< draft-mirsky-sfc-pmamm-07.txt   draft-mirsky-sfc-pmamm-08.txt >
SFC Working Group G. Mirsky SFC Working Group G. Mirsky
Internet-Draft ZTE Corp. Internet-Draft ZTE Corp.
Intended status: Standards Track G. Fioccola Intended status: Standards Track G. Fioccola
Expires: October 5, 2019 Huawei Technologies Expires: December 20, 2019 Huawei Technologies
T. Mizrahi T. Mizrahi
Huawei Network.IO Innovation Lab Huawei Network.IO Innovation Lab
April 3, 2019 June 18, 2019
Performance Measurement (PM) with Alternate Marking Method in Service Performance Measurement (PM) with Alternate Marking Method in Service
Function Chaining (SFC) Domain Function Chaining (SFC) Domain
draft-mirsky-sfc-pmamm-07 draft-mirsky-sfc-pmamm-08
Abstract Abstract
This document describes how the alternate marking method be used as This document describes how the alternate marking method can be used
the passive performance measurement method in a Service Function as the efficient performance measurement method taking advantage of
Chaining (SFC) domain. the actual data flows in a Service Function Chaining (SFC) domain.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on October 5, 2019. This Internet-Draft will expire on December 20, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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publication of this document. Please review these documents publication of this document. Please review these documents
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4.3. Multiplexed Mark Enabled Measurement . . . . . . . . . . 5 4.3. Multiplexed Mark Enabled Measurement . . . . . . . . . . 5
4.4. Residence Time Measurement with the Alternate Marking 4.4. Residence Time Measurement with the Alternate Marking
Method . . . . . . . . . . . . . . . . . . . . . . . . . 6 Method . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5.1. Mark Field in NSH Base Header . . . . . . . . . . . . . . 6 5.1. Mark Field in NSH Base Header . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 7 7. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
[RFC7665] introduced architecture of a Service Function Chain (SFC) [RFC7665] introduced the architecture of a Service Function Chain
in the network and defined its components as classifier, Service (SFC) in the network and defined its components as classifier,
Function Forwarder (SFF), and Service Function (SF). [RFC8321] Service Function Forwarder (SFF), and Service Function (SF).
describes the passive performance measurement method, which can be [RFC8321] describes the hybrid performance measurement method, which
used to measure packet loss, latency, and jitter on live traffic. can be used to measure packet loss, latency, and jitter on live
Because this method is based on marking consecutive batches of traffic. Because this method is based on marking consecutive batches
packets the method often referred to as Alternate Marking Method of packets the method often referred to as Alternate Marking Method
(AMM). (AMM).
This document defines how the alternate marking method can be used to This document defines how the alternate marking method can be used to
measure packet loss and delay metrics of a service flow over e2e or measure packet loss and delay metrics of a service flow over e2e or
any segment of the SFC. any segment of the SFC.
2. Conventions used in this document 2. Conventions used in this document
2.1. Terminology 2.1. Terminology
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14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Mark Field in NSH Base Header 3. Mark Field in NSH Base Header
[RFC8300] defines the format of the Network Service Header (NSH). [RFC8300] defines the format of the Network Service Header (NSH).
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver|O|M| TTL | Length |R|R|R|R|MD Type| Proto | |Ver|O|M| TTL | Length |U|U|U|U|MD Type| Proto |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: NSH Base format Figure 1: NSH Base format
This document defines the one-bit long field, referred to as Mark This document defines the one-bit long field, referred to as Mark
field (M in Figure 1, as part of NSH Base and designated for the field (M in Figure 1, as part of NSH Base and designated for the
alternate marking performance measurement method [RFC8321]. The Mark alternate marking performance measurement method [RFC8321]. The Mark
field MUST NOT be used in defining forwarding and/or quality of field MUST be set to 0 at initialization of NSH and ignored on the
service treatment of an SFC packet. The Mark field MUST be used only receipt when the method is not in use. The Mark field MUST NOT be
for the performance measurement of data traffic in the SFC layer. used in defining forwarding and/or quality of service treatment of an
Because the setting of the field to any value does not affect SFC packet. The Mark field MUST be used only for the performance
forwarding and/or quality of service treatment of a packet, the measurement of data traffic in the SFC layer. Though the setting of
alternate marking method in SFC layer can be viewed as a real example the field to any value likely not affect forwarding and/or quality of
of passive performance measurement method. service treatment of a packet, the alternate marking method in SFC
layer is characterized as an example of a hybrid performance
measurement method according to [RFC7799].
