Network Working Group Vishwas Manral Internet Draft Netplane Systems Russ White Cisco Systems Aman Shaikh Expiration Date: December 2003 University of California File Name: draft-ietf-bmwg-ospfconv-intraarea-06.txt June 2003 Benchmarking Basic OPSF Single Router Control Plane Convergence draft-ietf-bmwg-ospfconv-intraarea-06.txt 1. 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. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a "working draft" or "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. 2. Abstract This draft establishes standards for measuring OSPF single router control plane convergence [TERM]. Its initial emphasis is on the control plane of single OSPF routers. We do not address forwarding plane performance. NOTE: Within this document, the word convergence relates to single router control plane convergence only. Manral, et. all [Page 1] INTERNET DRAFT OSPF Benchmarking March 2003 3. Motivation There is a growing interest in routing protocol convergence testing, with many people looking at various tests to determine how long it takes for a network to converge after various conditions occur. The major problem with this sort of testing is that the framework of the tests has a major impact on the results; for instance, determining when a network is converged, what parts of the router's operation are considered within the testing, and other such things will have a major impact on what apparent performance routing protocols provide. This document attempts to provide a framework within which Open Shortest Path First [OSPF] performance testing can be placed, and provide some tests with which some aspects of OSPF performance can be measured. The motivation of the draft is to provide a set of tests that can provide the user comparable data from various vendors with which to evaluate the OSPF protocol performance on the devices. 4. Overview & Scope While this document describes a specific set of tests aimed at characterizing the single router control plane convergence performance of OSPF processes in routers or other boxes that incorporate OSPF functionality, a key objective is to propose methodology that will standardize the conducting and reporting of convergence-related measurements. Things which are outside the scope of this document include: o The interactions of convergence and forwarding; testing is restricted to events occurring within the control plane. For- warding performance is the primary focus in [INTERCONNECT] and it is expected to be dealt with in work that ensues from [FIB-TERM]. o Inter area route generation, AS-external route generation, and simultaneous traffic on the control and data paths within the DUT. While the tests outlined in this document measure SPF time, flooding times, and other aspects of all OSPF con- vergence performance, it does not provide tests for measuring external or summary route generation, route translation, or other OSPF interarea and external routing performance. These are expected to be dealt with in a later draft. Other drafts in the future may cover some of the items noted as not covered in the scope of this draft. For a discussion of the Manral, et. all [Page 2] INTERNET DRAFT OSPF Benchmarking March 2003 terminology used in this draft (in relation to the tests themselves), refer to [TERM]. For a discussion of the applicability of this draft, refer to [APPLICABILITY]. While this draft assumes OSPFv2, which only carries routing informa- tion for IPv4 destinations, nothing in this draft precludes it from use with OSPFv3, which carries IPv6 destinations. 5. Test Conditions In all tests, the following test conditions will be assumed: o The link speed should be high enough so that does not become a bottleneck. Link speeds of 10MBps or higher are recom- mended. The link speed between routers should be specified in the test report. o For all point-to-point links, it is assumed that a link failure results in an immediate notification to the operating system, and thus to the OSPF process; this is explained thoroughly in [MILLISEC]. o No data traffic will be running between the routers during these tests. o Optional capabilities which can reduce performance, such as authentication, should be noted in the test results if they are enabled. o Optional changes in the default timer values, such as the SPF, hello, router dead, and other intervals, should be noted in the test results. o All places where injecting a set of LSAs is referenced, the set can include varying numbers of LSAs of varying types representing a varying number of reachable destinations. See [TERM] for further information about issues with LSA sets and network topologies. Tests should be run more than once, since a single test run cannot be relied on to produce statistically sound results. The number of test runs and any variations between the tests should be recorded in the test results (see [TERM] for more information on what items should be recorded in the test results). Manral, et. all [Page 3] INTERNET DRAFT OSPF Benchmarking March 2003 6. Reference Topologies Several reference topologies will be used throughout the tests described in the remainder of this document. Rather than repeating these topologies, we've gathered them all in one section. o Reference Topology 1 (Emulated Topology) ( ) DUT----Generator----( emulated topology ) ( ) A simple back-to-back configuration. It's assumed that the link between the generator and the DUT is a point-to-point link, while the connections within the generator represent some emulated topology. o Reference Topology 2 (Generator and Collector) ( ) Collector-----DUT-----Generator--( emulated topology ) \ / ( ) \------------/ All routers are connected through point-to-point links. The cost