Orhan Ergun 5 Comments

Bad Network Design

Bad Network Design – Availability of  a system is mainly measured with two parameters. Mean time between failure (MTBF) and Mean time to repair (MTTR)

MTBF is calculated as average time between failures of a system. MTTR is the average time required to repair a failed component (Link, node, device in networking terms)

Operator mistakes is widely seen as the source of the failure of the systems. Thus although it is not individually used to calculate availability value of a system, Mean time between mistakes (MTBM) is commonly used term among the network engineers.

Most failures are caused by human error;estimate range between 70 to 80 percent. How can so many people are so incompetent?

Actually they are not ! It’s a design problem.

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Orhan Ergun 4 Comments

Root Cause Analysis

Designers should be trained to identify the real issues for customers in computer network designs. Developing an excellent solution for the wrong problem can cause more damage than doing nothing at all. Finding the right issue is vital for assisting customers.

Imagine a customer tells you that they need a CGN (Carrier Grade NAT) solution and wants you to design their network.

Instead of jumping immediately to that solution, you should take time to determine the real issue.

After analysing the problem, you find the customer’s real issue was an IP address exhaustion. Then you come up with a range of solutions that include IPv6, CGN, asking for a new block from registry, existing address redesign.

You should keep in mind the advantages and disadvantages for each solution, and also include possible future benefits and potential issues.

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