< draft-ietf-bier-pmmm-oam-05.txt   draft-ietf-bier-pmmm-oam-06.txt >
BIER Working Group G. Mirsky BIER Working Group G. Mirsky
Internet-Draft ZTE Corp. Internet-Draft ZTE Corp.
Intended status: Standards Track L. Zheng Intended status: Standards Track L. Zheng
Expires: June 13, 2019 M. Chen Expires: January 2, 2020 M. Chen
Huawei Technologies
G. Fioccola G. Fioccola
Telecom Italia Huawei Technologies
December 10, 2018 July 1, 2019
Performance Measurement (PM) with Marking Method in Bit Index Explicit Performance Measurement (PM) with Marking Method in Bit Index Explicit
Replication (BIER) Layer Replication (BIER) Layer
draft-ietf-bier-pmmm-oam-05 draft-ietf-bier-pmmm-oam-06
Abstract Abstract
This document describes a hybrid performance measurement method for This document describes a hybrid performance measurement method for
multicast service over Bit Index Explicit Replication (BIER) domain. multicast service through a Bit Index Explicit Replication 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.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on June 13, 2019. This Internet-Draft will expire on January 2, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2018 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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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 2 2. Conventions used in this document . . . . . . . . . . . . . . 2
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. OAM Field in BIER Header . . . . . . . . . . . . . . . . . . 3 3. OAM Field in BIER Header . . . . . . . . . . . . . . . . . . 3
4. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 3 4. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 4
4.1. Single Mark Enabled Measurement . . . . . . . . . . . . . 4 4.1. Single-Marking Enabled Measurement . . . . . . . . . . . 4
4.2. Double Mark Enabled Measurement . . . . . . . . . . . . . 5 4.2. Double-Marking Enabled Measurement . . . . . . . . . . . 5
4.3. Operational Considerations . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
[RFC8279] introduces and explains Bit Index Explicit Replication [RFC8279] introduces and explains the Bit Index Explicit Replication
(BIER) architecture and how it supports forwarding of multicast data (BIER) architecture and how it supports the forwarding of multicast
packets. [RFC8296] specified that in case of BIER encapsulation in data packets. [RFC8296] specified that in the case of BIER
MPLS network a BIER-MPLS label, the label that is at the bottom of encapsulation in an MPLS network, a BIER-MPLS label, the label that
the label stack, uniquely identifies the multicast flow. [RFC8321] is at the bottom of the label stack, uniquely identifies the
describes hybrid performance measurement method, per [RFC7799] multicast flow. [RFC8321] describes a hybrid performance measurement
classification of measurement methods. Packet Network Performance method, per RFC7799's classification of measurement methods
Monitoring (PNPM), which can be used to measure packet loss, latency, [RFC7799]. The method, called Packet Network Performance Monitoring
and jitter on live traffic. Because this method is based on marking (PNPM), can be used to measure packet loss, latency, and jitter on
consecutive batches of packets the method often referred to as live traffic complies with requirements #5 and #12 listed in
Marking Method (MM). [I-D.ietf-bier-oam-requirements]. Because this method is based on
marking consecutive batches of packets, the method is often referred
to as a marking method.
This document defines how marking method can be used on BIER layer to This document defines how the marking method can be used on the BIER
measure packet loss and delay metrics of a multicast flow in MPLS layer to measure packet loss and delay metrics of a multicast flow in
network. an MPLS network.
2. Conventions used in this document 2. Conventions used in this document
2.1. Terminology 2.1. Terminology
BFR: Bit-Forwarding Router BFR: Bit-Forwarding Router
BFER: Bit-Forwarding Egress Router BFER: Bit-Forwarding Egress Router
BFIR: Bit-Forwarding Ingress Router BFIR: Bit-Forwarding Ingress Router
BIER: Bit Index Explicit Replication
MM: Marking Method BIER: Bit Index Explicit Replication
OAM: Operations, Administration and Maintenance OAM: Operations, Administration and Maintenance
2.2. Requirements Language 2.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
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. OAM Field in BIER Header 3. OAM Field in BIER Header
[RFC8296] defined the two-bit long field, referred to as OAM, [RFC8296] defined the two-bits long field, referred to as OAM. The
designated for the marking performance measurement method. The OAM OAM field can be used for the marking performance measurement method.
field MUST NOT be used in defining forwarding and/or quality of
service treatment of a BIER packet. The OAM field MUST be used only
for the performance measurement of data traffic in BIER layer.
