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39 votes
Accepted

What's the Wireshark packet receiving and processing procedure on a Windows machine?

The I/O model in Windows is based on a stack of components. Data must flow through the various components of that stack that exists between the physical network card, and the application that will ...
Ryan Ries's user avatar
  • 56k
39 votes
Accepted

Is one 10 gig port the same as ten 1 gig ports

Simply put, no, they are different: with a 10 GbE interface, you get a bandwidth of 10 Gb/s even for a single connection with 10x 1GbE interfaces (and using 802.ad protocol), a single connection/...
shodanshok's user avatar
  • 51.1k
19 votes

Is one 10 gig port the same as ten 1 gig ports

10gb/s via x10 1gb/s ports I am answering only for completeness sake and to save you some headaches. I have over 20k servers doing something similar to this and I can tell you it is a bad idea. ...
Aaron's user avatar
  • 2,859
18 votes

What can cause network packets consisting of PUU?

Anyway, more seriously, other perfectly valid packets were being corrupted by this data. IPv4 headers were getting bytes replaced with U bytes as well as there being data corruption which would cause ...
Zac67's user avatar
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12 votes

What can cause network packets consisting of PUU?

Sounds like you have a bad NIC card. If the source MAC address valid, you can find it by checking the switch MAC tables. If it is corrupted, you'll just have to start unplugging devices to find it.
Ron Trunk's user avatar
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11 votes
Accepted

What is the minimum gigabit Ethernet latency I can expect?

A ping does not measure latency nor does it measure round-trip time. It measures ICMP echo request response time. ICMP messages run with low priority and take way longer than serious traffic. As @...
Zac67's user avatar
  • 12.2k
11 votes

What Ethernet twisted pair cable is best with a particular Ethernet switch

In short: 100BASE-TX (100 Mbit/s) and 1000BASE-T (1 Gbit/s) require category 5 ("100 MHz"). 10GBASE-T (10 Gbit/s) requires Category 6A ("500 MHz"). "Smartrate" 2.5GBASE-...
Zac67's user avatar
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11 votes
Accepted

What Ethernet twisted pair cable is best with a particular Ethernet switch

The Niquist rate says that the maximum rate of independent symbols (fp) is twice the frequency bandwidth of the channel (B). fp ≤ 2B Hartly's law introduces the idea that the amount of information ...
Peter Green's user avatar
  • 4,366
10 votes

Can tone ethernet cable into patch panel but it's not working

You can use a Fluke to test the pairs. That will tell you if the cable is bad; all the tone does is confirm that the two ends have electrical connectivity.
mfinni's user avatar
  • 36.3k
9 votes

e1000e Reset adapter unexpectedly / Detected Hardware Unit Hang

Disabling only TCP Segmentation Offload (TSO) does the trick for me. ethtool -K eth0 tso off Note: It does not seem to be necessary to also disable Generic Receive Offload (GRO) and Generic ...
David Scherfgen's user avatar
9 votes

e1000e Reset adapter unexpectedly / Detected Hardware Unit Hang

Disabling Enhanced C1 (C1E) in the BIOS fixed it for me. Not sure if the lower power state of C1E is messing with the driver, or that there's an oops in the driver when the processor is in this state....
SteveG's user avatar
  • 91
9 votes

How to check the physical status of an ethernet port in Linux?

To quickly add to @goo's answer, you would interpret the ip link or ip link show INTERFACE as follows. This is a port which is administratively up, but physically down: 2: eth0: <NO-CARRIER,...
iwaseatenbyagrue's user avatar
9 votes

Use of unused pairs in cat5 ethernet cables?

First, keep in mind that cat5 type of cables were designed for many uses, not only for "ethernet over twisted pair", although it's the most popular application of those cables nowadays. As you can ...
Learner's user avatar
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9 votes
Accepted

Can't connect ssh via wireless interface but t works using eth0

I had the same debug3: set_sock_tos: set socket 3 IP_TOS 0x10 trace that you mention and turns out that, for my specific case, I solved it with this answer, which was related to how my router managed ...
Axel's user avatar
  • 237
8 votes
Accepted

Hardware involved in Direct-connect (switchless) 2-node Storage Spaces Direct Cluster

1) You don't need any special Ethernet cabling for direct connection since 1 GbE era, everything will auto negotiate. https://en.wikipedia.org/wiki/Medium-dependent_interface 2) Broadcom NICs you ...
BaronSamedi1958's user avatar
8 votes
Accepted

Can I connect two Ethernet ports on the same adapter on the same host to test to check port performance and perform stress test?

