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For questions relating to Ethernet networking, as defined by the IEEE 802.3 standards.

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I can connect to the second router but no internet? [on hold]

Before I ask my initial question, I'll explain the setup and background. I am helping a business fix their internet after a camper reported that the internet had gone out. I went to check, and sure ...
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3answers
40 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
33 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
35 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
124 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
8 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
19 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
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1answer
56 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
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1answer
49 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, ...
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4answers
646 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
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2answers
75 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
74 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
516 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 ...
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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
115 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
32 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
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1answer
153 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 ...
0
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1answer
21 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
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1answer
37 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 ...
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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 ...
-1
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1answer
48 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
41 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
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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
36 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 ...
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3answers
551 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
106 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
36 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? ...
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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 ...
0
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1answer
31 views

Compatibility of CentreCom Transceiver 210TS 10BaseT Ethernet with modern Ethernet

I have two old legacy system communicating each other using CentreCom 210TS 10BaseT Ethernet Transceiver. The Transceivers are connected to AUI port of system. SQE test is disable on both transceiver. ...
3
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1answer
64 views

What is a fractional port?

I was reading a product sheet about a Metro-Ethernet backhaul service which mentions, which is described as a mechanism to connect two datacentres within the same region (ie, city) via point-to-point ...
3
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2answers
367 views

Is there 64k range VLAN support?

All i have learnt and understood so far about VLAN is - we can create a max of 4k VLANs (subjected to platform capability). However, as per the protocol 802.1Q there is only 12 bits kept for ...
4
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1answer
454 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 ...
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1answer
176 views

What is the EtherType of a BPDU frame sent by a switch which runs Spanning Tree Protocol

I want to know what is the EtherType field of a BPDU frame in various versions and variants of the Spanning Tree Protocol.
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2answers
207 views

Are normal packets ever combined into jumbo packets?

Do routers ever combine multiple small frames into a jumbo frame then split them up again on the other end? I know that most of the time it wouldn't make sense to do because you would add latency by ...
3
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2answers
68 views

Any reason to use hubs?

Given that hubs are essentially the same as switches, as far as I know, except they share bandwidth between all connected devices, while switches do not, resulting in faster connections. I am simply ...
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1answer
61 views

How might I test layer2 latency over ethernet without a target IP address? [closed]

Is there a way, via standard ethernet layer2 protocols, to test latency to a device without using it's IP address? Background: I have a fibre "box" provided by my ISP physically connected to my ...
4
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1answer
103 views

EHWIC-1GE-SFP for Cisco 1941

I was able to configure the interface but only the GE port is working, not the SFP port. Did I miss something?
2
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1answer
210 views

Verifying 802.3 auto negotiation

This is my setup: The Problem The end point, ethernet device B, is powered by the power injector but receives no data. Everything is connected using CAT5 cable. Ethernet device A signifies a GB/s ...
4
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5answers
534 views

Why can't two hosts (in two different logical networks) connected to each other through cross-over cable communicate?

Let us say, i have two computers (hosts) A and B. Where A has been assigned an IP address of 192.168.1.10/24 and host B has been assigned an IP address of 192.168.2.11/24. And both of them has been ...
4
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1answer
682 views

LACP and how to configure switches correctly

I want to set up a fast network and am considering options. I want a backbone switch that connects all my switches together. I can see options for SFP / SFP+ ports. Some SFP ports are 1 or 2 Gb from ...
4
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2answers
954 views

How does Ethernet Switch ensures the validity of the MAC address table?

Let us say I have switch S with 4 ports, PA, PB, PC, and PD, to which I have connected 4 hosts, A, B, C and D with the MAC addresses AA:AA:AA:AA:AA:AA, BB:BB:BB:BB:BB:BB, CC:CC:CC:CC:CC:CC and DD:DD:...
5
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3answers
1k views

How is data sent from multiple different sources (computers) to the same destination host (computer) on a local network is handled by switch?

Let us say I have switch S, to which I have connected 4 hosts (A, B, C and D). Now let us say hosts A and B both want to send a series of data to the same host D at the same time. So here, A and B are ...
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2answers
50 views

How to debug an unstable connection in a P2P configuration

I have a setup where I have two computers connected to each other (C1 and C2). Both have a static IP and they know each others IP. C2 sends UDP packets to C1 and C1 receives and logs them. Seems ...
2
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1answer
38 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
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3answers
343 views

What is likely to occur with the frames addressed to x, if x is disconnected from the switch. then reconnected on another link?

I don't see how this could be a problem, as the switch table would remember the destination MAC address. My teacher says this is a problem and that the switch would need to reconfigure. could you ...
3
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1answer
60 views

Does an ethernet checksum include padding bits?

For ethernet II (aka ethernet DIX) frames that are padded to contain 64 bytes total, is the checksum in the last 4 bytes computed with the padding bits as input?
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1answer
87 views

What's meant by AUI & MAU in ethernet networking?

The questions is so clear, what's meant by AUI (Attachment unit interface ) & MAU (Medium attachment unit) in the scope of Ethernet ? Background : I've recently started to work as software ...
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2answers
65 views

Why are WLAN packages translated to Ethernet packages by Wireshark?

When using Wireshark on my MacBook, I see all my packages wrapped inside Ethernet II frames, although I'm connected wirelessly, which I already figured must be because they are translated from 802.11 ...
1
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1answer
120 views

Bypass Router to connect to modem

The network has 2 subnets: i) 192.168.1.x ii) 192.168.100.x The telecom optical modem sits at 192.168.1.1 A cisco router and windows server are present on the network. DHCP and ...