CS 314 HARDWARE LAB - V (ATM) • • • • • • • • • • •
Simulation of ATM Switch performance, through put with mixed load conditions Implementing Ethernet on various platform (Windows NT, Window 95, UNIX, Mac OS Novell Netware) Installation of windows NT & Novell Netware Comparison of Network traffic Handling problems related to congestion using various tools (Net watcher etc) Comparison of utilization of various resources (Processor, memory, hard disk etc.) under different networking loads Familiarization with NDS in Novell. Memory Management Techniques in N/W Data compression & its Effects on N/W Security Aspects of N/W System efficiency Creation & maintenance user
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INDEX S.No Exp. No 1
1
Name of the Experiment
Page No
Simulation of ATM Switch performance, through put
3
with mixed load conditions 2
4
Comparison of Network traffic
18
3
5
Handling problems related to congestion using various
22
tools (Net watcher etc.) 4
6
Comparison of utilization of various resources
33
(Processor, memory, hard disk etc.) under different networking loads 5
11
Creation & maintenance user Accounts
39
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Experiment 1: Simulation of ATM Switch performance, through put with mixed load conditions Objective: Network performance analysis with an ATM switch implementing different scheduling techniques like First in First out (FIFO), Priority, and Round Robin Theory: In an ATM network, scheduling of cells is the major task of any ATM switch. Scheduling is the process by which the ATM switch determines the sequence of flow of the cells in network. The scheduling is done on various properties like service type, cell category, queue length, arrival time etc. First In First out (FIFO): FIFO is the simplest way of scheduling. As the name suggests, in this technique, the preference is given to that cell which comes first in the queue irrespective of its priority value. What comes next waits until the first finishes. The drawback of this technique is that some cells of very high priority like audio service encounter extra delay that is not ignorable. Priority: In this technique, each cell is assigned a certain priority value based on its traffic parameters. The scheduler checks the availability of highest priority cells and schedules them before going for the lower priority cells. The drawback of this algorithm is that cells of lowest priority starve for the resources when there are a large number of higher priority cells. Round Robin: In this technique, the scheduler gives equal preference for all priority types. Therefore, scheduler processes one cell of each priority type (If available) before going for the next cell and cycles through them. Here starvation never occurs because no priority is given. Round robin scheduling may not be desirable if QoS of the different priority type are highly variable. Procedure: In this experiment, we are going to analyze the link Utilization (%) of the outgoing link from an ATM switch
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First In First Out (FIFO): In NetSim, Select SimulationNewWANATM In the simulation environment window create the following scenario How to Create Scenario & generate traffic: •
Create Scenario: “Help NetSim Help Simulation New WAN ATM Create Scenario”.
Inputs: Follow the steps given in the different samples to arrive at the objective. In all Samples, •
Total no of CPE used: 4
•
Total no of ATM switch used: 2
The device are interconnected as given below •
CPE 1 is connected with switch 1 by link 1.
•
CPE 2 is connected with switch 1 by link 2.
•
CPE 3 is connected with switch 2 by link 4.
•
CPE 4 is connected with switch 2 by link 5.
•
Switch 1 and switch 2 are connected with link 3.
