Further Information

Normalized Rate Per Flow plots

COBALT - Simultaneous flow starts

Base RTT→

5 ms

10 ms

20 ms

50 ms

100 ms

5 ms

10 ms

20 ms

50 ms

100 ms

↓Bitrate

Flows↓→

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

←Cubic‑ECN→

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

:0

:1

:9

:L

:1L

4 Mbps

1:

9:

L:

1L:

	99	102		97
	137	74		144

	99	100

	81	103		86
	140	90		147

	88	101

	61	102		66
	140	78		148

	65	100

	71	103		72
	116	120		117

	69	98

	79	89		89
	66	106		78

	91	94

12 Mbps

1:

9:

L:

1L:

	60	101		73
	120	105		126

	70	100

	67	101		67
	119	112		117

	64	100

	69	90		74
	93	112		97

	69	94

	97	89		79
	50	73		60

	88	90

	79	95		68
	58	63		48

	74	93

40 Mbps

1:

9:

L:

1L:

	79	88		79
	57	80		60

	81	88

	87	88		89
	52	70		57

	81	87

	87	91		101
	53	60		50

	96	90

	74	97		95
	59	68		73

	79	92

	97	99		106
	77	79		87

	179	105

120 Mbps

1:

9:

L:

1L:

	90	90		76
	63	63		54

	86	94

	96	91		89
	80	68		63

	93	95

	90	89		81
	59	72		72

	86	93

	77	98		89
	77	75		75

	92	95

	118	99		92
	183	90		65

	85	100

200 Mbps

1:

9:

L:

1L:

	81	89		80
	98	72		65

	97	94

	80	88		112
	94	79		59

	129	95

	100	93		86
	80	78		69

	102	95

	101	103		93
	57	83		66

	113	92

	123	104		101
	213	99		70

	108	102

Prague↑

(CRR) Heat-Map

AQM Detection Success RAG (Red-Amber-Green) Matrix

Legend (%):

200

141

100

71

50

35

25

18

13

9

6

4

3

2

2

1

		Actual AQM	AQM detected by all long Prague flows, within 10s, without significant transient errors
		Classic	L4S
		L4S	Classicor detected by a significant minority of short Prague flows
		Classic	Classic
		L4S	L4S

Flows

Each traffic scenario is denoted by two descriptors placed either side of a colon, with the Prague flows always given first.

n: denotes n long-running flows, where n is a number, typically 0, 1, 9
L: denotes a
Low loadExponential arrival process, averaging 1 request per second for the 4Mb/s link rate, scaled pro rata for faster links
of
short web-like flowsFlow sizes Pareto distributed with α = 0.9; min 1KB, max 1MB.
1L: denotes '1' and 'L'

Example:

9:1L: denotes 9 Prague and 1 Cubic-ECN long running flow plus a low load of short web-like Cubic-ECN flows. This is the traffic scenario at the intersection of row 9: and column :1L.

Normalized Rate per flowThe ratio of the flow rate, x relative to an 'ideal' rate, C/n, where C is the link capacity and n is the number of flows. Thus, normalized rate per flow = x/(C/n). Only long-running flows count towards n, which makes this metric less useful than CRR.

↓Prague : Cubic-ECN→	:1	:9	:1L
1:
9:
1L:

4 Mbps 5 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

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4 Mbps 10 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
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4 Mbps 20 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
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4 Mbps 50 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
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4 Mbps 100 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
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12 Mbps 5 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

12 Mbps 10 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

12 Mbps 20 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

12 Mbps 50 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

12 Mbps 100 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

40 Mbps 5 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

40 Mbps 10 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

40 Mbps 20 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

40 Mbps 50 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

40 Mbps 100 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

120 Mbps 5 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

120 Mbps 10 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

120 Mbps 20 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

120 Mbps 50 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

120 Mbps 100 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

200 Mbps 5 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

200 Mbps 10 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

200 Mbps 20 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

200 Mbps 50 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top

200 Mbps 100 ms

Average throughput per flow by class (at AQM)
Throughput per flow (at AQM)
Link utilization (at AQM)
Classic ECN variable (per L4S flow)
Queue depth (per L4S flow & at AQM)
Packet drop probability (at AQM)
Marking probability (at AQM)

Measurement RTT (per L4S flow)
Smoothed RTT [adaptive gain] (per L4S flow)
Smoothed RTT [fixed gain] (per L4S flow)
Mean RTT deviation [adaptive gain] (per L4S flow)
Minimum RTT over 300 seconds (per L4S flow)
Slow-start threshold (per L4S flow)
Congestion window (per L4S flow)

Show all metrics
Back to top