4. Theory of Operation 4. Theory of Operation
The marking method can be successfully used in the SFC. Without The marking method can be successfully used in the SFC. Without
limiting any generality consider SFC presented in Figure 2. Any limiting any generality consider SFC presented in Figure 2. Any
combination of markings, Loss and/or Delay, can be applied to a combination of markings, Loss and/or Delay, can be applied to a
service flow by any component of the SFC at either ingress or egress service flow by any component of the SFC at either ingress or egress
point to perform node, link, segment or end-to-end measurement to point to perform node, link, segment or end-to-end measurement to
detect performance degradation defect and localize it efficiently. detect performance degradation defect and localize it efficiently.
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
|SF1| |SF2| |SF3| |SF4| |SF5| |SF6| |SF1| |SF2| |SF3| |SF4| |SF5| |SF6|
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
\ / \ / \ / \ / \ / \ /
+----------+ +----+ +----+ +----+ +----------+ +----+ +----+ +----+
|Classifier|---|SFF1|---------|SFF2|---------|SFF3| |Classifier|---|SFF1|---------|SFF2|---------|SFF3|
+----------+ +----+ +----+ +----+ +----------+ +----+ +----+ +----+
Figure 2: SFC network Figure 2: SFC network
Using the marking method a component of the SFC creates distinct sub- Using the marking method, a component of the SFC creates distinct
flows in the particular service traffic over SFC. Each sub-flow sub-flows in the particular service traffic over SFC. Each sub-flow
consists of consecutive blocks that are unambiguously recognizable by consists of consecutive blocks that are unambiguously recognizable by
a monitoring point at any component of the SFC and can be measured to a monitoring point at any component of the SFC and can be measured to
calculate packet loss and/or packet delay metrics. calculate packet loss and/or packet delay metrics.
4.1. Single Mark Enabled Measurement 4.1. Single Mark Enabled Measurement
As explained in the [RFC8321], marking can be applied to delineate As explained in the [RFC8321], marking can be applied to delineate
blocks of packets based either on the equal number of packets in a blocks of packets based either on the equal number of packets in a
block or based on the same time interval. The latter method offers block or based on the same time interval. The latter method offers
better control as it allows better account for capabilities of better control as it allows a better account for capabilities of
downstream nodes to report statistics related to batches of packets downstream nodes to report statistics related to batches of packets
and, at the same time, time resolution that affects defect detection and, at the same time, time resolution that affects defect detection
interval. interval.
The Loss flag is used to create alternate flows to measure the packet The Loss flag is used to create distinctive flows to measure the
loss by switching the value of the Loss flag every N-th packet or at packet loss by switching the value of the Loss flag every N-th packet
specified time intervals. Delay metrics MAY be calculated with the or at specified time intervals. Delay metrics MAY be calculated with
alternate flow using any of the following methods: the alternate flow using any of the following methods:
o First/Last Packet Delay calculation: whenever the marking, i.e., o First/Last Packet Delay calculation: whenever the marking, i.e.,
the value of Loss flag, changes a component of the SFC can store the value of Loss flag changes a component of the SFC can store
the timestamp of the first/last packet of the block. The the timestamp of the first/last packet of the block. The
timestamp can be compared with the timestamp of the packet that timestamp can be compared with the timestamp of the packet that
arrived in the same order through a monitoring point at a arrived in the same order through a monitoring point at a
downstream component of the SFC to compute packet delay. Because downstream component of the SFC to compute packet delay. Because
timestamps collected based on order of arrival, this method is timestamps collected based on the order of arrival, this method is
sensitive to packet loss and re-ordering of packets sensitive to packet loss and re-ordering of packets
o Average Packet Delay calculation: an average delay is calculated o Average Packet Delay calculation: an average delay is calculated
by considering the average arrival time of the packets within a by considering the average arrival time of the packets within a
single block. A component of the SFC may collect timestamps for single block. A component of the SFC may collect timestamps for
each packet received within a single block. Average of the each packet received within a single block. Average of the
timestamp is the sum of all the timestamps divided by the total timestamp is the sum of all the timestamps divided by the total
number of packets received. Then the difference between averages number of packets received. Then the difference between averages
calculated at two monitoring points is the average packet delay on calculated at two monitoring points is the average packet delay on
that segment. This method is robust to out of order packets and that segment. This method is robust to out of order packets and
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method only provides a single metric for the duration of the method only provides a single metric for the duration of the
block, and it doesn't give the minimum and maximum delay values. block, and it doesn't give the minimum and maximum delay values.
