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Questions tagged [layer1]

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

1
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1answer
24 views

How to use“ Multimode SFP GLC SX MMD” in Cisco Catalyst 2960 S connected LAN and single mode OFC network

We have single mode OFC network and CAT 6 CAT5 LAN with ethernet and gigabit Ethernet switches and ordered for "GE SFP, LC CONNECTOR LX/LH TRANSCEIVER FOR SINGLE MODE FIBER OF CISCO CATALYST 2960 S" ...
3
votes
1answer
30 views

PTP 1588 VS SyncE

I have been struggling a whole day to understand the real differences of Precise Time Protocol (IEEE 1588) and Synchronous Ethernet (syncE) and their role in the network. Greatly appreciated if you ...
5
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4answers
971 views

Do layer 3 protocols use layer 2 protocols?

I saw the STP on layer 2. The guy that made the tutorial says at the end : Even though it seems that Layer 2 access layer solutions are slowly being replaced by blazing fast Layer 3 solutions. ...
1
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1answer
46 views

Counting the Number of re-transmission for a single UDP packet transmission in IEEE 802.11?

I was working with a client-server project based on UDP and 802.11 as a link and physical layer. There, the client was trying to probe some packets in the wireless channel to gauge channel condition. ...
6
votes
1answer
384 views

Why is there a separate set of 10 Gigabit fiber-optic transmission standards for WANs/SONET?

So, I'm reviewing the different IEEE transmission standards for an exam, and I've noticed that for the 10GBASE-X standards, there's two different sets of fiber-optic standards, 10GBASE-xW and 10GBASE-...
17
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6answers
3k views

What is this thread-like material on this Cat6 U/UTP cable?

Does anyone know what this thread-like material to the right on the picture is? Does it have anything to do with grounding? It is a Cat6 U/UTP cable.
4
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3answers
414 views

How to debug L1 Auto negotiation issues?

One of our Linux hosts has started switching its gears recently. While checking the interface speed, I could see that the interface has switched down to 10Mbps. The NIC and Switch are capable of 1G ...
8
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5answers
2k views

Do network adapters read incoming bits in a single stream?

When a Gigabit network adapter is receiving data, how is it receiving the bits? Is it seeing it all in one stream of 0's and 1's? Or is there somehow multiple streams of 0's and 1's coming in at the ...
0
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1answer
59 views

What is physically different between 10base-t and 100base-t?

I would assume that the primary difference between 10base-t vs 100base-t is the speed of the clocks interpreting the electrical signal. In other words, if you ensure that a "bit" is transmitted in 1 ...
1
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1answer
96 views

What type of Cat5e cable is this?

I am a fairly new networker and today I was terminating some cable at a gas station that is being built. The network cable that had been run from the gas pumps to the wiring closet confused the crap ...
0
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0answers
22 views

Fibre Channel Forwarding between devices behind single NPIV port

How does Fibre Channel switch with NPIV enabled port operates, when two devices behind the single NPIV port want to communicate with each other? e.g. Ethernet switch, would just drop frames, if ...
1
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1answer
35 views

Circuit switching. How is the data rate divided for each circuit in a link for FDM and TDM?

FDM allocates portions of bandwidth to each circuit in the link. According to the Nquist equation, this would propotionally divide the data rate among the circuits. Now with TDM time slots are ...
2
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2answers
87 views

Effect of large amount of bare ethernet pairs on network performance

I have a client who has been experiencing a significant amount of performance issues in regards to their telemarketing floor. On my initial assessment, I found that where the ethernet is punched down, ...
0
votes
1answer
30 views

How to show all data (bitstream with preamble, SFD) on Ubuntu with an Intel Ethernet Interface?

On my PC I have an Intel Ethernet Connection I217-LM with e1000e driver. If I receive packets in Wireshark or any libpcap based tool, the received ethernet frames start with Ethernet II frame and end ...
0
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0answers
35 views

CDMA vs FDMA vs TDMA efficiency

I am still trying to grasp exactly how CDMA works and could use a little help. As far as I understand, if using a chipping sequence of length 16, that means that 16 different bits (voltage levels) are ...
0
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1answer
57 views

Can bad cabling affect the overall network?

TLDR: Can a handful of problematic lines negatively impact the performance of the network as a whole? ... or would any problems stop once it reaches the switch? Longer Version (background): A ...
3
votes
1answer
167 views

To shield between patch panel and switch or not?

