Internet DRAFT - draft-yz-nmrg-dtn-flow-simulation
draft-yz-nmrg-dtn-flow-simulation
Internet Research Task Force H. Yang
Internet-Draft C. Zhou
Intended status: Informational China Mobile
Expires: 24 April 2023 21 October 2022
Digital Twin Network Flow Simulation
draft-yz-nmrg-dtn-flow-simulation-01
Abstract
Some important application scenarios of digital twin network, such as
network new technology experiment, network configuration
verification, network performance optimization, etc., all require the
virtual traffic in the twin network to accurately simulate the real
traffic in the physical network.The real traffic in the physical
network is called the physical traffic, and the virtual traffic in
the twin network is called the twin traffic. In order to realize the
high-fidelity simulation of the physical traffic by the twin traffic,
this paper proposes that the twin traffic and the physical traffic
should satisfy three consistent characteristics, and an
implementation method of twin flow is introduced.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 4
3. Key characteristics of DTN flow . . . . . . . . . . . . . . . 4
4. DTN flow implementation method . . . . . . . . . . . . . . . 4
5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. Normative References . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Digital twin network is a virtual representation of the physical
network. Such virtual representation of the network is meant to be
used to analyze, diagnose, emulate, and then control the physical
network based on data, models, and interfaces. The DTN architecture
diagram is shown in Figure 1.
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+---------------------------------------------------------+
| +-------+ +-------+ +-------+ |
| | App 1 | | App 2 | ... | App n | Application|
| +-------+ +-------+ +-------+ |
+-------------^-------------------+-----------------------+
|Capability Exposure| Intent Input
| |
+-------------+-------------------v-----------------------+
| Instance of Digital Twin Network |
| +--------+ +------------------------+ +--------+ |
| | | | Service Mapping Models | | | |
| | | | +------------------+ | | | |
| | Data +---> |Functional Models | +---> Digital| |
| | Repo- | | +-----+-----^------+ | | Twin | |
| | sitory | | | | | | Network| |
| | | | +-----v-----+------+ | | Mgmt | |
| | <---+ | Basic Models | <---+ | |
| | | | +------------------+ | | | |
| +--------+ +------------------------+ +--------+ |
+--------^----------------------------+-------------------+
| |
| data collection | control
+--------+----------------------------v-------------------+
| Physical Network |
| |
+---------------------------------------------------------+
Figure 1: Figure1:Reference Architecture of Digital Twin Network
The digital twin layer forms a network element model by modeling
physical network elements, and the network element model forms a twin
network element through instantiation, that is, each physical network
element in the physical network has a corresponding twin network
element in the digital twin layer. Similarly, each physical flow of
the physical network also has a corresponding twin flow at the
digital twin layer.
Through the real-time data interaction between the physical network
and the twin network, the physical network elements, network
topology, network traffic, network status and other data in the
physical network are virtualized at the twin network layer. The
topology of the physical network and the twin network are consistent,
The number of NEs is the same, and the traffic information is the
same.
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2. Conventions Used in This Document
2.1. Terminology
DTN Digital Twin Network
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. Key characteristics of DTN flow
The twin network layer needs to accurately simulate the traffic of
the physical network to support the normal operation of the network
application layer.The twin traffic of the twin network layer and the
physical traffic of the physical network need to satisfy the
following three characteristics at the same time.
1) The two traffic forwarding paths are consistent, that is, the twin
nodes that twin traffic passes through at the twin network layer are
consistent with the physical nodes that physical traffic passes
through at the physical network layer;
2) The network performance of the two types of traffic is consistent,
that is, the twin traffic and the physical traffic have the same
performance as network delay, packet loss, and jitter;
3) The two traffic data characteristics are consistent, that is, the
data packets of twin traffic and physical traffic have the same key
characteristics such as traffic rate, quintuple information, data
packet length, and data packet priority;
4. DTN flow implementation method
If the twin flow and physical flow are to meet the above three
characteristics, three problems need to be solved:
1) The physical network element and the twin network element have
unique identifiers in the entire network, so as to realize the mutual
correspondence between the two. The physical traffic passes through
those physical network elements, and the twin traffic also passes
through the corresponding twin network element, so as to achieve the
same forwarding path;
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2) The physical flow is uniformly collected and managed by the Data
Repository of the twin network layer, and then distributed to each
twin network element. Because the time for each physical network
element to complete data collection and data transmission is
inconsistent, in order to ensure that the twin flow and physical flow
have the same performance as forwarding delay, packet loss, and
jitter, the twin flow must be delayed by a fixed time. That is, the
twin flow delays the physical flow by a fixed time.
