Internet DRAFT - draft-dang-ippm-multiple-path-measurement
draft-dang-ippm-multiple-path-measurement
Network Working Group D. Dang, Ed.
Internet-Draft Huawei
Intended status: Informational W. Wang
Expires: February 14, 2021 China Telecom
L. LEE
LG U+
C. Cheng
Huawei
August 13, 2020
Multi-Path Concurrent Measurement for IPPM
draft-dang-ippm-multiple-path-measurement-05
Abstract
This test method can test multi-paths concurrently from one edge node
to another edge node. This document details Multi-Path Concurrent
Measurement (MPCM).
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 https://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 February 14, 2021.
Copyright Notice
Copyright (c) 2020 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
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
Dang, et al. Expires February 14, 2021 [Page 1]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Terminology & Abbreviations . . . . . . . . . . . . . . . 3
2. Overview of MPCM . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Principle . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1. Single Path Measurement . . . . . . . . . . . . . . . 4
2.1.2. Multiple Path Measurement . . . . . . . . . . . . . . 6
3. MPCM-Test Packet Format and Content . . . . . . . . . . . . . 7
4. Expansion based on various measurement methods . . . . . . . 10
4.1. IOAM . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5. Data Export . . . . . . . . . . . . . . . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
9. Normative References . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
As we know, the current network has been already being in load
balancing mode, however it is partially congested. In other words,
from the same source node to the same destination node, some paths
have been congested to cause a decline in service quality, but some
paths carry less traffic and are lightly loaded. To solve the
problem of unbalanced network load[draft-liu-ican], the first is to
have the ability to detect the quality of the load sharing paths.
And then the traffic from the Scr node to the Dst node is required to
be steered from the congested paths into the lightly loaded path/
paths basing on the SLA's requirement. So it's necessary to measure
the multi-paths in load-balancing mode.
In the traditional method, the paths are measured separately because
they aren't maintained by the path group. If the multiple load
sharing paths are required to be selected based on the SLA
information, the measured SLA information needs to be comparable. If
you want to ensure that the data obtained by the test is available
and accurate, the multi-paths are required to maintain by the path
group in order that the test start and end points must be same.
For example, the low latency services require millisecond delays. If
the start time and the end time aren't same, the measured data may
Dang, et al. Expires February 14, 2021 [Page 2]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
not be in one test cycle, and the accuracy of this data is relatively
low and the data cannot be comparedFigure 1.
Path1
+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+
Path2
+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+
Path3
+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+
-----------------------------------------------------------------------
0 t
Figure 1: Measured Data in the Different Cycles
The Multi-Path Concurrent Measurement (MPCM) is required, which can
be used bi-directionally to concurrently measure multi-paths metrics
between two network elements. At the same time, this method also
consider saving the number of test messages to reduces the load on
the network.
1.1. 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.
1.2. Terminology & Abbreviations
o Muti-paths
* There are multiple paths between two nodes in the network.
These paths may be equal-cost multi-path (ECMP) mode or
unequal-cost multiple (UCMP) mode. In a real network, they
might be one [draft-ietf-spring-segment-routing-policy] or
[RFC7348] tunnel group.
o Concurrent
Dang, et al. Expires February 14, 2021 [Page 3]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
* In order to ensure comparability between multiple paths, the
test start point and the test end point are required to be
same.
2. Overview of MPCM
The Multi-Path Concurrent Measurement (MPCM) is the way of
measurement of multi-paths metrics.
MPCM can be embedded into a variety of transports such as NSH,
Segment Routing, VxLAN, native IPv6 (via extension header), or IPv4.
2.1. Principle
To complete the target scenario, we need to optimize the single-path
measurement mechanism, and then further diffuse the single-path
measurement mechanism to multiple-path.
1. For a single tunnel, the Dst needs to know when to start timing
in order to delimit. The Dst needs to solve various problems such as
congestion and discarding of measurement packets. Therefore, the Dst
needs to initiate a periodic response.
2. For multiple paths, the Dst needs to respond one measurement
message with multiple path information in its specific time, solving
the problems such as inconsistent initiation of any path,
inconsistent measurement periods, clock drift, and different delays.
2.1.1. Single Path Measurement
|-----ti-----|-----ti-----|-----ti-----|
t0 t1 t2
Src -----------------------------------------
| \ \
| \ \
| \ \
| \ \
Dst -----------------------------------------
t0' t1' t2'
Figure 2: Single path measurement
A path between Scr node and Dst node in the network to obtain
measurement results at equal intervals is as follows:
1) Set the measurement interval ti.
