For questions relating to Ethernet networking, as defined by the IEEE 802.3 standards.
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13 views
How do I set up a shielded cat6 cable? [on hold]
I am extending a home computer network about 120 feet to a workshop. The 110v, three phase power will also be run as well.
There will be about a 4” separation going through the foundation. Separate ...
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0answers
18 views
Many routers behind main router cause slow internet? [on hold]
I don't know if this is the correct place to ask, but here i go.
We live with 10 people in 10 rooms in a 3 floor student house.
Every room has an ethernet connection.
When I do a speedtest I get an ...
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0answers
8 views
What specs required for my devices to reach 100Mbps for download? [on hold]
I just upgraded my fiber internet from 50Mbps to 100Mbps for download. But then found out that most of my devices are not able to reach the full speed. I used CAT 6 Ethernet cable to connect a desktop ...
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0answers
12 views
What happens when I hook two computers up via an Ethernet cable? [on hold]
There are a couple of steps I don't understand about what happens on a low level when I hook up two computers directly to each other, via an Ethernet cable, when neither has Internet access.
It seems ...
-1
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0answers
9 views
Installed 70m cat6 cable with fiber! But it did not reach the maximum speed [on hold]
Installed 70m cat6 cable with fiber! But it did not reach the maximum speed, I suppose to get 300 mp”/ but i get only 100 mega bit , i spoke with the provider company they said because of the length ...
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0answers
20 views
Creating a fast path directly to FPGA fabric [on hold]
We're developing a system based on a Xilinx Zynq 7000 FPGA/Cortex A9 ARM SoC.
The device has a hard gigabit MAC which connects to the ARM core, but it is also possible to implement a MAC in the FPGA ...
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3answers
41 views
How can 1000BaseT transmit on Rx & receive on Tx pins?
How can 1000-BaseT (Gigabit ethernet twisted copper pairs) technology transmit over the Rx pins & receive over the Tx pins?
It's baseband technology (hence the name), right? Discrete digital ...
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0answers
38 views
Whats wrong in my TCP connection [closed]
I'm writing software to control some ethernet-connected device. With the software delivered by the manufacturer this works fine.. they can send commands and the device acknowledges. In my ...
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1answer
103 views
Data link layer acknowledgement
I'm confused with some concepts please help me out,
Data link layer manage flow control hop to hop. Flow control requires acknowledgement receiving but If we observe data link layer header, it does ...
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2answers
89 views
Accessing Internet without WIFI or Ethernet
Theoretically, is it possible to access the internet through a browser without connecting to an ethernet cable or using WIFI?
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1answer
37 views
How does a device differentiate between a router interface and switch interface
We have a device in work, in the manual it says connect via a switch.
Obviously it works fine with any other device, once it is connected via a switch.
But say in a topology, it could be directly ...
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1answer
32 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 ...
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2answers
805 views
Ethernet padding value
When the data sent in an Ethernet frame is less than 46 bytes, extra padding needs to be added to the payload. The question is:
Which is the value of that Ethernet padding?
I'm asking since in real ...
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1answer
39 views
Feeding a PoE capable device with variable power supply over TIA568 A cable (DC spares)
The purpose of such a variable power over Ethernet supply would be to test network equipment that are receiving power over PoE under condition of conditions of low voltage or current and determining ...
1
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0answers
42 views
How to design network with high availability in a multilevel small workplace [closed]
I want to create a network in my work 4 floors 50m2*4 workplace.
Requirements are simple:
Share internet ( < 20mb/s ADSL) while blocking someone from abusing download speed for long period. (...
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1answer
20 views
Can QSFP28 (aka zQSFP) DACs be used in place of QSFP+ DACs for 40GBase-CR4 Applications?
All:
Have an testbed configuration where we're running 24 servers with Intel XL710DA1 40G NIC into a switch with 40/100G ports. Trying to use DACs to hold the cost down, but parsing the specs for ...
1
vote
1answer
23 views
For ethernet with bandwidth B, how much time a node has to wait before sensing the channel after the first collision detected?
Let's say one node detected a collision at t=0, in B Mbps ethernet, how long will that node wait before sensing the channel again?
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2answers
78 views
Determine whether the MAC address is of a router or the destination computer?
In a given Ethernet frame containing the HTTP GET message can we tell apart whether the MAC address of the destination is of a router or end host?
The link to ethernet-ethereal trace :: https://drive....
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1answer
26 views
How to compute the round trip delay
I have a query on how to compute round trip delay. I know it is 2 times the propagation time, but let's say I have a packet of 100 bits and a transmission speed of 2 Gbit/sec, how do I compute the ...
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1answer
30 views
Unconnected cable in a switch
A cable plugged into a switch but unconnected on the other end, might lead to any problem in a "noisy" environment (industrial)?
It's short, 50 cm, but there are motors, inverters, power supplies ...
1
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2answers
70 views
What are the reasons for ADSL to use ATM instead of Ethernet
I'm a newbie to networking and I wonder what are the reasons for ADSL to use ATM instead of Ethernet ?
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1answer
36 views
What is meant by “technology dependent” PHYs? [closed]
Is there something like "technology independent" PHYs?
To add the context as Zac67 correctly mentioned, I was reading clause 73 of 802.3-2015. 73.3 - Functional specifications.
Excerpt:
"The Auto-...
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3answers
59 views
Why do we need an ethernet MAC address? [duplicate]
Don't think it's a duplicate. I've searched really many articles and couldn't find the satisfying answer.
I understand :
how ARP works
MAC address is an unique address for each NIC
IP is network ...
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1answer
65 views
Setting MAC source address to broadcast
How would a network behave if one were to set the source address of an Ethernet frame to the broadcast address FF:FF:FF:FF:FF:FF?
