 3.4.1 Packet Loss Definition: The number of packets that should have been forwarded by a DUT under a constant offered load that were not forwarded due to lack of resources. Discussion: Packet Loss is a modified version of the term "Frame Loss Rate" as defined in [Ba91]. The term "Frame Loss" is intended for Ethernet Frames while "Packet Loss" is intended for IP packets. Packet Loss can be measured as a reduction in forwarded traffic from the Throughput [Ba91] of the DUT. Measurement units: Number of offered packets that are not forwarded. Issues: None See Also: Convergence Packet Loss 3.4.2 Convergence Packet Loss Definition: The number of packets lost due to a Convergence Event until Full Convergence completes. Discussion: Convergence Packet Loss includes packets that were lost and packets that were delayed due to buffering. The Convergence Packet Loss observed in a Packet Sampling Interval may or may not be equal to the number of packets in the offered load during the interval following a Convergence Event (see Figure 1). Measurement Units: number of packets Issues: None See Also: Packet Loss Route Convergence Convergence Event Packet Sampling Interval Poretsky, Imhoff [Page 13]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 3.4.3 Rate-Derived Convergence Method Definition: The method to calculate convergence time benchmarks from the amount of time that Convergence Packet Loss persists upon occurrence of a Convergence Event. Rate-Derived Convergence Method can be calculated as the time difference from the Convergence Event Instant to the Convergence Recovery Instant, as shown with Equation 1. (Equation 1) Rate-Derived Convergence Method = Convergence Recovery Instant - Convergence Event Instant. Discussion: It is RECOMMENDED that the Rate-Derived Convergence Method be measured when benchmarking convergence times. The Rate-Derived Convergence Method SHOULD be measured with an Offered Load at the Throughput of the DUT. At least one packet per route in the FIB for all routes in the FIB MUST be offered to the DUT within the Packet Sampling Interval. It is possible to measure no packet loss, which results in a Rate-Derived Convergence Time benchmark of zero. Failure to achieve Full Convergence results in a Rate-Derived Convergence Time benchmark of infinity. Measurement Units: seconds Issues: None See Also: Convergence Packet Loss Convergence Recovery Instant Convergence Event Instant Full Convergence 3.4.4 Loss-Derived Convergence Method Definition: The method to calculate convergence time benchmarks from the amount of Convergence Packet Loss. Loss-Derived Convergence Method can be calculated from Convergence Packet Loss as shown with Equation 2. Equation 2 - Loss-Derived Convergence Method = Convergence Packets Loss / Offered Load where units are packets / packets/second = seconds Poretsky, Imhoff [Page 14]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence Discussion: Ideally, the Convergence Event Transition and Convergence Recovery Transition are instantaneous so that the Rate-Derived Convergence Method = Loss-Derived Convergence Method. However, router implementations are less than ideal. Loss-Derived Convergence Method gives a better than actual result when converging many routes simultaneously because it ignores the transitions. The Rate-Derived Convergence Method takes the transitions into account. Equation 2 calculates the average convergence time over all routes to which packets have been sent. The average convergence time is often lower than the maximum convergence time over all routes, so it can produce a result that is faster than the actual convergence time.. Therefore, Loss-Derived Convergence Method is not the preferred method to measure convergence benchmarks. For these reasons the RECOMMENDED method to obtain a benchmark metric for convergence time is the Rate-Derived Convergence Method. Measurement Units: seconds Issues: None See Also: Convergence Packet Loss Rate-Derived Convergence Method Route-Specific Convergence Convergence Event Transition Convergence Recovery Transition 3.4.5 Packet Sampling Interval Definition: The interval at which the tester (test equipment) polls to make measurements for arriving packet flows. Discussion: At least one packet per route in the FIB for all routes in the FIB MUST be offered to the DUT within the Packet Sampling Interval. Metrics measured at the Packet Sampling Interval MUST include Forwarding Rate and Convergence Packet Loss. Packet