Shivkumar KalyanaramanRensselaer Polytechnic Institute
1
Efficient Path Aggregation and Error Control for Video Streaming
OMESH TICKOO, Shiv Kalyanaraman, John Woods
Rensselaer Polytechnic Institute (RPI)
Sponsors: ARO, DARPA-NMS, Intel
: “shiv rpi”
Shivkumar KalyanaramanRensselaer Polytechnic Institute
2
Introduction Motivation: Video over best-effort Internet
Broadband => more access bandwidth End-to-end (E2E) => constraints due to path
congestion Virtual extension of broadband access pipe E2E using
multi-paths
Path Diversity: dimensions Aggregate Capacity Delay diversity Loss diversity Correlations in path performance characteristics
Key: Match inherent content diversity to path diversity
Shivkumar KalyanaramanRensselaer Polytechnic Institute
3
Motivation: Internet Path Congestion limits E2E bandwidth
Internet
Server Access Link
Client Access Link
Per
form
ance
Access Link Speed
Performance Saturation (even w/ many flows/path)
Shivkumar KalyanaramanRensselaer Polytechnic Institute
4
Multi-paths?
Overlays or peers can provide path diversity even if multi-paths not available natively in the Internet.
Issue: diversity of performance (b/w, delay, loss), possible correlations…
Shivkumar KalyanaramanRensselaer Polytechnic Institute
5
Path (Flow) Aggregator/ Multiplexer
Path (Flow) Aggregator/ De-multiplexer
Internet
E2E Broadband Virtual Pipe Abstraction!!
Server Access Link
Client Access Link
Per
form
ance
Access Link Speed
Smart Multi-path Capacity Aggregation (SMCA): Motivation
Performance Scaling
Shivkumar KalyanaramanRensselaer Polytechnic Institute
6
Time
Lossy
Low Capacity
High Delay/Jitter
Network paths usually have:• low e2e capacity, • high latencies and • high/variable loss rates.
Single path issues: capacity, delay, loss…
Shivkumar KalyanaramanRensselaer Polytechnic Institute
7
SMCA: Leverage Diversity!
Low Perceived Delay/Jitter
Low Perceived Loss
High Perceived Capacity
Shivkumar KalyanaramanRensselaer Polytechnic Institute
8
Delay Diversity Unit
Loss Diversity Unit
Network
Receive Buffer
Content
SMCA: Framework
Shivkumar KalyanaramanRensselaer Polytechnic Institute
9
Paths Ranked by LatencyApplication Data
Low DelayRANK
High DelayRANK
SMCA: Delay Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
10
Paths Ranked by LatencyApplication Data
Low DelayRANK
High DelayRANK
Early deadline packets mapped to low-delay paths
SMCA: Delay Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
11
Paths Ranked by LatencyTransmit Queue
Low DelayRANK
High DelayRANK
Early deadline packets (in order of rank) mapped to low-delay paths (in order of rank)
SMCA: Delay Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
12
Paths Ranked by LatencyTransmit Queue
Low DelayRANK
High DelayRANK
Late deadline packets mapped to high-delay paths…
Note: these packets leave the sender roughly at the same time as the early-deadline packets
SMCA: Delay Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
13
Paths Ranked by LatencyTransmit Queue
Low Delay
High Delay
Consider a delay-based group of paths and the associatedpackets…
SMCA: Delay Diversity Loss Diversity
Shivkumar KalyanaramanRensselaer Polytechnic Institute
14
Paths Ranked by LatencyTransmit Queue
Low Delay
High Delay
Consider a delay-based group of paths and the associatedpackets…
SMCA: Delay Diversity Loss Diversity
Shivkumar KalyanaramanRensselaer Polytechnic Institute
15
Paths Ranked by Loss Raten GOPs
Low LossRANK
High LossRANK
Re-rank Paths within this group based upon packet loss rates
SMCA: Loss Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
16
I
Paths Ranked by Loss Raten GOPs
Low LossRANK
High LossRANK
Enlarged View of Packets (with content labels) and Paths
P
BBPBB
SMCA: Loss Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
17
I
Paths Ranked by Loss Raten GOPs
Low LossRANK
High LossRANK
P
BBPBB
Map high priority packets (eg: I-frame packets) to low loss rate rank paths
SMCA: Loss Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
18
I
Paths Ranked by Loss Raten GOPs
Low LossRANK
High LossRANK
P
BBPBB
Continue map packets to low loss rank paths based upon priority(Eg: P-frames get the next set of loss-ranked paths)
SMCA: Loss Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
19
I
Paths Ranked by Loss Raten GOPs
Low LossRANK
High LossRANK
P
BBPBB
Lowest priority packets get high loss rate paths(within the delay-based group of paths)
SMCA: Loss Diversity Unit
Shivkumar KalyanaramanRensselaer Polytechnic Institute
20
I
Paths Ranked by Loss Raten GOPs
Low LossRANK
High LossRANK
P
BBPBB
FEC (unequal FEC) for a GOP mapped within the same delay-group, but mapped to the higher loss paths
SMCA: Loss Diversity Unit + FEC
I-FEC
P-FEC
Shivkumar KalyanaramanRensselaer Polytechnic Institute
21
SMCA: Performance with increasing number of Paths
Num. Of
Paths
1
2
3
4
5
PSNR (dB)
20.98
22.48
25.42
26.02
28.04
Table 1. Average PSNR Variation with Number of Paths
Background traffic
generatorBackground traffic sink
Content Source Content Sink
Shivkumar KalyanaramanRensselaer Polytechnic Institute
22
Topology to test delay diversity and loss diversity gains
Content Source Content Sink
Background traffic generator Background traffic
sink
5 paths
Shivkumar KalyanaramanRensselaer Polytechnic Institute
23
SMCA gains with delay diversity
Avg. Delay(ms)
SMCAPSNR(dB)
PTPSNR(dB)
OPMSPSNR(dB)
300 21.78 18.73 11.03
100 25.12 24.21 19.19
50 28.32 29.46 24.33
30 30.12 31.63 27.96
Table 3. Gains with Delay Variation
SMCA achieves even better performance (than simple multi-path mapping: OPMS) when average delay and jitter is higher
Shivkumar KalyanaramanRensselaer Polytechnic Institute
24
SMCA gains with loss diversity
Avg. Loss Prob.
SMCAPSNR(dB)
PTPSNR(dB)
OPMSPSNR(dB)
0.4 22.78 20.31 11.64
0.35 26.32 26.86 18.21
0.1 29.03 29.02 24.43
0.05 29.32 31.82 26.06
Table 2. Gains with Loss Variation
SMCA achieves even better performance (than simple multi-path mapping: OPMS) when average loss and loss variations are
higher!
Shivkumar KalyanaramanRensselaer Polytechnic Institute
25
Summary Multi-path performance diversity can be leveraged E2E
Key: must be mapped to content diversity (Similar to lessons learnt from content-driven unequal FEC protection
vs uniform FEC protection)
Ideas: Map late deadline packets to high latency paths Map higher priority packets to lower loss rate paths (within a delay-
based group of paths) FEC packets sent on paths different from that of associated content
(FEC: lower priority)
Our scheme can scale to handle lots of paths Possible with p2p networks (eg: 10-100 kbps from single path, but 10s
of paths) Does not require MD coding, or high complexity optimization
Top Related