Network Working Group J. Karthik Internet Draft Cisco Systems Expires: January 2008 R. Papneja Isocore Charles Rexrode Verizon July, 2007 Methodology for Benchmarking LDP Data Plane Convergence Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. This document may only be posted in an Internet-Draft. 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 Abstract This document describes methodology which includes procedure and network setup, for benchmarking Label Distribution Protocol (LDP) [MPLS-LDP] Convergence. The proposed methodology is to be used for benchmarking LDP convergence independent of the underlying IGP used (OSPF or ISIS) and the LDP operating modes. The terms used in this document are defined in a companion draft [LDP-TERM]. Karthik, et al Expires February, 2007 [Page 1] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Table of Contents 1. Introduction...................................................2 2. Existing definitions...........................................3 3. Test Considerations............................................4 3.1. Convergence Events........................................4 3.2. Failure Detection [LDP-TERM]..............................4 3.3. Use of Data Traffic for LDP Convergence...................4 3.4. Selection of IGP..........................................5 3.5. LDP FEC Scaling...........................................5 3.6. Timers....................................................5 3.7. BGP Configuration.........................................5 3.8. Traffic generation........................................6 4. Test Setup.....................................................6 4.1. Topology for Single NextHop FECs (Link Failure)...........6 4.2. Topology for Multi NextHop FECs (Link and Node Failure)...7 5. Test Methodology...............................................7 6. Reporting Format...............................................8 7. Security Considerations........................................9 8. Acknowledgements...............................................9 9. References.....................................................9 10. Author's Address..............................................9 1. Introduction Results of several recent surveys indicate that LDP is becoming one of the key enabler of large number of MPLS based services such as Layer 2 and Layer 3 VPNs. Given the revenue that these services generate for the service providers, it becomes imperative that reliability and recovery of these services from failures is very quick or may be un-noticeable to the end user. This is ensured when implementations can guarantee very short convergence times from any planned or unplanned failures. Given the criticality of network convergence, service providers are considering convergence as a key metric to evaluate router architectures and LDP implementations. End customers monitor the service level Karthik, et al Expires January 23, 2008 [Page 2] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology agreements based on total packets lost in a given time frame, hence convergence becomes a direct measure of reliability and quality. This document describes the methodology for benchmarking LDP Data Convergence. An accompanying document describes the Terminology related to LDP data convergence benchmarking [LDP-TERM]. The primary motivation for this work is the increased focus on minimizing convergence time for LDP as an alternative to other solutions such as MPLS Fast Reroute (i.e. protection techniques using RSVP-TE extensions). The procedures outlined here are transparent to the Advertisement type (Downstream on Demand Vs Downstream Unsolicited), Label Retention mode in use as well as the Label Distribution Control and hence can be used in all of these types. The test cases defined in this document considers black-box type tests that emulate the network events causing route convergence events. This is similar to that defined in [IGP APP]. The LDP methodology (and terminology) for benchmarking LDP FEC convergence is independent to any link-state IGP such as ISIS [IGP-ISIS] and OSPF [IGP-OSPF]. These methodologies apply to IPv4 and IPv6 traffic as well as IPv4 and IPv6 IGPs. Future versions of this document will include ECMP benchmarks, LDP targeted peers and correlated failure scenarios. 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. The reader is assumed to be familiar with the commonly used MPLS terminology, some of which is defined in [LDP-TERM]. Karthik, et al Expires January 23, 2008 [Page 3] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology 3. Test Considerations This section discusses the fundamentals of LDP data plane convergence benchmarking: -Network events that cause rerouting -Failure detections -Data traffic -Traffic generation -IGP Selection 3.1. Convergence Events FEC reinstallation by LDP is triggered by link or node failures downstream of the DUT (Device Under Test) that impact the network stability: - Interface Shutdown on DUT side with POS Alarm - Interface Shutdown on remote side with POS Alarm - Interface Shutdown on DUT side with BFD - Interface Shutdown on remote side with BFD - Fiber Pull on DUT side - Fiber Pull on remote side - Online Insertion and Removal (OIR) of line cards on DUT side - Online Insertion and Removal (OIR) on remote side - Downstream node failure - New peer coming up - New link coming up 3.2. Failure Detection [LDP-TERM] Local failures can be detected via SONET failure with directly connected LSR. Failure detection may vary with the type of alarm - LOS, AIS, or RDI. Failures on Ethernet links such as Gigabit Ethernet sometimes rely upon Layer 3 signaling indication for failure. L3 failures could also be detected using BFD 3.3. Use of Data Traffic for LDP Convergence Customers of service providers use packet loss as the metric for failover time. Packet loss is an externally observable event having direct impact on customers' application performance. LDP convergence Karthik, et al Expires January 23, 2008 [Page 4] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology benchmarking aim at measuring traffic loss to determine the down time when a convergence event occurs. 3.4. Selection of IGP The LDP convergence methodology presented here is independent of the type of underlying IGP used. 3.5. LDP FEC Scaling The number of installed LDP FECs will impact the measured LDP convergence time for the entire LDP FEC table. To obtain results similar to those that would be observed in an operation network, it is recommended that number of installed routes closely approximate that for the routers in the real network. The number of IGP areas, or levels may not impact the LDP convergence time, however it does impact the performance of the IGP route convergence. 