Download - AQM performance for VOIP
Performance Analysis of AQM for VOIP Application
MakkawiAbdelsalmMohammed KhairFuture university ,249915001523, [email protected]
Dr. Mohammed Hussain Supervisor
• VOIP • Problems • Objectives• AQM
• RED• ARED• GRED• WRED
• Scenario 1• Scenario 2 • Results • Conclusion• Future work
Overview
VOIP
• Voice Over Internet Protocol• Is the technology that uses the Internet Protocol to transmit voice conversation over a data network.
• The primary advantages of moving voice over a data network are increased efficiency and decrease cost.
• Delay• Jitter• Packet loss
VoIP QoS Issue
Enterprise: Private Branch Exchange (PBX)
7043
7040
7041
7042
External line
Telephoneswitch
Private BranchExchange
212-8538080
Anotherswitch
Corporate/Campus
InternetCorporate/Campus LAN
Post-divestiture phenomenon...
Enterprise VoIP: Yesterday’s networksCircuit Switched Networks (Voice)
Packet Switched Networks (IP)
PBXPBX
COCO
CO
Router
RouterRouter
Router
Router
Headquarters Branch Offices
Enterprise VoIP: Today’s networksToll by-pass
Circuit Switched Networks (Voice)
Packet Switched Networks (IP)
PBXPBX
COCO
CO
Router
RouterRouterRouter
Router
Headquarters Branch Offices
Enterprise VoIP: Tomorrow’s networksUnified/Converged Networks
Unified Networks (Voice over IP)
Router
RouterRouter
Router
Router
COCO
Legacy PSTN
Headquarters Branch Offices
ProblemsThe main problem of this work is that voice is highly sensitive for delay and packet loss
in network (Cisco Systems, 1992–2008).
It is crucial to have a proper QoS mechanism to guarantee minimum delay and packet
loss
Therefore, it is the purpose of this research to determine how does the AQM mechanisms
deal with the services such as VoIP. Furthermore, it will try to investigate what are the
most powerful mechanisms that can provide the best results to meet the objective of the
Quality of Services (QoS).
Objectives
It is the objective of this research to compare the performance of four mechanism of AQM in terms of packet delay,
packet loss, variation of delay and throughput.
Specifically it would like to achieve the following: 1. Determine the performance of RED (Random Early Detection) in terms of:
a) Packet delayb) Packet lossc) Variation of packet delayd) Throughput
2. Determine the performance of ARED (Adaptive Random Early Detection) in terms of a) Packet delayb) Packet lossc) Variation of packet delayd) Throughput
Objectives3. Determine the performance of GRED (Gentle Random Early Detection) in terms of
3. Packet delay4. Packet loss5. Variation of packet delay6. Throughput
4. Determine the performance of WRED (Weighted Random Early Detection) in terms of a) Packet delayb)Packet lossc) Variation of packet delayd)Throughput
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Active Queue Management
Queue
SinkOutbound LinkRouterInbound Link
SinkACK…
ACK…
Queue
SinkOutbound LinkRouterInbound Link
SinkACK…
ACK…
Queue
SinkOutbound LinkRouterInbound Link
SinkACK…
Drop!!!
Queue
SinkOutbound LinkRouterInbound Link
Sink
Queue
SinkOutbound LinkRouterInbound Link
Sink
AQM
Congestion
Congestion Notification…
ACK…
Queue
SinkOutbound LinkRouterInbound Link
Sink
AQM
Advantages• Reduce packet losses (due to queue overflow)• Reduce queuing delay
scr2
scr1
Let us See How This Mechanisms Works ….
RED (Random Early Detection)
PP
PP
PP
PP
PP
PP
RED MECHANISM
minmax
PP
PP
PP
PP
PP
PP
RED MECHANISM
minmax
P
PP
Case1 : packets < min threshold = no drop
PP
PP
PP
PP
PP
PP
RED MECHANISM
minmax
P
PP
P
PP
Case2 : min threshold< packets< max threshold = drop with probability
PP
PP
PP
PP
PP
PP
RED MECHANISM
minmax
P
PP
PP
P
PP
Case2 : min threshold< packets< max threshold = increase the drop
PP
PP
PP
PP
PP
PP
RED MECHANISM
minmax
P
PP
PP
PP
PP
P
PP
PPP
Case3 : packets > max threshold = drop all incoming packets
What About ARED ?!!
