7 - Results and Analysis of the Second Scenario vs the Third Scenario

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7 - Results and Analysis of the Second Scenario vs the

Third Scenario

7.1 - Overview

In this chapter a comparison between the second and the third scenario will be made,

trying to show the differences between them and the improvements brought by the last

scenario. Like in the previous scenario, in the third scenario a DiffServ treatment will be applied to the flows together with Constraint based Routing to obtain a dynamic traffic

engineering, but the difference is in the use of a dynamic bandwidth reservation

(semi-dynamic as regards UDP) depending on the traffic pattern, as has been explained in

section 5.6.

The following sections will analyze in the same order the same variables analyzed in the previous chapter. The examination of the various data will require a constant glance to the

ones in the chapter 6, not represented here to avoid an excessive redundancy.

In section 7.2, three simulations will be analyzed, overloading at first the Gold UDP traffic,

then the Silver UDP and at last both Gold UDP and Silver TCP traffic.

In section 7.3, many simulations will be used to analyze trough a series of graphs the TCP traffic pattern.

Also for the third scenario, it will be shown that the objectives specified by the SLA are

fully respected.

It will also be shown that the dynamic bandwidth will offer levels of quality of service, for

different load patterns, more consistent with the importance of the traffic classes and to what clients are expected to pay.

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7.2 - UDP Varying

7.2.1 – Simulation 1 - Gold class overloaded, Silver class underloaded

.

In the third scenario, as explained in chapter 5, through the Admission Control, the Gold

UDP exceeding bandwidth is dynamically reassigned till filling the Silver availability (if

there is availability). Looking at Tab 6.1, Tab 6.2 and Tab 7.1, it can be noticed the

different behaviors of the two scenarios.

A good example for a better understanding of the dynamic reassignment mechanism is

still the aggregated flow between nodes 13 and 17 (remembering that the normal load

assignment is 300 Kbit/s for each Gold aggregated flow, while it is 150 Kbit/s for each

Silver one). From Table 6.1, there is 450 Kbit/s for this Gold aggregated flow. As a

consequence there is an exceeding bandwidth for this flow of 150 Kbit/s, whereas the bandwidth that can be used from the corresponding Silver aggregated flow is just

100 Kbit/s. In the third scenario, the ingress Label Edge Router of the MPLS domain

reserves a bandwidth of 400 Kbit/s to the Gold aggregated flow, leaving 50 Kbit/s to the

Silver and declassing the remaining 50 Kbit/s to the best effort class.

Traffic Rate Full Duplex (CBR Sources) Gold Traffic Kbit/sec

From / To Node 17 Node 16 Node 15 Total Rate

Node 14 350 350 300 1000

Node 13 400 450 350 1200

Node 12 300 400 300 1000

Total Rate 1050 1200 950 3200

Silver Traffic Kbit/sec

Node 14 100 100 50 250

Node 13 50 0 100 150

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Total Rate 150 100 200 450 Bronze Traffic Kbit/sec

Node 14 100 50 50 200

Node 13 100 0 100 200

Node 12 0 0 50 50

Total Rate 200 50 200 450

Tab 7.1 – Traffic effective with the third scenario

We obtain an average rate of 356 Kbit/s for Gold, 50 Kbit/s for Silver and 50 Kbit/s for

Bronze. The total rate is 4100 Kbit/s.

Percentage of Packets Lost for single service class

Gold Silver Bronze

0% 0% 17%

Percentage of Packets Received for single service class

Gold Silver Bronze

100% 100% 83%

Tab 7.2 – UDP Packet Loss scenario 3

Goodput Gold

3200 Kbit/s

Goodput Silver Total rate

450 Kbit/s 4023,5 Kbit/s

Goodput Bronze

373,5 Kbit/s

Tab 7.3 – UDP Goodput scenario 3

Average delay ms

Gold Flows Silver Flows Bronze Flows

37,16 36,90 56,47

Standard Deviation ms

14,00 10,52 18,39

Tab 7.4 – UDP Delay scenario 3

Average jitter ms

2,35 5,76 10,87

0,76 4,78 10,31

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From Tab 7.2, 7.3, 6.5, 6.6, it is shown that the percentage of packets lost is quite similar between the two scenarios. However, as regards the goodput, the Gold goodput is

increased in the third scenario, as less flows are downgraded to a lower traffic class,

increasing the Gold load. For the same reason, the Silver goodput is smaller in the third

scenario, as less traffic is downgraded to Silver, resulting in a lower load for this class.

