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Network Working Group                                            J. DunnRequest for Comments: 3134                                     C. MartinCategory: Informational                                        ANC, Inc.                                                               June 2001Terminology for ATM ABR BenchmarkingStatus of this Memo   This memo provides information for the Internet community.  It does   not specify an Internet standard of any kind.  Distribution of this   memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2001).  All Rights Reserved.Abstract   This memo discusses and defines terms associated with performance   benchmarking tests and the results of these tests in the context of   Asynchronous Transfer Mode (ATM) based switching devices supporting   ABR (Available Bit Rate).  The terms defined in this memo will be   used in addition to terms defined in RFCs 1242, 2285, and 2544 and   2761.  This memo is a product of the Benchmarking Methodology Working   Group (BMWG) of the Internet Engineering Task Force (IETF).1. Introduction   This document provides terminology for benchmarking ATM based   switching devices supporting ABR.  It extends terminology already   defined for benchmarking network interconnect devices in RFC's 1242,   2285, and 2544 and 2761.  Although some of the definitions in this   memo may be applicable to a broader group of network interconnect   devices, the primary focus of the terminology in this memo is on ATM   ABR.   This memo contains two major sections: Background and Definitions.   The background section provides the reader with an overview of the   technology and IETF formalisms.  The definitions section is split   into two sub-sections.  The formal definitions sub-section is   provided as a courtesy to the reader.  The measurement definitions   sub-section contains performance metrics with inherent units.   This document assumes that necessary services are available and   active.  For example, IP connectivity requires SSCOP connectivity   between signaling entities.  Further, it is assumed that the SUT hasDunn & Martin                Informational                      [Page 1]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   the ability to configure ATM addresses (via hard coded addresses,   ILMI or PNNI neighbor discovery), has the ability to run SSCOP, and   has the ability to perform signaled call setups (via UNI or PNNI   signaling).  Finally, this document presents only the terminology   associated with benchmarking IP performance over ATM; therefore, it   does not represent a total compilation of ATM test terminology.   The BMWG produces two major classes of documents: Benchmarking   Terminology documents and Benchmarking Methodology documents.  The   Terminology documents present the benchmarks and other related terms.   The Methodology documents define the procedures required to collect   the benchmarks cited in the corresponding Terminology documents.2. Existing Definitions.RFC 1242, "Benchmarking Terminology for Network Interconnect   Devices", should be consulted before attempting to make use of this   document.RFC 2544, "Benchmarking Methodology for Network   Interconnect Devices", contains discussions of a number of terms   relevant to the benchmarking of switching devices and should be   consulted.RFC 2285, "Benchmarking Terminology for LAN Switching   Devices", contains a number of terms pertaining to traffic   distributions and datagram interarrival.RFC 2761, "Terminology for   ATM Benchmarking", contains a number terms pertaining to traffic   management [TM4.0, TM4.1].  Many of the metrics defined inRFC 2761   (e.g., CDV, CER, CLR, CMR, and CTD) also apply to ABR performance   benchmarking.  These metrics will not be redefined in this document.   For the sake of clarity and continuity, this RFC adopts the template   for definitions set out inSection 2 of RFC 1242.II. Definitions   The definitions presented in this section have been divided into two   groups.  The first group is formal definitions, which are required in   the definitions of the performance metrics but are not themselves   strictly metrics.  These definitions are subsumed from other work   done in other working groups both inside and outside the IETF.  They   are provided as a courtesy to the reader.1. Formal Definitions1.1. Definition Format (fromRFC 1242)   Term to be defined.   