Because the setting of the field to any value does not affect Because the setting of the field to any value does not affect
forwarding and/or quality of service treatment of a packet, the forwarding and/or quality of service treatment of a packet, using the
marking method in BIER layer can be viewed as the example of the OAM field for PNPM in BIER layer can be viewed as the example of the
hybrid performance measurement method. hybrid performance measurement method.
The Figure 1 displays format of the OAM field Figure 1 displays the interpretation of the OAM field defined in this
specification for the use by PNPM method.
0 0
0 1 0 1
+-+-+-+-+ +-+-+-+-+
| L | D | | S | D |
+-+-+-+-+ +-+-+-+-+
Figure 1: OAM field of BIER Header format Figure 1: OAM field of BIER Header format
where: where:
o L - Loss flag; o S - Single-Marking flag;
o D - Delay flag. o D - Double-Marking flag.
4. Theory of Operation 4. Theory of Operation
The marking method can be successfully used in the multicast The marking method can be used in the multicast environment supported
environment supported by BIER layer. Without limiting any generality by BIER layer. Without limiting any generality consider multicast
consider multicast network presented in Figure 2. Any combination of network presented in Figure 2. Any combination of markings can be
markings, Loss and/or Delay, can be applied to a multicast flow by applied to a multicast flow by the Bit Forwarding Ingress Router
any Bit Forwarding Router (BFR) at either ingress or egress point to (BFIR) at either ingress or egress point to perform node, link,
perform node, link, segment or end-to-end measurement to detect segment or end-to-end measurement to detect performance degradation
performance degradation defect and localize it efficiently. defect and localize it efficiently.
----- -----
--| D | --| D |
----- / ----- ----- / -----
--| B |-- --| B |--
/ ----- \ ----- / ----- \ -----
/ --| E | / --| E |
----- / ----- ----- / -----
| A |--- ----- | A |--- -----
----- \ --| F | ----- \ --| F |
\ ----- / ----- \ ----- / -----
--| C |-- --| C |--
----- \ ----- ----- \ -----
--| G | --| G |
----- -----
Figure 2: Multicast network Figure 2: Multicast network
Using the marking method, a BFR creates distinct sub-flows in the Using the marking method, a BFIR creates distinct sub-flows in the
particular multicast traffic over BIER layer. Each sub-flow consists particular multicast traffic over BIER layer. Each sub-flow consists
of consecutive blocks, consisting of identically marked packets, that of consecutive blocks of identically marked packets. For example, a
are unambiguously recognizable by a monitoring point at any BFR and block of N packets, with each packet being marked as X, is followed
can be measured to calculate packet loss and/or packet delay metrics. by the block of M packets with each packet being marked as Y. These
It is expected that the marking values be set and cleared at the edge blocks are unambiguously recognizable by a monitoring point at any
of BIER domain. Thus for the scenario presented in Figure 2 if the Bit Forwarding Router (BFR) and can be measured to calculate packet
operator initially monitors A-C-G and A-B-D segments he may enable loss and/or packet delay metrics. It is expected that the marking
measurements on segments C-F and B-E at any time. values be set and cleared at the edge of BIER domain. Thus for the
scenario presented in Figure 2 if the operator initially monitors the
A-C-G and A-B-D segments he may enable measurements on segments C-F
and B-E at any time.
4.1. Single Mark Enabled Measurement 4.1. Single-Marking Enabled Measurement
As explained in the [RFC8321], marking can be applied to delineate As explained in [RFC8321], marking can be applied to delineate blocks
blocks of packets based either on the equal number of packets in a of packets based either on the equal number of packets in a block or
block or based on equal time interval. The latter method offers based on the equal time interval. The latter method offers better
better control as it allows better account for capabilities of control as it allows a better account for capabilities of downstream
downstream nodes to report statistics related to batches of packets nodes to report statistics related to batches of packets and, at the
and, at the same time, time resolution that affects defect detection same time, time resolution that affects defect detection interval.
interval.
If the Single Mark measurement used to measure packet loss, then the If the Single-Marking measurement is used to measure packet loss,
D flag MUST be set to zero on transmit and ignored by monitoring then the D flag MUST be set to zero on transmit and ignored by the
point. monitoring point.
