Considerations of deploying AI services in a distributed approach
draft-hong-nmrg-ai-deploy-00
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| Authors | Yong-Geun Hong , Oh Seokbeom , SooJeong Lee , Hyun-Kook Kahng | ||
| Last updated | 2022-03-07 | ||
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draft-hong-nmrg-ai-deploy-00
Network Working Group Y-G. Hong
Internet-Draft Daejeon University
Intended status: Informational S-B. Oh
Expires: 7 September 2022 KSA
S-J. Lee
Korea University/KT
H-K. Kahng
Korea University
March 2022
Considerations of deploying AI services in a distributed approach
draft-hong-nmrg-ai-deploy-00
Abstract
As the development of AI technology matured and AI technology began
to be applied in various fields, AI technology is changed from
running only on very high-performance servers with small hardware,
including microcontrollers, low-performance CPUs and AI chipsets. In
this document, we consider how to configure the system in terms of AI
inference service to provide AI service in a distributed approach.
Also, we describe the points to be considered in the environment
where a client connects to a cloud server and an edge device and
requests an AI service.
Status of This Memo
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This Internet-Draft will expire on 2 September 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Procedure to provide AI services . . . . . . . . . . . . . . 5
3. Network configuration structure to provide AI services . . . 6
3.1. AI inference service on Local machine . . . . . . . . . . 6
3.2. AI inference service on Cloud server . . . . . . . . . . 7
3.3. AI inference service on Edge device . . . . . . . . . . . 8
3.4. AI inference service on Cloud server and Edge device . . 9
4. Considerations when configuring a system to provide AI
services . . . . . . . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
8. Informative References . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
In the Internet of Things (IoT), the amount of data generated from
IoT devices has exploded along with the number of IoT devices due to
industrial digitization and the development and dissemination of new
devices. Various methods are being tried to effectively process the
explosively increasing IoT devices and data of IoT devices. One of
them is to provide IoT services in a place located close to IoT
devices and users, away from cloud computing that transmits all data
generated from IoT devices to a cloud
server[I-D.irtf-t2trg-iot-edge].
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IoT services also started to break away from the traditional method
of analyzing IoT data collected so far in the cloud and delivering
the analyzed results back to IoT objects or devices. In other words,
AIoT (Artificial Intelligence of Things) technology, a combination of
IoT technology and artificial intelligence (AI) technology, started
to be discussed at international standardization organizations such
as ITU-T. AIoT technology, discussed by the ITU-T CG-AIoT group, is
defined as a technology that combines AI technology and IoT
infrastructure to achieve more efficient IoT operations, improve
human-machine interaction, and improve data management and
analysis[CG-AIoT].
The first work started by the IETF to apply IoT technology to the
Internet was to research a lightweight protocol stack instead of the
existing TCP/IP protocol stack so that various types of IoT devices,
not traditional Internet terminals, could access the Internet. It
was a technology that made it possible to connect to the
Internet[RFC6574][RFC7452]. These technologies have been developed
by 6LoWPAN working group, 6lo working group, 6tisch working group,
core working group, t2trg group, etc. As the development of AI
technology matured and AI technology began to be applied in various
fields, just as IoT technology was mounted on resource-constrained
devices and connected to the Internet, AI technology is also changed
from running only on very high-performance servers with the old GPU
installed. The technology is being developed to run on small
hardware, including microcontrollers, low-performance CPUs and AI
chipsets. This technology development direction is called On-device
AI or TinyML[tinyML].
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In this document, we consider how to configure the system in terms of
AI inference service to provide AI service in the IoT environment.
In the IoT environment, the technology of collecting sensing data
from various sensors and delivering it to the cloud has already been
studied by many standardization organizations including the IETF and
many standards have been developed. Now, after creating an AI model
to provide AI services based on the collected data, how to configure
this AI model as a system has become the main research goal. Until
now, it has been common to develop AI services that collect data and
perform inferences from the trained servers, but in terms of the
spread and spread of AI services, it is not appropriate to use
expensive servers to provide AI services. In addition, since the
server that collects and trains data mainly exists in the form of a
cloud server, there are also many problems in proceeding in the form
of requesting AI service by connecting a large number of terminals to
these cloud servers to provide AI services. Therefore, when an AI
service is requested to an edge device located at a close distance,
it may have effects such as real-time service support, network
traffic reduction, and important data security rather than requesting
an AI service to an AI server located in a distant
cloud.[I-D.irtf-t2trg-iot-edge]
Even if an edge device is used to serve AI services, it is still
important to connect to an AI server in the cloud for tasks that take
a lot of time or require a lot of data. Therefore, an offloading
technique for properly distributing the workload between the cloud
server and the edge device is also a field that is being actively
studied. In this contribution, in the following proposed network
structure, the points to be considered in the environment where a
client connects to a server and an edge device and requests an AI
service are derived and described. That is, the following
considerations and options could be derived.
