Switched observer – Network Instruments Observer User Manual

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Switched Observer

© 2002 Network Instruments, LLC


Switched Observer

Switches provide both performance advantages and debugging headaches for

network administrators.

The advantages are obvious: since a switch enables the network to handle

traffic effectively, in a way transparent to devices on the network and the

people using them, it provides efficiency and functionality from a centralized

location. Substituting virtual port connections for hard-wired port

connections enables multiple simultaneous connections between stations. It

also permits more efficient use of bandwidth by managing heavily trafficked

connections without the necessity of any intervention (or awareness, for that

matter) on the part of the user on either end.

The disadvantages should also be obvious: since the entire purpose of a

switch is to handle traffic in a way transparent to the rest of the network, it's

difficult to monitor the performance of a switch. This is not a problem when

the network is consistently performing optimally—if it is not broken, or

breaking, there’s no need to fix it—but when a problem does arise, the very

nature and function of a switch makes it difficult to detect, diagnose, and treat

the problem, as a switch is intended to hide what it is doing from the rest of

the network. Because of these complexities, it’s necessary to reconfigure

Observer’s Probe to monitor a switch.

When monitoring a switch, many of Observer’s modes/tools remain

available, but some act differently in order to help the network administrator

monitor the functionality of a switch.

Those modes that become unavailable will be grayed out.