Definition: The specific definition for the term.Dunn & Martin                Informational                      [Page 2]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   Discussion: A brief discussion of the term, its application and any   restrictions on measurement procedures.   Specification: The working group and document in which the terms are   specified and are listed in the references section.1.2. Related Definitions.1.2.1. Allowed Cell Rate (ACR)   Definition: An ABR service parameter, ACR is the current rate   (cells/second) at which a source is allowed to send.   Discussion: For ABR traffic, ACR constitutes the actual data   throughput for a particular VC.  The time change of this value   effects TCP round trip time calculations, which in turn effects TCP   throughput.   Specification: AF-TM4.01.2.2. ACR Decrease Time Factor (ADTF)   Definition: This is the time permitted between sending RM-cells   before the rate is decreased to ICR (Initial Cell Rate). The time   units are .01 to 10.23 seconds with a granularity of 10 ms.   Discussion: For ABR traffic, ADTF constitutes the time rate of the   ACR.  This value effects TCP round trip time calculations, which in   turn effects TCP throughput.   Specification: AF-TM4.01.2.3. Additive Increase Rate (AIR)   Definition: An ABR service parameter, AIR controls the rate at which   the cell transmission rate increases.  It is signaled as AIRF, where       AIRF = AIR*Nrm/PCR.   Discussion: For ABR traffic, AIR effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.01.2.4. Additive Increase Rate Factor (AIRF)   Definition: Refer to AIR.Dunn & Martin                Informational                      [Page 3]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   Discussion: Refer to AIR.   Specification: AF-TM4.01.2.5. Available Bit Rate (ABR)   Definition: ABR is an ATM layer service category for which the   limiting ATM layer transfer characteristics provided by the network   may change subsequent to connection establishment.  A flow control   mechanism is specified which supports several types of feedback to   control the source rate in response to changing ATM layer transfer   characteristics.   Discussion: It is expected that an end-system that adapts its traffic   in accordance with the feedback will experience a low cell loss ratio   and obtain a fair share of the available bandwidth according to a   network specific allocation policy.  Cell delay variation is not   controlled in this service, although admitted cells are not delayed   unnecessarily.   Specification: AF-TM4.11.2.6. Available Bit Rate (ABR) Compliance (Conformance)   Definition: ABR connection conformance refers to the behavior   specified for ABR destination and switches, but allows for delays   between the source and the UNI [UNI3.1, UNI4.0], which may perturb   the traffic flow.   Discussion: The cells on an ABR connection applies to CLP=0 cells,   which are tested upon arrival.  At the arrival point, each cell is   identified as conforming or non-conforming.  The minimal conformance   definition for ABR is GCRA((1/PCR),t1), where PCR is defined for   CLP=0 flow.   Specification: AF-TM4.11.2.7. BN   Definition: The BN bit in the RM-cell indicated whether the RM-cell   is a BECN cell or not.   Discussion: If BN=0, the RM cells were generated by the source.  If   BN=1, the RM cells were generated by the destination or a switch.   Specification: AF-TM4.1Dunn & Martin                Informational                      [Page 4]

RFC 3134          Terminology for ATM ABR Benchmarking         June 20011.2.8. CCR   Definition: The CCR field in the RM-cell is set by the source to its   current ACR.  CCR is formatted as a rate.   Discussion: For BECN cells, CCR=0.   Specification: AF-TM4.11.2.9. Cell Blocks (CB)   Definition: Cell blocks are a sequence of N cells transmitted   consecutively on a given connection.   Discussion: A cell block will normally correspond to the number of   information cells transmitted between successive OAM cells.   Specification: AF-TM4.11.2.10. Congestion Indication (CI)   Definition: The CI bit in the RM-cell allows a network element to   indicate that there is congestion in the network.   Discussion: When the source receives a backward RM-cell with CI=1,   ACR is decreased.  When the destination turns around a forward RM-   cell, the CI is set to 1 to indicate that the previously received   data cell had the EFCI state set.   Specification: AF-TM4.11.2.11. Cutoff Decrease Factor (CDF)   Definition: CDF controls the decrease in ACR (Allowed Cell Rate)   associated with CRM (missing RM cell count).   Discussion: For ABR traffic, CDF effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.0Dunn & Martin                Informational                      [Page 5]