* AI inference service execution entity
* Hardware specifications of the machine to perform AI inference
services
* Selection of AI models to perform AI inference services
* A method of providing AI services from cloud servers or edge
devices
* Communication method to transmit data to request AI inference
service
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2. Procedure to provide AI services
Since research on AI services has been started for a long time, there
may be shapes to provide various types of AI services. However, due
to the nature of AI technology, in general, a system for providing AI
services consists of the following
steps[AI_inference_archtecture][Google_cloud_iot].
+-----------+ +-----------+ +-----------+ +-----------+ +-----------+
| Collect & | | Analysis &| | Train | | Deploy & | | Monitor & |
| Store |->| Preprocess|->| AI model |->| Inference |->| Maintain |
| data | | data | | | | AI model | | Accuracy |
+-----------+ +-----------+ +-----------+ +-----------+ +-----------+
|<--------->| |<------------------------>| |<--------->| |<--------->|
Sensor, DB AI Server Target AI Server &
machine Target machine
|<---------------->|<--------------------->|<-------------->|<--------->|
Interent Local Internet Local &
Internet
Figure 1: AI service workflow
* Data collection & Store
* Data Analysis & Preprocess
* AI Model Training
* AI Model Deploy & Inference
* Monitor & Maintain Accuracy
In the data collection step, data required for training is prepared
by collecting data from sensors and IoT devices or by using data
stored in a database. Equipment involved in this step includes
sensors, IoT devices and servers that store them, and database
servers. Since the operations performed at this step are conducted
through the Internet, many IoT technologies studied by the IETF so
far have developed technologies suitable for this step.
In the data analysis and pre-processing step, the features of the
prepared data are analyzed and pre-processing for training is
performed. Equipment involved in this step includes a high-
performance server equipped with a GPU and a database server, and is
mainly performed in the local network.
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In the model training step, a training model is created by applying
an algorithm suitable for the characteristics of the data and the
problem to be solved. Equipment involved in this step includes a
high-performance server equipped with a GPU, and is mainly performed
on a local network.
In the model deploying and inference service provision step, the
problem to be solved (e.g., classification, regression problem) is
solved using AI technology. Equipment involved in this step may
include a target machine, a client, a cloud, etc. that provide AI
services, and since various equipment is involved in this stage, it
is conducted through the Internet. This document summarizes the
factors to be considered at this step.
In the accuracy monitoring step, if the performance deteriorates due
to new data, a new model is created through re-training, and the AI
service quality is maintained by using the newly created model. This
step is the same as described in the model training, model deploying,
and inference service provision steps described in the previous step
because re-training and model deploying are performed again.
3. Network configuration structure to provide AI services
In general, after training the AI model, the AI model can be built on
a local machine for AI model deploying and inference services to
provide AI services. Alternatively, we can place AI models on cloud
servers or edge devices and make AI service requests remotely. In
addition, for overall service performance, some AI service requests
to the cloud server and some AI service requests to edge devices can
be performed through appropriate load balancing.
3.1. AI inference service on Local machine
The following figure shows a case where a client module requesting AI
service on the same local machine requests AI service from an AI
server module on the same machine.
+---------------------------------------------------------------------+
| |
| +-----------------+ Request AI +-----------------+ |
| | Client module | Inference service | Server module | |
| | for AI service |----------------------->| for AI service | |
| | |<-----------------------| | |
| +-----------------+ Reply AI +-----------------+ |
| Inference result |
+---------------------------------------------------------------------+
Local machine
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Figure 2: AI inference service on Local machine
This method is often used when configuring a system focused on
training AI models to improve the inference accuracy and performance
of AI models without considering AI services or AI model deploying
and inference in particular. In this case, since the client module
that requests the AI inference service and the AI server module that
directly performs the AI inference service are on the same machine,
it is not necessary to consider the communication/network environment
or service provision method too much. Alternatively, this method can
be used when we want to simply decorate the AI inference service on
one machine without changing the AI service in the future, such as an
embedded machine or a customized machine.
In this case, a high level of hardware performance is not required to
train the AI model, but hardware performance sufficient to run the AI
inference service is required, so it is possible on a machine with a
certain amount of hardware performance.
3.2. AI inference service on Cloud server
The following figure shows the case where the client module that
requests AI service and the AI server module that directly performs
AI service run on different machines.