I don't have a good way to test this right this moment, but I would try using namespaces to isolate the interfaces, and then test them as you would with two different systems. ip netns add test1 ip ...
Rob M's user avatar
  • 1,492
7 votes

What Ethernet twisted pair cable is best with a particular Ethernet switch

I understand your confusion. The source of that is that some standards originate from the fields of electrical engineering and others from signal processing and network engineering, each with their ...
Bob's user avatar
  • 6,061
6 votes

How to find unix eth port link speed

You can use the ethtool command http://linux.die.net/man/8/ethtool EDIT: You need to check the 'Speed' section. Check below: root ~ ethtool eth0 Settings for eth0: Supported ports: [ TP ] ...
Mugurel's user avatar
  • 923
6 votes

How to test cat5/cat6 cable runs, using software-only, or simple tools?

If you are doing Cat5e/6 gigabit and your PC auto negotiates to gigabit then your data pairs are terminated correctly. If it auto negotiates to 10/100 or doesn't work at all your data pairs are out of ...
Brian D.'s user avatar
  • 469
6 votes

Dangers of using computers as wireless access points?

No. No. No. To list just a few things (of the dozens) that are horrible about this proposal: Traffic behind each workstation would be NATted, making auditing impossible. Also, likely breaking ...
EEAA's user avatar
  • 110k
6 votes

Why do we need a LAN physical interface bridged with OpenVPN TAP interface to get functional OpenVPN in bridge mode?

OpenVPN tap interface operates at the layer 2 of the ISO/OSI model and so it needs a layer 2 (read: bridge/switch) connection to the main, real interface. I strongly suggest you to reconfigure your ...
shodanshok's user avatar
  • 51.1k
6 votes

Do all ethernet switches support multicast?

Yes, even unmanaged "bargain" switches will likely have some minimal support for multicast, to the extent that a host connected to the switch will be able to receive a multicast stream. Look at the ...
James Sneeringer's user avatar
6 votes
Accepted

Connecting two buildings, 250 meters, heavy snow country, high lighting risk

Cat6 for outdoor usage will cost more than a fiber of the same outdoor grade and regardless of lightning protection it will cause trouble sooner or later - we had an abundance of aerial lines of all ...
Peter Zhabin's user avatar
  • 2,931
6 votes

Hardware involved in Direct-connect (switchless) 2-node Storage Spaces Direct Cluster

For Base-T networking, you have to use Cat6a or Cat7 cables. The main difference between them is the distance (up to 55m in Cat6a and 100m in Cat7). However, as already mentioned, SFP+ is much better ...
Strepsils's user avatar
  • 5,125
6 votes
Accepted

Is it safe to connect a PoE injector switch to an ordinary PC?

There are many different manufacturers of network devices, and you didn't say what you are using, but I work with 24V PoE devices from Ubiquiti, so I'll answer based on those. If you are using ...
Moshe Katz's user avatar
  • 3,182
6 votes

What Ethernet twisted pair cable is best with a particular Ethernet switch

Anything that is of a specification suitable for link speed, link length, and the environment it is used in, and meets that specification(!), should be absolutely fine. There are basically, ...
rackandboneman's user avatar
5 votes
Accepted

Is it possible to mix jumbo frames VLAN and standard mtu VLAN on the same switch port?

After testing and using it for some months, I can say that yes it works. The switch MTU settings acts merely as it names suggests, a maximum transfer unit [size]. Increasing it above what a VLAN ...
Luke404's user avatar
  • 5,918
5 votes

How could one speed up SSHFS in LAN?

sshfs -o Ciphers=arcfour,Compression=no,auto_cache compression slows on pack/unpack arcfour is blazing fast !!!WHILE!!!! not 100% safe. LAN ONLY auto_cache allows you to store file localy in temp ...
deil's user avatar
  • 51
5 votes
Accepted

Why one of virtual NICs called bond0?

I suspect that eth2, and eth3 are the physical devices that make up the bond0 device. See the master/slave flags. But your system probably has 2 physical interfaces, these are being combined in some ...
Zoredache's user avatar
  • 132k
5 votes

Can tone ethernet cable into patch panel but it's not working

Since your talking about SOHO routers etc. I'm assuming that a tester from Fluke is way over budget to test one cable? And I've been in the same position where I've had to troubleshoot a cable without ...
BitGen01100000's user avatar

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