All network cables run from the outlets to the server room. They run next to power cables so it was decided to shield them. In the server room, they are going to be connected to a patch panel which ...
4
votes
1answer
469 views

How do data packets travel without merging?

I have been very interested in networking for quite a while, and I have been wondering this question. I've been thinking about this in complete binary, meaning how does a 0 of a data packet not get ...
1
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3answers
63 views

Custom CAT6A cable not reaching 1000mpbs

I purchased this CAT6A cable: https://www.amazon.co.uk/gp/product/B01M0VB4YD/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1 and did some network cables by myself in various lengths ranging from 1 ...
1
vote
2answers
122 views

CSMA/CD - CSMA/CA switch mix

Suppose I have 2 switches; one CSMA/CA (gigabit) and the other CSMA/CD (gigabit), would they work together when connected and if so would there be any dip in network performance? Thanks in advance!
7
votes
7answers
3k views

How LAN works in video games if only one station is permitted to transmit?

I've read the in a LAN the data is transmitted in packets so as to allow only one station to transmit at a given time, so how could this be applied in video games LAN parties if only one device is ...
2
votes
1answer
49 views

Cisco Router 1002f Sfp Port to Cisco swtich c3750 gigabit port

an anyone please instruct me how to connectCcisco router 1002f SFP ports to gigabit ports? I have an RJ45 port on switch side and an SFP port on router side. I like to use switch as dump switch. I ...
3
votes
2answers
141 views

How close can Ethernet cables be to power line if in parallel?

How close can unshielded CAT 5e/6/6a cables be in parallel to 110V power lines in rooms of common residential/commercial buildings before interference becomes an issue? If proximity between the two ...
1
vote
2answers
59 views

Transceiver for MM links up to 2k

I have 2 links of 1.5 mm f.o mm c / u I want to know if a transceiver GLC-GE-100FX would work for me, why and what are its variations.
0
votes
1answer
86 views

Stack cable connection concept in Cisco switch

Can you please share the concept of stack cable connection concept with redundancy and without for all kind of cisco switches, concept for if we have four switches in the same rack and if we have 8 ...
54
votes
9answers
19k views

Is 30 Mbit/s fibre faster than 30 Mbit/s copper? [duplicate]

A network engineer professional is overseeing our town's installation of fibre and was explaining how much faster it was. I pointed out that it wasn't a silver bullet as you had to pay the provider ...
2
votes
2answers
60 views

110 Block Frames and TIA-606-B

I have a large industrial work site with numerous Switch- and Control-Rooms containing horizontal and vertical patch panels, switches, etc. There has historically been no formal identification or ...
1
vote
4answers
96 views

Can we use two pairs of UTP with hubs?

I understand that hub always supports for half-duplex communication. In that case we should use one out of four UTP pairs. However, I read that for 10BaseT ethernet two pairs of UTP cables are used ...
1
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1answer
219 views

Fibre vs Copper short Distance

I am thinking of running Fibre optic from one room to a Nearby ONT/Router, I currently have about 15-20 meters of Cat 6, With a Gigabit UFB internet plan. With a short distance of around 20 meters ...
0
votes
2answers
45 views

Cable for 4Gb Fibre Channel

I have two servers with 4Gb Fibre Channel HBA adapters. Looking for cable for them, I found reasonably priced cables that say they're 10Gb. I know that if this was copper, it would be overkill, but I ...
4
votes
1answer
531 views

Why do we need a crossover cable for 1000BASE-T?

I'm doing course for CCNA and in one lecture teacher showed how to make a crossover cable for Gigabit Ethernet. But as I know Gigabit Ethernet uses all wires of twisted pair cable and each pair is ...
0
votes
2answers
53 views

Cat 5e wiring Type A incompatibility with Type B

I am not an engineer but I’m having problems with my small network in my business. I have 11 computers after 13 yrs am having major problems. My network keeps shutting down, and my dental software on ...
4
votes
3answers
141 views

Where are UTP cable speeds defined for Ethernet?

I have consulted several Network+ exam preparation books, Network+ practice exam questions, the IEEE 802.3-2015 standard, and several older TIA-568 standards. However, I'm having trouble finding a ...
1
vote
1answer
75 views

Connecting two PCs together via External Ethernet cards (T568A or T568B?)