3.6. Timers There are some timers that will impact the measured LDP Convergence time. While the default timers may be suitable in most cases, it is recommended that the following timers be configured to the minimum value prior to beginning execution of the test cases: Timer Recommended Value ----- ----------------- Link Failure Indication Delay <10milliseconds IGP Hello Timer 1 second LDP Hello Timer 1 second LDP Hold Timer 3 seconds IGP Dead-Interval 3 seconds LSA Generation Delay 0 LSA Flood Packet Pacing 0 LSA Retransmission Packet Pacing 0 SPF Delay 0 3.7. BGP Configuration The observed LDP convergence numbers could be different if BGP routes are installed, and will further worsen, if any failure event imposed Karthik, et al Expires January 23, 2008 [Page 5] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology to measure the LDP convergence causes BGP routes to flap. BGP routes installed will not only consume memory but also CPU cycles when routes need to reconverge. 3.8. Traffic generation It is suggested that at least 3 traffic streams be configured using a traffic generator. In order to monitor the DUT performance for recovery times a set of route prefixes should be advertised before traffic is sent. The traffic should be configured to be sent to these routes. A typical example would be configuring the traffic generator to send the traffic to the first and last of the advertised routes. Also In order to have a good understanding of the performance behavior one may choose to send the traffic to the route, lying at the middle of the advertised routes. For example, if 100 routes are advertised, the user should send traffic to route prefix number 1, route prefix number 50 and to last route prefix advertised, which is 100 in this example. If the traffic generator is capable of sending traffic to multiple prefixes without losing granularity, traffic could be generated to more number of prefixes than the recommended 3. 4. Test Setup Topologies to be used for benchmarking the LDP Convergence: 4.1. Topology for Single NextHop FECs (Link Failure with parallel links) -------- A -------- TG-|Ingress |----| Egress |-TA | DUT |----| Node | -------- B -------- A - Preferred egress interface B - Next-best egress interface Karthik, et al Expires January 23, 2008 [Page 6] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology TA – Traffic Analyzer TG – Traffic Generator Figure 1: Topology for Single NextHop FECs (Link Failure) 4.2. Topology for Multi NextHop FECs (Link and Node Failure) -------- --------| Midpt |--------- | | Node 2 | | | B -------- | | | -------- -------- --------- TG-|Ingress |----| Midpt |----| Egress |-TA | DUT | A | Node 1 | | Node | -------- -------- --------- A - Preferred egress interface B - Next-best egress interface TA – Traffic Analyzer TG – Traffic Generator Figure 2: Topology for Multi NextHop FECs (Node Failure) 5. Test Methodology The procedure described here can apply to all the convergence benchmarking cases. Objective To benchmark the LDP Data Plane Convergence time as seen on the DUT when a Convergence event occurs resulting in the current best FEC is not reachable anymore. Test Setup Karthik, et al Expires January 23, 2008 [Page 7] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology - Based on whether 1 hop or multi hop case is benchmarked use the appropriate setup from the ones described in section 4. Test Configuration 1. Configure LDP and other necessary Routing Protocol configuration on the DUT and on the supporting devices 2. Advertise FECs over parallel interfaces upstream to the DUT. Procedure 1. Verify that the DUT installs the FECs in the MPLS forwarding table 2. Generate traffic destined to the FECs advertised by the egress. 3. Verify and ensure there is 0 traffic loss 4. Trigger any choice of failure/convergence event as described in section 3.1 5. Verify that forwarding resumes over the next best egress i/f. 6. Stop traffic stream and measure the traffic loss. 7. Convergence time is calculated as defined in section 6, Reporting format. 6. Reporting Format For each test, it is recommended that the results be reported in the following format. Parameter Units IGP used for the test ISIS-TE/ OSPF-TE Interface types Gige, POS, ATM, etc. Packet Sizes offered to the DUT Bytes IGP routes advertised number of IGP routes Benchmarks Karthik, et al Expires January 23, 2008 [Page 8] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology 1st Prefix's convergence time milliseconds Mid Prefix's convergence time milliseconds Last Prefix's convergence time milliseconds Convergence time suggested above is calculated using the following formula: (Numbers of packet drop/rate per second * 1000) milliseconds 7. Security Considerations Documents of this type do not directly affect the security of the Internet or of corporate networks as long as benchmarking is not performed on devices or systems connected to operating networks. 8. Acknowledgements We thank Bob Thomas for providing valuable comments to this document. We also thank Andrey Kiselev for his review and suggestions. 9. References [LDP-TERM] Eriksson, et al, “Terminology for Benchmarking LDP Data Plane Convergence”, draft-eriksson-ldp-convergence-term- 04 (Work in progress), February 2007. [MPLS-LDP] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and B. Thomas, "LDP Specification", RFC 3036, January 2001. [IGP-METH] S. Poretsky, B. Imhoff, "Benchmarking Methodology for IGP Data Plane Route Convergence," draft-ietf-bmwg-igp- dataplane-conv-meth-11.txt,” work in progress. [IGP OSPF] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998. 10. Author's Address Jay Karthik Karthik, et al Expires January 23, 2008 [Page 9] Internet-Draft LDP Data Plane Convergence July 2007 Benchmarking Methodology Cisco System 300 Beaver Brook Road Boxborough, MA 01719 USA Phone: +1 978 936 0533 Email: jkarthik@cisco.com Rajiv Papneja Isocore 12359 Sunrise Valley Drive, STE 100 Reston, VA 20190 USA Phone: +1 703 860 9273 Email: rpapneja@isocore.com Charles Rexrode Verizon 320 St Paul Place, 14th Fl Baltimore, MD 21202 USA Email: charles.a.rexrode@verizon.com Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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