![Page 1: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/1.jpg)
End-to-end Asymmetric End-to-end Asymmetric Link Capacity EstimationLink Capacity Estimation
Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario GerlaLing-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario GerlaDept. of Computer Science, University of California at Los AngelesDept. of Computer Science, University of California at Los Angeles
![Page 2: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/2.jpg)
DefinitionDefinition CapacityCapacity: maximum IP-layer throughput that a flow can
get, without any cross traffic. Available BandwidthAvailable Bandwidth: maximum IP-layer throughput that
a flow can get, given (stationary) cross traffic.
![Page 3: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/3.jpg)
Previous Work on Capacity EstimationPrevious Work on Capacity Estimation
Per-hop basedpathchar: use different packet sizes to probe
the per-hop link capacityclink, pchar: variants of pathcharNettimer: use “packet tailgating” technique
End-to-end basedPathrate, Sprobe, CapProbe
These approaches are either one-way based or unable to estimate asymmetric link capacities.
![Page 4: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/4.jpg)
Estimating Asymmetric LinksEstimating Asymmetric Links
Asymmetric links are becoming popular (e.g. DSL, cable modems, and satellite links).
Knowing the capacity of BOTH direction links is important for applications.
Related work: ALBP [Yu et al, ICC’03] employs a multi-packet delay
model to estimate “per-hop” capacity of asymmetric links.
![Page 5: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/5.jpg)
Our ContributionOur Contribution
We propose an end-to-end asymmetric link capacity estimation technique, called AsymProbeAsymProbe.
AsymProbe is CapProbe based:round trip methodpacket pair basedsimple, fast, and accurate
![Page 6: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/6.jpg)
Packet Pair DispersionPacket Pair DispersionT3
T2 T3
T3
T1
T3
Narrowest Link
20Mbps 10Mbps 5Mbps 10Mbps 20Mbps 8Mbps
Capacity = (Packet Size) / (Dispersion)
![Page 7: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/7.jpg)
Issues: Compression and ExpansionIssues: Compression and Expansion
• Queueing delay on the first packet => compression
• Queueing delay on the second packet => expansion
![Page 8: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/8.jpg)
CapProbe CapProbe (Rohit et al, SIGCOMM’04)(Rohit et al, SIGCOMM’04)
Key insight: a packet pair that gets through with zero queueing delay yields the exact estimate.
CapProbe uses “Minimum Delay Sum” filter.
CapacityCapacity
![Page 9: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/9.jpg)
Proposed Approach: AsymProbeProposed Approach: AsymProbe
''
''
)','max('
22
11
21
2
22
1
11
T
PC
T
PC
TTT
C
PT
C
PT
![Page 10: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/10.jpg)
AsymProbe: ExampleAsymProbe: ExampleC1 C2 P1 P2 T1 T2 C'1 C'2
1000kbps
500kbps
1500 bytes 100 bytes 12 ms 1.6 ms 1000.00 kbps 66.67 kbps
1500 bytes 300 bytes 12 ms 4.8 ms 1000.00 kbps 200.00 kbps
1500 bytes 500 bytes 12 ms 8 ms 1000.00 kbps 333.33 kbps
1500 bytes 700 bytes 12 ms 11.2 ms 1000.00 kbps 466.67 kbps
1500 bytes 900 bytes 12 ms 14.4 ms 833.33 kbps 500.00 kbps
1500 bytes 1100 bytes 12 ms 17.6 ms 681.82 kbps 500.00 kbps
1500 bytes 1300 bytes 12 ms 20.8 ms 576.92 kbps 500.00 kbps
1500 bytes 1500 bytes 12 ms 24 ms 500.00 kbps 500.00 kbps
500kbps
1000kbps
100 bytes 1500 bytes 1.6 ms 12 ms 66.67 kbps 1000.00 kbps
300 bytes 1500 bytes 4.8 ms 12 ms 200.00 kbps 1000.00 kbps
500 bytes 1500 bytes 8 ms 12 ms 333.33 kbps 1000.00 kbps
700 bytes 1500 bytes 11.2 ms 12 ms 466.67 kbps 1000.00 kbps
900 bytes 1500 bytes 14.4 ms 12 ms 500.00 kbps 833.33 kbps
1100 bytes 1500 bytes 17.6 ms 12 ms 500.00 kbps 681.82 kbps
1300 bytes 1500 bytes 20.8 ms 12 ms 500.00 kbps 576.92 kbps
1500 bytes 1500 bytes 24 ms 12 ms 500.00 kbps 500.00 kbps
C=P/TC=P/TC=P/TC=P/T
![Page 11: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/11.jpg)
AsymProbe AlgorithmAsymProbe Algorithm
AsymProbe has four phases:
Phase 1: the probing phase (P1=Pmax ; P2=Pmax ) (=> CapProbe)
Phase 2: the probing phase (P1=Pmax ; P2=Pmin)
Phase 3: the probing phase (P1=Pmin ; P2=Pmax )
Phase 4: the decision phase
![Page 12: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/12.jpg)
AsymProbe AlgorithmAsymProbe Algorithm The decision phase:
![Page 13: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/13.jpg)
IssuesIssues AsymProbe is able to estimate asymmetric link capacities when
the “asymmetric ratio” is larger than Pmin /Pmax and smaller than Pmax /Pmin.