The total goodput is similar in the second and third scenarios.

Also as regards the delay (Tab 7.4 and 6.8) and the jitter (Tab 7.5 and 6.10), the value for

the Gold delay is worse in the third scenario as compared to the second and the value for

the Silver delay is better because of the load difference, as explained in the previous

paragraph. The remaining values are similar, even if just a little bit worse.

As explained in the last part of section 5.6, the path assignment can be different between the second and the third scenario, leading to differences in the treatments and in the

results. For this reason, the results as regards Packet Loss, Delay and Jitter are (and will

also be in the next sections) sometimes a little bit better and sometimes a little bit worse

for the third scenario.

What is important is that this new scenario reduces the number of downgraded clients for

the UDP traffic, resulting in more satisfied customers.

7.2.1.1 - TCP Flows Rate

Total average rate Kbit/s total rate Kbit/s

Gold _51,57 ₃₃₂₄

Silver _24,98 ₁₀₁₉

Bronze _3,12 ₂₈₁

Total 4624

Tab 7.6 – TCP Flows Rate Scenario 3

tot reserved Kbit/s

Gold 2983

Silver 1067

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In Tab 7.7 is represented the total bandwidth that is reserved to Gold TCP traffic and Silver TCP traffic. Tab 7.6 shows the simulation values for the total average rates in each

traffic class, that are close to those reserved. The average number of Gold and Silver TCP

active sources per aggregated flow are respectively 6.56 and 4.78, this leads to 331 Kbit/s

and 119 Kbit/s of average bandwidth reservation, multiplying by nine (i.e. the number of

TCP aggregated flows per single TCP class) we arrive to the values in Tab 7.7.

Looking at Tab 6.12 and at tab 7.6, it can be noticed that the service obtained is better for

the Gold TCP flows. In particular, the average rate obtained for a single Gold flow is

about the double than the average rate obtained for a single Silver flow. The dynamic

redistribution of bandwidth mechanism from this third scenario increased the Gold

bandwidth and reduced the Silver bandwidth so that the average rate for Gold flows is approximately double of the average rate for Silver flows, respecting the SLA.

7.2.2 – Simulation 2 - Gold class under loaded, Silver class overloaded.

In this second simulation, the Silver traffic is exceeding the reservation (Tab 6.13). This

implies no reassignment of the bandwidth for UDP traffic. The behavior is the same as in

the second scenario, that is: the admission control declasses the Silver exceeding traffic

into best effort traffic (Bronze).

For this reason Tab 7.8 and Tab 6.14 are identical.

Traffic Rate Full Duplex (CB R Sources) Gold Traffic Kbit/sec

Node 14 0 250 150 400

Node 13 250 150 150 550

Node 12 200 250 50 500

Total Rate 450 650 350 1450

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Node 14 150 150 150 450

Node 13 150 150 150 450

Node 12 150 150 150 450

Total Rate 450 450 450 1350

Bronze Traffic Kbit/sec

Node 14 ₁₀₀ ₅₀ ₁₅₀ ₃₀₀

Node 13 ₂₀₀ ₅₀ ₅₀ ₃₀₀

Node 12 ₅₀ ₅₀ ₁₀₀ ₂₀₀

Total Rate ₃₅₀ ₁₅₀ ₃₀₀ ₈₀₀

We obtain an average rate of 161 Kbit/s for Gold 150 Kbit/s for Silver and 89 Kbit/s for Bronze. The Total rate is 3600 Kbit/s. All values exactly equal to second scenario.

