Suitable ratio to select your TAP
When a user wish to insert an optical TAP within the network, a part of the light signal was abosrbed to copy the traffic. lorsqu'un utilisateur souhaite insérer un TAP Optique sur sa chaîne de liaison, une partie du signal lumineux sera absorbée pour la copie du trafic. The proportion between the signal within the prduction link and the power within the link to the equipment is the TAP RATIO.
Problematic: the ratio is the same for each manufacturer: 50/50, 60/40, 70/30, 80/20 and 90/10. The firsyt number indicates the percentage keeped for the production link, the secont number indicates the percentage of the light reserved for the monitoring port. The issue is to select the right compromise between the nessity to presure the necessary energy ensuring the proper functioning of the production links and of the monitoriing links.
What are the right questions to determine the good TAP ratio ?
What is the least sensibility to ensure the running of the active equipments: this value provides the luminous intensity to ensure the proper functioning of the optical interfaces embedded within the equipments below:
- production servers,
- monitoring probe or security appliance,
- switches (in that case, it's important to keep in mind the SFP connectors. These values are calculated in dBm. Our white paper describes the mathematical notions for a right comprehension - follow the link here)
The optical attenuation due to the optical fiber: an optical fiber generate an optical attenuation. For a multimode fiber, this attenuation is greater than for a monomode fiber with a sae length. The connectivity of the fiber is a very important variable too as the quality of the fiber itselfdependaing of the classification OM1, OM2, OM3 and OM4. The available throughputs within OM1 and OM2 fiber are up to 1Gbps due to a refractive index greater with this kind of fibers. Attenuation are calculated in dBm.
Power provided by active équipements: most of the active equipments display the value of the power generated. It is fundamental to know this value with a CLI instruction or by measurement with an accurate optical measurement tool.
By knowing those different parameter, it is possible to prepare the implementation scheme to deduct the proper TAP ratio. This last step could be realise by yourself or you can contact Tapics Professional Services to do it.
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