AsymProbe can not estimate “extremely asymmetric” links.
Pmax is limited by MTU.
Pmin is limited by the supported system time resolution.
Packet SizeNarrow Link Capacity
100 Mbps 10 Mbps 1 Mbps
500 bytes 0.04 ms 0.4 ms 4 ms
1000 bytes 0.08 ms 0.8 ms 8 ms
1500 bytes 0.12 ms 1.2 ms 12 ms
![Page 14: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/14.jpg)
SimulationSimulation AsymProbe: A <-> B; Cross Traffic: C <->B E->D: 1.5Mbps; D->E: 128kbps
![Page 15: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/15.jpg)
Simulation ResultsSimulation Results
Pmax=1500 bytes ; Pmin=100 bytes
![Page 16: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/16.jpg)
EmulationEmulation
Pmax=1500 bytes ; Pmin=500 bytes
![Page 17: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/17.jpg)
Emulation ResultsEmulation Results
![Page 18: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/18.jpg)
Internet ExperimentsInternet Experiments P1=1500 bytes, P2=500 bytes Supported “asymmetric ratio” = 3:1
![Page 19: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/19.jpg)
Application – TCP ProbeApplication – TCP Probe
The concept of AsymProbe can be integrated with other data transmission protocols, e.g. TCP.
TCP packet size: forward direction: TCP data 1500 bytes reverse direction: TCP ACK 40 bytes
According to AsymProbe algorithm: If , then T1>T2
TCP Probe estimates the capacity of the forward direction link If , then T1<T2
TCP Probe estimates the capacity of the reverse direction link
40
1500
Re
verse
forward
C
C
40
1500
Re
verse
forward
C
C
![Page 20: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/20.jpg)
TCP ProbeTCP Probe
DelAck
TCP Probe:
CapProbe:
More details in [Anders et al, GI’05]
![Page 21: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/21.jpg)
TCP Probe ApplicationTCP Probe Application
Vertical handoff usually results in a dramatic change in the path capacity.
Service agility using “Fast Rate Adaptation” (FRA) algorithm FRA forces TCP to enter Slow Start when detecting a handoff from
LOW to HIGH
![Page 22: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/22.jpg)
Service Agility – TCP ProbeService Agility – TCP Probe
Unit: bps
TCP Probe with “fast rate adaptation” Vertical handoff from 10Mbps to 100Mbps
![Page 23: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/23.jpg)
SummarySummary
We propose an end-to-end asymmetric link capacity estimation technique, called AsymProbe.
We evaluate AsymProbe by simulation and Internet experiments.
The concept of AsymProbe can be integrated with other data transmission protocols.
We present a passive capacity estimation technique, called TCP Probe, which integrates AsymProbe with TCP.
![Page 24: End-to-end Asymmetric Link Capacity Estimation Ling-Jyh Chen, Tony Sun, Guang Yang, M.Y. Sanadidi, Mario Gerla Dept. of Computer Science, University of](https://reader030.vdocuments.site/reader030/viewer/2022032723/56649d1f5503460f949f3075/html5/thumbnails/24.jpg)
Thanks!Thanks!
CapProbe:CapProbe: http://nrl.cs.ucla.edu/CapProbe/