Network Working Group INTERNET-DRAFT Expires in: December 2003 Scott Poretsky Avici Systems June 2003 Terminology for Benchmarking IGP Data Plane Route Convergence Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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. Table of Contents 1. Introduction ...............................................2 2. Existing definitions .......................................2 3. Term definitions............................................2 3.1 Network Convergence.....................................2 3.2 Protocol Convergence....................................3 3.3 Route Convergence.......................................3 3.4 Full Route Convergence Time.............................4 3.5 Route Convergence Packet Loss...........................5 3.6 Average Route Convergence Time..........................5 3.7 Route Convergence Event Slope...........................6 3.8 Route Convergence Recovery Slope........................6 3.9 Reroute Convergence Time...............................7 3.10 Local Interface........................................7 3.11 Neighbor Interface.....................................8 3.12 Remote Interface.......................................8 4. Security Considerations.....................................8 5. References..................................................9 Poretsky [Page 1] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Route Convergence 7. Author's Address............................................9 8. Full Copyright Statement....................................9 1. Introduction This draft describes the terminology for benchmarking IGP Route Convergence. The motivation and applicability for this benchmarking is provided in [1]. The methodology to be used for this benchmarking is described in [2]. The methodology and terminology to be used for benchmarking route convergence can be applied to any link-state IGP such as ISIS [3] and OSPF [4]. The data plane is measured to obtain the convergence benchmarking metrics. The purpose of this document is to introduce new terms required to complete execution of the IGP Route Convergence Methodology [2]. 2. Existing definitions For the sake of clarity and continuity this RFC adopts the template for definitions set out in Section 2 of RFC 1242. Definitions are indexed and grouped together in sections for ease of reference. 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. 3. Term definitions 3.1 Network Convergence Definition: The completion of updating of all routing tables, including the FIB, in all routers throughout the network. Discussion: Network Convergence can be approximated to the sum of Route Convergence for all routers in the network. Network Convergence can only be determined by the occurrence of packet loss or stale forwarding due to an out-of-date FIB. Measurement Units: Converged or Not Converged Issues: None See Also: Protocol Convergence Route Convergence Poretsky [Page 2] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Data Plane Route Convergence 3.2 Protocol Convergence Definition: The completion of updating a router's RIB and the forwarding of an route update message (LSA for OSPF/LSP for ISIS) to a neighboring peer. Discussion: Protocol Convergence considers only the Control Plane. IGP messaging is used to verify and measure convergence. Updating of the FIB, hardware updating, rerouting of traffic, and packet loss are not considered. Measurement Units: LSA/LSP Transmitted or LSA/LSP Not Transmitted. Issues: Protocol Convergence does not consider updating of the FIB, hardware updating, rerouting of traffic, and resultant packet loss. Protocol Convergence is only a partial measurement of Route Convergence. See Also: Network Convergence Route Convergence 3.3 Route Convergence Definition: The completion of the router's FIB becoming fully converged. Discussion: All components of the router have been updated with the most recent route change(s) including the RIB and FIB, along with software and hardware tables. Route Convergence can be observed externally by the rerouting of data traffic. Measurement Units: Converged or Not Converged Issues: None See Also: Route Convergence Time Network Convergence Protocol Convergence Poretsky [Page 3] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Data Plane Route Convergence 3.4 Full Route Convergence Time Definition: The amount of time it takes for Route Convergence to complete as measured by the time to drop from maximum forwarding rate and return to maximum forwarding rate after occurrence of a network event. Discussion: Full Route Convergence Time is a metric applied to a single router. Convergence Time could be calculated from packet loss. However, this will give a better than actual result when converging many routes simultaneously. The preferred method to obtain Route Convergence Time is to measure the time to drop from maximum forwarding rate and return to maximum forwarding rate. Figure 1 shows a graph model of Convergence Time as measured from the data plane. IGP Route Convergence Time is the amount of time for the Forwarding Rate to begin its downward slope upon occurrence of a network event and then fully recover to the Maximum Forwarding Rate. This is calculated as (eq 1) Time(Convergence) = Time(Recovery) - Time(Network Event). Forwarding Rate versus Time Time=Recovery Time=Network Event Time = 0sec Maximum ^ ^ ^ Forwarding Rate--> ----\ /----------- \ /<----Route Convergence