Internet DRAFT - draft-du-ippm-self-contained-alt-mark
draft-du-ippm-self-contained-alt-mark
Network Working Group Z. Du
Internet-Draft P. Liu
Intended status: Experimental China Mobile
Expires: April 27, 2022 October 24, 2021
Self-Contained Alternate-Marking Mechanism for Performance Monitoring in
High-Quality Network
draft-du-ippm-self-contained-alt-mark-00
Abstract
This document introduces a self-contained method that can involve the
client in based on some extensions to the alternate-marking
(coloring) technique.
Requirements Language
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].
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 April 27, 2022.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Traditional Mechanism Description . . . . . . . . . . . . . . 3
3. Proposed Mechanism Description . . . . . . . . . . . . . . . 4
4. Analysis of the Potential Problems . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The network operators are planning to provide network services with
higher quality than the traditional BE (Best Effort) service, such as
the DetNet service [RFC8655] and the Network Slicing service. In
these practices, it is important to monitor the performance of the
service, such as the packet loss, delay, and jitter of the flow with
guaranteed quality.
In [RFC8321], an alternate-marking method for passive and hybrid
performance monitoring is proposed. It marks the packet by using one
or more bits in the packet headers, and collects the number of
packets in a block sent on one end and the number of packets in the
same block received on the other end. Finally, the two values are
compared and accordingly, the packet loss of the flow are computed.
The alternate-marking method is potential applied to any kind of
packet-based traffic, and easy to implement. However, a controller
or NMS needs to collect the information from the coloring point and
the monitoring point, and correlate the two pieces of information by
using the same block ID. It is hard to make it an end-to-end
solution because the client is not in the scope.
In this document, we propose a method that can involve the client in
based on some extensions to the alternate-marking (coloring)
technique. In this method, the block information is serialized and
encoded in the packets of the block by the client. Then, the
monitoring points can recover the information from the received
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packets, such as the block ID, number of packets in the block,
timestamps in the packet, and compute the target measurement values.
2. Traditional Mechanism Description
As described in [RFC8321], the alternate-marking method is based on
the "block", which represents a measurable entity unambiguously
recognizable by all network devices along the path.
In the alternate-marking (coloring) technique, the coloring point
creates packet blocks, colors the packets in the block, and reports
information including block ID to the controller or the NMS. The
monitoring points recognize the coloring information, record some
needed information and report it to the controller or the NMS.
___________________________
| Controller or |
| NMS |
---------------------------
/ \ \ \
/ \ \ \
/ Information including Block ID \
/ \ \ \
/ \ \ \
__________ ____________ ____________ ____________
| Coloring | | Monitoring | | Monitoring | | |
| point | | point1 | | point2 | | ... |
---------- ------------ ------------ ------------
Coloring Information:
000000111111 000000111111 000000111110 ...
Traffic Flow
====================================================================>
Figure 1: Mechanism in the traditional alternate-marking method
For example, if some packets are lost in the network, the packet
numbers of the same block will be different between the coloring
point and the monitoring point. If we need to compute the delay or
jitter of the flow, the coloring point and the monitoring point can
also report the timestamps of the packets in the block to the
controller or NMS.
Traffic coloring can be implemented by setting a specific bit in the
packet header and changing the value of that bit periodically. Thus,
we only need two colors, and the packets belonging to the same block
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have the same color, whilst consecutive blocks will have different
colors.
When the color changes, the previous block terminates and the new one
begins. Two mechanisms of switching color are introduced in
[RFC8321]. The first one is to switch the color after a fixed number
of packets. The second one is to switch according to a fixed timer.
For example, the timer may be 5 minutes.
3. Proposed Mechanism Description
To make the block information self-contained in the block, we need to
occupy another specific bit to encode the block information. Thus,
the client in the proposed mechanism needs not to report anything to
the controller or NMS, and the monitoring points can compute target
measurement values themselves and report any problem if needed.
For example, we assume the fixed timer mechanism is used, and there
are about 300 packets in a block. In the client, each packet carries
one bit of the block information. Thus, if all the packets are
received orderly, a monitoring point can recover the block
information encoded in those 300 packets.
___________________________
| Controller or |
| NMS |
---------------------------
\ \ \
\ \ \
\ Target Measurement Values\
\ \ \
\ \ \
__________ ____________ ____________ ____________
| Coloring | | Monitoring | | Monitoring | | |
| point | | point1 | | point2 | | ... |
---------- ------------ ------------ ------------
Coloring Information:
000000111111 000000111111 000000111110 ...
Block Information:
001101010100 001101010100 001101010100 ...
Traffic Flow
====================================================================>
Figure 2: Mechanism in the self-contained alternate-marking method
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The block information can include the block ID (32 bits), CRC
(32bits), and some TLVs as described below.
o TLV 1 may be the interval of the block (32bits).
o TLV 2 may be the packet number of the last block (32bits).
o TLV 3 may be the timestamp of the first packet in the block
(32bits).
The encoding of the block information is done in the client, and the
monitoring points need to understand the meaning of the encoding.
4. Analysis of the Potential Problems
As described in the last section, we assume that all the packets in a
block are received in the monitoring point orderly. Normally, it is
hard for the IP network with a relatively high packet loss rate.
However, the situation may be much better in the DetNet service or
the Network Slicing service, for which no or few packets would be
lost. Meanwhile, an additional recovery block may also appear after
several blocks, in which we will encode recovery information for the
past several blocks, instead of the block information. Other fault
tolerance mechanisms can also be considered.
Another problem is similar to the situation in [RFC8321]. It is
whether we can find at least two reserved bits in the packet header
to encode the coloring information and the block information. The
detailed analysis can be found in that document.
5. IANA Considerations
TBD.
6. Security Considerations
TBD.
7. Acknowledgements
TBD.
8. References
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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>.
[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
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>.
Authors' Addresses
Zongpeng Du
China Mobile
No.32 XuanWuMen West Street
Beijing 100053
China
Email: duzongpeng@foxmail.com
Peng Liu
China Mobile
No.32 XuanWuMen West Street
Beijing 100053
China
Email: liupengyjy@chinamobile.com
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