Gold Silver Bronze

0% 0% 34%

Gold Silver Bronze

100% 100% 66%

Tab 7.9 – UDP Packet Loss Scenario 3

Goodput Gold

1450 Kbit/s

1350 Kbit/s 3328 Kbit/s

Goodput Bronze

528 Kbit/s

Tab 7.10 – UDP Goodput Scenario 3

Average delay ms

30,2 37,4 51,8

9,2 7,1 21,8

Tab 7.11 – UDP Delay Scenario 3

Average jitter ms

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2,31 1,62 9,26

Tab 7.12 – UDP Jitter Scenario 3

As regards Tab 7.9 and Tab 7.10, the values are exactly the same as in the second scenario

(Tab 6.17 and 6.18). Also in this case the values obtained as regards the Delay and the

Jitter are similar for the two scenarios (although more Delay and Jitter values are a little

bit better for this third scenario).

7.2.2.1 - TCP Flows Rate

Total average rate Kbit/s Total rate Kbit/s

Gold _52,51 ₃₁₄₉

Silver _25,58 ₁₁₈₅

Bronze _3,86 ₃₄₇

Total 4681

Tab 7.13 - TCP Flows Rate Scenario 3

Total rate reserved Kbit/s

Gold 2983

Silver 1067

Tab 7.14 - TCP total bandwidth reserved to the first two classes

The total rate values are better than those reserved.

The service obtained is what we expected, that is an average rate per single Gold TCP

flow double (a little more than double in this case) than the average rate per Silver TCP flow.

7.2.3 – Simulation 3 - Gold and Silver classes overloaded.

Tab 6.25 shows the effective traffic for this third scenario, where both the Gold and the

Silver traffic are exceeding the reservation. As a consequence there is no reassignment of

the UDP bandwidth also in this case, and, also in this case, the behavior is the same as in the second scenario (Tab 6.26 and 7.21), that is: the admission control declasses the

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exceeding Gold traffic and the exceeding Silver traffic to best effort traffic (no Silver bandwidth is available).

For this reason Tab 7.21 and Tab 6.26 are identical.

We obtain an average rate of 300 Kbit/s for Gold, 150 Kbit/s for Silver and 144 Kbit/s for

Bronze. The total rate is 5350 Kbit/s.

Traffic Rate Full Duplex (CBR Sources) Gold Traffic Kbit/sec

Node 14 300 300 300 900

Node 13 300 300 300 900

Node 12 300 300 300 900

Total Rate 900 900 900 2700

Silver Traffic Kbit/sec

Node 14 ₁₅₀ ₁₅₀ ₁₅₀ ₄₅₀

Node 13 ₁₅₀ ₁₅₀ ₁₅₀ ₄₅₀

Node 12 ₁₅₀ ₁₅₀ ₁₅₀ ₄₅₀

Total Rate ₄₅₀ ₄₅₀ ₄₅₀ ₁₃₅₀

Bronze Traffic Kbit/sec

Node 14 ₁₅₀ ₁₀₀ ₅₀ ₃₀₀

Node 13 ₂₅₀ ₂₅₀ ₂₅₀ ₇₅₀

Node 12 ₅₀ ₁₅₀ ₅₀ ₂₅₀

Total Rate ₄₅₀ ₅₀₀ ₃₅₀ ₁₃₀₀

Gold Silver Bronze

0% 0% 60%

Gold Silver Bronze

100% 100% 40%

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Goodput Gold

2700 Kbit/s

1350 Kbit/s 4570 Kbit/s

Goodput Bronze

520 Kbit/s

Tab 7.17 – UDP Goodput Scenario 3

Average delay ms

37,8 43,1 60,9

9,8 12,3 23,1

Tab 7.18 – UDP Delay Scenario 3

Average jitter ms

2,78 4,83 16,70

0,62 2,00 9,99

Tab 7.19 – UDP Jitter Scenario 3

In this simulation of the third scenario, the results for the UDP traffic (Tab 7.16, 7.17,

7.18, 7.19) are a little bit worse than in the second scenario (Tab 6.29, 6.30, 6.32, 6.34);

but the difference is too small to speak about worse results, moreover the results are still

very good if compared with those obtained in the first scenario.