Set the properties for each device by following the tables,
Switch Properties
Switch 1
Switch 2
Scheduling technique
FIFO
FIFO
Buffer size
4096 KB
4096 KB
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CPE Properties
CPE 1
Destination
CPE 3
Transmission Type
Point to Point
Traffic Type
Data
Application Data Size Distribution
Constant
Mean Application Data Size (Bytes)
10000
Inter arrival time Distribution
Constant
Mean Inter-arrival time (Micro-sec)
10000
Generation rate (Mbps)
8
Scheduling
FIFO
Peak cell rate (cells/sec)
99999
Cell delay Variation tolerance (Micro-sec)
99999
GCRA type
VSA
CPE Properties
CPE 2
Destination
CPE 4
Transmission Type
Point to Point
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Traffic Type
Voice
Codec
Constant
Application Data Size (Bytes)
10000
Inter-arrival time (Micro-sec)
20000
Service Type
CBR
Generation rate (Mbps)
4
Scheduling
FIFO
Peak cell rate (cells/sec)
99999
Cell delay Variation tolerance (Micro-sec)
99999
GCRA type
VSA
Link Properties Bit
Error
Link 1 Rate No Error
Link 2
Link 3
Link 4
Link 5
No Error
No Error
No Error
No Error
(BER) Physical medium
E2
E2
E0
T1
T1
Data Rate (MbPS)
8.448
8.448
0.064
1.54
1.54
Distance
1
1
1
1
1
Simulation Time –10 Sec. (Note: The Simulation Time can be selected only after doing the following two tasks,
6 NetSim Experiment Manual
•
Set the properties of CPE and Switch,
•
Then click on the Validate & Simulate button).
“Save” it, upon completion of the experiment. Output: Select the metrics Utilization and Delay report (Link). Note down the link utilization of link 4 and link 5.
Priority: In NetSim, Select SimulationNewWANATM In the simulation environment window create the following scenario How to Create Scenario & generate traffic: •
Create Scenario: “Help NetSim Help Simulation New WAN ATM Create Scenario”.
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Inputs: Follow the steps given in the different samples to arrive at the objective. In all Samples, •
Total no of CPE used: 4
•
Total no of ATM switch used: 2
The device are interconnected as given below •
CPE 1 is connected with switch 1 by link 1.
•
CPE 2 is connected with switch 1 by link 2.
•
CPE 3 is connected with switch 2 by link 4.
•
CPE 4 is connected with switch 2 by link 5.
•
Switch 1 and switch 2 are connected with link 3.
Set the properties for each device by following the tables, Switch Properties
Switch 1
Switch 2
Scheduling technique
Priority
FIFO
Buffer size
4096 KB
4096 KB
CPE Properties
CPE 1
Destination
CPE 3
Transmission Type
Point to Point
Traffic Type
Data
Application Data Size
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Distribution
Constant
Mean Application Data Size (Bytes)
10000
Inter arrival time Distribution
Constant
Mean Inter-arrival time (Micro-sec)
10000
Generation rate (Mbps)
8
Scheduling
FIFO
Peak cell rate (cells/sec)
99999
Cell delay Variation tolerance (Micro-sec)
99999
GCRA type
VSA
CPE Properties
CPE 2
Destination
CPE 4
Transmission Type
Point to Point
Traffic Type
Voice
Codec
Constant
Application Data Size (Bytes)
10000
Inter-arrival time (Micro-sec)
20000
Service Type
CBR
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Generation rate (Mbps)
4
Scheduling
FIFO
Peak cell rate (cells/sec)
99999
Cell delay Variation tolerance (Micro-sec)
99999
GCRA type
VSA
Link Properties Bit
Error
Link 1 Rate No Error
Link 2
Link 3
Link 4
Link 5
No Error
No Error
No Error
No Error
(BER) Physical medium
E2
E2
E0
T1
T1
Data Rate (MbPS)
8.448
8.448
0.064
1.54
1.54
Distance
1
1
1
1
1
Simulation Time –10 Sec. (Note: The Simulation Time can be selected only after doing the following two tasks, •
Set the properties of CPE and Switch,
•
Then click on the Validate & Simulate button).
“Save” it, upon completion of the experiment. Output: Select the metrics Utilization and Delay report (Link). Note down the link utilization of link 4 and link 5.
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Round Robin: In NetSim, Select SimulationNewWANATM In the simulation environment window create the following scenario How to Create Scenario & generate traffic: •
Create Scenario: “Help NetSim Help Simulation New WAN ATM Create Scenario”.
Inputs: Follow the steps given in the different samples to arrive at the objective. In all Samples, •
Total no of CPE used: 4
•
Total no of ATM switch used: 2
The device are interconnected as given below •
CPE 1 is connected with switch 1 by link 1.