Sampling Interval can influence the Convergence Graph. This is particularly true when implementations complete Full Convergence in less time than the Packet Sampling Interval. The Convergence Event Transition and Convergence Recovery Transition Poretsky, Imhoff [Page 15]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence can become exaggerated when the Packet Sampling Interval is too long. In this condition, the Rate-Derived Convergence Method may produce a larger than actual convergence time. In such cases the Loss-Derived Convergence Method may produce a more accurate result. The recommended value for configuration of the Packet Sampling Interval is provided in [Po07m]. Measurement Units: seconds Issues: None See Also: Convergence Packet Loss Convergence Event Transition Convergence Recovery Transition 3.5 Benchmarks 3.5.1 Full Convergence Time Definition: The amount of time it takes for Full Convergence to occur. Discussion: Full Convergence Time can be determined using the Rate-Derived Convergence Method or Loss-Derived Convergence Method. The Rate-Derived Convergence Method is RECOMMENDED. When measuring Route-Specific Convergence Time, there may be conditions in which the maximum Route Specific Convergence Time can be reported as the Full Convergence Time. Full Convergence may or may not be sustained over time. The Sustained Convergence Validation Time MUST be applied. Measurement Units: seconds Issues: None See Also: Full Convergence Rate-Derived Convergence Method Loss-Derived Convergence Method 3.5.2 First Route Convergence Time Definition: The amount of time for Convergence Packet Loss until the convergence of a first route entry on the Next-Best Egress Interface, as indicated by the First Route Convergence Instant. Poretsky, Imhoff [Page 16]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence Discussion: The First Route Convergence Time benchmarking metric can be measured when benchmarking either Full Convergence or Route-Specific Convergence. When benchmarking Full Convergence, First Route Convergence Time can be measured as the time difference from the Convergence Event Instant and the First Route Convergence Instant, as shown with Equation 4a. (Equation 4a) First Route Convergence Time = First Route Convergence Instant - Convergence Event Instant First Route Convergence Time should be measured at the maximum Throughput of the DUT. At least one packet per route in the FIB for all routes in the FIB MUST be offered to the DUT within the Packet Sampling Interval. Failure to achieve the First Route Convergence Instant results in a First Route Convergence Time benchmark of infinity. Measurement Units: seconds Issues: None See Also: Convergence Packet Loss First Route Convergence Instant 3.5.3 Route-Specific Convergence Time Definition: The amount of time it takes for Route-Specific Convergence to be completed as calculated from the amount of Convergence Packet Loss for the flow associated to a specific route. Route-Specific Convergence Time can be calculated from Convergence Packet Loss as shown with Equation 3. (Equation 3) Route-Specific Convergence Time = Convergence Packets Loss / Offered Load where units are packets / packets/second = seconds Poretsky, Imhoff [Page 17]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence Discussion: It is possible to provide an offered load that has flows matching every route entry in the FIB and benchmarking Route-Specific Convergence Time for all route entries. The number of flows that can be measured is dependent upon the flow measurement capabilities of the Tester. When benchmarking Route-Specific Convergence, Convergence Packet Loss is measured for specific flow(s) and Equation 3 is applied for each flow. Each flow has a single destination address matching a different route entry. The fastest measurable convergence time is equal to the time between two consecutive packets of a flow offered by the Tester. In practice, the fastest measurable convergence time is the Packet Sampling Interval of the Tester. The Route-Specific Convergence Time benchmarks enable minimum, maximum, average, and median convergence time measurements to be reported by comparing the results for the different route entries. It also enables benchmarking of convergence time when configuring a priority value for route entry(ies). Since multiple Route-Specific Convergence Times can be measured it is possible to have an array of results. The format for reporting Route-Specific