7.2.3.1 - TCP Flows Rate

Total average rate Kbit/s Total rate Kbit/s

Gold _54,46 ₃₁₁₁

Silver _26,78 ₁₀₈₂

Bronze _1,21 ₁₀₉

Total 4302

Tab 7.20 - TCP Flows Rate Scenario 3

tot reserved Kbit/s

Gold 2983

Silver 1067

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Like in the previous simulation, the values are very close to those reserved, and the service

obtained is better.

The service obtained is still improved, the average rate per single Gold TCP flow is the

double (a little more here too) than the average rate per Silver TCP flow.

If compared with the total TCP rate shown by the second scenario, we can see that it

increases by about 170 Kbit/s in the third scenario.

7.3 - TCP Varying

As in the previous chapter, in this set of simulations we will vary the TCP load leaving the

UDP fixed to heavily loaded values. This case is the ideal to show the differences between

the second and the third scenario, because this last scenario has been thought particularly

to improve the treatment of the Gold TCP traffic. Those differences are shown through the

use of 18 graphs regarding 6 simulations with the same characteristics as in the preceding

chapter.

In the following section, some considerations will be made about the third scenario

simulations in general. In the subsequent sections, the differences between the second

scenario and the third scenario will be analyzed in more detail, first fixing the number of

Silver TCP sources per aggregated flow to 1, 5 and 10, and varying the number of Gold

TCP Sources, then the number of Gold TCP Sources per aggregated flow will be fixed to

those numbers and the Silver will vary.

The values represented in the graphs are still the average rate per single class (Gold, Silver,

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7.3.1 – Third scenario simulation results (general)

The fist thing that can be noticed looking at the Graphs from 7.1 till 7.6 in this third scenario,

is that the rates of both Gold values and Silver values decrease, differently from the second

scenario (Graph 6.2, 6.4, 6.6, 6.8, 6.10, 6.12), where only one of the two rates decreases.

But the most important thing shown in each Graph, as expected, is that the Gold rates are

always more or less (many times more, few times less) the double than the Silver rates.

Scenario 3 - 1 Silver TCP sources

0,00 50,00 100,00 150,00 200,00 250,00 300,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 3 Silver 3 Bronze 3 Graph 7.1

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Scenario 3 - 5 Silver TCP sources 0,00 20,00 40,00 60,00 80,00 100,00 120,00 140,00 160,00 180,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 3 Silver 3 Bronze 3 Graph 7.2

Scenario 3 - 10 Silver TCP sources

0,00 20,00 40,00 60,00 80,00 100,00 120,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 3 Silver 3 Bronze 3 Graph 7.3

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Scenario 3 - 1 Gold TCP sources 0,00 50,00 100,00 150,00 200,00 250,00 300,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 3 Silver 3 Bronze 3 Graph 7.4

Scenario 3 - 5 Gold TCP sources

0,00 10,00 20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 3 Silver 3 Bronze 3 Graph 7.5

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Scenario 3 - 10 Gold TCP sources 0,00 5,00 10,00 15,00 20,00 25,00 30,00 35,00 40,00 45,00 50,00 1 2 3 4 5 6 7 8 9 10 Silver TCP sources Rate Kbit/s Gold 3 Silver 3 Bronze 3 Graph 7.6

7.3.2 – Silver class TCP fixed to 1, Gold class TCP varying

Looking at Graph 7.6, it is clear that in the third scenario the Gold rate is higher than in the

second scenario. In all the subsequent graphs the rate of the first scenario will be always

represented to remember the great improvements brought by both the second and the third

scenarios in comparison to the first.

