Performance Measurement (PM) with Marking Method in Bit Index Explicit Replication (BIER) Layer
draft-ietf-bier-pmmm-oam-05
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (bier WG) | |
|---|---|---|---|
| Authors | Greg Mirsky , Lianshu Zheng , Mach Chen , Giuseppe Fioccola | ||
| Last updated | 2019-07-01 (Latest revision 2018-12-11) | ||
| Replaces | draft-mirsky-bier-pmmm-oam | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text xml htmlized pdfized bibtex | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Suneesh Babu | ||
| Shepherd write-up | Show Last changed 2019-05-29 | ||
| IESG | IESG state | AD Evaluation::Revised I-D Needed | |
| Consensus boilerplate | Yes | ||
| Telechat date | (None) | ||
| Responsible AD | Alvaro Retana | ||
| Send notices to | Suneesh Babu <suneeshbk@gmail.com>, aretana.ietf@gmail.com |
draft-ietf-bier-pmmm-oam-05
BIER Working Group G. Mirsky
Internet-Draft ZTE Corp.
Intended status: Standards Track L. Zheng
Expires: June 13, 2019 M. Chen
Huawei Technologies
G. Fioccola
Telecom Italia
December 10, 2018
Performance Measurement (PM) with Marking Method in Bit Index Explicit
Replication (BIER) Layer
draft-ietf-bier-pmmm-oam-05
Abstract
This document describes a hybrid performance measurement method for
multicast service over Bit Index Explicit Replication (BIER) domain.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on June 13, 2019.
Copyright Notice
Copyright (c) 2018 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
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 2
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. OAM Field in BIER Header . . . . . . . . . . . . . . . . . . 3
4. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 3
4.1. Single Mark Enabled Measurement . . . . . . . . . . . . . 4
4.2. Double Mark Enabled Measurement . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
[RFC8279] introduces and explains Bit Index Explicit Replication
(BIER) architecture and how it supports forwarding of multicast data
packets. [RFC8296] specified that in case of BIER encapsulation in
MPLS network a BIER-MPLS label, the label that is at the bottom of
the label stack, uniquely identifies the multicast flow. [RFC8321]
describes hybrid performance measurement method, per [RFC7799]
classification of measurement methods. Packet Network Performance
Monitoring (PNPM), which can be used to measure packet loss, latency,
and jitter on live traffic. Because this method is based on marking
consecutive batches of packets the method often referred to as
Marking Method (MM).
This document defines how marking method can be used on BIER layer to
measure packet loss and delay metrics of a multicast flow in MPLS
network.
2. Conventions used in this document
2.1. Terminology
BFR: Bit-Forwarding Router
BFER: Bit-Forwarding Egress Router
BFIR: Bit-Forwarding Ingress Router
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BIER: Bit Index Explicit Replication
MM: Marking Method
OAM: Operations, Administration and Maintenance
2.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. OAM Field in BIER Header
[RFC8296] defined the two-bit long field, referred to as OAM,
designated for the marking performance measurement method. The OAM
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
forwarding and/or quality of service treatment of a packet, the
marking method in BIER layer can be viewed as the example of the
hybrid performance measurement method.
The Figure 1 displays format of the OAM field
0
0 1
+-+-+-+-+
| L | D |
+-+-+-+-+
Figure 1: OAM field of BIER Header format
where:
o L - Loss flag;
o D - Delay flag.
4. Theory of Operation
The marking method can be successfully used in the multicast
environment supported by BIER layer. Without limiting any generality
consider multicast network presented in Figure 2. Any combination of
markings, Loss and/or Delay, can be applied to a multicast flow by
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any Bit Forwarding Router (BFR) at either ingress or egress point to
perform node, link, segment or end-to-end measurement to detect
performance degradation defect and localize it efficiently.
