What Is The Value Of The Network?

A network has no value by itself

Networks allow users and applications to access information

To be of value, a network must provide

Reliable connectivity

Acceptable performance

New networking infrastructures are growing

Each technology increases performance, reliability, or both

Today’s Performance Management Tools

Performance Management:  Designing, testing, monitoring, and stressing computer networks

Simulation and Modeling Tools

Passive Monitors

Traffic Generators

Simulation and Modeling Tools

Mathematical representations of the network

Rely on detailed information about network devices, links, protocols, and data traffic

Allow what-if analysis without changing the network

Identify bottlenecks in the network’s design

Help minimize tariffs

Have difficulties accurately predicting performance in dynamic, complex, multi-vendor networks

Passive Monitors

Monitor traffic passing on a LAN or WAN link

Examples include LAN analyzers, RMON probes, and SNMP agents

Give the most accurate view of the traffic flowing on segments of a network

Have difficulties providing an end-to-end view of network performance

Traffic Generators

Create network traffic to proactively evaluate    performance and reliability

Simple applications such as Ping and FTP

Specialized products, e.g., packet generators

Can create controlled, repeatable network traffic

Difficult to simulate real application flows

Hard to extend to a production network

A Reality Check

What happens when an ATM cell is dropped in a TCP connection?

Cell Generator

Lost one cell, the rest were fine

Real Applications

Lost one cell

Discard the rest of the cells in the TCP frame

Sending side times out waiting for an acknowledgment

Retransmit lost frame

Go into TCP Slow Start

What’s Missing

Simulate real application flows over multiple protocols

Measure end-to-end performance

Run on existing software and hardware

Scale for very large tests

Many users

High bandwidth

Work well in test labs or in production networks

Be easy to use

Qualify Hardware and Software

Evaluate performance of protocol stacks

Evaluate performance of hardware vendors

Use same network configuration and applications to compare vendor results

Profile Application Demands

Install  endpoints in the production network

Performance of new applications can be tested before deploying

What will user response time be?

What effect will they have on other applications?

Does the network or application need to be changed?

Verify Network Changes

Use established benchmarks to test network performance

Make network changes to devices, routing tables, topology

Validate performance of new devices or topology using the same benchmarks

Testing Data Compression

Choose the type of data sent between endpoints

Standard Calgary Corpus support as well as user-defined data

Evaluate performance of various devices

Test performance for remote access applications

https://www.bestitdocuments.com/Samples