Hi, I need some expert networking advise here. I have to connect two different PC together via a unique ethernet path. Please see attach picture. I however cannot go thru a switch or a hub. **my ...
4
votes
3answers
120 views

The recommended settings for giga ethernet connected to Ethernet port

What is the recommended duplex and speed configuration for giga ethernet port connected to legacy ethernet (10 mbps) port and there is no available duplex command available on the ethernet side? If ...
0
votes
1answer
53 views

Fiber Optic between two residential buildings [closed]

I'm not sure if this is the right forum, but thanks for your consdieration. Also, I apologize for the speculative nature of the question, I'm looking to extend internet to another building about ...
1
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1answer
80 views

TDM medium access control

In a TDM medium access control bus LAN, suppose the channel has a effective bandwidth of 10Mbps and each station has effective throughput of 1Mbps, then what is the maximum number of stations allowed ?...
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2answers
164 views

Why Ethernet was chosen to be the primary protocol + why carrier ethernet was created?

I'm currently trying to investigate the extra benefit that Ethernet has to offer for the internet today. As far as i investigated & know, Ethernet gives us a new hardware, cables and functionality ...
0
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0answers
67 views

Effects of CAT6A UTP cable being terminated with a CAT6A FTP RJ45 module

The rule of thumb is to pair the cable with the same type of termination. However, the wiring in place is CAT6A UTP and the equivalent RJ45 wall modules aren't easily available so wanted to ask if ...
1
vote
1answer
58 views

Can ethernet port be used for getting a signal from passive circuit

If we short circuit RX, TX of Serial port we can detect it by echos. Then we can detect whether Serial port is short circuited or not. Using that phenomenon I can create simple serial socket with ...
6
votes
4answers
3k views

Why preamble is not considered a part of the Ethernet Header?

If I search where does my data start in an Ethernet frame, I get a common answer which says TCP header( 20 bytes) + IP header ( 20 bytes) + Ethernet header( SA + DA + Type) i.e 14 bytes. So, in short ...
1
vote
2answers
87 views

What classifies as crossover cable?

The definitions I've read say that crossover cable is cabling which the receive and transmit pairs are swapped around. My question is based on the fact that beyond this, I've seen some diagrams which ...
1
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2answers
62 views

Do CAT5e structure weaken Voice signal when RJ-61 termination is used?

RJ-45 & RJ-61 does have different pins termination. Straight-A, Straight-B, Cross-Over (A & B each end) for RJ-45 (Data). Paired at middle going out method meaning 4 & 5 pin + 3 & 6 ...
3
votes
2answers
141 views

Which is preferred: Pulling or 'walking' cable?

I'm running some basic lines at a factory and I have basic training on punchdowns and where I am allowed to run the cable(in this case, CAT5e/6). I need to run a maximum of about 200 feet of cable. ...
1
vote
3answers
1k views

Why exactly is soldering discouraged in UTP networks?

I am aware that punch-down junction boxes and other solutions are the recommended methods for continuing an UTP cable that is too short, but you are not in control of replacing (for example, solid-...
1
vote
1answer
60 views

Is it possible.. Partial Duplex: 100mb one way & 1000mb the other

I have a potential application where the vast majority of the traffic will be in one direction, and, concurrently, I have a potential alternate use for a pair of wires in the cable that would ...
1
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2answers
70 views

Unknow category of a RJ45 cable

I need to buy some rj45 connectors for the following cable. Unfortunately, I've never seen this type of rj45 cable. From which category comes it? Cat-4, Cat-5, ... Thanks
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3answers
110 views

Are there any advantages in using optic fiber to connect a host computer to an ethernet LAN?

I saw that computer Network Interface Cards (NICs) that use fiber ports (SFP) instead of RJ-45 ports and I wonder if there would be any significant advantage in connecting the computers directly ...
10
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2answers
737 views

What does the naming convention for ethernet standards mean: 1000BASE-T , BASE-TX, BASE-SX, etc.? What is the meaning of the components of the name?

I understand the number in the naming convention. The number represents how many Megabits per second can the standard support. However, I do not understand the rest of the naming convention. What do "...
4
votes
1answer
295 views

How does a NIC know where the start of a frame is?

A question popped into my head today and after a quick few searches on google, I have no idea. When a device is sent a frame there is a layer 1 header/preamble saying the length and layer 2 protocol (...