RFC 3134          Terminology for ATM ABR Benchmarking         June 20011.2.12. DIR   Definition: The DIR bit in the RM-cell indicates which direction of   data flow is associated with the RM-cell.  DIR is changed from 0 to 1   when an RM-cell is turned around at the destination.   Discussion: A forward RM-cell is indicated by DIR=0 and is associated   with data cells flowing in the same direction.  A backward RM-cell is   indicated by DIR=1 and is associated with data cells flowing in the   opposite direction.   Specification: AF-TM4.11.2.13. Explicit Rate (ER)   Definition: The ER field in the RM-cell is used to limit the source   ACR to a specific value.  For each RM-cell, ER is set by the source   to a requested rate (e.g., PCR).  It may be reduced by any network   element in the path to a value that the element can sustain.  ER is   formatted as a rate.   Discussion: None.   Specification: AF-TM4.11.2.14. Feedback   Definition: Information carried in the backward RM-cells provided by   the network elements and/or the destination back to the source.   Discussion: Feedback may include information in the ER field, or the   CI or NI bits of each backward RM-cell.   Specification: AF-TM4.11.2.15. Ideal Transmission Time (ITT)   Definition: The transmission time for ABR CLP=0 cells, if the   difference between itself and the transmission time for the previous   CLP=0 cell on the connection is greater than or equal to the minimum:   a) the inverse of the ACR in effect immediately after the   transmission time of the first of the two cells b) the inverse of the   ACR in effect immediately before the transmission time of the second   of the two cells.   Discussion: The transmission time for the first cell on the   connection is automatically an ITT.Dunn & Martin                Informational                      [Page 6]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   Specification: AF-TM4.11.2.16. Initial Cell Rate (ICR)   Definition: An ABR service parameter, in cells/sec, that is the rate   at which a source should send initially and after an idle period.   Discussion: none.   Specification: AF-TM4.01.2.17. In-Rate Cells   Definition: In-Rate ABR cells are sent with CLP=0.   Discussion: ABR RM-cells shall be sent with CLP=0 except in certain   circumstances, See Out-of-Rate Cells.  All other ABR cells shall be   sent with CLP=0.   Specification: AF-TM4.11.2.18. Minimum Cell Rate (MCR)   Definition: An ABR service traffic descriptor, in cells/sec, that is   the rate at which the source is always allowed to send.   Discussion: MCR may be set to zero.  The bandwidth available from the   network may vary, but shall not become less than MCR.   Specification: AF-TM4.11.2.19. Mrm   Definition: An ABR service parameter that controls allocation of   bandwidth between forward W-cells, backward RM-cells, and data cells.   Discussion: none.   Specification: AF-TM4.01.2.20. No Increase (NI)   Definition: The NI bit in the RM-cell is used to prevent a source   from increasing its ACR.  NI does not require any decrease in value.   Discussion: None.   Specification: AF-TM4.0Dunn & Martin                Informational                      [Page 7]

RFC 3134          Terminology for ATM ABR Benchmarking         June 20011.2.21. Nrm   Definition: An ABR service parameter, Nrm is the maximum number of   cells a source may send for each forward RM-cell.   Discussion: none.   Specification: AF-TM4.01.2.22. Out-of-Rate Cells   Definition: Out-of-Rate ABR cells are sent with CLP=1.   Discussion: This may be used to enable a rate increase for a   connection that has an ACR=0.  The source would generate out-of-rate   cells to probe the network to learn when it may increase its rate.   Specification: AF-TM4.11.2.23. Rate Decrease Factor (RDF)   Definition: An ABR service parameter, RDF controls the decrease in   the cell transmission rate.  RDF is a power of 2 from 1/32,768 to 1.   Discussion: For ABR traffic, RDF effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.01.2.24. Rate Increase Factor (RIF)   Definition: This controls the amount by which the cell transmission   rate may increase upon receipt of a RM-cell.  