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Existing Network Study

CPIT 375Data Network Designing and

Evaluation

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Outline:

– Existing Network Study• Network Availability• Network Utilization• Network Accuracy• Delay and Response Time• Checking the Status of internetworking devices

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Existing Network Study• After development team finish from writing the

requirements specification document and before the design process begin, they must analyze the existing network and any other resources the new network may depend.

• The effectiveness of a new network design depends on whether the current computing infrastructure can support the new requirement or not.

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Existing Network Study1. Analyzing the Current Network Availability

– Calculate the mean time between failures (MTBF) and the mean time to repair (MTTR) for the network

– Compare these results with information you have gathered (the goals)

– Does the customer expect your new design to increase MTBF and decrease MTTR?

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Existing Network Study

MTBF MTTR Date and Duration of Last Major Downtime

Cause of Last Major Downtime

Network ( as whole)

Segment 1

Segment 2

Segment n

1. Analyzing the Current Network Availability (Example)

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Existing Network Study2. Analyzing Network Utilization

– It’s a measurement of how much bandwidth is in use during a specific time interval.

– Utilization is commonly specified as a percentage of capacity.– Select the most appropriate network-monitoring tool to

computing network utilization (like: Capsa software)– It will help you in determine the capacity requirements of

devices and segments.

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Existing Network Study

2. Analyzing Network Utilization (Example)

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Existing Network Study3. Analyzing Network Accuracy

– It’s a measurement of lost or damaged packets.– It will help you to determine weather a need to increase

bandwidth, or upgrade internetworking devices.

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Existing Network Study4. Analyzing Delay and Response Time– To verify that performance of a new network design

meets a customer's requirements, it is important to measure response time between significant network devices before and after a new network design is implemented.

– A more common way to measure response time is to send ping packets and measure the round-trip time (RTT) to send a request and receive a response.

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Existing Network Study5. Checking the Status of Major Routers,

Switches, and Firewalls– It’s a process to check the behavior of the current

internetworking devices that have the most significant roles in the network.

– Checking the behavior and health of an internetworking device includes determining how busy the device is (CPU utilization), how many packets it has processed, how many packets it has dropped, and the status of buffers and queues.

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Existing Network Study5. Checking the Status of Major Routers, Switches, and

Firewalls• The method for checking the health of an internetworking device depends on the

vendor and architecture of the device. • In the case of Cisco routers, switches, and firewalls, you can use the following Cisco

IOS commands:– show buffers. Displays information on buffer sizes, buffer creation and deletion, buffer

usage, and a count of successful and unsuccessful attempts to get buffers when needed.

– show environment. Displays temperature, voltage, and blower information

– show memory. Displays statistics about system memory, including total bytes, used bytes, and free bytes.

– show processes. Displays CPU utilization, and the percentage of CPU used by various processes including routing protocols, buffer management, and user-interface processes.

– show version. Displays software version and features, the names and sources of configuration files, the boot images, the configuration register, router uptime, and the reason for the last reboot.

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Second Project’s Task• Collect as much information as possible about

current environment for the organization where you will develop new network in it– Present technology at client site– Present setup– Documentation of work, diagrams, schedules, list

hardware and software used, financial budget and cost…etc.

– User feedback about possible improvement in present service.