Presentation: Extended summary of “Cloudy with a Chance of Short RTTs Analyzing Cloud Connectivity in the Internet"

1. Extended summary of
"Cloudy with a Chance of Short RTTs
Analyzing Cloud Connectivity in the Internet"
Università degli Studi di Trieste
Dipartimento di Ingegneria e Architettura
Corso di Laurea in Ingegneria Elettronica e Informatica
Relatore:
Prof.Alberto Bartoli
Candidata:
IsabellaFilippo
A.A. 2022/2023

2. Introduction: Cloud Computing
• Model for delivering computing services over the internet
• Flexible and on-demand access
✓Storage
✓Processing
✓Applications
• Crucial for the ever-increasing growth of network services
on the internet
2
Instead of unlimited computing capacity, applications of today
demand lower latencies.

3. Introduction: Need for Short RTTs
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Human Reaction Time (HRT): delay
difference between visual stimulus and
associated motor response
• Typically less than 250 ms end-to-end
• Requirement for remote human-in-the-
loop application
Perceivable Latency (PL): latency when the
user starts experience lags in application
• Typically within 80-100 ms end-to-end
• Strict requirement for interactive
application
Motion-To-Photon (MTP): delay between
user input and its effect reflecting on
display
• Typically within 10-20 ms end-to-end
• Strict requirement for immersive
applications

4. Introduction: Problem
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• Focus of the study:
o Comparison between Speedchecker measurements and a
previous experiment
o Analysis of the global cloud access latency
o Analysis of the impact of wireless last-mile on overall latency
Can current cloud infrastructure support the low latency
requirements of such apps?

5. Methodology: Vantage Points and End-Points
Vantage Points
• More than 115,000 Speedchecker
(SC) probes
• Probes are softwareized application
• Cover 95.6% of Internet population
• Comparison with RIPE Atlas:
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9K vs 115K total probes wired vs wireless
End-Points
• 195 cloud regions operated by
9 major cloud providers of
different size
• Operators have different WAN
deployments

6. Global Cloud Access Latency
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• Achieving Motion-to-photon (MTP)
threshold (≤ 20 ms) is difficult for
real Internet users globally
• Achievable Perceivable latency
(PL) threshold (≤ 100 ms) in
Europe, Oceania and North
America
• In South America only probes
geographically “close” to data
centers enjoy low latencies
• Severe under-provisioning of
DCs in Africa results in
unachievable Human Reaction
Time (HRT) threshold (≤ 250 ms)

7. Influence of Wireless Last-Mile
• Cloud providers
o Continue to expand their WAN
deployment
o Reduce user path lengths to their
network through peering
o Last-mile remains out of reach
• Previous studies show LTE and Wi-
Fi to be the major latency
bottleneck
o Packet drops, invariable delays
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8. Influence of Wireless
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• Absolute latency due to
last-mile similar for
home (Wi-Fi + Router)
and cellular (only
wireless), i.e. ≥ 20 ms
• Wired connection
shows similar behaviour
to RIPE Atlas
Wi-Fi
Router: Wired part
of the connection

9. Last-mile wireless connection remains a challenge for cloud access.
Conclusions:
1. Impact on latency comes from geographical distance to data
centres
2. Choice of measurement platform can significantly influence results
3. Wireless last-mileaccess contributes significantly to overall latency
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Discussion:
Edge computing:
o Could help to reach low latency requirements
but…

10. Thank You
For Your Attention
Presented by Isabella Filippo
The Khang Dang, Nitinder Mohan, Lorenzo Corneo, Aleksandr Zavodovski, Jörg Ott, Jussi Kangasharju.
Cloudy with a Chance of Short RTTs Analyzing Cloud Connectivity in the Internet.