The additive increase   rate AIR=PCR*RIF.  RIF is a power of 2, ranging from 1/32,768 to 1.   Discussion: For ABR traffic, RIF effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.01.2.25. Resource Management (RM) Cells   Definition: RM cells are used to convey network status  (available   bandwidth, congestion levels) and request peak cell rates for ATM   blocks.  The RM cell has the following format:Dunn & Martin                Informational                      [Page 8]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   Header: 5 bytes, same as the ATM cell header Protocol ID: 3 bytes,   protocol ID value is 1 for ABR service Function specific field: 45   bytes, data required for the specific protocol (See DIR, BN, CI, NI,   ER, CCR, and MCR for field information.)  Rsvd: 6 bytes, reserved for   future specification EDC: 10 bytes, CRC-10 error detection code   computed over the cell payload .ti6 (except the CRC-10 field) and   used to check for data corruption   Discussion: RM information can exist at the VP and/or VC level.  VP   level cells are identified with a VCI value of 6.  VC level cells are   identified with a PT of 6.  See DIR, BN, CI, NI, ER, CCR, and MCR for   additional protocol field information.   Specification: AF-TM4.01.2.26. Severely Errored Cell Block (SECB)   Definition: A severely cell block outcome occurs when more than M   errored cells, lost cells, or misinserted cell outcomes are observed   in a received cell block.   Discussion: none.   Specification: AF-TM4.11.2.27. Tagged Cell Rate (TCR)   Definition: An ABR service parameter, TCR limits the rate at which a   source may send out-of-rate forward RM-cells.  TCR is a constant   fixed at 10 cells/second.   Discussion: none.   Specification: AF-TM4.01.2.28. TDF   Definition: An ABR service parameter, TDF controls the decrease in   ACR associated with TOF.  TDF is signaled as TDFF, where TDF=TDFF/RDF   times the smallest power of 2 greater or equal to PCR.  TDF is in   units of 1/seconds.   Discussion: For ABR traffic, TDF effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.0Dunn & Martin                Informational                      [Page 9]

RFC 3134          Terminology for ATM ABR Benchmarking         June 20011.2.29. TDFF   Definition: Refer to TDF.  TDFF is either zero or a power of two in   the range 1/64 to 1 in units of 1 /cells.   Discussion: Refer to TDF.   Specification: AF-TM4.0   1.2.30. Time Out Factor (TOF)   Definition: An ABR service parameter, TOF controls the maximum time   permitted between sending forward RM-cells before a rate decrease is   required.  It is signaled as TOFF where TOF=TOFF+1.  TOFF is a power   of 2 in the range: 1/8 to 4,096.   Discussion: For ABR traffic, TOF effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.01.2.31. Time Out Factor (TOFF)   Definition: Refer to TOF.   Discussion: none.   Specification: AF-TM4.01.2.32. Trm   Definition: An ABR service parameter that provides an upper bound on   the time between forward RM-cells for an active source.  It is 100   times a power of two with a range of 100*2-7 to 100*20   Discussion: For ABR traffic, Trm effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.01.2.33. Virtual Source/Virtual Destination (VSND)   Definition: An ABR connection may be divided into two or more   separately controlled ABR segments.  Each ABR control segment, except   the first, is sourced by a virtual source.  A virtual source   implements the behavior of an ABR source endpoint.  Backward RM-cellsDunn & Martin                Informational                     [Page 10]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   received by a virtual source are removed from the connection.  Each   ABR control segment, except the last, is terminated by a virtual   destination.  A virtual destination assumes the behavior of an ABR   destination endpoint.  Forward RM-cells received by a virtual   destination are turned around and not forwarded to the next segment   of the connection.   Discussion: none.   Specification: AF-TM4.01.2.34. Xrm Decrease Factor (XDM)   Definition: An ABR service parameter, XDF controls the decrease in   ACR associated with Xrm.  It is a power of two in range: [0, 1].   Discussion: For ABR traffic, XDM effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.01.2.35. Xrm   Definition: An ABR service parameter, Xrm limits the number of   forward RM-cells which may be sent in the absence of received   backward PM-cells.  