Route Convergence------->\ / Event Slope Recovery Slope \_______/<------100% Packet Loss X-axis = Time Y-axis = Forwarding Rate Figure 1. Convergence Graph Measurement Units: seconds/milliseconds Issues: None See Also: Route Convergence Route Convergence Packet Loss Average Route Convergence Time Poretsky [Page 4] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Data Plane Route Convergence 3.5 Route Convergence Packet Loss Definition: The amount of packet loss until Route Convergence completes. Discussion: Route Convergence Packet Loss is used to calculate the Route Convergence Time. Packet loss is an externally measurable metric. Measurement Units: number of packets Issues: None See Also: Route Convergence Full Route Convergence Time Route Convergence Event Slope Route Convergence Recovery Slope 3.6 Average Route Convergence Time Definition: The amount of time it takes for Route Convergence to complete as calculated from the amount of packet loss and known forwarding rate. Discussion: Average Route Convergence Time is a metric applied to a single router. It can be calculated from packet loss that occurs due to a network event and subsequent Route Convergence. Measurement Units: seconds/milliseconds Issues: Use of Packet loss to calculate Route Convergence Time will give a better than actual result when converging many routes simultaneously. Full Route Convergence Time is the preferred benchmark for IGP Route Convergence. See Also: Route Convergence Route Convergence Packet Loss Full Route Convergence Time Route Convergence Event Slope Route Convergence Recovery Slope Poretsky [Page 5] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Data Plane Route Convergence 3.7 Route Convergence Event Slope Definition: The characteristic of routers in which forwarding rate gradually reaches zero as output queues drain after a network event. Discussion: Route Convergence Event Slope is externally observable. Full Route Convergence Time ignores the Route Convergence Event Slope. Average Route Convergence Time based upon the amount of packet loss takes the Route Convergence Event Slope into account. Measurement Units: seconds/milliseconds Issues: None See Also: Route Convergence Full Route Convergence Time Average Route Convergence Time Route Convergence Packet Loss Route Convergence Recovery Slope 3.8 Route Convergence Recovery Slope Definition: The characteristic of routers in which forwarding rate gradually rises to the maximum value as many routes converge to recover from a network event. Discussion: Route Convergence Recovery Slope is externally observable. Full Route Convergence Time ignores the Route Convergence Recovery Slope. Average Route Convergence Time based upon the amount of packet loss takes the Route Convergence Recovery Slope into account. Measurement Units: seconds/milliseconds Issues: None See Also: Route Convergence Full Route Convergence Time Average Route Convergence Time Route Convergence Packet Loss Route Convergence Event Slope Poretsky [Page 6] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Data Plane Route Convergence 3.9 Reroute Convergence Time Definition: The amount of time it takes for Route Convergence to complete as observed from rerouting of traffic to a new egress interface. Discussion: Reroute Convergence Time is the IGP Route Convergence benchmark to be used for network events that produce a change in next-hop without packet loss. An example of this is a cost change in which an backup path becomes the preferred path. Measurement Units: seconds/milliseconds Issues: None See Also: Route Convergence Full Route Convergence Time Average Route Convergence Time 3.10 Local Interface Definition: An interface on the DUT. Discussion: None Measurement Units: N/A Issues: None See Also: Neighbor Interface Remote interface 3.11 Neighbor Interface Definition: The interface on the neighbor router or tester that is directly linked to the DUT's Local Interface. Discussion: None Measurement Units: N/A Poretsky [Page 7] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Data Plane Route Convergence Issues: None See Also: Local Interface Remote interface 3.12 Remote Interface Definition: An interface on a neighboring router that is not directly linked to any interface on the DUT. Discussion: None Measurement Units: N/A Issues: None See Also: Local interface Neighbor Interface 4. Security Considerations Documents of this type do not directly effect the security of the Internet or of corporate networks as long as benchmarking is not performed on devices or systems connected to operating networks. 5. References [1] Poretsky, S., "Benchmarking Applicability for IGP Data Plane Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-00, work in progress, June 2003. [2] Poretsky, S., "Benchmarking Terminology for IGP Data Plane Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-term-00, work in progress, June 2003. [3] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual Environments", RFC 1195, December 1990. [4] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998. Poretsky [Page 8] INTERNET-DRAFT Benchmarking Terminology for June 2003 IGP Data Plane Route Convergence 6. Author's Address Scott Poretsky Avici Systems 101 Billerica Avenue N. Billerica, MA 01862 USA Phone: + 1 978 964 2287 EMail: sporetsky@avici.com 7. Full Copyright Statement Copyright (C) The Internet Society (1998). All Rights Reserved. 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