Network Working Group A. Morton Internet-Draft AT&T Labs Intended status: Informational October 6, 2010 Expires: April 9, 2011 IMIX Genome: Specification of variable packet sizes for additional testing draft-morton-bmwg-imix-genome-00 Abstract Benchmarking Methodologies have always relied on test conditions with constant packet sizes, with the goal of understanding what network device capability has been tested. Constant packets sizes differ significantly from the conditions encountered in operational deployment, and so additional tests are sometimes conducted with a mixture of packet sizes, or "IMIX". The mixture of sizes a networking device will encounter is highly variable and depends on many factors. An IMIX suited for one networking device and deployment will not be appropriate for another. However, the mix of sizes may be known and the tester may be asked to augment the fixed size tests. To address this need, and the additional goal of repeatable test conditions, this draft proposes a way to specify the exact repeating sequence of packet sizes from the usual set of fixed sizes. Requirements Language 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]. 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." Morton Expires April 9, 2011 [Page 1]
Internet-Draft IMIX Genome October 2010 This Internet-Draft will expire on April 9, 2011. Copyright Notice Copyright (c) 2010 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. Morton Expires April 9, 2011 [Page 2]
Internet-Draft IMIX Genome October 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. First Draft . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Scope and Goals . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Specification of the IMIX Genome . . . . . . . . . . . . . . . 5 4. Reporting Long or Pseudo-Random Packet Sequences . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 Morton Expires April 9, 2011 [Page 3]
Internet-Draft IMIX Genome October 2010 1. Introduction This memo defines a method to unambiguously specify the sequence of packet sizes used in a load test. Benchmarking Methodologies [RFC2544] have always relied on test conditions with constant packet sizes, with the goal of understanding what network device capability has been tested. Tests with the smallest size stress the header processing capacity, and tests with the largest size stress the overall bit processing capacity. Tests with sizes in-between may determine the transition between these two capacities. Constant packets sizes differ significantly from the conditions encountered in operational deployment, and so additional tests are sometimes conducted with a mixture of packet sizes. The set of sizes used is often called an Internet Mix, or "IMIX" [Spirent], [IXIA], [Agilent]. The mixture of sizes a networking device will encounter is highly variable and depends on many factors. An IMIX suited for one networking device and deployment will not be appropriate for another. However, the mix of sizes may be known and the tester may be asked to augment the fixed size tests. To address this need, and the additional goal of repeatable test conditions, this draft proposes a way to specify the exact repeating sequence of packet sizes from the usual set of fixed sizes: the IMIX Genome. 1.1. First Draft In this first draft, some section are very short or to-be-provided (TBP), and there are several questions identified for further discussion. 2. Scope and Goals This memo defines a method to unambiguously specify the sequence of packet sizes that have been used in a load test, assuming that a relevant mix of sizes is known to the tester and the length of the repeating sequence is not very long (<30 packets). The IMIX Genome will allow an exact sequence of packet sizes to be communicated as a single-line name, resolving the current ambiguity with results that simply refer to "IMIX". Morton Expires April 9, 2011 [Page 4]
Internet-Draft IMIX Genome October 2010 While documentation of the exact sequence is ideal, the memo also covers the case where the sequence of sizes is very long or may be generated by a pseudo-random process. It is a colossal non-goal to standardize one or more versions of the IMIX. This topic has been discussed on many occasions on the bmwg- list[IMIXonList]. The goal is to enable customization with minimal constraints while fostering repeatable testing once the fixed size testing is complete. 3. Specification of the IMIX Genome The IMIX Genome is specified in the following format: IMIX - 123456...x where each number is replaced by the letter corresponding to the packet size of the packet at that position in the sequence. The following table gives the letter encoding for the [RFC2544] standard sizes (64, 128, 256, 512, 1024, 1280, and 1518 bytes). +-------------+--------------------+ | Size, bytes | Genome Code Letter | +-------------+--------------------+ | 64 | a | | 128 | b | | 256 | c | | 512 | d | | 1024 | e | | 1280 | f | | 1518 | g | | MTU ?? | h | +-------------+--------------------+ For example: a five packet sequence with sizes 64,64,64,1280,1518 would be designated: IMIX - aaafg While this approach allows some flexibility, there are also constraints. o Non-RFC2544 packet sizes would need to be approximated by those available in the table. o The Genome for very long sequences can become undecipherable by humans. Morton Expires April 9, 2011 [Page 5]
Internet-Draft IMIX Genome October 2010 o Whether h=MTU is useful/desirable is TBD. o Whether more tabulated packet sizes would be useful is TBD. Some open issues with this format are: 1. Multiple Source-Destination Address Pairs: is the IMIX sequence applicable to each pair, across multiple pairs in sets, or across all pairs? 2. Multiple Tester Ports:is the IMIX sequence applicable to each port, across multiple ports in sets, or across all ports? 4. Reporting Long or Pseudo-Random Packet Sequences When the IMIX-Genome cannot be used (when the sheer length of the sequence would make the genome unmanageable) or when the sequence is designed to vary within some proportional constraints, a table is necessary. +-----------+---------------------+-----------------+ | IP Length | Percentage of Total | Other Length(s) | +-----------+---------------------+-----------------+ | 64 | 23 | 82 | | 128 | 67 | 146 | | 1000 | 10 | 1018 | +-----------+---------------------+-----------------+ Note that this approach also allows non-standard packet sizes, but trades the short genome specification and ability to specify the exact sequence for other flexibilities. >>> Specification for psuedo-random size generation here? <<< 5. Security Considerations Benchmarking activities as described in this memo are limited to technology characterization using controlled stimuli in a laboratory environment, with dedicated address space and the other constraints [RFC2544]. The benchmarking network topology will be an independent test setup and MUST NOT be connected to devices that may forward the test traffic into a production network, or misroute traffic to the test management network. Morton Expires April 9, 2011 [Page 6]
Internet-Draft IMIX Genome October 2010 Further, benchmarking is performed on a "black-box" basis, relying solely on measurements observable external to the DUT/SUT. Special capabilities SHOULD NOT exist in the DUT/SUT specifically for benchmarking purposes. Any implications for network security arising from the DUT/SUT SHOULD be identical in the lab and in production networks. 6. IANA Considerations This memo makes no requests of IANA, and hopes that IANA will leave it alone as well. 7. Acknowledgements 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for Network Interconnect Devices", RFC 2544, March 1999. 8.2. Informative References [Agilent] http://www.ixiacom.com/pdfs/test_plans/ agilent_journal_of_internet_test_methodologies.pdf, "The Journal of Internet Test Methodologies", 2007. [IMIXonList] http://www.ietf.org/mail-archive/web/bmwg/current/ msg00691.html, "Discussion on IMIX", 2003. [IXIA] http://www.ixiacom.com/library/test_plans/ display?skey=testing_pppox, "Library: Test Plans", 2010. [Spirent] http://gospirent.com/whitepaper/ IMIX%20Test%20Methodolgy%20Journal.pdf, "Test Methodology Journal: IMIX (Internet Mix) Journal", 2006. Morton Expires April 9, 2011 [Page 7]
Internet-Draft IMIX Genome October 2010 Author's Address Al Morton AT&T Labs 200 Laurel Avenue South Middletown,, NJ 07748 USA Phone: +1 732 420 1571 Fax: +1 732 368 1192 Email: acmorton@att.com URI: http://home.comcast.net/~acmacm/ Morton Expires April 9, 2011 [Page 8]