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•
CPE 2 is connected with switch 1 by link 2.
•
CPE 3 is connected with switch 2 by link 4.
•
CPE 4 is connected with switch 2 by link 5.
•
Switch 1 and switch 2 are connected with link 3.
Set the properties for each device by following the tables, Switch Properties
Switch 1
Switch 2
Scheduling technique
Round Robin
FIFO
Buffer size
4096 KB
4096 KB
CPE Properties
CPE 1
Destination
CPE 3
Transmission Type
Point to Point
Traffic Type
Data
Application Data Size Distribution
Constant
Mean Application Data Size (Bytes)
10000
Inter arrival time Distribution
Constant
Mean Inter-arrival time (Micro-sec)
10000
Generation rate (Mbps)
8
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Scheduling
FIFO
Peak cell rate (cells/sec)
99999
Cell delay Variation tolerance (Micro-sec)
99999
GCRA type
VSA
CPE Properties
CPE 2
Destination
CPE 4
Transmission Type
Point to Point
Traffic Type
Voice
Codec
Constant
Application Data Size (Bytes)
10000
Inter-arrival time (Micro-sec)
20000
Service Type
CBR
Generation rate (Mbps)
4
Scheduling
FIFO
Peak cell rate (cells/sec)
99999
Cell delay Variation tolerance (Micro-sec)
99999
GCRA type
VSA
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Link Properties Bit
Error
Link 1 Rate No Error
Link 2
Link 3
Link 4
Link 5
No Error
No Error
No Error
No Error
(BER) Physical medium
E2
E2
E0
T1
T1
Data Rate (MbPS)
8.448
8.448
0.064
1.54
1.54
Distance
1
1
1
1
1
Simulation Time –10 Sec. (Note: The Simulation Time can be selected only after doing the following two tasks, •
Set the properties of CPE and Switch,
•
Then click on the Validate & Simulate button).
“Save” it, upon completion of the experiment. Output: Select the metrics Utilization and Delay report (Link). Note down the link utilization of link 4 and link 5.
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Comparison:
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Traffic analysis:
High-speed links
CPE 1 is transmitting Data traffic (being generated at 8 Mbps) to CPE 3 through links 1, 3, and 4. CPE2 transmitting voice traffic (being generated at 4 Mbps) to CPE4 through link 2, 3, and 5. Here, voice traffic has priority over data traffic. Link speed of link 1 and 2 is high (8.448 mbps) as compared to data rate and also the PCR and CDVT of CPE1 and CPE 2 are high. So there is a low probability that these cells will be dropped. Therefore, all the cells reach switch1 where scheduling will happens. Link speed of link 3 is very low (0.064 mbps) which means it does not have enough resources to handle the cells. Hence, it will only pass those cells that have high priority (based on Scheduling technique). Link speed of 4 and 5 is high compared to link 3 and so there is no queue is buildup on switch 2. Based on what type of cells pass through link 3, determines the utilization of the link 4 and link 5.
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Inference: As we see in chart 1 and table 1, the utilization of link 4 is double of link 5 in case of FIFO. Because, in case of FIFO, scheduler gives preference to which come cells first. Note that the data rate of CPE1 id double than CPE2 data rate and link speed is same hence switch 1 gets two cells from CPE 1 and one cell from CPE2. Hence, switch 1 schedules two packets of CPE1 and one packet of CPE2. Therefore, the number of packet transmitted through link 4 is double than link 5 and hence utilization is also double. In case of priority, the utilization of the link 4 is 0.006 % and link 5 is 4.138%. This is because the ATM scheduler gives priority to the voice traffic (generated by CPE2 to CPE 4 via link 2, 3, and 5) over data traffic (generated by CPE 1 to CPE 3 via link 1, 3 and 4). The generation rate of voice traffic is 4 mbps which is much greater than the link speed of link 3 (0.064mbps). Hence, scheduler only schedules voice traffic and data traffic keeps waiting in the queue. In case of round robin the utilization of both the links is the same. Because, in case of Round robin, scheduler schedules the packet in circular fashion means one packet from CPE1 and one packet from CPE2. Note that the data rate of CPE1 and CPE2 is sufficiently high to ensure presence of a packet in the buffer from both the CPEs. Therefore, the number of packets transmitted through link four is same as link five and hence utilization is also same.