of all links is assumed to be the same unless otherwise noted. o Reference Topology 3 (Broadcast Network) DUT R1 R2 | | | -+------+------+-----..... Any number of routers could be included on the common broad- cast network. o Reference Topology 4 (Parallel Links) /--(link 1)-----\ ( ) DUT Generator--( emulated topology ) \--(link 2)-----/ ( ) In all cases the tests and topologies are designed to allow perfor- mance measurements to be taken all on a single device, whether the DUT or some other device in the network. This eliminates the need for syncronized clocks within the test networks. Manral, et. all [Page 4] INTERNET DRAFT OSPF Benchmarking March 2003 7. Basic Process Performance Tests These tests will measure aspects of the OSPF implementation as a pro- cess on the device under test, including: o Time required to process an LSA o Flooding time o Shortest Path First computation 7.1. Time required to process an LSA o Using reference topology 1 (Emulated Topology), begin with all links up and a full adjacency established between the DUT and the generator. o Send an LSA that is already there in the DUT (a duplicate LSA), note the time difference between when the LSA is sent to when the ack is received. This measures the time to pro- pagate the LSA and the ack, as well as processing time of the duplicate LSA. This is dupLSAprocTime. o Send a new LSA from the generator to the DUT, followed immediately by a duplicate LSA (LSA that already resides in the database of DUT, but not the same as the one just sent). o The DUT will acknowledge this second LSA immediately; note the time of this acknowledgement. This is newLSAprocTime. The amount of time required for an OSPF implementation to process the new LSA can be computed by subtracting dupLSAprocTime from newLSAprocTime. Note: The duplicate LSA cannot be the same as the one just sent because of the MinLSInterval restriction.[RFC2328] This test is taken from [BLACKBOX]. 7.2. Flooding Time o Using reference topology 2 (Generator and Collector), enable OSPF on all links and allow the devices to build full adjacencies. Configure the collector so it will block Manral, et. all [Page 5] INTERNET DRAFT OSPF Benchmarking March 2003 all flooding towards the DUT, although it continues receiving advertisements from the DUT. o Inject a new set of LSAs from the generator towards the collector and the DUT. o On the collector, note the time the flooding is complete across the link to the generator. Also note the time the flooding is complete across the link from the DUT. Two measurements can be taken from this test: o The time between the last LSA is received on the collec- tor from the generator and the time the last LSA is received on the collector from the DUT. o The time between the last LSA is received on the collector from the generator and the time the first LSA is received on the collector from the DUT. Depending on the number of LSAs flooded, the sizes of the LSAs, and the rate of flooding, these numbers could vary by some amount. The settings and variances of these numbers should be reported with the test results. This time is important in link state protocols, since the loop free nature of the network is reliant on the speed at which revised topology information is flooded. 7.3. Shortest Path First Computation Time o Use reference topology 1 (Emulated Toplogy), beginning with the DUT and the generator fully adjacent. o The default SPF timer on the DUT should be set to 0, so that any new LSA that arrives, immediately results in the SPF calculation [BLACKBOX]. o The generator should inject a set of LSAs towards the DUT; the DUT should be allowed to converge and install all best paths in the local routing table, etc.. o Send an LSA that is already there in the DUT (a duplicate LSA), note the time difference between when the LSA is Manral, et. all [Page 6] INTERNET DRAFT OSPF Benchmarking March 2003 sent to when the ack is received. This measures the time to propagate the LSA and the ack, as well as processing time of the duplicate LSA. This is dupLSAprocTime. o Change the link cost between the generator and the emu- lated network it is advertising. o Immediately inject another LSA which is a duplicate of some other LSA the generator has previously injected (preferrably a stub network someplace within the emulated network). o Measure the time between transmitting the second (dupli- cate) LSA and the acknowledgement for that LSA; this is the totalSPFtime. The total time required to run SPF can be computed by subtracting dupLSAprocTime from totalSPF- time. The accuracy of this test is crucially dependant on the amount of time between the transmission of the first and second LSAs. If there is too much time between them, the test is meaningless because the SPF run will complete before the second (duplicate) LSA is received. If there is too little time between the LSAs being generated, then they will both be handled before the SPF run is scheduled and started, and thus the measurement would only be for the handling of the dupli- cate LSA. This test is also specified in [BLACKBOX]. Note: This test may not be accurate on systems which implement OSPF as a multithreaded process, where the flooding takes place in a separate process (or on a dif- ferent processor) than shortest path first computations. It is also possible to measure the SPF time using white box tests (using output supplied by the OSPF software impelem- tor). For instance: o Using reference topology 1 (Emulated Topology), establish a full adjacency between the generator and the DUT. o Inject a set of LSAs from the generator towards the DUT. Allow the DUT to stabilize and install all best paths in the routing table, etc. o Change the link cost between the