+--------------------------------------+
+------------------------+ | +---------------------------+ |
| +-----------------+ | | | +-----------------+ | |
| | Client module |<-+--------+-----+---->| Server module | | |
| | for AI service | | | | | for AI service | | |
| +-----------------+ | | | +-----------------+ | |
+------------------------+ | + --------------------------+ |
Client machine | Server machine |
+--------------------------------------+
Cloud(Internet)
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Figure 3: AI inference service on Cloud server
In this case, the client module requesting the AI inference service
runs on the client machine, and the AI server module that directly
performs the AI inference service runs on a separate server machine,
and this server machine is in the cloud network. In this case, the
performance of the client machine does not need to be high because
the client machine simply needs to request the AI inference service
and, if necessary, deliver only the data required for the AI service
request. For the AI server module that directly performs AI
inference service, we can set up our own AI server, or we can use
commercial clouds such as Amazon, Microsoft, and Google.
3.3. AI inference service on Edge device
The following figure shows the case where the client module that
requests AI service and the AI server module that directly performs
AI service are separated, and the AI server module is located in the
edge device.
+--------------------------------------+
+------------------------+ | +---------------------------+ |
| +-----------------+ | | | +-----------------+ | |
| | Client module |<-+--------+-----+---->| Server module | | |
| | for AI service | | | | | for AI service | | |
| +-----------------+ | | | +-----------------+ | |
+------------------------+ | + --------------------------+ |
Client machine | Edge device |
+--------------------------------------+
Edge network
Figure 4: AI inference service on Edge device
Even in this case, the client module that requests the AI inference
service runs on the client machine, the AI server module that
directly performs the AI inference service runs on the edge device,
and the edge device is in the edge network. Even in this case, the
client module that requests the AI inference service runs on the
client machine, the AI server module that directly performs the AI
inference service runs on the edge device, and the edge device is in
the edge network. The AI module that directly performs the AI
inference service on the edge device can directly configure the edge
device or use a commercial edge computing module.
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The difference from the above case where the AI server module is in
the cloud is that the edge device is usually close to the client,
whereas the performance is lower than that of the server in the
cloud, so there are advantages in data transfer time and inference
time, but in unit time Inference service performance is poor.
3.4. AI inference service on Cloud server and Edge device
The following figure shows the case where AI server modules that
directly perform AI services are distributed in the cloud and edge
devices.
+--------------------------------------+
+------------------------+ | +---------------------------+ |
| +-----------------+ | | | +-----------------+ | |
| | Client module |<-+---+----+-----+---->| Server module | | |
| | for AI service |<-+---+ | | | for AI service | | |
| +-----------------+ | | | | +-----------------+ | |
+------------------------+ | | + --------------------------+ |
Client machine | | Edge device |
| +--------------------------------------+
| Edge network
|
| +--------------------------------------+
| | +---------------------------+ |
| | | +-----------------+ | |
+----+-----+---->| Server module | | |
| | | for AI service | | |
| | +-----------------+ | |
| + --------------------------+ |
| Server machine |
+--------------------------------------+
Cloud(Internet)
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Figure 5: AI inference service on Cloud sever and Edge device
There is a difference between the AI server module performed in the
cloud and the AI server module performed on the edge device in terms
of AI inference service performance. Therefore, the client
requesting the AI inference service may request by distributing the
AI inference service request to the cloud and edge device
appropriately in order to perform the desired AI service. In other
words, in the case of an AI service with low inference accuracy but
short inference time, we can request an AI inference service to the
edge device.
4. Considerations when configuring a system to provide AI services
As described in the previous chapter, the AI server module that
directly performs AI inference services by utilizing AI models can be
performed on a local machine or a cloud server or an edge device. In
theory, if AI inference service is performed on a local machine, AI
service can be provided without communication delay time or packet
loss, but a certain amount of hardware performance is required to
perform AI service inference. So, in the future environment where AI
services become popular, such as when various AI services are
activated and AI services are disseminated, the cost of a machine
that performs AI services is important and this case would not that
many. If so, whether the AI inference service will be performed on
the cloud server or the discount price on the edge device can be a
determining factor in the system configuration.
When AI inference service request is made to a distant cloud server,
it may take a lot of time to transmit, but it has the advantage of
being able to perform many AI inference service requests in a short
time, and the accuracy of AI service inference increases.
Conversely, when an AI service request is made to a nearby edge
device, the transmission time is short, but many AI inference service
requests cannot be performed at once, and the accuracy of AI service
inference is lowered. Therefore, by analyzing the characteristics
and requirements of the AI service to be performed, it is necessary
to determine where to perform the AI inference service on a local
machine, a cloud server, or an edge device.
According to the characteristics of the AI service, the
characteristics of the data used for training and the problem to be
solved, the hardware characteristics of the machine performing the AI
service varies. In general, machines on cloud servers are viewed as
machines with higher performance than edge devices. However, the
performance of AI inference service varies depending on how the
hardware such as CPU, RAM, GPU, and network interface is configured
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for each cloud server and edge device. If we do not think about
cost, it is good to configure a system for performing AI services
with a machine with the best hardware performance, but in reality, we
should always consider the cost when configuring the system. So,
according to the characteristics and requirements of the AI service
to be performed, the performance of the local machine, cloud server,
and edge device must be determined.