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Experiment 4: Comparison of Network traffic Objective: Study the effect of overheads for Voice and Data traffic on the performance of an ATM Networks Procedure: •
Create Scenario: “Help NetSim Help F1 Simulation New WAN ATM Create Scenario”.
Inputs: Follow the steps given in the different samples to arrive at the objective. In this Sample, •
Total no of CPEs used: 2
•
Total no of Switches used: 2
The devices are inter connected as given below, •
CPE 1, CPE 2 is connected with Switch 1 and Switch 2 by Link 1 and Link 3 respectively.
•
Switch 1 is connected with Switch 2 by Link 2.
Set the properties of Switch and CPE by following the tables for each sample, Switch Properties
Switch 1
Scheduling Technique Priority
Buffer Size (KB)
8
Switch 2 Priority
8
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Link Properties
Link 1
Link 2
Link 3
Bit Error Rate
No Error No Error
No Error
Physical Medium
E0
E0
E0
Distance (Kms)
1
1
1
Inputs for Sample 1: CPE Properties
CPE 1
Destination
CPE 2
Transmission Type
Point to Point
Traffic Type
Data
Application Data Size Distribution
Exponential
Mean Application Data Size (Bytes)
1500
Inter Arrival Time Distribution
Exponential
Mean Inter Arrival Time (micro sec)
20000
Peak Cell Rate (cells/second)
10000
Cell Delay Variation Tolerance 10000 (micro secs)
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Inputs for Sample 2 CPE Properties
CPE 1
Destination
CPE 2
Transmission Type
Point to Point
Traffic Type
Voice
Codec
G.711
Packet size (Bytes)
160
Inter Arrival Time (micro sec)
20000
Service Type
CBR
Peak Cell Rate (cells/second)
10000
Cell Delay Variation Tolerance 10000 (micro secs)
Simulation Time – 10 sec Output: To view the output by using NetSim Sample experiments need to be added onto the Analytics interface. The navigation for analytics is “Simulation Analytics”. Select the experiments by selecting WAN Protocols Select the Experiments (Note: Click one experiment after another to compare the experiments in the Analytics interface). Select the Metric: Overhead (%)
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Comparison Charts:
Inference: In ATM Reference Model there are three layers named as ATM Adaptation Layer (AAL), ATM Layer and Physical Layer. •
AAL will segment the data coming from higher layers and transfer it to ATM Layer.
•
AAL 2 supports voice and AAL5 supports data.
•
AAL 2 receives higher layer voice packet and adds 3 bytes overhead. It segments the packet into 47 bytes and adds 1 byte overhead. ATM layer adds 5 bytes overhead with that segment to make a 53 bytes cell.
•
AAL 5 segment the data packet into 48 bytes. ATM layer adds 5 bytes overhead with that segment to make a 53 bytes cell.
•
The overheads for the data are comparatively less than voice.
