Internet DRAFT - draft-mirsky-bier-pmmm-oam
draft-mirsky-bier-pmmm-oam
BIER Working Group G. Mirsky
Internet-Draft Ericsson
Intended status: Standards Track L. Zheng
Expires: September 17, 2016 M. Chen
Huawei Technologies
G. Fioccola
Telecom Italia
March 16, 2016
Performance Measurement (PM) with Marking Method in Bit Index Explicit
Replication (BIER) Layer
draft-mirsky-bier-pmmm-oam-01
Abstract
This document describes a passive 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.
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 17, 2016.
Copyright Notice
Copyright (c) 2016 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
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
Mirsky, et al. Expires September 17, 2016 [Page 1]
Internet-Draft PM with Marking Method in BIER March 2016
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 . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
[I-D.ietf-bier-architecture] introduces and explains Bit Index
Explicit Replication (BIER) architecture and how it supports
forwarding of multicast data packets.
[I-D.ietf-bier-mpls-encapsulation] specified that in case of BIER
encapsulation in MPLS network a BIER-MPLS label, label that is at the
bottom of the label stack, uniquely identifies the multicast flow.
[I-D.tempia-ippm-p3m] describes passive performance measurement
method , 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 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
Mirsky, et al. Expires September 17, 2016 [Page 2]
Internet-Draft PM with Marking Method in BIER March 2016
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
[RFC2119].
3. OAM Field in BIER Header
[I-D.ietf-bier-mpls-encapsulation] defined two bit long field,
referred 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 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 true example of passive
performance measurement method.
The Figure 1 displays format of the OAM field
0
0 1
+-+-+-+-+
| S | D |
+-+-+-+-+
Figure 1: OAM field of BIER Header format
where:
o S- Single mark method;
o D - Double mark method.
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
any Bit Forwarding Router (BFR) at either ingress or egress point to
Mirsky, et al. Expires September 17, 2016 [Page 3]
Internet-Draft PM with Marking Method in BIER March 2016
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 that are unambiguously recognizable by a
monitoring point at any BFR and can be measured to calculate packet
loss and/or packet delay metrics.
4.1. Single Mark Enabled Measurement
As explained in the [I-D.tempia-ippm-p3m], marking can be applied to
delineate blocks of packets based either on 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, then the D flag MUST be set to
zero on transmit and ignored by monitoring point.
The S flag is used to create alternate flows to measure the packet
loss by switching value of the S 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 S flag, changes a BFR can store the timestamp of the
Mirsky, et al. Expires September 17, 2016 [Page 4]
Internet-Draft PM with Marking Method in BIER March 2016
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 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 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 an 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 S 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 (S 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 have not only
the average delay but also the minimum and maximum delay values 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:
Mirsky, et al. Expires September 17, 2016 [Page 5]
Internet-Draft PM with Marking Method in BIER March 2016
+--------------+---------+--------------------------+---------------+
| 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
[I-D.ietf-bier-architecture]
Wijnands, I., Rosen, E., Dolganow, A., P, T., and S.
Aldrin, "Multicast using Bit Index Explicit Replication",
draft-ietf-bier-architecture-03 (work in progress),
January 2016.
[I-D.ietf-bier-mpls-encapsulation]
Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J., and
S. Aldrin, "Encapsulation for Bit Index Explicit
Replication in MPLS Networks", draft-ietf-bier-mpls-
encapsulation-03 (work in progress), February 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
8.2. Informative References
[I-D.tempia-ippm-p3m]
Capello, A., Cociglio, M., Fioccola, G., Castaldelli, L.,
and A. Bonda, "A packet based method for passive
performance monitoring", draft-tempia-ippm-p3m-02 (work in
progress), October 2015.
Mirsky, et al. Expires September 17, 2016 [Page 6]
Internet-Draft PM with Marking Method in BIER March 2016
Authors' Addresses
Greg Mirsky
Ericsson
Email: gregory.mirsky@ericsson.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
Mirsky, et al. Expires September 17, 2016 [Page 7]