(Adaptive Random Early Detection)
PP
PP
PP
PP
PP
PP
ARED MECHANISM
minmax
PP
PP
PP
PP
PP
PP
ARED MECHANISM
min
P
PP
max
Case1 : packets > min threshold = adapt the queue (decreas max threshold)
PP
PP
PP
PP
PP
PP
ARED MECHANISM
min
P
PP
P
PP
max
Case1 : packets < min threshold = drop with probability
PP
PP
PP
PP
PP
PP
ARED MECHANISM
minmax
P
PP
PP
P
PP
Case2 : packets < min threshold = adapt the queue (move min threshold)
P
P
PP
PP
PP
PP
PP
ARED MECHANISM
minmax
P
PP
PP
P
PP
P
PPP
PP
P
PP
max
PPP
Case3: packets > max threshold = adapt the queue (move max threshold)
Drop all incoming packets
We still have GRED
(Gentle Random Early Detection)
P
P
PP
PP
PP
PP
PP
GRED MECHANISM
minmax
P
PP
P
PP
P
PP
PP
PP
PP
P
PP
minmaxDouble max
P
PP
P
PP
P
PP
P
PP
P
PP
P
PP
PPP
Increase the length of the queue by doubling the maximum threshold
Finally we have WRED
(Weighted Random Early Detection)
PP
PP
PP
PP
PP
PP
WRED MECHANISM
minmax
PPP
PPP
PPP
PPP
PPP
PPP
P High priority P Mid priority P Low priority
Deal with the data according to it’s priority
OPNET Object Hierarchy
C/C++ Code
Process
Node
Subnet
Scenario
Project
First Scenario
First scenario parameters
• This scenario based on changing the number of users while the other parameters remain constant
• The below table shows the simulation parameters that used in this scenario
Simulation parameters
Number of User Variable from 5-300
Data forwarding rate (packets/second) 500000
Maximum queue size 100
Minimum threshold 10
Maximum threshold 20
Mark probability denominator 0.1
Simulation duration 1 hour
Encoder scheme G.711 (silence)
Voice frame per packet 5
Dumbbell Topology
10 users results
50 Users Topology
50 Users Results
300 Users Topology
300 Users Results
Second Scenario
Second scenario parameters
• This scenario based on changing the number of users while the other parameters remain constant
• The below table shows the simulation parameters that used in this scenario
Simulation parametersNumber of User 10 ,50,300
Data forwarding rate (packets/second) 500000
Maximum queue size Variable 200,300,500,1000
Minimum threshold 20
Maximum threshold 60
Mark probability denominator 0.1
Simulation duration 1 hour
Encoder scheme G.711 (silence)
Voice frame per packet 5
Maximum queue size(packets)=200 (jitter)
10 users 50 users 300 users
Maximum queue size(packets)=200 (drop)
Router A 50 users Router A 300 users Router A 10 users
Maximum queue size(packets)=200 (drop)
Router B 10 users Router B 50 users Router B 300 users
Maximum queue size(packets)=200 (delay)
10 users 50 users 300 users
Maximum queue size(packets)=1000 (Jitter)
10 users 50 users 300 users
Maximum queue size(packets)=1000 (drop)
Router A 10 users Router A 50 users Router A 300 users
Maximum queue size(packets)=1000 (drop)
Router B 10 users Router B 50 users Router B 300 users
Maximum queue size(packets)=1000 (delay)
10 users 300 users 50 users
Conclusion• This study evaluated the performance of VoIP over Ethernet WAN by applying AQM mechanism
using OPNET simulation tool. • A comparison has been conducted between four of (AQM Active Queue Management) methods
RED, ARED, GRED and WRED This comparison aimed to identify which method offers more satisfactory performance measures for application like VOIP.
• A decision which method offers more satisfactory performance measure results is only made depending on varying the number of users and number of maximum queue size in the routers
• It has been found that the configuration of the RED algorithm and GRED is not axiomatic. They must consider many situations such as network traffic, the traffic type, nature and duration of possible bursts, delays in the network, etc.
• It has been seen that in general, the ARED and GRED algorithms performs better, achieving a lower discard rate and lower overall delay. One problem that has been is the average queue size parameter tends to oscillate, especially given configuration changes and wq the minimum threshold, so care must be taken to configure.
Future work • This study used the comparison according to one type of traffic, it recommend that to use some
other traffic such as Http or video to see how this mechanism will deal with the VoIP packets while there is another types of packet.
• Other parameters could be considered such as different encoder scheme and number of voice frame per packet.
Thank you