IPFIX Information Elements for Flow Performance Measurement
draft-akhter-opsawg-perfmon-ipfix-02
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| Author | Aamer Akhter | ||
| Last updated | 2012-03-27 | ||
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draft-akhter-opsawg-perfmon-ipfix-02
Network Working Group A. Akhter
Internet-Draft Cisco Systems
Intended status: Standards Track March 27, 2012
Expires: September 28, 2012
IPFIX Information Elements for Flow Performance Measurement
draft-akhter-opsawg-perfmon-ipfix-02.txt
Abstract
There is a need to be able to quantify and report the performance of
network applications and the network service in handling user data.
This performance data provides information essential in validating
service level agreements, fault isolation as well as early warnings
of greater problems. This document describes IPFIX Information
Elements related to performance measurement of network based
applications. In addition, to the performance information several
non-metric information elements are also included to provide greater
context to the reports. The measurements use audio/video
applications as a base but are not restricted to these class of
applications.
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."
This Internet-Draft will expire on September 28, 2012.
Copyright Notice
Copyright (c) 2012 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
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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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. General Usage . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Quality of Service (QoS) Monitoring . . . . . . . . . . . 5
3.2. Service Level Agreemnt (SLA) Validation . . . . . . . . . 5
3.3. Fault Isolation and Troubleshooting . . . . . . . . . . . 6
4. New Information Elements . . . . . . . . . . . . . . . . . . . 6
4.1. Transport Layer . . . . . . . . . . . . . . . . . . . . . 6
4.1.1. perfPacketLoss . . . . . . . . . . . . . . . . . . . . 6
4.1.2. perfPacketExpected . . . . . . . . . . . . . . . . . . 7
4.1.3. perfPacketLossRate . . . . . . . . . . . . . . . . . . 8
4.1.4. perfPacketLossEvent . . . . . . . . . . . . . . . . . 8
4.1.5. perfPacketInterArrivalJitterAvg . . . . . . . . . . . 9
4.1.6. perfPacketInterArrivalJitterMin . . . . . . . . . . . 9
4.1.7. perfPacketInterArrivalJitterMax . . . . . . . . . . . 10
4.1.8. perfRoundTripNetworkDelay . . . . . . . . . . . . . . 10
4.2. User and Application Layer . . . . . . . . . . . . . . . . 11
4.2.1. perfSessionSetupDelay . . . . . . . . . . . . . . . . 11
4.3. Contextual Elements . . . . . . . . . . . . . . . . . . . 12
4.3.1. mediaRTPSSRC . . . . . . . . . . . . . . . . . . . . . 12
4.3.2. mediaRTPPayloadType . . . . . . . . . . . . . . . . . 12
4.3.3. mediaCodec . . . . . . . . . . . . . . . . . . . . . . 13
5. Security Considerations . . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . . 14
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
Today's networks support a multitude of highly demanding and
sensitive network applications. Network issues are readily apparent
by the users of these applications due to the sensitivity of these
applications to impaired network conditions. Examples of these
network applications include applications making use of IP based
audio, video, database transactions, virtual desktop interface (VDI),
online gaming, cloud services and many more. In some cases, the
impaired application translates directly to loss of revenue. In
other cases, there may be regulatory or contractual service level
agreements that motivate the network operator. Due to the
sensitivity of these types of applications to impaired service it
leaves a poor impression of the service on the user-- regardless of
the actual performance of the network itself. In the case of an
actual problem within the network service, monitoring the performance
may yield a early indicator of a much more serious problem.
Due to the demanding and sensitive nature of these applications,
network operators have tried to engineer their networks towards
wringing better and differentiated performance. However, that same
differentiated design prevents network operators from extrapolating
observational data from one application to another, or from one set
of synthetic (active test) test traffic to actual application
performance. This gap highlights the importance of generic
measurements as well as the reliance on user traffic measurents--
rather than synthetic tests.
Performance measurements on user data provide greater visibility not
only into the quality of experience of the end users but also
visibility into network health. With regards to network health, as
flow performance is being measured, there will be visibility into the
end to end performance which means that not only visibility into
local network health, but also viability into remote network health.
If these measurements are made at multiple points within the network
(or between the network and end device) then there is not only
identification that there might be an issue, but a span of area can
be established where the issue might be. The resolution of the fault
increases with the number of measurement points along the flow path.
The IP Flow Information Export Protocol (IPFIX) [RFC5101] provides
new levels of flexibility in reporting from measurement points across
the life cycle of a network based application. IPFIX can provide
granular results in terms of flow specificity as well as time
granularity. At the same time, IPFIX allows for summarization of
data along different types of boundaries for operators that are
unconcerned about specific sessions but about health of a service or
a portion of the network. This documet details the expresison of
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IPFIX Information Elements whose calculation is defined in an
accompanying document.