Although not directly related to communication/network, the biggest
influence on AI inference services is the AI model to be used for AI
inference service. For example, in AI services such as image
classification, there are various types of AI models such as ResNet,
EfficientNet, VGG, and Inception. These AI models differ in AI
inference accuracy, but also in AI model file size and AI inference
time. AI models with the highest inference accuracy typically have
very large file sizes and take a lot of AI inference time. So, when
constructing an AI service system, it is not always good to choose an
AI model with the highest AI inference accuracy. Again, it is
important to select an AI model according to the characteristics and
requirements of the AI service to be performed.
Experimentally, it is recommended to use an AI model with high AI
inference accuracy in the cloud server, and use an AI model that can
provide fast AI inference service although the AI inference accuracy
is slightly lower for the fast AI inference service in the edge
device.
It might be a bit of an implementation issue, but we should also
consider how we deliver AI services on cloud servers or edge devices.
With the current technology, a traditional web server method or a
server method specialized for AI service inference (e.g., Google's
Tensorflow Serving) can be used. Traditional web server methods such
as Flask and Django have the advantage of running on various types of
machines, but since they are designed to support general web
services, the service execution time is not fast. Tensorflow Serving
uses the features of Tensorflow to make AI service inference services
very fast and efficient. However, older CPUs that do not support AVX
cannot use the Tensorflow serving function because Google's
Tensorflow does not run. Therefore, rather than unconditionally
using the server method specialized in AI service inference, it is
necessary to decide the AI server module method that provides AI
services in consideration of the hardware characteristics of the AI
system that can be built.
The communication method for transferring data to request AI
inference service is also an important decision in constructing an AI
system. Using the traditional REST method, it can be used for
various machines and services, but its performance is inferior to
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Google's gRPC. There are many advantages to using gRPC for AI
inference services because Google's gRPC enables large-capacity data
transfer and efficient data transfer compared to REST.
5. IANA Considerations
There are no IANA considerations related to this document.
6. Security Considerations
When AI service is performed on a local machine, there is no security
issue, but when AI service is provided through a cloud server or edge
device, IP address and port number may be known to the outside can
attack. Therefore, when providing AI services by utilizing machines
on the network such as cloud servers and edge devices, it is
necessary to analyze the characteristics of the modules to be used
well, identify vulnerabilities in security, and take countermeasures.
7. Acknowledgements
TBA
8. Informative References
[RFC6574] Tschofenig, H. and J. Arkko, "Report from the Smart Object
Workshop", RFC 6574, DOI 10.17487/RFC6574, April 2012,
<https://www.rfc-editor.org/info/rfc6574>.
[RFC7452] Tschofenig, H., Arkko, J., Thaler, D., and D. McPherson,
"Architectural Considerations in Smart Object Networking",
RFC 7452, DOI 10.17487/RFC7452, March 2015,
<https://www.rfc-editor.org/info/rfc7452>.
[I-D.irtf-t2trg-iot-edge]
Hong, J., Hong, Y., de Foy, X., Kovatsch, M., Schooler,
E., and D. Kutscher, "IoT Edge Challenges and Functions",
Work in Progress, Internet-Draft, draft-irtf-t2trg-iot-
edge-04, 11 January 2022,
<https://www.ietf.org/archive/id/draft-irtf-t2trg-iot-
edge-04.txt>.
[CG-AIoT] "ITU-T CG-AIoT", <https://www.itu.int/en/ITU-T/
studygroups/2017-2020/20/Pages/ifa-structure.aspx>.
[tinyML] "tinyML Foundation", <https://www.tinyml.org/>.
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[AI_inference_archtecture]
"IBM Systems, AI Infrastructure Reference Architecture",
<https://www.ibm.com/downloads/cas/W1JQBNJV>.
[Google_cloud_iot]
"Bringing intelligence to the edge with Cloud IoT",
<https://cloud.google.com/blog/products/gcp/bringing-
intelligence-edge-cloud-iot>.
Authors' Addresses
Yong-Geun Hong
Daejeon University
62 Daehak-ro, Dong-gu
Daejeon
Phone: +82 42 280 4841
Email: yonggeun.hong@gmail.com
SeokBeom Oh
KSA
Digital Transformation Center, 5
Teheran-ro 69-gil, Gangnamgu
Seoul
Phone: +82 2 1670 6009
Email: isb6655@korea.ac.kr
SooJeong Lee
Korea University/KT
2511 Sejong-ro
Sejong City
Email: ngenius@korea.ac.kr
Hyun-Kook Kahng
Korea University
2511 Sejong-ro
Sejong City
Email: kahng@korea.ac.kr
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