The document discusses message-oriented middleware for edge computing applications, highlighting the differences between centralized cloud resources and decentralized edge resources such as IoT devices and cloudlets. It emphasizes the MQTT protocol for messaging, addressing challenges like latency, privacy, and the need for elasticity in resource management. The goals for future development include enhancing message delivery guarantees and adapting broker functionality to manage the heterogeneity of edge resources.

1. Message-Oriented Middleware
for Edge Computing Applications
Thomas Rausch
Distributed Systems Group
TU Wien
http://dsg.tuwien.ac.at

2. 2

3. 3
Amazon AWS IoT

4. 4
The Internet
Decoupled messaging

5. 5
Subscribe to topic:
/robot/arm

6. 6
Publish “move x,y,z” to
/robot/arm

7. 7
Topic Subscriber
/robot/arm robot-client
/robot/arm ...Subscriber:
robot-client
Publisher
Subscriber:
...
Topic
/robot/arm

8. 8
Trust?!
Availability?!
End-to-end latency: ??ms!

9. 9
IoT Edge Cloud
Edge Computing
S. Nastic, T. Rausch, et al. 2017. A Serverless Real-Time Data Analytics Platform for Edge Computing. IEEE Internet Computing 21, 4 (2017), 64–71.
G. Lewis, et al. 2014. Tactical Cloudlets: Moving Cloud Computing to the Edge. In 2014 IEEE Military Communications Conference. IEEE, 1440–1446.
Proximity Scale

10. 10
IoT Edge Cloud
Edge Computing
S. Nastic, T. Rausch, et al. 2017. A Serverless Real-Time Data Analytics Platform for Edge Computing. IEEE Internet Computing 21, 4 (2017), 64–71.
G. Lewis, et al. 2014. Tactical Cloudlets: Moving Cloud Computing to the Edge. In 2014 IEEE Military Communications Conference. IEEE, 1440–1446.
Proximity Scale

11. 11
Data centers
Internet
Mobile
edge
Extreme
edge
IoT
Cloudlets
Message broker
Cloud-based MOM
Edge-enabled MOM
Edge-Enabled MOM

12. 12
Sound familiar?
NCA’05
DEBS’05
MW’05
PODC’07

13. 13
What’s new?
● The Cloud
– Centralized on-demand resources
● Edge resources
– Decentralized, heterogeneous, and volatile resources
(Mobile devices, IoT gateways, Cloudlets)
● Internet of Things
– Plethora of devices and protocol standards
● A new form of elasticity: Cloud to Edge
– Osmotic Computing
M. Villari, et al. 2016. Osmotic Computing: A new Paradigm for Edge/Cloud Integration. IEEE Cloud Computing

14. 14
Data centers
Internet
Mobile
edge
Extreme
edge
IoT
Cloudlets
Challenges

15. 15
Data centers
Mobile
edge
Extreme
edge
IoT
Proximity awareness

16. 16
Data centers
Mobile
edge
Extreme
edge
IoT
Elasticity from the Cloud to the Edge
Runtime
provisioning
of brokers
Network
reconfiguration

17. 17
Data centers
Mobile
edge
Extreme
edge
IoT
Privacy
& Trust

18. 18
State of the Art – Research & Prototypes

19. 19
Messaging Model
● MQTT: ISO standardized pub/sub protocol
– TCP/IP
– Small code footprint, low-bandwidth design
– Has become a common platform for IoT [1]
● Simple protocol
– CONNACK
– SUBSCRIBE(t), SUBACK(t)
– PUBLISH(t,msg)
– ...
[1] A. Al-Fuqaha, et al. 2015. Internet of Things: A Survey on Enabling Technologies, Protocols, and Applications
IEEE Commun. Surv. Tutorials, vol. 17, no. 4, pp. 2347–2376, 2015.

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Messaging Model
● Message delivery guarantees (MQTT “QoS”)
– (0) At most once
– (1) At least once
– (2) Exactly once
● Maintaining guarantees despite distribution

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State of the Art – The Real World
● Static topic bridging for proximity-based messaging
(Mosquitto & HiveMQ)
Local Broker Central Broker
Shared Topic
Internal Topics
Static
config
Static
config
Edge Cloud
Steve. 2017. Mosquitto MQTT Bridge-Usage and Configuration http://www.steves-internet-guide.com/mosquitto-bridge-configuration/

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State of the Art – The Real World
ScalAgent. JoramMQ, a distributed MQTT broker for the Internet of Things. White paper. 2014.

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The EMMA Project
Client
GW
c
GW
c
Broker
Broker
Device
Monitoringprotocol
Controller
Bridging
Tables
Gateway
Bridging
Table
Reconfigura-
tion Engine
REST Endpoints
Network
monitor
Buffer out
Buffer in
MQTT
Server
https://git.dsg.tuwien.ac.at/emma
Architecture Bridging & Reconfiguration
T. Rausch, S. Nastic, S. Dustdar. 2018. EMMA: Distributed QoS-Aware MQTT Middleware for Edge Computing Applications. IC2E’18.

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Prototype Evaluation
us-east eu-west
eu-central
BrokerGateway BrokerGateway
Controller
... ...
Gateway
Broker
98 ms 27 ms
85 ms

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Goals for short/mid-term future
● Elicit algorithmic challenges and novelties
● Message delivery guarantees (MQTT QoS)
● Elastic diffusion of brokers to the Edge
– Control heterogeneity of Edge resources
– Efficient monitoring and network reconfiguration
Cloud

26. Dipl.-Ing. (MSc)
Thomas Rausch
Research Assistant
TU Wien
Distributed Systems Group
Argentinierstraße 8/184-1, 1040, Vienna, Austria
T: +43 1 58801 184 838
E: rausch@dsg.tuwien.ac.at
dsg.tuwien.ac.at/staff/trausch