The L flag is used to create alternate flows to measure the packet The S flag is used to create sub-flows to measure the packet loss by
loss by switching the value of the L flag every N-th packet or at switching the value of the S flag every N-th packet or at certain
certain time intervals. Delay metrics MAY be calculated with the time intervals. Delay metrics MAY be calculated with the sub-flow
alternate flow using any of the following methods: 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.,
value of L flag changes, a BFR can store the timestamp of the the value of S flag changes, a BFR can store the timestamp of the
first/last packet of the block. The timestamp can be compared first/last packet of the block. The timestamp can be compared
with the timestamp of the packet that arrived in the same order with the timestamp of the packet that arrived in the same order
through a monitoring point at downstream BFR to compute packet through a monitoring point at a downstream BFR to compute packet
delay. Because timestamps collected based on order of arrival delay. Because timestamps collected based on the order of arrival
this method is sensitive to packet loss and re-ordering of packets this method is sensitive to packet loss and re-ordering of packets
(see Section 4.3 for more details).
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 BFR may collect timestamps for each packet single block. A BFR may collect timestamps for each packet
received within a single block. Average of the timestamp is the received within a single block. Average of the timestamp is the
sum of all the timestamps divided by the total number of packets sum of all the timestamps divided by the total number of packets
received. Then the difference between averages calculated at two received. Then the difference between the average packet arrival
monitoring points is the average packet delay on that segment. time calculated for the downstream monitoring point and the same
metric but calculated at the upstream monitoring point is the
average packet delay on the segment between these two points.
This method is robust to out of order packets and also to packet This method is robust to out of order packets and also to packet
loss (only a small error is introduced). This method only loss on the segment between the measurement points (packet loss
provides a single metric for the duration of the block and it may cause a minor loss of accuracy in the calculated metric
doesn't give the minimum and maximum delay values. This because the number of packets used is different at each
limitation could be overcome by reducing the duration of the block measurement point). This method only provides a single metric for
by means of a highly optimized implementation of the method. the duration of the block, and it doesn't give the minimum and
maximum delay values. This limitation of producing only the
single metric could be overcome by reducing the duration of the
block. As a result, the calculated value of the average delay
will better reflect the minimum and maximum delay values of the
block's duration time.
4.2. Double Mark Enabled Measurement 4.2. Double-Marking Enabled Measurement
Double Mark method allows measurement of minimum and maximum delays Double-Marking method allows measurement of minimum and maximum
for the monitored flow but it requires more nodal and network delays for the monitored flow, but it requires more nodal and network
resources. If the Double Mark method used, then the L flag MUST be resources. If the Double-Marking method used, then the S flag is
used to create the alternate flow, i.e. mark larger batches of used to create the sub-flow, i.e., mark blocks of packets. The D
packets. The D flag MUST be used to mark single packets to measure flag is used to mark single packets within a block to measure delay
delay jitter. and jitter.
The first marking (L flag alternation) is needed for packet loss and The first marking (S flag alternation) is needed for packet loss and
also for average delay measurement. The second marking (D flag is also for average delay measurement. The second marking (D flag is
put to one) creates a new set of marked packets that are fully put to one) creates a new set of marked packets that are fully
identified over the BIER network, so that a BFR can store the identified over the BIER network, so that a BFR 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 a second BFR to compute packet the timestamps of the same packets on a second BFR to compute packet
delay values for each packet. The number of measurements can be delay values for each packet. The number of measurements can be
easily increased by changing the frequency of the second marking. easily increased by changing the frequency of the second marking. On
But the frequency of the second marking must be not too high in order the other hand, the higher frequency of the second marking will cause
to avoid out of order issues. This method is useful to measure not a higher volume of the measurement data being transported through the
only the average delay but also the minimum and maximum delay values BIER domain. An operator should consider and balance both effects.
and, in wider terms, to know more about the statistic distribution of This method is useful to measure not only the average delay but also
delay values. the minimum and maximum delay values and, in wider terms, to know
more about the statistic distribution of delay values.
4.3. Operational Considerations
For the ease of operational procedures, the initial marking of a
multicast flow is performed at BFIR. and cleared, by way of removing
BIER encapsulation form a payload packet, at the edge of the BIER
domain by BFERs.
Since at the time of writing this specification, there are no
proposals to using auto-discovery or signaling mechanism to inform
downstream nodes what methodology is used each monitoring point MUST
be configured beforehand.