DUT and the generator (or Manral, et. all [Page 7] INTERNET DRAFT OSPF Benchmarking March 2003 the link between the generator and the emulated network it is advertising), such that a full SPF is required to run, although only one piece of information is changed. o Measure the amount of time required for the DUT to compute new shortest path tree as a result of the topology changes injected by the generator. These measurements should be taken using available show and debug information on the DUT. Several caveats must be mentioned when using a white box method of measuring SPF time; for instance, such white box tests are only applicable when testing various versions or variations within a single implementation of the OSPF proto- col. Futher, the same set of commands must be used in each iteration of such a test, to ensure consistent results. There is some interesting relationship between the SPF times reported by white box (internal) testing, and black box (external) testing; these two types of tests may be used as a "sanity check" on the other type of tests, by comparing the results of the two tests. See [APPLICABILITY] for further discussion. 8. Basic Intra-Area OSPF tests These tests measure the performance of an OSPF implementation for basic intra-area tasks, including: o Forming Adjacencies on Point-to-Point Link (Initialization) o Forming Adjacencies on Point-to-Point Links o Link Up with Information Already in the Database o Initial convergence Time on a Designated Router Electing (Broad- cast) Network o Link Down with Layer 2 Detection o Link Down with Layer 3 Detection o Designated Router Election Time on A Broadcast Network Manral, et. all [Page 8] INTERNET DRAFT OSPF Benchmarking March 2003 8.1. Forming Adjacencies on Point-to-Point Link (Initialization) This test measures the time required to form an OSPF adjacency from the time a layer two (data link) connection is formed between two devices running OSPF. o Use reference topology 1 (Emulated Topology), beginning with the link between the generator and DUT disabled on the DUT. OSPF should be configured and operating on both devices. o Inject a set of LSAs from the generator towards the DUT. o Bring the link up at the DUT, noting the time that the link carrier is established on the generator. o Note the time the acknowledgement for the last LSA transmitted from the DUT is received on the generator. The time between the carrier establishment and the ack- nowledgement for the last LSA transmitted by the generator should be taken as the total amount of time required for the OSPF process on the DUT to react to a link up event with the set of LSAs injected, including the time required for the operating system to notify the OSPF process about the link up, etc.. The acknowledgement for the last LSA transmitted is used instead of the last acknowledgement received in order to prevent timing skews due to retransmitted acknowledgements or LSAs. 8.2. Forming Adjacencies on Point-to-Point Links This test measures the time required to form an adjacency from the time the first communication occurs between two devices running OSPF. o Using reference topology 1 (Emulated Topology), configure the DUT and the generator so traffic can be passed along the link between them. o Configure the generator so OSPF is running on the point- to-point link towards the DUT, and inject a set of LSAs. o Configure the DUT so OSPF is initialized, but not running on the point-to-point link between the DUT and the genera- tor. Manral, et. all [Page 9] INTERNET DRAFT OSPF Benchmarking March 2003 o Enable OSPF on the interface between the DUT and the gen- erator on the DUT. o Note the time of the first hello received from the DUT on the generator. o Note the time of the acknowledgement from the DUT for the last LSA transmitted on the generator. The time between the first hello received and the ack- nowledgement for the last LSA transmitted by the generator should be taken as the total amount of time required for the OSPF process on the DUT to build a FULL neighbor adjacency with the set of LSAs injected. The acknowledgement for the last LSA transmitted is used instead of the last acknowledge- ment received in order to prevent timing skews due to retransmitted acknowledgements or LSAs. 8.3. Forming adjacencies with Information Already in the Database o Using reference topology 2 (Generator and Collector), con- figure all three devices to run OSPF. o Configure the DUT so the link between the DUT and the gen- erator is disabled . o Inject a set of LSAs into the network from the generator; the DUT should receive these LSAs through normal flooding from the collector. o Enable the link between the DUT and the generator. o Note the time of the first hello received from the DUT on the generator. o Note the time of the acknowledgement from the DUT for the last LSA transmitted on the generator. The time between the hello received from the DUT by the gen- erator and the acknowledgement for the last LSA transmitted by the generator should be taken as the total amount of time required for the OSPF process on the DUT to build a FULL neighbor adjacency with the set of LSAs injected. In this test, the DUT is already aware of the entire network topol- ogy, so the time required should only include the processing of each LSA from the generator and transmitting an Manral, et. all [Page 10] INTERNET DRAFT OSPF Benchmarking March 2003 acknowledgement. The acknowledgement for the last LSA transmitted is used instead of the last acknowledgement received in order to prevent timing skews due to retransmit- ted acknowledgements or LSAs. 8.4. Designated Router Election Time on A Broadcast Network o Using reference topology 3 (Broadcast Network), configure R1 