From Graph 7.8, it can be noticed that the Silver rate of the third scenario is decreasing and

crosses the second one very soon. This fact is due to the increasing number of Gold sources

that are sharing the same bandwidth. When there are more Gold sources, the rate per Gold

source decreases, resulting in a decrease of the Silver rate, according to the specified

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3 Scenarios Gold - 1 Silver TCP sources 0,00 50,00 100,00 150,00 200,00 250,00 300,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 1 Gold 2 Gold 3 Graph 7.7

3 Scenarios Silver - 1 Silver TCP sources

0,00 20,00 40,00 60,00 80,00 100,00 120,00 140,00 160,00 180,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Silver 1 Silver 2 Silver 3 Graph 7.8

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7.3.3 – Silver class TCP fixed to 5, Gold class TCP varying

Looking at Graph 7.9, it can be noticed that the Gold rate in the third scenario is higher than

the rate in the second scenario when there are many TCP Gold sources, while it is lower when

there are few Gold sources. The behavior of the two scenarios is more or less the same with 5

Gold sources. This is obvious because the same number of sources implies a total Gold

bandwidth assignment that is exactly the double of the Silver, and, as the total rate must be 450 Kbit/s, the total bandwidth assigned to the Gold traffic is 300 Kbit/s and to the Silver

traffic is 150 Kbit/s, that is the same assignment as in the second scenario.

Graph 7.10 shows that the Silver rate in the third scenario is decreasing and crosses the rate of

the second scenario for around 5 sources. As explained in the previous section, this happens

because the rate per Gold source decreases in the third scenario, and to keep the established proportion, the rate per Silver source decreases also in the third scenario.

The total bandwidth assignment is higher than 300 Kbit/s for the Gold (and lower than 150

Kbit/s for the Silver), if the number of Gold sources is higher than the number of the Silver

sources. For this reason, the values in the graphs are better for the Gold class when there are

more than 5 Gold sources, the opposite happens for the Silver class.

For this reason, for both the following graphs, it makes sense to speak about the crossing of

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3 Scenarios Gold - 5 Silver TCP sources 0,00 50,00 100,00 150,00 200,00 250,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 1 Gold 2 Gold 3 Graph 7.9

3 Scenarios Silver - 5 Silver TCP sources

0,00 10,00 20,00 30,00 40,00 50,00 60,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Silver 1 Silver 2 Silver 3 Graph 7.10

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7.3.4 – Silver class TCP fixed to 10, Gold class TCP varying

Looking at Graph 7.11, it can be noticed that the Gold rate in the third scenario is always

lower than the rate in the second scenario independently of the number of TCP Gold sources.

But, even if higher, the behavior of the two scenarios is more or less the same with a high

number of Gold sources; while it is quite the same with 10 sources, because, as explained in

the previous section, the bandwidth assignment is the same in the two scenarios.

Graph 7.12 shows that the Silver rate in third scenario is decreasing but higher than in the

second scenario, this happens because with a number of Gold sources that is inferior to the

number of Silver sources, the proportion leads to a total Silver bandwidth assignment that is

higher than the 150 Kbit/s (and consequently lower than 300 Kbit/s for the Gold) obtained

with the second scenario, obviously similar values are reached with a high number of sources being quite the same with 10 sources.

3 Scenarios Gold - 10 Silver TCP sources

0,00 50,00 100,00 150,00 200,00 250,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Gold 1 Gold 2 Gold 3 Graph 7.11

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3 Scenarios Silver - 10 Silver TCP sources 0,00 5,00 10,00 15,00 20,00 25,00 30,00 35,00 40,00 1 2 3 4 5 6 7 8 9 10 Gold TCP sources Rate Kbit/s Silver 1 Silver 2 Silver 3 Graph 7.12

7.3.5 – Gold class TCP fixed to 1, Silver class TCP varying

It can be observed in all the following Graphs, that what was the rate of the first and the

second graph in the previous paragraphs, in a certain sense, now is inverted. This happens

because now the number of Gold sources is fixed, while it is the number of Silver sources to

vary. As they are sharing the same bandwidth, when there are more Silver sources, the rate

per Silver source decreases, resulting in a decrease of the Gold rate, according to the specified

proportion between their rates.