The range is 0-255.   Discussion: For ABR traffic, Xrm effects the time rate of change of   the ACR.  This value effects TCP round trip time calculations, which   in turn effects TCP throughput.   Specification: AF-TM4.02. Performance Metrics2.1. Definition Format (fromRFC 1242)   Metric to be defined.   Definition: The specific definition for the metric.   Discussion: A brief discussion of the metric, its application and any   restrictions on measurement procedures.   Measurement units: Intrinsic units used to quantify this metric.   This includes subsidiary units; e.g., microseconds are acceptable if   the intrinsic unit is seconds.Dunn & Martin                Informational                     [Page 11]

RFC 3134          Terminology for ATM ABR Benchmarking         June 20012.2. Definitions2.2.1. ABR Rate Decrease Response Time (ARDRT)   Definition: The amount of time required by the SUT to adjust its   transmission rate based on an ABR rate decrease request.   Discussion:  During the ARDRT, cells transmitted by the SUT may be   dropped by the network due to traffic policing.  These dropped cells   may contain a portion of an IP datagram.  This may cause IP and TCP   packet loss.   Measurement Units: seconds2.2.2. ABR Rate Increase Response Time (ARIRT)   Definition: The amount of time required by the SUT to adjust its   transmission rate based on an ABR rate increase request.   Discussion: During the ARIRT, the SUT will not fully utilize the   available bandwidth.  This will negatively impact IP and TCP   throughput.   Measurement Units: seconds2.2.3. RM-Cell Delay Variation (RM-CDV)   Definition: The variation in RM-cell transfer delay (RM-CTD) of RM-   cells associated with a given traffic load, orientation and   distribution, as well as an integration period.  RM-CDV = max (RM-   CTD) - min (RM-CTD) where max and min indicate the maximum and   minimum over the integration period, respectively.   Discussion:  RM-CDV is a component of RM-cell transfer delay, induced   by buffering and RM-cell scheduling.   RM-CDV effects the time required to notify the source of a change in   the condition of the network.  This in turn effects TCP round trip   time calculations. Large values of RM-CDV will adversely effect TCP   throughput and cause SAR timeout.   Measurement Units: seconds2.2.4. RM-Cell Error Ratio (RM-CER)   Definition: The ratio of RM-cells with payload errors in a   transmission in relation to the total number of RM-cells sent in a   transmission associated with a given traffic load, orientation andDunn & Martin                Informational                     [Page 12]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   distribution, as well as an integration period. Note that errors   occurring in the RM-cell header will cause RM-cell loss at the ATM   layer. Note further that multiple errors in a payload will only be   counted as one cell payload error.     RM-CER = RM-Cells with payload errors / Total RM-Cells Transmitted.   Discussion: The measurement is taken over a time interval and is   desirable to be measured on an in-service circuit. RM-CER effects the   time required to notify the source of a change in the condition of   the network. This in turn effects TCP round trip time calculations.   Large values of RM-CER will adversely effect TCP throughput and cause   SAR timeout.   Measurement Units: dimensionless.2.2.5. RM-Cell Loss Ratio (RM-CLR)   Definition: The ratio of lost RM-cells in a transmission in relation   to the total RM-cells sent in a transmission associated with a given   traffic load, orientation and distribution, as well as an integration   period.      RM-CLR = Lost RM-Cells / Total RM-Cells Transmitted.   Discussion: The objective is to minimize RM-CLR.  It is expressed as   an order of magnitude, having a range of 10^-1 to 10^-15 and   unspecified.   RM-CLR effects the time required to notify the source of a change in   the condition of the network.  This in turn effects TCP round trip   time calculations.  Large values of RM-CLR will adversely effect TCP   throughput and cause SAR timeout.   Measurement Units: dimensionless.2.2.6. RM-Cell Misinsertion Ratio (RM-CMR)   Definition: The ratio of RM-cells received at an endpoint that were   not originally transmitted by the source end in relation to the total   number of RM-cells properly transmitted associated with a given   traffic load, orientation and distribution, as well as an integration   period.      