Convergence Time is provided in [Po07m]. Measurement Units: seconds Issues: None See Also: Convergence Event Convergence Packet Loss Route-Specific Convergence 3.5.4 Sustained Convergence Validation Time Definition: The amount of time for which the completion of Full Convergence is maintained without additional packet loss. Discussion: The purpose of the Sustained Convergence Validation Time is to produce Convergence benchmarks protected against fluctuation in Throughput after the completion of Full Convergence is observed. The RECOMMENDED Sustained Convergence Validation Time to be used is 5 seconds. The BMWG selected 5 seconds based upon RFC 2544 [Ba99] which recommends waiting 2 seconds for residual frames to arrive and 5 seconds for DUT restabilization. Poretsky, Imhoff [Page 18]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence Measurement Units: seconds Issues: None See Also: Full Convergence Convergence Recovery Instant 3.5.5 Reversion Convergence Time Definition: The amount of time for the DUT to complete Full Convergence to the Preferred Egress Interface, instead of the Next-Best Egress Interface, upon recovery from a Convergence Event. Discussion: Reversion Convergence Time is the amount of time for Full Convergence to the original egress interface. This is achieved by recovering from the Convergence Event, such as restoring the failed link. Reversion Convergence Time can be measured using the Rate-Derived Convergence Method or Loss-Derived Convergence Method. The Rate-Derived Convergence Method is RECOMMENDED. It is possible to have the Reversion Convergence Time differ from the Full Convergence Time. Measurement Units: seconds Issues: None See Also: Preferred Egress Interface Convergence Event Rate-Derived Convergence Method 4. IANA Considerations This document requires no IANA considerations. 5. Security Considerations Documents of this type do not directly affect the security of Internet or corporate networks as long as benchmarking is not performed on devices or systems connected to production networks. Security threats and how to counter these in SIP and the media layer is discussed in RFC3261, RFC3550, and RFC3711 and various other drafts. This document attempts to formalize a set of common terminology for benchmarking IGP convergence performance in a lab environment. Poretsky, Imhoff [Page 19]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 6. Acknowledgements Thanks to Sue Hares, Al Morton, Kevin Dubray, Ron Bonica, David Ward, Kris Michielsen and the BMWG for their contributions to this work. 7. References 7.1 Normative References [Ba91] Bradner, S. "Benchmarking Terminology for Network Interconnection Devices", RFC1242, July 1991. [Ba99] Bradner, S. and McQuaid, J., "Benchmarking Methodology for Network Interconnect Devices", RFC 2544, March 1999. [Br97] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997 [Ca90] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual Environments", RFC 1195, December 1990. [Ma98] Mandeville, R., "Benchmarking Terminology for LAN Switching Devices", RFC 2285, February 1998. [Mo98] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998. [Mo06] Morton, A., et al, "Packet Reordering Metrics", RFC 4737, November 2006. [Po06] Poretsky, S., et al., "Terminology for Benchmarking Network-layer Traffic Control Mechanisms", RFC 4689, November 2006. [Po07a] Poretsky, S., "Benchmarking Applicability for Link-State IGP Data Plane Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-17, work in progress, March 2009. [Po07m] Poretsky, S. and Imhoff, B., "Benchmarking Methodology for Link-State IGP Data Plane Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-17, work in progress, March 2009. 7.2 Informative References [Ca01] S. Casner, C. Alaettinoglu, and C. Kuan, "A Fine-Grained View of High Performance Networking", NANOG 22, June 2001. [Ci03] L. Ciavattone, A. Morton, and G. Ramachandran, "Standardized Active Measurements on a Tier 1 IP Backbone", IEEE Communications Magazine, pp90-97, May 2003. Poretsky, Imhoff [Page 20]

INTERNET-DRAFT Benchmarking Terminology for March 2009 Link-State IGP Data Plane Route Convergence 8. Author's Address Scott Poretsky Allot Communications 67 South Bedford Street, Suite 400 Burlington, MA 01803 USA Phone: + 1 508 309 2179 Email: sporetsky@allot.com Brent Imhoff Juniper Networks 1194 North Mathilda Ave Sunnyvale, CA 94089 USA Phone: + 1 314 378 2571 EMail: bimhoff@planetspork.com Poretsky, Imhoff [Page 21]