Highly optimized implementation of the method can reduce the Highly optimized implementation of the method can reduce the
duration of the block and thus overcome the limitation. duration of the block and thus overcome the limitation.
4.2. Double Mark Enabled Measurement 4.2. Double Mark Enabled Measurement
Double Mark method allows measurement of minimum and maximum delays Double Mark method allows measurement of minimum and maximum delays
for the monitored flow, but it requires more nodal and network for the monitored flow, but it requires more nodal and network
resources. If the Double Mark method used, then the Loss flag MUST resources. If the Double Mark method used, then the Loss flag MUST
be used to create the alternate flow, i.e., mark larger batches of be used to create the alternate flow, i.e., mark more substantia
packets. The Delay flag MUST be used to denote single packets to batches of packets. The Delay flag MUST be used to denote single
measure delay jitter. packets to measure delay jitter.
The first marking (Loss flag alternation) is needed for packet loss The first marking (Loss flag alternation) is needed for packet loss
and also for average delay measurement. The second marking (Delay and also for average delay measurement. The second marking (Delay
flag is put to one) creates a new set of marked packets that are flag is put to one) creates a new set of marked packets that are
fully identified over the SFC, so that a component can store the fully identified over the SFC, so that a component can store the
timestamps of these packets; these timestamps can be compared with timestamps of these packets; these timestamps can be compared with
the timestamps of the same packets on another element of the SFC to the timestamps of the same packets on another element of the SFC to
compute packet delay values for each packet. The number of compute packet delay values for each packet. The number of
measurements can be easily increased by changing the frequency of the measurements can be easily increased by changing the frequency of the
second marking. But the rate of the second marking must be not too second marking. But the rate of the second marking must be not too
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"Network Service Header (NSH)", RFC 8300, "Network Service Header (NSH)", RFC 8300,
DOI 10.17487/RFC8300, January 2018, DOI 10.17487/RFC8300, January 2018,
<https://www.rfc-editor.org/info/rfc8300>. <https://www.rfc-editor.org/info/rfc8300>.
8.2. Informative References 8.2. Informative References
[I-D.mizrahi-ippm-compact-alternate-marking] [I-D.mizrahi-ippm-compact-alternate-marking]
Mizrahi, T., Arad, C., Fioccola, G., Cociglio, M., Chen, Mizrahi, T., Arad, C., Fioccola, G., Cociglio, M., Chen,
M., Zheng, L., and G. Mirsky, "Compact Alternate Marking M., Zheng, L., and G. Mirsky, "Compact Alternate Marking
Methods for Passive and Hybrid Performance Monitoring", Methods for Passive and Hybrid Performance Monitoring",
draft-mizrahi-ippm-compact-alternate-marking-03 (work in draft-mizrahi-ippm-compact-alternate-marking-04 (work in
progress), October 2018. progress), April 2019.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function [RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665, Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015, DOI 10.17487/RFC7665, October 2015,
<https://www.rfc-editor.org/info/rfc7665>. <https://www.rfc-editor.org/info/rfc7665>.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.
[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
"Alternate-Marking Method for Passive and Hybrid "Alternate-Marking Method for Passive and Hybrid
Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
January 2018, <https://www.rfc-editor.org/info/rfc8321>. January 2018, <https://www.rfc-editor.org/info/rfc8321>.
Authors' Addresses Authors' Addresses
Greg Mirsky Greg Mirsky
ZTE Corp. ZTE Corp.
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