Questions tagged [layer1]
For questions about the OSI layer-1 (physical layer).
321 questions
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How do DS1, DS2, and DS3 differ from ITU-T G.704?
I like to go to the source documentation to deeply understand topics.
I see the DS1 and DS3 data rates mentioned here:
ITU-T G.704: Synchronous frame structures used at 1544, 6312, 2048, 8448 and 44 ...
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Cat cable pairs' twist rate and how that affects crosstalk
I understand that more twists result is a cleaner signal because the crosstalk is reduced, but how is the rate of twist affecting the physical properties of the wire pair themselves to reduce that ...
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Question about the way networks are described vs their modern implementations
I am a networking student and I am currently pursuing my CCNA. I am primarily enrolled in the Cisco NetAcad.
My question is in regards to how certain networks are described in these courses compared ...
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Relationship between reconciliation sub-layer and PLS_Service Primitives, MII Signals in IEEE Clause 22
While reading the IEEE Standard for Ethernet, I'm confused about the direction of the arrows in this figure:
(The arrows point from RS sub-layer to PLS_Service Primitives.)
First, I want to know if ...
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How to calculate or specify these terms Throughput, Data rate, Bandwidth? [duplicate]
The term "throughput" clearly refers to the actual data received in a system. For instance, with a bandwidth of 5MHz and a channel capacity (data rate) of 10Mbps, if the received data is ...
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Baffled: No continuity but excellent speed on six new Cat6 runs
For my first post on Stack Exchange I have a situation that seems to be impossible: fast internet on cables that show no continuity.
I just installed 16 Cat6 ethernet runs in an office. All of them ...
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TCP/IP and data cut
I would like to clarify my understand about TCP/IP model and packet cutting. I think it's done by layer 3 (Transport, eg. TCP) but I'm note sure about layer 2 (Network, eg. IP) or even layer 1 (...
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What are different encoding schemes used in gigabit ethernet?
I was reading about digital transmission, there are many steps namely:
Analog to Digital conversion
Source coding
Channel coding
Line coding
Pulse shaping
Modulation
Multiple access techniques
...
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Camera instead of ethernet cables
My electricians messed up and installed some sort of camera (or very old cat3?) cables, instead of the requested ethernet cables (see picture). Now I have two of those, running for about 15 meters ...
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How does a network hub work? [closed]
When reading about hubs, I always found some information in the following sense:
"The hub is a dumb device, it has no information about the devices that are connected to, his mission is all about ...
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What is Ethernet MDI in the case of SFP interfaces
I am reading on Ethernet and I understand that for copper ports, the MDI is the physical connections from the PHY to the medium's connector, including the physical port itself, where the cable is ...
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Length of Ethernet Preamble on 10Gb network
I know (see https://en.wikipedia.org/wiki/Ethernet_frame) that an Ethernet frame includes a 7 byte preamble of 0x55s and a one byte start frame delimiter (SFD) 0xD5, for a total of 8 bytes before the ...
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MTU mismatch scenario, two hosts handle in a different way ingoing packets bigger than local interface MTU. How does MTU really work?
I’ve been struggling with the MTU topic for a while and I still can’t get how it really works. The majority of books that I read and the courses that I attended all seem to treat this subject in a ...
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Do telephone calls work at Layer2?
We know that Wi-Fi works in both layer1 and layer2 and travel through air in layer1.
My question is when we create mobile phone call during connection establishment phase sender Mac address and ...
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What is difference between broadband and baseband signal with respect to full duplex?
We know that broadband signal is full-duplex, for example television cable line where all TV channel is used portion of bandwidth not full bandwidth. And modern baseband is also full duplex but all ...
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