to be the designated router on the link, and the DUT to be the backup designated router. o Enable OSPF on the common broadcast link on all the routers in the test bed. o Disble the broadcast link on R1. o Note the time of the last hello received from R1 on R2. o Note the time of the first network LSA generated by the DUT as received on R2. The time between the last hello received on R2 and the first network LSA generated by the DUT should be taken as the amount of time required for the DUT to complete a designated router election computation. Note this test includes the dead interval timer at the DUT, so this time can be factored out, or the hello and dead intervals reduced to make these timers impact the overall test times less. All changed timers, the number of routers connected to the link, and other variable factors should be noted in the test results. 8.5. Initial convergence Time on a Designated Router Electing (Broad- cast) Network o Using reference topology 3 (Broadcast Network), begin with the DUT connected to the network with OSPF enabled. OSPF should be enabled on R1, but the broadcast link should be disabled. o Enable the broadcast link between R1 and the DUT. Note the time of the first hello received by R1. o Note the time the first network LSA is flooded by the DUT at R1. Manral, et. all [Page 11] INTERNET DRAFT OSPF Benchmarking March 2003 o The differential between the first hello and the first network LSA is the time required by the DUT to converge on this new topology. This test assumes that the DUT will be the designated router on the broadcast link. A similar test could be designed to test the convergence time when the DUT is not the designated router as well. This test may be performed with varying numbers of devices attached to the broadcast network, and varying sets of LSAs being advertised to the DUT from the routers attached to the broadcast network. Variations in the LSA sets and other fac- tors should be noted in the test results. The time required to elect a designated router, as measured in Designated Router Election Time on A Broadcast Network, above, may be subtracted from the results of this test to provide just the convergence time across a broadcast network. 8.6. Link Down with Layer 2 Detection o Using reference topology 4 (Parallel Links), begin with OSPF in the full state between the generator and the DUT. Both links should be point-to-point links with the ability to notify the operating system immediately upon link failure. o Disable link 1; this should be done in such a way that the keepalive timers at the data link layer will have no impact on the DUT recognizing the link failure (the operating system in the DUT should recognize this link failure immediately). Disconnecting the cable on the gen- erator end would be one possibility, or shutting the link down. o Note the time of the link failure on the generator. o At the generator, note the time of the receipt of the new router LSA from the DUT notifying the generator of the link 2 failure. The difference in the time between the initial link failure and the receipt of the LSA on the generator across link 2 should be taken as the time required for an OSPF implementa- tion to recognize and process a link failure. Manral, et. all [Page 12] INTERNET DRAFT OSPF Benchmarking March 2003 8.7. Link Down with Layer 3 Detection o Using reference topology 4 (Parallel Links), begin with OSPF in the full state between the generator and the DUT. o Disable OSPF processing on link 1 from the generator. This should be done in such a way so it does not affect link status; the DUT must note the failure of the adjacency through the dead interval. o At the generator, note the time of the receipt of the new router LSA from the DUT notifying the generator of the link 2 failure. The difference in the time between the initial link failure and the receipt of the LSA on the generator across link 2 should be taken as the time required for an OSPF implementa- tion to recognize and process an adjacency failure. 9. Security Considerations This draft adds no new security considerations nor does it resolve any security considerations from the protocols tested. 10. Acknowledgements Thanks to Howard Berkowitz, (hcb@clark.net), for his encouragement and support. Thanks also to Gurpreet Singh (Gurpreet.Singh@SpirentCom.COM) and Yasuhiro Ohara (yasu@sfc.wide.ad.jp) for their comments as well. 11. Normative References [OPSF]Moy, J., "OSPF Version 2", RFC 2328, April 1998. [TERM]Manral, V., "OSPF Convergence Testing Terminiology and Concepts", draft-ietf-bmwg-ospfconv-term-04, March 2003 [APPLICABILITY] Manral, V., "Benchmarking Applicability for Basic OSPF Conver- gence", draft-ietf-bmwg-ospfconv-applicability-03, March 2003 Manral, et. all [Page 13] INTERNET DRAFT OSPF Benchmarking March 2003 12. Informative References [INTERCONNECT] Bradner, S., McQuaid, J., "Benchmarking Methodology for Network Interconnect Devices", RFC2544, March 1999. [MILLISEC] Alaettinoglu C., et al., "Towards Milli-Second IGP Convergence" draft-alaettinoglu-isis-convergence [FIB-TERM] Trotter, G., "Terminology for Forwarding Information Base (FIB) based Router Performance", RFC3222, October 2001. [BLACKBOX] Shaikh, Aman, Greenberg, Albert, "Experience in Black-Box OSPF measurement" 13. Authors' Addresses Vishwas Manral Netplane Systems 189 Prashasan Nagar Road number 72 Jubilee Hills Hyderabad, India vmanral@netplane.com Russ White Cisco Systems, Inc. 7025 Kit Creek Rd. Research Triangle Park, NC 27709 riw@cisco.com Aman Shaikh University of California School of Engineering 1156 High Street Santa Cruz, CA 95064 aman@soe.ucsc.edu Manral, et. all [Page 14] INTERNET DRAFT OSPF Benchmarking March 2003 Manral, et. all [Page 15]