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Experiment 5: Handling problems related to congestion using various tools Objective: During client-server TCP downloads study the throughputs of Slow start + Congestion avoidance (also known as Old Tahoe) and Fast Retransmit(also known as Tahoe), Congestion Control Algorithms. Theory: One of the important functions of a TCP Protocol is congestion control in the network. Given below is a description of how Old Tahoe and Tahoe variants (of TCP) control congestion. Old Tahoe: Congestion can occur when data arrives on a big pipe (i.e. a fast LAN) and gets sent out through a smaller pipe (i.e. a slower WAN). Congestion can also occur when multiple input streams arrive at a router whose output capacity is less than the sum of the inputs. Congestion avoidance is a way to deal with lost packets. The assumption of the algorithm is that the packet loss caused by damaged is very small (much less than 1%), therefore the loss of a packet signals congestion somewhere in the network between the source and destination. There are two indications of packets loss: a timeout occurring and the receipt of duplicate ACKs Congestion avoidance and slow start are independent algorithms with different objectives. But when congestion occurs TCP must slow down its transmission rate and then invoke slow start to get things going again. In practice they are implemented together. Congestion avoidance and slow start requires two variables to be maintained for each connection: a Congestion Window (i.e. cwnd) and a Slow Start Threshold Size (i.e. ssthresh). Old Tahoe algorithm is the combination of slow start and congestion avoidance. The combined algorithm operates as follows,
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1. Initialization for a given connection sets cwnd to one segment and ssthresh to 65535 bytes. 2. When congestion occurs (indicated by a timeout or the reception of duplicate ACKs), onehalf of the current window size (the minimum of cwnd and the reciever’s advertised window, but at least two segments) is saved in ssthresh. Additionally, if the congestion is indicated by a timeout, cwnd is set to one segment (i.e. slow start). 3. When new data is acknowledged by the other end, increase cwnd, but the way it increases depends on whether TCP is performing slow start or congestion avoidance. If cwnd is less than or equal to ssthresh, TCP is in slow start. Else TCP is performing congestion avoidance. Slow start continues until TCP is halfway to where it was when congestion occurred (since it recorded half of the window size that caused the problem in step 2). Then congestion avoidance takes over. Slow start has cwnd begins at one segment and be incremented by one segment every time an ACK is received. As mentioned earlier, this opens the window exponentially: send one segment, then two, then four, and so on. Congestion avoidance dictates that cwnd be incremented by 1/cwnd, compared to slow start’s exponential growth. The increase in cwnd should be at most one segment in each round trip time (regardless of how many ACKs are received in that RTT), whereas slow start increments cwnd by the number of ACKs received in a round-trip time. Tahoe (Fast Retransmit): The Fast retransmit algorithms operating with Old Tahoe is known as the Tahoe variant. TCP may generate an immediate acknowledgement (a duplicate ACK) when an out-of-order segment is received out-of-order, and to tell it what sequence number is expected. Since TCP does not know whether a duplicate ACK is caused by a lost segment or just a reordering of segments, it waits for a small number of duplicate ACKs to be received. It is assumed that if there is just a reordering of the segments, there will be only one or two duplicate ACKs before the re-ordered segment is processed, which will then generate a new ACK. If three or more duplicate ACKs are received in a row, it is a strong indication that a segment has been lost. TCP then performs a retransmission of what appears to be the missing segment, without waiting for a re-transmission timer to expire. 23 NetSim Experiment Manual
Procedure: •
Create Scenario: “Help NetSim Help F1Simulation New WAN TCP Create Scenario”.
Sample Inputs: Follow the steps given in the different samples to arrive at the objective. Sample 1.a: Old Tahoe (1 client and 1 server) In this Sample, •
Total no of CPE’s used: 2
•
Total no of Routers used: 2
The devices are inter connected as given below, •
CPE 1 is connected with Router 1 by Link 1.
•
CPE 2 is connected with Router 2 by Link 3.
•
Router 1 and Router 2 are connected by Link 2.
24 NetSim Experiment Manual
Set the properties for each device by following the tables, CPE Properties
CPE2
Destination
CPE 1
Traffic Type
Data
Application Data Size Distribution
Constant
Application Data Size (Bytes)
1460
Window size (Bytes)
11680
Congestion Control
Old Tahoe
Router Properties
Router1
Router2
Buffer Size (KB)
8
8
Scheduling Type
FIFO
FIFO
Link Properties
Link 1
Link 2
Link 3
Distance (kms)
1
1
1
10-6
10-6
CAT5 (10 Mbps)
E2
Bit
Error
Rate 10-6
(BER) Physical Medium
E2
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Simulation Time - 10 Sec (Note: The Simulation Time can be selected only after doing the following two tasks, •
Set the properties of CPE , Router, & Link
•
Then click on the Validate & Simulate button).