As this document covers the reporting of these metrics via IPFIX,
consideration is taken with mapping the metric's capabilities and
context with the IPFIX information and data representation model.
The guidelines outlined in [I-D.trammell-ipfix-ie-doctors] are used
to ensure proper IPFIX information element definition.
There has been related work in this area such as [RFC2321].
[I-D.huici-ipfix-sipfix], and [VoIP-monitor]. This document is also
an attempt to generalize as well as standardize the reporting formats
and measurement methodology.
2. Terminology
Terms used in this document that are defined in the Terminology
section of the IPFIX Protocol [RFC5101] document are to be
interpreted as defined there.
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].
In addition, the information element definitions use the following
terms:
Name: Name of the information element per the IPFIX rules defined in
Section 2.3 of [RFC5102]
Description: Short description of what the information element is
trying to convey.
Observation Point: Where the measurement is meant to be performed.
Either at an intermediate point (for example, a router) or end
system.
Element Data Type: The IPFIX informationElementDataTypeas defined in
Section 3.1 of [RFC5610]
Element Semantics: The IPFIX informationElementSemantics as defined
in section Section 3.6 of [RFC5610]
Element Units: The IPFIX informationElementUnits as defined in
section Section 3.7 of [RFC5610]
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Element Range Begin: The IPFIX informationElementRangeBegin as
defined in section Section 3.7 of [RFC5610]
Element Range End: The IPFIX informationElementRangeEnd as defined
in section Section 3.7 of [RFC5610]
Element Id: The IPFIX global unique element ID as defined in Section
3.2 of [RFC5101]
Status: The status of the specification of this IPFIX Information
Element.
3. General Usage
3.1. Quality of Service (QoS) Monitoring
The network operator needs to be able to gauge the end user's
satisfaction with the network service. While there are many
components of the satisfaction such as pricing, packaging, offering,
etc., a major component of satisfaction is delivering a consistent
service. The user builds trust on this consistency of the network
service and is then to be able to run network applications-- which is
of course the end goal. Without the ability to deliver a consistent
service for end user network applications network operator will be
left dealing with price sensitive disgruntled users with very low
expectations (if they don't have choice of operator) or abandonment
(if they have choice).
For QoS monitoring, it is importnat to be able to capture the
applicaiton context. For example, in the case of interactive audio
flows, the codec and the fact that the application is interactive
shoudl be captured. The codec type can be used to determine loss
thresholds affecting end user quality and the interactive nature
would suggest threshodlds over one way delay. The IPFIX reporting
would need to keep this information organized together for opeartor
to be able to perform correlated analysis.
3.2. Service Level Agreemnt (SLA) Validation
Similar to QoS and QoE validation, there might be contractual or
regulatory requirements that need to be met by the network operator.
Monitoring the performance of the flows allows the application
operator, network operator as well as the end user to validate of the
target service is being delivered. While there is quite a diversity
in the codification of network SLAs they may eventually involve some
measurement of network uptime, end to end latency, end to end jitter
and perhaps service response time. In the case violation of the SLA,
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the start and end times, nature and network scope of the violation
needs to be captured to allow for the most accurate settling of the
SLA.
3.3. Fault Isolation and Troubleshooting
It has been generally easier to troubleshoot and fix problems that
are binary in nature: it either works or does not work. The host is
pingable or not pingable. However, the much more difficult to
resolve issues that are transitory in nature, move from location to
location, more complicated that simple ICMP reachability and many
times unverifiable reports by the users themselves. It is these
intermittent and seemingly inconsistent network impairments that
performance metrics can be extremely helpful with. Just the basic
timely detection that there is a problem (or an impending problem)
can give the provider the confidence that there is a real problem
that needs to be resolved. The next step would be to assist the
operator in a speedy resolution by providing information regarding
the network location and nature of the problem.
4. New Information Elements
The information elements are organized into two main groups:
Transport Layer: Metrics that might be calculated from observations
at higher layers but essentially provide information about the
network transport of user date. For example, the metrics related
to packet loss, latency and jitter would be defined here.
User and Application Layer: Metrics that are might be affected by
the network indirectly, but are ultimately related to user, end-
system and session states. For example, session setup time,
transaction rate and session duration would be defined here.
Contextual Elements Information elements that provide further
context to the metrics. For example, media type, codec type, and
type of application would be defined here.
4.1. Transport Layer
4.1.1. perfPacketLoss
Name: perfPacketLoss
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Description: The packet loss metric reports the number of individual
packets that were lost in the reporting interval.
Observation Point: The observation can be made anywhere along the
media path or on the endpoints them selves. The observation is
only relevant in a unidirectional sense.