-----
--| D |
----- / -----
--| B |--
/ ----- \ -----
/ --| E |
----- / -----
| A |--- -----
----- \ --| F |
\ ----- / -----
--| C |--
----- \ -----
--| G |
-----
Figure 2: Multicast network
Using the marking method, a BFR creates distinct sub-flows in the
particular multicast traffic over BIER layer. Each sub-flow consists
of consecutive blocks, consisting of identically marked packets, that
are unambiguously recognizable by a monitoring point at any BFR and
can be measured to calculate packet loss and/or packet delay metrics.
It is expected that the marking values be set and cleared at the edge
of BIER domain. Thus for the scenario presented in Figure 2 if the
operator initially monitors 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
As explained in the [RFC8321], marking can be applied to delineate
blocks of packets based either on the equal number of packets in a
block or based on equal time interval. The latter method offers
better control as it allows better account for capabilities of
downstream nodes to report statistics related to batches of packets
and, at the same time, time resolution that affects defect detection
interval.
If the Single Mark measurement used to measure packet loss, then the
D flag MUST be set to zero on transmit and ignored by monitoring
point.
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The L flag is used to create alternate flows to measure the packet
loss by switching the value of the L flag every N-th packet or at
certain time intervals. Delay metrics MAY be calculated with the
alternate flow using any of the following methods:
o First/Last Packet Delay calculation: whenever the marking, i.e.
value of L flag changes, a BFR can store the timestamp of the
first/last packet of the block. The timestamp can be compared
with the timestamp of the packet that arrived in the same order
through a monitoring point at downstream BFR to compute packet
delay. Because timestamps collected based on order of arrival
this method is sensitive to packet loss and re-ordering of packets
o Average Packet Delay calculation: an average delay is calculated
by considering the average arrival time of the packets within a
single block. A BFR may collect timestamps for each packet
received within a single block. Average of the timestamp is the
sum of all the timestamps divided by the total number of packets
received. Then the difference between averages calculated at two
monitoring points is the average packet delay on that segment.
This method is robust to out of order packets and also to packet
loss (only a small error is introduced). This method only
provides a single metric for the duration of the block and it
doesn't give the minimum and maximum delay values. This
limitation could be overcome by reducing the duration of the block
by means of a highly optimized implementation of the method.
4.2. Double Mark Enabled Measurement
Double Mark method allows measurement of minimum and maximum 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
used to create the alternate flow, i.e. mark larger batches of
packets. The D flag MUST be used to mark single packets to measure
delay jitter.
The first marking (L flag alternation) is needed for packet loss and
also for average delay measurement. The second marking (D flag is
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
timestamps of these packets; these timestamps can be compared with
the timestamps of the same packets on a second BFR to compute packet
delay values for each packet. The number of measurements can be
easily increased by changing the frequency of the second marking.
But the frequency of the second marking must be not too high in order
to avoid out of order issues. This method is useful to measure not
only the average delay but also the minimum and maximum delay values
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and, in wider terms, to know more about the statistic distribution of
delay values.
5. IANA Considerations
This document requests IANA to register format of the OAM field of
BIER Header as the following:
+--------------+---------+--------------------------+---------------+
| Bit Position | Marking | Description | Reference |
+--------------+---------+--------------------------+---------------+
| 0 | S | Single Mark Measurement | This document |
| 1 | D | Double Mark Measurement | This document |
+--------------+---------+--------------------------+---------------+
Table 1: OAM field of BIER Header
6. Security Considerations
This document list the OAM requirement for BIER-enabled domain and
does not raise any security concerns or issues in addition to ones
common to networking.
7. Acknowledgement
TBD
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
for Bit Index Explicit Replication (BIER) in MPLS and Non-
MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
2018, <https://www.rfc-editor.org/info/rfc8296>.
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8.2. Informative References
[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>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017,
<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
Greg Mirsky
ZTE Corp.
Email: gregimirsky@gmail.com
Lianshu Zheng
Huawei Technologies
Email: vero.zheng@huawei.com
Mach Chen
Huawei Technologies
Email: mach.chen@huawei.com
Giuseppe Fioccola
Telecom Italia
Email: giuseppe.fioccola@telecomitalia.it
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