Sample 1.b: Tahoe (1 client and 1 server) In this Sample, •
Total no of CPE’s used: 2
•
Total no of Routers used: 2
The devices are inter connected as given below, •
CPE 1 is connected with Router 1 by Link 1.
•
Router 1 and Router 2 are connected by Link 2.
•
CPE 2 is connected with Router 2 by Link 3.
•
CPE 1 is not transmitting data in this sample.
Set the properties for each device by following the tables, CPE Properties
CPE2
Destination
CPE 1
Traffic Type
Data
Application Data Size Distribution
Constant
Application Data Size (Bytes)
1460
Window size (Bytes)
11680
Congestion Control
Tahoe
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Router Properties
Router1
Router2
Buffer Size (KB)
8
8
Scheduling Type
FIFO
FIFO
Link Properties
Link 1
Link 2
Link 3
Distance (kms)
1
1
1
10-6
10-6
CAT5 (10 Mbps)
E2
Bit
Error
Rate 10-6
(BER) Physical Medium
E2
Sample 2.a: Old Tahoe (2 clients and 2 servers) In this Sample, •
Total no of CPE’s used: 4
•
Total no of Routers used: 2
The devices are inter connected as given below, •
CPE 1 and CPE 2 are connected with Router 1 by Link 1 and Link 2.
•
Router 1 and Router 2 are connected by Link 3.
•
CPE 3 and CPE 4 are connected with Router 2 by Link 4 and Link 5.
•
CPE 1 and CPE 2 are not transmitting data in this sample.
Set the properties for each device by following the tables, CPE Properties
CPE3
CPE4
Destination
CPE 1
CPE 2
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Traffic Type
Data
Data
Constant
Constant
Application Data Size Distribution
Application Data Size (Bytes) 1460
1460
Window size (Bytes)
11680
11680
Congestion Control
Old Tahoe
Old Tahoe
Router Properties
Router1
Router2
Buffer Size (KB)
8
8
Scheduling Type
FIFO
FIFO
Link Properties
Link 1
Link 2
Link 3
Link 4
Link 5
Distance (kms)
1
1
1
1
1
10-6
10-6
10-6
10-6
E2
(CAT5
E2
E2
Bit
Error
Rate 10-6
(BER) Physical Medium
E2
10Mbps)
Simulation Time - 10 Sec (Note: The Simulation Time can be selected only after doing the following two tasks, •
Set the properties of CPE , Router, & Link
28 NetSim Experiment Manual
•
Then click on the Validate & Simulate button).
Sample 2.b: Tahoe (2 clients and 2 servers) Do the experiment as sample 2.a, and change the congestion control algorithm to Tahoe. Sample 3.a: Old Tahoe (3 clients and 3 servers) In this Sample, •
Total no of CPE’s used: 6
•
Total no of Routers used: 2
The devices are inter connected as given below, •
CPE 1, CPE 2 and CPE 3 are connected with Router 1 by Link 1, Link 2 and Link 3.
•
Router 1 and Router 2 are connected by Link 4.
•
CPE 4, CPE 5 and CPE 6 are connected with Router 2 by Link 5, Link 6 and Link 7.
•
CPE 1, CPE 2 and CPE 3 are not transmitting data in this sample.
Set the properties for each device by following the tables, CPE Properties
CPE 4
CPE 5
CPE 6
Destination
CPE 1
CPE 2
CPE 3
Traffic Type
Data
Data
Data
Constant
Constant
Constant
1460
1460
Application Data Size Distribution
Application Data Size (Bytes) 1460 Window size (Bytes)
11680
11680
11680
Congestion Control
Old Tahoe
Old Tahoe
Old Tahoe
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Router Properties
Router1
Router2
Buffer Size (KB)
8
8
Scheduling Type
FIFO
FIFO
Link Properties
Link 1 Link 2 Link 3
Link 4
Link 5
Link 6
Link 7
Distance (kms)
1
1
1
1
1
1
1
Bit Error Rate
10-6
10-6
10-6
10-6
10-6
10-6
10-6
E2
E2
E2
(CAT5
E2
E2
E2
(BER) Physical Medium
10Mbps)
Simulation Time - 10 Sec (Note: The Simulation Time can be selected only after doing the following two tasks, •
Set the properties of CPE , Router, & Link
•
Then click on the Validate & Simulate button).