Obviously, one would have to manually alter the relevant field in the ...
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2answers
44 views
What Are LAN technologies?
I know about different LAN topologies(like star, bus, ring,...) and that Ethernet is one of the ways to practically implement wired LANs. I wonder what other technologies exist to make LANs? And, is ...
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3answers
138 views
Can Ethernet use fiber optic cables?
I am new to networking, know about Ethernet and that Ethernet cables exist to make a wired networks. I also know about fiber optic cables which have a glass like material inside and transmit light ...
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0answers
11 views
How an MKA key server decides if it shall use MACSec and how it announce that?
According to IEEE 802.1X-2010 the standard for defining MACSec Key agreement protocol Clause 9.6, that's how the key-server decides to use MACSec or no.
Each participant advertises whether it is ...
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0answers
64 views
How are required Keys inside MACSec Key agreement protocol (MKA) generated?
I am trying to wrap my head around MACSec Key agreement protocol (MKA) and its relation with MACSec and other protocols. So bear with me.
To my understanding in order to MACSec to work, all nodes ...
2
votes
1answer
68 views
Packet vs Circuit switching
I have a 1Mb/s link each user uses 100Kb/s when active.
With 10 user active 10% of the time, I can have 10 users in a circuit switched environment. Packet switching with 35 users, probability > 10 ...
2
votes
1answer
98 views
End-to-End delay
I’m working through questions from computer networking top down approach and was hoping to get some clarity on the end-to-end delay calculation. At this stage we are not considering processing, ...
5
votes
4answers
677 views
Why is the Ethernet Connection Symmetric?
I know that cable connection (DSL) is asymmetric, there is a certain bandwidth on the channel, and for a better user experience, they allocate a bigger portion to the downstream. I suppose Ethernet ...
2
votes
2answers
81 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, ...
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1answer
81 views
Improve ping speed (lower up ping time) [closed]
In normal network with Cisco 3650 (1Gbps) and Linux base servers, the ping time is between 0.150ms to 0.250ms. (I also mean using ping or ICMP is to refer to all protocols)
I want to know is there ...
4
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1answer
546 views
Do we send ack frames in ethernet? if not then how does a router know if its neighbors are down or not?
So first off, do ethernet sends ack frames or not?
if it doesn't : then how does a router know whether its neighbors are down or not?
if it does : then is it cumulative ack with an ack timer or one ...
11
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2answers
3k views
Is the MTU of Ethernet still 1500 Bytes?
So basically do the modern routers in the internet still use 1500 as the MTU of Ethernet? or the 1500 Byte was for the old days?
What I'm asking here is what is the MTU of Ethernet in modern Networks?...
2
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2answers
197 views
Does Ethernet still use CSMA/CD?
So considering that CSMA/CD is for detecting collisions, mostly in a bus scenario with a lot of stations, then is CSMA/CD still used?
Because right now most of the connections are point to point (for ...
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1answer
70 views
Part of ethernet crc showing up in tcpdump
I am testing the ethernet transmission on my Digilent Nexus4 DDR FPGA. I created a really simple packet with a broadcast destination address and some made up ethernet type. Here is the packet as ...
3
votes
1answer
161 views
Dot1q tags, sub-interfaces
Please consider dot1q frames tagged 100 circulating on a LAN (VLAN 100).
To go out onto the Internet, frames have to go through a PPPoE sub-interface which is configured as below:
interface ...
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1answer
24 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 ...
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5answers
2k views
Does a Layer 3 switch become a Layer 4 device when telnetting?
In order to Telnet to a switch (Layer 2) we create an SVI, thus a layer 3 point of contact is made. The switch inspects each packet sent from the remote client and responds to it so that it gets ...
2
votes
1answer
45 views
Ethernet's frame format, length or EtherType?
Ethernet defines a 2 byte header for the payload's length in its frame format.
This header has an ambiguous meaning:
if smaller than or equal to 1500 it represents the payload length.
if ...
1
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0answers
18 views
SSH into device attached to another router [closed]
I saw this questionwhich looks kind of related, but I'm not sure as the answers are too confusing.
Basically, I want to SSH into my Raspberry Pi from my laptop. Eventually I want to have the Pi ...
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1answer
52 views
What is Ether? is it the same meaning with Ethernet?
What is Ether? is it the same meaning with Ethernet?
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1answer
43 views
IP/Device Question
I am very new to this field and I want to ask a quick question about IP/Device HTTPS.
When we type in the IP address of the device (cisco switch, router, firewall, etc), we can access to the web ...
4
votes
2answers
191 views
What is the springing mechanism for on the top of this transceiver module?
Some Ethernet SFP modules have them, some do not. What is the yellow springing mechanism and the attached metal wire meant for?
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1answer
42 views
Calculating buffer capacity
The serialization delay is the amount of time it takes to forward bits out of an interface. A 1 gigabit per second interface can send 1 billion bits per second. One billion bits per second equates to ...
2
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3answers
717 views
Is Ethernet a broadcast or point-to-point protocol?
Theoretically speaking, as far as I know Ethernet was developed to be used as a broadcasting protocol and technology. I guess nowadays it is not being used this way. Since ALL the examples I see refer ...
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2answers
133 views
Access a subnet through another network
We have some devices connected together through a switch. We need to access them through another network, but because of IP counts limitation we cant get IP from that network.
Q: How to access my ...
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2answers
38 views
Can a switch segregate traffic that is before the switch from after the switch?
Per the question, Lets try to clarify a bit. Can a switch that has a router connected to it, segregate traffic (using a VLAN) from traffic that is part of the modem/router the switch is connected to?
...
1
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1answer
36 views
Initial connection to WI-FI
My question is what is happening during the initial connection to a wireless network , is there an Ethernet connection first and then DHCP or something else is happening before the device receive an ...