Section 4.3 [RFC8321] provides a detailed analysis of how packet re-
ordering and the duration of the block in the Single-Marking mode of
the marking method impact the accuracy of the packet loss
measurement. Re-ordering of packets in the Single-Marking mode will
be noticeable only at the edge of a block of packets (re-ordering
within the block cannot be detected in the Single-Marking mode). If
the extra delay for some packets is much smaller than half of the
duration of a block, then it should be easier to attribute re-ordered
packets to the proper block and thus maintain the accuracy of the
packet loss measurement.
5. IANA Considerations 5. IANA Considerations
This document requests IANA to register format of the OAM field of This document requests IANA to register format of the OAM field of
BIER Header as the following: BIER Header as the following:
+--------------+---------+--------------------------+---------------+ +--------------+---------+-----------------+---------------+
| Bit Position | Marking | Description | Reference | | Bit Position | Marking | Description | Reference |
+--------------+---------+--------------------------+---------------+ +--------------+---------+-----------------+---------------+
| 0 | S | Single Mark Measurement | This document | | 0 | S | Single-Marking | This document |
| 1 | D | Double Mark Measurement | This document | | 1 | D | Double-Marking | This document |
+--------------+---------+--------------------------+---------------+ +--------------+---------+-----------------+---------------+
Table 1: OAM field of BIER Header Table 1: OAM field of BIER Header
6. Security Considerations 6. Security Considerations
This document list the OAM requirement for BIER-enabled domain and Regarding using the marking method, [RFC8321] stressed two types of
does not raise any security concerns or issues in addition to ones security concerns. First, the potential harm caused by the
common to networking. measurements, is a lesser threat as [RFC8296] defines OAM field used
by the marking method so that the value of "two bits have no effect
on the path taken by a BIER packet and have no effect on the quality
of service applied to a BIER packet." Second security concern,
potential harm to the measurements can be mitigated by using policy,
suggested in [RFC8296], to accept BIER packets only from trusted
routers, not from customer-facing interfaces.
All the security considerations for BIER discussed in [RFC8296] are
inherited by this document.
7. Acknowledgement 7. Acknowledgement
TBD TBD
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
skipping to change at page 7, line 5 skipping to change at page 8, line 5
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
for Bit Index Explicit Replication (BIER) in MPLS and Non- for Bit Index Explicit Replication (BIER) in MPLS and Non-
MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
2018, <https://www.rfc-editor.org/info/rfc8296>. 2018, <https://www.rfc-editor.org/info/rfc8296>.
[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
"Alternate-Marking Method for Passive and Hybrid
Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
January 2018, <https://www.rfc-editor.org/info/rfc8321>.
8.2. Informative References 8.2. Informative References
[I-D.ietf-bier-oam-requirements]
Mirsky, G., Nordmark, E., Pignataro, C., Kumar, N.,
Aldrin, S., Zheng, L., Chen, M., Akiya, N., and S.
Pallagatti, "Operations, Administration and Maintenance
(OAM) Requirements for Bit Index Explicit Replication
(BIER) Layer", draft-ietf-bier-oam-requirements-07 (work
in progress), February 2019.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>. May 2016, <https://www.rfc-editor.org/info/rfc7799>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279, Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017, DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>. <https://www.rfc-editor.org/info/rfc8279>.
[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
"Alternate-Marking Method for Passive and Hybrid
Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
January 2018, <https://www.rfc-editor.org/info/rfc8321>.
Authors' Addresses Authors' Addresses
Greg Mirsky Greg Mirsky
ZTE Corp. ZTE Corp.
Email: gregimirsky@gmail.com Email: gregimirsky@gmail.com
Lianshu Zheng Lianshu Zheng
Huawei Technologies Huawei Technologies
skipping to change at page 7, line 39 skipping to change at page 9, line 4
Lianshu Zheng Lianshu Zheng
Huawei Technologies Huawei Technologies
Email: vero.zheng@huawei.com Email: vero.zheng@huawei.com
Mach Chen Mach Chen
Huawei Technologies Huawei Technologies
Email: mach.chen@huawei.com Email: mach.chen@huawei.com
Giuseppe Fioccola Giuseppe Fioccola
Telecom Italia Huawei Technologies
Email: giuseppe.fioccola@telecomitalia.it Email: giuseppe.fioccola@huawei.com
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