Element Data Type: unsigned32
Element Semantics: deltaCounter
Element Units: packets
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
Element Id: TBDperfPacketLoss
Status: current
4.1.2. perfPacketExpected
Name: perfPacketExpected
Description: The number of packets there were expected within a
monitoring interval.
Observation Point: The observation can be made anywhere along the
media path or on the endpoints them selves. The observation is
only relevant in a unidirectional sense.
Element Data Type: unsigned32
Element Semantics: deltaCounter
Element Units: none
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
Element Id: TBDperfPacketExpected
Status: current
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4.1.3. perfPacketLossRate
Name: perfPacketLossRate
Description: Percentage of number of packets lost out of the total
set of packets sent.
Observation Point: The observation can be made anywhere along the
media path or on the endpoints them selves. The observation is
only relevant in a unidirectional sense.
Element Data Type: unsigned16
Element Semantics: quantity
Element Units: none
Element Range Begin: 0
Element Range End: 0xFFFE
Element Id: TBDperfPacketLossRate
Status: current
4.1.4. perfPacketLossEvent
Name: perfPacketLossEvent
Description: The packet loss event metric reports the number of
continuous sets of packets that were lost in the reporting
interval.
Observation Point: The observation can be made anywhere along the
media path or on the endpoints them selves. The observation is
only relevant in a unidirectional sense.
Element Data Type: unsigned32
Element Semantics: deltaCounter
Element Units: none
Element Range Begin: 0
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Element Range End: 0xFFFFFFFE
Element Id: TBDperfPacketExpected
Status: current
4.1.5. perfPacketInterArrivalJitterAvg
Name: perfPacketInterArrivalJitterAvg
Description: This metric measures the absolute deviation of the
difference in packet spacing at the measurement point compared to
the packet spacing at the sender.
Observation Point: The observation can be made anywhere along the
media path or on the receiver. The observation is only relevant
in a unidirectional sense.
Element Data Type: unsigned32
Element Semantics: quantity
Element Units: microseconds
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
Element Id: TBDperfPacketInterArrivalJitterAvg
Status: current
4.1.6. perfPacketInterArrivalJitterMin
Name: perfPacketInterArrivalJitterMin
Description: This metric measures the minimum value the calculation
used for perfPacketInterArrivalJitterAvg within the monitoring
interval.
Observation Point: The observation can be made anywhere along the
media path or on the receiver. The observation is only relevant
in a unidirectional sense.
Element Data Type: unsigned32
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Element Semantics: quantity
Element Units: microseconds
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
Element Id: TBDperfPacketInterArrivalJitterMin
Status: current
4.1.7. perfPacketInterArrivalJitterMax
Name: perfPacketInterArrivalJitterMax
Description: This metric measures the maximum value the calculation
used for perfPacketInterArrivalJitterAvg within the monitoring
interval.
Observation Point: The observation can be made anywhere along the
media path or on the receiver. The observation is only relevant
in a unidirectional sense.
Element Data Type: unsigned32
Element Semantics: quantity
Element Units: microseconds
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
Element Id: TBDperfPacketInterArrivalJitterMax
Status: current
4.1.8. perfRoundTripNetworkDelay
Name: perfRoundTripNetworkDelay
Description: This metric measures the network round trip time
between end stations for a flow.
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Observation Point: The observation can be made anywhere along the
flow path as long as the bidirectional network delay is accounted
for.
Element Data Type: unsigned32
Element Semantics: quantity
Element Units: microseconds
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
Element Id: TBDperfRoundTripNetworkDelay
Status: current
4.2. User and Application Layer
4.2.1. perfSessionSetupDelay
Name: perfSessionSetupDelay
Description: The Session Setup Delay metric reports the time taken
from a request being initiated by a host/endpoint to the response
(or request indicator) to the request being observed. This metric
is defined in [RFC4710], however the units have been updated to
microseconds.
Observation Point: This metric needs to be calculated where both
request and response can be observed. This could be at network
choke points, application proxies, or within the end systems
themselves.
Element Data Type: unsigned32
Element Semantics: quantity
Element Units: microseconds
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
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Element Id: TBDperfSessionSetupDelay
Status: current
4.3. Contextual Elements
4.3.1. mediaRTPSSRC
Name: mediaRTPSSRC
Description: Value of the synchronization source (SSRC) field in the
RTP header of the flow. This field is defined in [RFC3550]
Observation Point: This metric can be gleaned from the RTP packets
directly, so the observation point needs to on the flow path or
within the endpoints.
Element Data Type: unsigned32
Element Semantics: identifier
Element Units: octets
Element Range Begin: 0
Element Range End: 0xFFFFFFFE
Element Id: TBDmediaRTPSSRC
Status: current
4.3.2. mediaRTPPayloadType
Name: mediaRTPPayloadType
Description: The value of the RTP Payload Type Field as seen in the
RTP header of the flow. This field is defined in [RFC3550]
Observation Point: This metric can be gleaned from the RTP packets
directly, so the observation point needs to on the flow path or
within the endpoints.
