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Adaptive Congestion
Control for Unpredictable
Cellular Networks
Flow
Highlight the unpredictability of cellular network
Verus
Comparing with TCP and its variants
Experiment Set-up
1. 2 commercial networks Du and Etisalat
2. Rack server
3. Laptop tethered to a mobile phone
1. Burst Scheduling
2. Competing Traffic
3. Channel Unpredictability
Verus
W(t+1) Next Sending Window
f Delay profile function
d(t) Network delay
𝛿(t) Delay increment/decrement
Verus
Delay Estimator Delay Profiler Window Estimator Loss Handler
Verus
1. Delay Estimator
Round trip delay(Dp,i) = current time – packet sent time
Verus
2. Delay Profiler
Verus
3. Window Estimator+
Verus
Loss Handler
Delay Profile Initialization and
Maintenance
Timeouts and Retransmissions
Timeout = 3 * delay
Finding the right values for the
parameters
Epoch Ɛ
Delay Profile Updates
𝛿1 and 𝛿2
Experiment
OPNET network simulator.
4 Android smartphones and 1 server. Both endpoints,
server and smartphones, send UDP packets with an
MTU size of 1400 bytes
Data rate for each device is set to 5 Mbps and 2.5
Mbps for downlink and uplink, respectively.
7 different scenarios with different mobility properties.
Finding the right values for the
parameters
Epoch Ɛ: Smaller, better. 5ms
Delay Profile Updates: 1s
𝛿1:1ms and 𝛿2:2ms
Evaluation
Macro-Evaluation
Throughput
Delay
Characteristics
Micro-Evaluation
Fairness
Adaptation
Macro-Evaluation: Comparison with Other TCP Variants
TCP Cubic
TCP New Reno
Sprout
TCP Cubic
Macro-Evaluation
Real-world
EvaluationTrace-driven
Evaluation
Real-world Evaluation
Etisalat network
Verus mobile device, TCP Verus, TCP Cubic,
Sprout laptop
Mode of each phone connect to appropriate
network to test both 3G and 4Gs
Performed at fixed places with no mobility and
simultaneously
Each run was 2 minutes and each experiment was
repeated 5 times
Trace-driven Evaluation
OPNET simulator
Traffic shaper
Shared Queue: Min of 3MBit, Max of 9MBit, Drop
Probability = 10%
Mobility
Fairness
Micro-Evaluation
3 laptops connected to a switch which is
connected to the server
Linux Traffic Control
1) Control server outgoing bandwidth
2) Imitate some form of delay for each client
1. Rapidly Changing Network
1. Rapidly Changing Network
2. Newly Arriving Flows
3. Verus vs TCP
4. Effect of Verus Delay Curve
Related
Work:
Legacy Congestion Control Protocols
Router-feedback-based Protocols
Recent Congestion Control Protocols
Cellular Performance
Points for
Discussion
Formulas
Choice of values for parameters
Real-World Evaluation
3G vs LTE experiments
Work:
Advanced 5G-TCP: Transport protocol for 5G Mobile Networks,
http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7983089
Radio Link and Transport Protocol Engineering for Future-Generation Wireless
Mobile Data Networks,
http://onlinelibrary.wiley.com/doi/10.1002/wcm.297/pdf
References Used:
Adaptive Congestion Control for Unpredictable Cellular Networks,
https://cs.nyu.edu/~jchen/publications/sigcomm15-zaki.pdf
TCP Congestion Control Comparison,
http://www.satnac.org.za/proceedings/2012/papers/2.Core_Network_Techn
ologies/15.pdf
Stochastic Forecasts Achieve High Throughput and Low Delay over Cellular
Networks, https://www.usenix.org/system/files/conference/nsdi13/nsdi13-
final113.pdf
Thank you ☺