Dang, et al. Expires February 14, 2021 [Page 4]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
a) Before the test starts, the Scr sends a protocol packet to the Dst
and sets the test interval ti.
b) After receiving the protocol message, the Dst sets the test
interval ti for the Scr and Dst, and replies to the Scr to confirm
that the setting is successful. The congestion at the Dst will be
counted at intervals ti.
c) After receiving the interval setting successfully, the Scr starts
to start measurement.
2) The Scr sends the first delimited message, which includes the
sending timestamp t0, and starts to count the data packets sent.
3) After receiving the first delimited message, the Dst end stamps
the time stamp t0 'and starts to count the received data messages.
4) The Scr sends the second delimited message at time t1, where t1 =
t0 + ti, the message includes the sending timestamp t1, and counts
the number of data packets sent. The first delimited message uses
high priority, and the second delimited message uses normal priority.
Because the second delimitation message has a low priority and a
large queuing delay, the interval between the first delimitation
message and the second delimitation message shall become larger at
the Dest.
5) At the time t0 '+ ti, the Dst counts the number of packets
received between t0' and t0 '+ ti, and sends the message back to the
Src with the number of packets, the sending time t0 and the receiving
time t0'. If the delimitation message has not been received at t0' +
2 * ti time, the Dst repeats the previous actions, and so on.
6) When the second delimited message arrives at the Dst, the Dst
counts the number of packets received between t0 'and t1' at t1
'time, and sends the message back to the Src with the number of
packets, the packet sending time t0 and the packet receiving time t0
'.
7) After t1 ', the sending time in the message from the Dst is
updated to t1, and the receiving time in the message from the Dst is
updated to t1'. The number of packets is still the number of packets
received within ti time.
8) Assuming that t1' is between t0' + (x-1) * ti and t0' + x * ti,
then the congestion in the interval ti is calculated in two parts.
The first part is from t0 '+ (x-1) * ti to t1', The statistics
packets sent at t1' must include the packet statistics and time t0';
Dang, et al. Expires February 14, 2021 [Page 5]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
the second part is from t1 'to t0' + x * ti, t0 '+ x * ti need to
include the packet statistics and t1'.
9) Repeat the above steps.
2.1.2. Multiple Path Measurement
| <-----------> | <------------>| <------------> |
| Ti | Ti | Ti |
Path1 | m1 m2 | m3 | m4 m5 | m6
---------------------------------------------------------------
| | | |
Path2 | m1 | m2 m3 m4 | m5
--------------------------------------+------------------------
| | | |
Path3 | m1 m2 m3 m4 | m5 | m6
--------+---------------+----------------+----------------+----
Figure 3: Multiple path measurement
There are multiple paths in the tunnel between Src node and Dst nodes
in the network. This method is mainly implemented at the Dst.
1) Set the measurement interval ti.
a) Before the test starts, the Src sends a protocol packet to the
Dst, setting the number of paths and the measurement interval ti.
The measurement result of each path is a message with measurement
data.
b) After receiving the protocol message, the Dst sets the number of
paths and measurement interval ti, and replies to the source to
confirm the successful setting.
c) After receiving the message with the number of paths and
measurement interval, the Src starts to start measurement.
2) On each path, the Src continuously sends measurement packets, and
the Dst continuously calculates the measurement results at intervals
ti.
3) The Dst collects the measurement results of each path at intervals
ti after the earliest measurement result of multiple paths is came
out.
4) The results of multiple paths in the same interval time ti are
counted as a group. If there is no measured results on the specific
path in the interval ti, the relevant information is set 0 in the
Dang, et al. Expires February 14, 2021 [Page 6]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
group results. A set of measurement results packaged of multiple
paths are taken back to the Src.
5) The measurement results of multiple paths on the Dst are
continuously packaged at intervals ti and sent back to the Src. The
packaged message carries the sequence number within the message to
prevent out of order.
3. MPCM-Test Packet Format and Content
This section defines path header and associated data types required
for MPCM.
Firstly one path packet formatFigure 4 of multi-path can be defined.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path ID | Path-E2E-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Transaction ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: MPCM Path header
o Session ID: A set of load sharing paths
o Path ID: One path of the session.
o Path-E2E-Type: A 16-bit identifier which Indicates whether the
packet type is a send message or a request message.
o Flags: 8-bit field. Identify the query or response type.
Following flags are defined:
* Bit 0 Identify the query type
* Bit 1 Identify the response type
* Reserved
o Transaction ID: 16-bit identifier of one measurement transaction.
The sender and receiver to identify measurement transactions based
on Transaction ID.
Dang, et al. Expires February 14, 2021 [Page 7]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
When a measurement is for a set of paths, each query message is made
for each path, but only one unified response message repliesFigure 5.