3) The flow data collected by the Data Repository should include the
key information of physical flow, so that the twin flow and physical
flow data characteristics are consistent; when the Data Repository
collects physical flow, it can be collected in full package by
package or partially collected at a certain sampling rate;
+--------------------------------------------------------------+
| Digital Twin Network +----------+ |
| +---------+ Twin NE 3+----------+ |
| | +----------+ | |
| | | |
| -----------+ +-----+----+ +----------+ +-----+----+ |
| | Twin NE 1+----+ Twin NE 2+----+ Twin NE 4+----+ Twin NE n| |
| -----------+ +----------+ +----------+ +----------+ |
| +-----------------+ |
| | Data Repository | |
| +-----------------+ |
+--------------------------------------------------------------+
|
+-------------------------------+------------------------------+
| Delay Deterministic Networking |
+-------------------------------^------------------------------+
|
+---------------------------------+---------------------------------+
| Phsical Network +------------+ |
| +----------+Physical NE3+----------+ |
| | +------------+ | |
| | | |
| +------------+ +-----+------+ +------------+ +------+-----+ |
| |Physical NE1+---+Physical NE2+---+Physical NE4+---+Physical NEn| |
| +------------+ +------------+ +------------+ +------------+ |
+-------------------------------------------------------------------+
Figure 2: Figure 2: Twin Flow and Physical Flow
For the above three problems, use the following three methods to
solve:
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1) Each physical network element has a system MAC address, because
the MAC address is unique in the whole network and can be used as the
identifier of the physical network element. The twin NE ID can be
extended based on the physical NE ID. For example, an 8-bit custom
field is added after the MAC address of the physical NE system, for
example, to identify the device type. The twin NE is identified
based on the MAC address of the physical NE, which not only realizes
the one-to-one correspondence between the physical NE and the twin
NE, but also realizes the unique identification of the twin NE in the
entire network.
2) The data transmission network between the physical network element
and the Data Repository uses a delay deterministic network, such as
TSN (Time Sensitive Network), DIP (Deterministic Internet Network),
etc. Since the delays of different physical network elements to
transmit data to the Data Repository may be different, if a delay
deterministic network is used, the data transmission delays T1~Tn are
fixed and can be pre-calculated. After the Data Repository
calculates T1~Tn, the maximum value Tmax is selected as the reference
time. Assume that the data collected from each physical network
element arrives at the Data Repository from t1 to tn. If the data
transmission time Tn<Tmax, the Data Repository waits for (Tmax-Tn)
time before transmitting the data to the twin network elements. If
Tn =Tmax, then Tmax-Tn=0, the Data Repository immediately transmits
the data to the twin network elements. Because the Data Repository
and twin network elements are deployed in the same local area network
or the same physical entity (such as a server), the transmission
delay between the Data Repository and each twin network element can
be ignored. So far, all twin flow is delayed by a fixed time Tmax
compared to physical flow, but the forwarding delay, jitter, packet
loss and other performances of the two are the same.
3) The data collected by the Data Repository needs to contain key
information of physical flow, such as physical network element MAC
address, traffic sampling rate, source MAC, destination MAC, protocol
type, source IP address, destination IP address, protocol number,
source port number , destination port number, packet priority, packet
length, packet forwarding delay, etc. The first two parameters are
mandatory, and the latter fields are optional according to
application requirements.
The implementation steps of twin flow are as follows, as shown in
Figure 3:
(1) To build a digital twin network, the physical network elements
and the twin network elements are in one-to-one correspondence
through the unique identifiers of the entire network, and the number
of network elements and the topology are consistent;
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(2) The physical network element forms a data set of key flow
information, such as {network element identification, sampling rate,
source MAC, destination MAC, protocol type, source IP address,
destination IP address};
(3) The Data Repository collects the data sets of each physical
network element, and calculates the maximum delay Tmax of data
transmission;
(4) After the Data Repository collects the data set, it is sent to
the corresponding twin network element according to the physical
network element identifier
(5) Twin network elements generate twin flow according to the
sampling rate and flow information of the dataset. Because the data
transmission delay between the physical network element and the Data
Repository is fixed at Tmax, all the flow of the twin network is
delayed by Tmax relative to the physical flow. . Because the Data
Repository and the twin network elements are in the same server or
local area network, the transmission delay is negligible.
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+---------+ +-------+ +-----------+ +------+
| Physical| |Detnet | | Data | | Twin |
| NE | | | | Repository| | NE |
+-----+---+ +---+---+ +-----+-----+ +---+--+
| | | |
| | | |
|1.According to the characteristics of
|physical NEs, build twin NEs |
+----------+------------+------------>
| | | |
| | | |
+-------------------------+ | | |
| 2. Physical NEs|collect | | | |
| key flow information | | | |
| and form a data|set | | | |
+-------------------------+ | | |
| | | |
| | | |
3.The|dataset is|sent to the Data Repository
+---------------------->| |
| | 4.The Data Repository sendsto
| | the corresponding twin NE
| | according to the NE identifier
| | of the data|set |
| | +----------->+
| | | |
| | | +----------+---------------+
| | | | 5.The twin NEs generate |
| | | | twin flow|according to |
| | | | the data set information |
| | | +----------+---------------+
| | | |
Figure 3: Figure 3: The generation process of twin traffic
5. Conclusion
This paper realizes high-precision simulation of DTN twin flow, so
that twin flow and physical flow meet the following three
characteristics:
1) The forwarding paths of the two types of flow are the same, that
is, the nodes they pass through are the same;
2) The network performance of the two types of flow is the same, that
is, the two have the same performance as network delay, packet loss,
and jitter;
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3) The data characteristics of the two types of flow are consistent,
that is, they have the same key characteristics such as flow rate,
five-tuple information, data packet length, and data packet priority.
6. Security Considerations
TBD.
7. IANA Considerations
TBD.
8. 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>.
Authors' Addresses
Hongwei Yang
China Mobile
Beijing
100053
China
Email: yanghongwei@chinamobile.com
Cheng Zhou
China Mobile
Beijing
100053
China
Email: zhouchengyjy@chinamobile.com
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