Questions tagged [layer1]

For questions about the OSI layer-1 (physical layer).

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5 votes
3 answers

Importance of encoding data to signal

We all know that there are various encoding schemes to encode data like Manchester Encoding, before sending it. But why is there a need to encode the data to a signal? Why can't we just transmit the ...
20 votes
5 answers

Cable Colors and Purpose

I've been doing some work with some big businesses and so far I've learned yellow is internet and blue is phone. Is this a standard or is this just a personal chose? Do colors mean different tasks?
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16 votes
3 answers

DWDM active and passive comparison

I am trying to understand the cross-over point for when I would deploy active DWDM over passive DWDM (as active seems to be more expensive based on my initial research); Passive DWDM takes in various ...
  • 5,290
20 votes
5 answers

Where to cross RX/TX line in fibre optical cabling

I'm in the process of connecting together some sites via optical fibre. The trans-site multimode fibres are terminated with SC jacks on patch panels from where they are patched to the corresponding ...
3 votes
5 answers

Routing Serial cables instead of Ethernet

I am doing some CCNA training videos and using packet tracer and they showed using a serial cable to connect two routers. Why are serial cables used instead of Ethernet cables? Does it depend on the ...
3 votes
2 answers

How fast can information travel through various media?

I'm working on compiling some information about network latency and designing tests to help our support folks troubleshoot problems. In order to do this, I need some basic information that I don't ...
  • 379
4 votes
2 answers

Connecting 2 FCoE Switches together with optical cable

I'm designing a network and have 2 cabinets on each floor, and I'm thinking of using FCoE switches in both cabinets so that I can connect them with fibreoptic cable. I think I can easily find switches ...
1 vote
5 answers

Is it common for rackmountable servers to have fibroptic input and output? or is it cat 5 and you have to convert after?

If the switching hub is in the floor above the server, I've heard its best to use fibre-optic cabling to avoid interference from unrelated electrical cabling in the ceiling for lights etc... Is it ...
4 votes
5 answers

How do the different types of materials used in Ethernet cables affect reliability?

There are many metals used in different types of network cables, such as aluminum and copper. Some are expensive and some are cheap. What scenarios constitute the use of these types of different wire ...

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