Element Data Type: unsigned8
Element Semantics: identifier
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Element Units: octets
Element Range Begin: 0
Element Range End: 0xFF
Element Id: TBDmediaRTPPayloadType
Status: current
4.3.3. mediaCodec
Name: mediaCodec
Description: The media codec used in the flow.
Observation Point: The ideal location of this metric is on the media
generators and consumers. However, given application inspection
or static configuration it is possible that intermediate nodes are
able to generate codec information.
Element Data Type: string
Element Semantics: identifier
Element Units: octets
Element Id: TBDmediaCodec
Status: current
5. Security Considerations
The recommendations in this document do not introduce any additional
security issues to those already mentioned in [RFC5101] and [RFC5477]
6. IANA Considerations
This document requires an elements assignment to be made by IANA.
7. Acknowledgements
The authors would like to thank Shingo Kashima for their invaluable
review and comments. Thank-you.
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8. References
8.1. Normative References
[RFC5101] Claise, B., "Specification of the IP Flow Information
Export (IPFIX) Protocol for the Exchange of IP Traffic
Flow Information", RFC 5101, January 2008.
[RFC5610] Boschi, E., Trammell, B., Mark, L., and T. Zseby,
"Exporting Type Information for IP Flow Information Export
(IPFIX) Information Elements", RFC 5610, July 2009.
[RFC4710] Siddiqui, A., Romascanu, D., and E. Golovinsky, "Real-time
Application Quality-of-Service Monitoring (RAQMON)
Framework", RFC 4710, October 2006.
[RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J.
Meyer, "Information Model for IP Flow Information Export",
RFC 5102, January 2008.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003.
[RFC3497] Gharai, L., Perkins, C., Goncher, G., and A. Mankin, "RTP
Payload Format for Society of Motion Picture and
Television Engineers (SMPTE) 292M Video", RFC 3497,
March 2003.
[RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
"Session Traversal Utilities for NAT (STUN)", RFC 5389,
October 2008.
[I-D.ietf-pmol-sip-perf-metrics]
Malas, D. and A. Morton, "Basic Telephony SIP End-to-End
Performance Metrics", draft-ietf-pmol-sip-perf-metrics-07
(work in progress), September 2010.
[iana-ipfix-assignments]
Internet Assigned Numbers Authority, "IP Flow Information
Export Information Elements
(http://www.iana.org/assignments/ipfix/ipfix.xml)".
8.2. Informative References
[I-D.ietf-pmol-metrics-framework]
Clark, A. and B. Claise, "Guidelines for Considering New
Performance Metric Development",
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draft-ietf-pmol-metrics-framework-12 (work in progress),
July 2011.
[I-D.trammell-ipfix-ie-doctors]
Trammell, B. and B. Claise, "Guidelines for Authors and
Reviewers of IPFIX Information Elements",
draft-trammell-ipfix-ie-doctors-03 (work in progress),
October 2011.
[RFC2508] Casner, S. and V. Jacobson, "Compressing IP/UDP/RTP
Headers for Low-Speed Serial Links", RFC 2508,
February 1999.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, March 2004.
[RFC2250] Hoffman, D., Fernando, G., Goyal, V., and M. Civanlar,
"RTP Payload Format for MPEG1/MPEG2 Video", RFC 2250,
January 1998.
[RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE",
RFC 2890, September 2000.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, December 2005.
[RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and
Control Packets on a Single Port", RFC 5761, April 2010.
[I-D.huici-ipfix-sipfix]
Huici, F., Niccolini, S., and S. Anderson, "SIPFIX: Use
Cases and Problem Statement for VoIP Monitoring and
Exporting", draft-huici-ipfix-sipfix-00 (work in
progress), June 2009.
[nProbe] "nProbe - NetFlow/IPFIX Network Probe
(http://www.ntop.org/nProbe.html)".
[RFC2321] Bressen, A., "RITA -- The Reliable Internetwork
Troubleshooting Agent", RFC 2321, April 1998.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5477] Dietz, T., Claise, B., Aitken, P., Dressler, F., and G.
Carle, "Information Model for Packet Sampling Exports",
RFC 5477, March 2009.
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[VoIP-monitor]
L. Chang-Yong, H. Kim, K. Ko, J. Jim, and H. Jeong, "A
VoIP Traffic Monitoring System based on NetFlow v9,
International Journal of Advanced Science and Technology,
vol. 4, Mar. 2009".
Author's Address
Aamer Akhter
Cisco Systems, Inc.
7025 Kit Creek Road
RTP, NC 27709
USA
Email: aakhter@cisco.com
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