Sample 3.b: Tahoe (3 clients and 3 servers) Do the experiment as sample 3.a, and change the congestion control algorithm to Tahoe.
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Comparison Table: Slow start + TCP Downloads
Metrics
Congestion
Fast Retransmit
avoidance User lever throughput 1 client and 1
Reliability
server
Segments retransmitted User lever throughput 2 clients and 2
Reliability
servers
Segments retransmitted User lever throughput 3 clients and 3
Reliability
servers
Segments retransmitted
6.21
7.25
1
1
161
206
7.99
8.57
1
1
226
383
8.68
8.83
1
1
255
387
Inference: User lever throughput: User lever throughput of Fast Retransmit is higher when compared then the Old Tahoe (SS + CA). This is because, if a segment is lost due to error, Old Tahoe waits until the RTO Timer expires to retransmit the lost segment, whereas Tahoe (FR) retransmits the lost 31 NetSim Experiment Manual
segment immediately after getting three continuous duplicate ACK’s. This results in the increased segment transmissions, and therefore throughput is higher in the case of Tahoe. Reliability: The main feature of transmission control protocol is reliability. The reliability can be the ratio of number of segments that reach the destination to the number of segments transmitted in source. TCP ensures the reliability in the form of retransmission of those segments that are errored. Irrespective of SS + CA or FR algorithm, the reliability of the system is 1. Segments retransmitted As explained ion the inference on user level throughput, the segments re-transmitted of a FR algorithm are higher than the SS + CA algorithm.
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Experiment 6: Comparison of utilization of various resources (Processor, memory, hard disk etc.) under different networking loads Objective: To design a WAN Network and to analyze the concepts of utilization and Quality of services. Theory: Wide Area Network (WAN) is a computer network that covers a broad area (i.e., any network across metropolitan, regional, or national boundaries). The largest and most well-known example of a WAN is the Internet. •
What is Utilization?
Fraction of network capacity devoted to carrying the Payload + Overheads of the successful packets/ frames/ cells. The different components of Utilization are 1. Effective Utilization 2. Overheads 3. Loss
•
What is Link performance?
The performance of each link used in the WAN network. (i.e.) Link performance provides the Utilization, Effective Utilization, Loss, Overheads, Delay, Queuing Delay, Transmission Time and Propagation Delay values for all links used.
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What is Quality of Service?
•
QoS is the performance specification of a communications channel or system. QOS may be quantitatively indicated by channel or system performance parameters, such as Throughput, Loss etc. Procedure: •
Create Scenario: “Help Simulation New WAN Routing Create Scenario”.
Scenario:
In this Sample, •
Total no of CPE’s used: 6
•
Total no of Routers used: 3
The devices are inter connected as given below, •
CPE 1, 2 are connected with Router 1 by link 4,5 respectively
•
CPE 3, 4 are connected with Router 2 by link 6,7 respectively
•
CPE 5,6 are connected with Router 3 by link 8, 9 respectively
•
Router 1 is connected with Router 2 by link 1
•
Router 2 is connected with Router 3 by link 2
•
Router 3 is connected with Router 1 by link 3.