RM-CMR = Misinserted RM-Cells / Total RM-Cells Transmitted.Dunn & Martin                Informational                     [Page 13]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   Discussion: The measurement is taken over a time interval and is   desirable to be measured on an in-service circuit.   RM-CMR effects the time required to notify the source of a change in   the condition of the network.  This in turn effects TCP round trip   time calculations.  Large values of RM-CMR will adversely effect TCP   throughput and cause SAR timeout.   Measurement Units: dimensionless.2.2.7. RM-CRC Error Ratio   Definition: The ratio of RM-cells received at an endpoint which   contain an invalid CRC in relation to the total number of RM-cells   properly transmitted associated with a given traffic load,   orientation and distribution, as well as an integration period.   Discussion: RM-CRC errors cause ATM RM-cells to be lost.   RM-CRC effects the time required to notify the source of a change in   the condition of the network.  This in turn effects TCP round trip   time calculations.  Large values of RM-CRC will adversely effect TCP   throughput and cause SAR timeout.   Measurement Units: dimensionless2.2.8. RM-Cell Transfer Delay (RM-CTD)   Definition: The elapsed time between a RM-cell exit event at the   measurement point 1 (e.g., at the source UNI) and the corresponding   RM-cell entry event at a measurement point 2 (e.g., the destination   UNI) for a particular connection.   Discussion: The RM-cell transfer delay between two measurement points   is the sum of the total inter-ATM node transmission delay and the   total ATM node processing delay.  This number is a constant and   should not adversely effect performance.   Measurement units: seconds2.2.9. Severely Errored Cell Block Ratio (SECBR)   Definition: The ratio of severely errored cell blocks in a   transmission in relation to the total cell blocks sent in a   transmission associated with a given traffic load, orientation and   distribution, as well as an integration period.      SECBR = Severely Errored Cell Blocks/Total Transmitted Cell BlocksDunn & Martin                Informational                     [Page 14]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001   Discussion: SECBR may cause the SUT to drop cells that may contain a   portion of an IP datagram.  This may cause IP and TCP packet loss.   Measurement Units: dimensionless.3. Security Considerations   As this document is solely for providing terminology and describes   neither a protocol nor an implementation, there are no security   considerations associated with this document.4. References   [AF-TM4.0]  ATM Forum, Traffic Management Specification Version 4.0,               af-tm-0056.00, April 1996.   [AF-TM4.1]  ATM Forum, Traffic Management Specification Version 4.1,               af-tm-0121.000, March 1999.   [AF-UNI3.1] ATM Forum, User Network Interface Specification Version               3.1, September 1994.   [AF-UNI4.0] ATM Forum, User Network Interface Specification Version               4.0, July 1996.5. Editors' Addresses   Jeffrey Dunn   Advanced Network Consultants, Inc.   4214 Crest Place   Ellicott City, MD 21043 USA   Phone: +1 (410) 750-1700   EMail: Jeffrey.Dunn@worldnet.att.net   Cynthia Martin   Advanced Network Consultants, Inc.   4214 Crest Place   Ellicott City, MD 21043 USA   Phone: +1 (410) 750-1700   EMail: Cynthia.E.Martin@worldnet.att.netDunn & Martin                Informational                     [Page 15]

RFC 3134          Terminology for ATM ABR Benchmarking         June 2001Full Copyright Statement   Copyright (C) The Internet Society (2001).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implementation may be prepared, copied, published   and distributed, in whole or in part, without restriction of any   kind, provided that the above copyright notice and this paragraph are   included on all such copies and derivative works.  However, this   document itself may not be modified in any way, such as by removing   the copyright notice or references to the Internet Society or other   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assigns.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Dunn & Martin                Informational                     [Page 16]