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SIMULATION RESULTS FOR MULTI-STREAM . draft-ietf-avtcore-rtp-multi-stream-01 d raft-ietf-avtcore-rtp-multi-stream-optimisation-00. Overview. Current Status Simulation Purposes SSRC Report Aggregation Issue Report Group Extension performance gains RTCWEB use case - PowerPoint PPT Presentation
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draft-ietf-avtcore-rtp-multi-stream-01draft-ietf-avtcore-rtp-multi-stream-optimisation-00
SIMULATION RESULTS FOR MULTI-STREAM
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 2
› Current Status› Simulation Purposes› SSRC Report Aggregation Issue› Report Group Extension performance gains
– RTCWEB use case– Selective Forwarding Middlebox use case
› Next Steps
Overview
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 3
› Neither drafts was updated before this meeting› draft-ietf-avtcore-rtp-multi-stream-01 Issues:
– How does the RTCP Scheduler work when aggregating– How does one calculate avg_rtcp_size when aggregating– Need for unicast session joiners use of no initial delay
› draft-ietf-avtcore-rtp-multi-stream-optimisation-00– Missing Signaling Specification– Security Considerations needs extended
› Both Drafts will benefit from further editing› However, focus on first resolving open issues
Current Status
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 4
› Determine size of issue with SSRC aggregation› Enable trying out proposals to fix issues› Verifying that what we write works as intended
Simulation Purpose
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 5
› Simulating what happens when an end-point performs SSRC RTCP Report aggregation
› Implementation does the following:– Schedule all SSRCs– When a SSRC is scheduled for transmission– Fill compound packet with the triggered SSRC’s:
- RTCP SR/RR- SDES CNAME
› Plus as many of the nearest scheduled SSRCs reports that fit in MTU
– Send Packet– Reschedule all of the sent SSRCs
SSRC Aggregation
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 6
› Simulation case RTC:– Two endpoints– Each endpoint has 4 SSRC, all four active senders
› Members = 8› Senders = 8
– RTCP bandwidth› RS: 10 kbps› RR: 15 kbps
– Regular AVPF› T_RR_INT = 0› Include Full Cross Reporting
- Each SSRC reports on the other 7
SSRC Aggregation
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 7
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 30
5000
10000
15000
20000
25000
30000
35000
40000
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BaselineAggregatedAdjusted
Freqency (RTCP Packets / bin)
Transmissioninterval (s)
SSRC AGGREGATIONRTCP Transmission Interval Distribution
Bitrates AVG_RTCP_SIZE
Aggregated: 7807,92 916
Baseline: 24987,46 250
Adjusted: 31251,69 228
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 8
› The documented issue for SSRC aggregation in draft-ietf-avtcore-rtp-multi-stream-01:
› The issue really exists:– RTCP transmission interval significantly increased– Implementation of scheduling changes the interval distribution
› Using the basic idea and scaling AVG_RTCP_SIZE with number of reporting SSRCs per packet
– Overshoots the RTCP bandwidth significantly (25%)– Appears to be due to scheduling implementation
› Picks the best out of the SSRCs (4) being aggregated› Need to figure out better compensation / scheduling
Conclusions
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 9
› Implements the report group extensions from– draft-ietf-avtcore-rtp-multi-stream-optimisation-00
› Active Reporter:– Reports on remote SSRCs, not any within the same report group– Includes an extra Source Description item with report group– Will be multiple ones if SSRC to report are more than 31
› Non Reporter– Only sends regular SR or RR without any report blocks– Extra Reporter Sources RTCP Packet (4+4*Reporters bytes)– These simulations are done without SSRC aggregation
› Simulated Two different Use Cases
Report Grouping
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 10
› Simulation case RTC:– Two endpoints– Each endpoint has 4 SSRC, all four active senders
› Members = 8› Senders = 8
– RTCP bandwidth› RS: 10 kbps› RR: 15 kbps
– Regular Reporting in AVPF› T_RR_INT = 0
– Baseline:› Include Full Cross Reporting
Report Grouping: RTC CASE
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 11
RTC Use case ResultsRTCP Transmission Interval
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
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70000
BaselineReport Groups
Transmission Interval (s)
Frequency (RTCP Packets / bin)
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 12
RTC Use case ResultsPacket Size Distribution
0 25 50 75 100 125 150 175 200 225 2500
20000
40000
60000
80000
100000
120000
BaselineReport Group
Frequency (RTCP Packets / bin)
Packet Size (Bytes)
AVG_RTCP_SIZE
Baseline 250
Report Groups 119
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 13
– RTCP bandwidth› RS: 75 kbps› RR: 50 kbps
– Regular Reporting in AVPF› T_RR_INT = 0
– Baseline:› Include Full Cross
Reporting
› Simulation case SFM:– Two endpoints– Endpoint 1:
› Total SSRCs: 80› Sending SSRCs: 20
– Endpoint 2:› Total SSRCs: 120› Sending SSRCs: 42
– Members = 200– Senders = 62
Selective Forwarding MiddleBOX Use CASE
STM STMCC
C
C
C
C
C
C
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 14
SFM Use case ResultsRTCP Transmission Interval
0.00 1.20 2.40 3.60 4.80 6.00 7.20 8.40 9.60 10.80 12.00 13.20 14.40 15.60 16.80 18.00 19.20 20.40 21.60 22.800
2000
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14000
16000
Report GroupsBaseline
Frequency (RTCP Packets / bin)
Transmission Inter-vall (s)
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 15
0 50100
150200
250300
350400
450500
550600
650700
750800
850900
9501000
10501100
11501200
12501300
13500
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50000
60000
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80000
Report GroupBaseline
Frequency (RTCP Packets / bin)
Packet Size (Bytes)
SFM Use case ResultsPacket Size Distribution
AVG_RTCP_SIZE
Baseline 818
Report Groups 101
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 16
› Report Groups are as effective as we expected– Allows either
› More frequent reporting› Reduced consumption for regular reporting
› Significant improvements– Even in quite small sessions of the RTC use case
› Gain should be even more with SSRC Aggregation
Conclusions
Simulation Results for Multi-Stream | IETF 88 AVTCORE WG | Magnus Westerlund | Page 17
› draft-ietf-avtcore-rtp-multi-stream-01– SSRC Aggregation Issue
› Needs proposals for solutions- Simple to implement- Maintain RTCP Bandwidth Target
– Need to look at effects of RTCP packet burst of joining multi-SSRC endpoint
› draft-ietf-avtcore-rtp-multi-stream-optimisation-00– Resolve editorial and missing sections
Next Steps