34 NetSim Experiment Manual
Sample Input: Set the properties of router by following the tables Router Properties
Router 1
Router 2
Router 3
Buffer Size (KB)
8
8
8
Scheduling Type
Priority
Priority
Priority
Protocol Type
RIP
RIP
RIP
Periodic Time (sec)
30
30
30
Expiration Time (sec)
180
180
180
Collection 120
120
120
Garbage Time (sec)
Set the following CPE and Link properties CPE Properties
CPE 1
CPE2
CPE3
CPE4
CPE5
CPE6
Destination
6
4
5
1
2
3
Priority
LOW
LOW
LOW
LOW
LOW
LOW
Traffic Type
Data
Data
Data
Data
Data
Data
Application Data 1472
1472
1472
1472
1472
1472
Size (Bytes) Distribution
Constant Constant Constant Constant Constant Constant
Arrival 1000
1000
1000
1000
1000
1000
MTU Size(Bytes) 1500
1500
1500
1500
1500
1500
Inter Time (µs)
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Link Properties
Link 1
Link 2
Link 3
Link 4
Link 5
Distance (km)
1
1
1
1
1
Bit Error Rate (BER)
No Error No Error No Error No Error No Error
Physical Medium
CAT 5
CAT 5
CAT 5
E2
E2
Link Properties
Link 6
Link 7
Link 8
Link 9
Distance (km)
1
1
1
1
Bit Error Rate (BER)
No Error
No Error
No Error
No Error
Physical Medium
E2
E2
E2
E2
Simulation Time - 10 Sec (Note: The Simulation Time can be selected only after the following two tasks, •
Set the properties of CPE & Router
• Click on the Validate & Simulate button) Output: Utilization Report:
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Link performance:
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Quality of service:
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Experiment 11: Creation & maintenance user Accounts Objective: To create a user account and edit the created account. Procedure: •
What is User account?
A user account is that which can be created in an operating system. Once this is Created, picture, password, type of access can be set. Only system Administrator has the privilege to open an account. •
How to create a user account in Windows XP?
To set up user accounts please follow the below given steps, (1) Log on to your computer as an administrator. Click Start, and then click Control Panel (2) Under “pick a category”, select “User Accounts”.
(3) Under “pick a task”, click “Create a new Account”. (4) In the User Accounts wizard, on the “Name the new account” page, type the name for the user. You can use the person's full name, first name, or a nickname. Then click Next.
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(5) The User Accounts wizard displays the “Pick an account type” page. Click Limited, and then click Create Account. Refer fig. (6) An account has been successfully been created. (7) To create another account, return to step 3. (Note: By using these steps, you have created a Limited Account. Limited accounts offer better security than Computer administrator accounts. However, limited accounts cannot make systemwide changes or install some applications. If you need to make changes to your system, log on with the administrator account you used to create the new accounts. Now that you have added new user accounts, you can change the default display pictures or create passwords for the accounts.) •
How to choose pictures for user accounts?
By default, accounts have standard pictures would be set. You can add your own picture for your account, which helps you identify your account easily. To choose a picture of your choice follow the below listed steps, (1) Log on to your computer as an administrator. Click Start, and then click Control Panel. (2) Under “Pick a category”, click User Accounts.
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(3) Under “or pick an account to change”, click the account for which you want to choose a picture or create a password. (4) To choose a custom picture •
Click “Change the Picture”.
•
Click Browse for more pictures which are available on the hard disk. Refer fig.
•
Click the picture you want to display for that account, and then click Open.
Windows XP will display the picture you select on the log-on screen. Refer fig.
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(5) Similarly by using fig, “Change the name” option can be used to give new name to the account (i.e. Haruni instead of Deepika.) Password can be set by using “Create a Password” option. Other users (except Administrator users) can be prevented. “Change the account type” can be used to change the type of account (i.e. Limited privileges to Administrator privilege). “Delete the account” option can be used to delete the account from the computer. This can be done only by the user who has the Administrator privilege. Also the user having an Administrator privilege can Add as many user as he/she wants and also delete the created ones.
Result: Example: In the name of Deepika (The user name that you create must be written), a user account. Also her picture has been changed by using the Change Picture option. Now you need to follow the above given procedure and do the following tasks, Create a User Account, Change the Picture, Change Name, Create Password, Change User Account Type and also Delete Account and give the respective outputs for them.
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