Sender Receiver
| |
| Query message of Path1 |
| -------------------------------------->|
| Query message of Path2 |
|--------------------------------------->|
| ... |
| ... |
| Query message of PathN |
|--------------------------------------->|
| |
| |
| |
| |
| |
| Response message of All multi-paths |
|<---------------------------------------|
| |
| |
Figure 5: Query and Response message
The measurement response packet format of a path is as
followsFigure 6.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| E2E PathN Option Header |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| PathN Edge-to-Edge Option Data |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Query message
The field of PathN Edge-to-Edge Option Data can refer to Edge-to-Edge
Option Data of [draft-ietf-ippm-ioam-data-04].
It suppose there are N paths between two points.The measurement
response packet format of multi-paths is as followsFigure 6.
Dang, et al. Expires February 14, 2021 [Page 8]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| E2E Path1 Option Header |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Path1 Edge-to-Edge Option Data |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
~ ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
| |
| E2E PathN-1 Option Header |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| PathN-1 Edge-to-Edge Option Data |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| E2E PathN Option Header |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| PathN Edge-to-Edge Option Data |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Response message
o Long-term measurement
* The receiver can wait until it receives all measurement
requests of a set of path and then responds.
o Short-term measurement
* The Sender can query once t.
* The receiver can reply once t.
The overall solution needs to consider two methods of long-period
measurement and short-period measurement.
Dang, et al. Expires February 14, 2021 [Page 9]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
4. Expansion based on various measurement methods
The measurement message format defined by this document can be
extended based on various measurement methods.
4.1. IOAM
A new type may be added in IOAM-E2E-Type of IOAM Edge-to-Edge Option
header[draft-ietf-ippm-ioam-data-04-section4.4] as follow.
o Bit 4: Multiple paths measurement.
This bit is set by the headend node if Multi-Path Concurrent
Measurement is activated.
A common registry is maintained for IOAM-Types, see Section 6.
For path-based quality measurements, there is no need to measure each
message because the large-scale deployment consumes too much network
resources. Here, the way of periodic measurement is recommended.In a
period, if there is a packet, the appropriate packet is selected to
be inserted into the iOAM packet; if there is no packet, a
measurement packet is directly generated[draft-dang-ippm-congestion].
5. Data Export
MPCM nodes collect information for packets traversing a domain that
supports MPCM. MPCM process the information further and export the
information using e.g., IPFIX. Raw data export of IOAM data using
IPFIX is discussed in [draft-spiegel-ippm-ioam-rawexport-00].
6. IANA Considerations
This document requests the following IANA Actions.
IOAM E2E Type Registry:
Bit 4 Multiple ways measurement
7. Security Considerations
The Proof of Transit option (Section Section 4.3 In-situ OAM
[draft-ietf-ippm-ioam-data-04-section4.4]) is used for verifying the
path of data packets.
Dang, et al. Expires February 14, 2021 [Page 10]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
8. Acknowledgements
TBD
9. Normative References
[draft-dang-ippm-congestion]
"A One-Path Congestion Metric for IPPM",
<https://tools.ietf.org/html/draft-dang-ippm-congestion-
02>.
[draft-ietf-ippm-ioam-data-04]
"A Variety of Transports",
<https://datatracker.ietf.org/doc/draft-ietf-ippm-ioam-
data/>.
[draft-ietf-ippm-ioam-data-04-section4.4]
"IOAM Edge-to-Edge Option",
<https://datatracker.ietf.org/doc/draft-ietf-ippm-ioam-
data/>.
[draft-ietf-spring-segment-routing-policy]
"Segment Routing Policy Architecture",
<https://tools.ietf.org/html/draft-ietf-spring-segment-
routing-policy-02>.
[draft-liu-ican]
"Instant Congestion Assessment Network (iCAN) for Traffic
Engineering", <https://tools.ietf.org/html/draft-dang-
ippm-congestion-02>.
[draft-spiegel-ippm-ioam-rawexport-00]
"In-situ OAM raw data export with IPFIX",
<https://tools.ietf.org/html/draft-spiegel-ippm-ioam-
rawexport-00>.
[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>.
[RFC7348] "Virtual eXtensible Local Area Network (VXLAN)",
<https://datatracker.ietf.org/doc/rfc7348/>.
Dang, et al. Expires February 14, 2021 [Page 11]
Internet-Draft Multi-Path Concurrent Measurement for IPPM August 2020
Authors' Addresses
Joanna Dang (editor)
Huawei
Beijing
China
Email: dangjuanna@huawei.com
Jianglong
China Telecom
Beijing
China
Email: wangjl50@chinatelecom.cn
Shinyoung
LG U+
Seoul
Korea
Email: leesy@lguplus.co.kr
Liang
Huawei
Beijing
China
Email: liang.cheng@huawei.com
Dang, et al. Expires February 14, 2021 [Page 12]