As can be seen in Graph 7.13, in the third scenario, the Gold rate is lower than that rate in the

second scenario. The only exception is the simulation with one Gold source and one Silver,

that is the same as in Graph 7.7, where the value of the third scenario is higher.

Graph 7.14 shows that the Silver rate of the third scenario is decreasing and always higher

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As explained in the previous section, this happens because with a number of Gold sources that is inferior to the number of Silver sources, the proportion leads to an assignment that is higher

than 150 Kbit/s for the total Silver bandwidth.

3 Scenarios Gold - 1 Gold TCP sources

0,00 50,00 100,00 150,00 200,00 250,00 300,00 1 2 3 4 5 6 7 8 9 10 Silver TCP sources Rate Kbit/s Gold 1 Gold 2 Gold 3 Graph 7.13

3 Scenarios Silver - 1 Gold TCP sources

0,00 20,00 40,00 60,00 80,00 100,00 120,00 140,00 160,00 180,00 1 2 3 4 5 6 7 8 9 10 Silver TCP sources Rate Kbit/s Silver 1 Silver 2 Silver 3 Graph 7.14

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7.3.6 – Gold class TCP fixed to 5, Silver class TCP varying

Looking at Graph 7.15, it appears that in the third scenario the Gold rate is higher than in the

second scenario for a low number of Silver sources, while it is lower for a high number. The

intersection is placed near 5 sources, because, as should be well know now, 5 sources implies

the same bandwidth assignment between the third and the second scenario.

In Graph 7.16 the situation is inverted, the Silver rate of the third scenario is higher than in the

second scenario when the number of Silver sources is high, while it is lower when the number

is low. The intersection is still around five.

The reasons for the rate variations in the graphs are exactly the same as explained in section

7.3.3, with the only difference that here the Silver sources are varying, while the Gold sources

are fixed to 5.

3 Scenarios Gold - 5 Gold TCP sources

0,00 10,00 20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 1 2 3 4 5 6 7 8 9 10 Silver TCP sources Rate Kbit/s Gold 1 Gold 2 Gold 3 Graph 7.15

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3 Scenarios Silver - 5 Gold TCP sources 0,00 20,00 40,00 60,00 80,00 100,00 120,00 140,00 1 2 3 4 5 6 7 8 9 10 Silver TCP sources Rate Kbit/s Silver 1 Silver 2 Silver 3 Graph 7.16

7.3.7 – Gold class TCP fixed to 10, Silver class TCP varying

As can be noticed in Graph 7.17, thanks to the number of Gold sources that is always higher

than the number of Silver sources, the Gold rate in the third scenario is always higher than in

the second scenario. The values are near just towards 10 Silver TCP sources.

In Graph 7.18 it appears that the Silver rate of the third scenario is decreasing and always

lower than the rate of the second. The values are near for a high number of Silver TCP

sources.

Also in this case the reasons of the proximity of the two graphs for the same number of

sources are due to the same reservation made in both the cases of the second and the third scenario.

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3 Scenarios Gold - 10 Gold TCP sources 0,00 5,00 10,00 15,00 20,00 25,00 30,00 35,00 40,00 45,00 50,00 1 2 3 4 5 6 7 8 9 10 Silver TCP sources Rate Kbit/s Gold 1 Gold 2 Gold 3 Graph 7.17

3 Scenarios Silver - 10 Gold TCP sources

0,00 20,00 40,00 60,00 80,00 100,00 120,00 140,00 1 2 3 4 5 6 7 8 9 10 Silver TCP sources Rate Kbit/s Silver 1 Silver 2 Silver 3 Graph 7.18