Ethernet frame Puns

When I play doom, even though I was getting 144 fps it was terrible. Tons of frame drops, and even without the drops it still didn’t feel good. And I had to turn on v sync. When I unplugged the cord it still didn’t feel totally smooth but there were no drops and it did feel smoother. There was a noticeable difference between no v/adaptive sync tho. Was much smoother with it on. Even though I was going from 140-160 > 144.

In rocket league I didn’t get any drops. Until I turned graphics settings to max and then I was getting weird spike patterns. There’d be like 6 spikes close, and then none. And then it’d repeat.

Edit: I tried two ethernet cords. I also had chipset software for maybe a week until like yesterday when I went on another deleting spree. Fyi, been dealing with this issue since Aug 13th.

Edit2 (other things): https://imgur.com/a/3ko1yKN

It says in my textbook:

>One way that an adaptor will send only 96 bits—which is sometimescalled a runt frame—is if the two hosts are close to each other. Had thetwo hosts been farther apart, they would have had to transmit longer, andthus send more bits, before detecting the collision.

Why send more bits when transmitting longer? Why not just send only the 96 bits over the link?

Edit:

This is in the context of CSMA/CD.

>the round-trip delay has been determined to be 51.2 μs, which on a 10-Mbps Ethernet corresponds to 512 bits.

Is this suggesting that .1 microsecond on 10-Mbps is equivalent to 1 bit? Why is there a bit added for every microsecond?

My streams used to work fine. I'm using OBS. But now, for the past week, none of my streams are watchable, I'm constantly getting serious dropped frame issues and I'm streaming in 720p with 4000 bitrate (I even tried 2500). I watched a few tutorial videos about fixing frame rates dropping but none of the solutions worked yet. I tried streaming on Twitch and also YouTube, but same issue

I'm using an ethernet cable, my internet usually runs at 200MB Down 35 Up, but when I start streaming, my speed test shows 5Mb Down and 0.2 Up. Any idea what could be causing this?

Hello,

As part of my internship, I have to develop a custom driver for the STM32H7's ETH interface. My company is aware that one already exists within the STM32Cube package, but they specifically want me to write my own.

My issue is that the interface does not receive frames directed to my interface, only broadcast frames, unless I either set the interface in "receive all" or promiscuous mode.

I programmed the board's MAC address in the MACA0HR and MACA0LR registers. I did not modify the other MAC address registers. I did the rest of the initialization following what is done in STM32Cube for my board (NUCLEO H743ZI).

I checked the state of the MACA0HR and MACA0LR registers with a debugger and it seems OK. I also use source address replacement for TX, and the correct MAC address is inserted by the interface before transmitting frames.

Is there anything else I need to make filtering work? Basically, I want the interface to accept broadcast frames, and frames with dest MAC addr == my board's interface MAC addr.

Regards.

We are using QinQ a lot in our network, because we are working on multiple sites and between some of these sites we have only a single VLAN. The switches have a management-vlan with qinq stacking enable. The servers are sending single tagged ethernet frames which will be stacked in the outer VLAN on the switch interface. This all works quite well.

But now we need to add another device to our management VLAN that doesn't support VLAN tagging at all. So luckily our Huawei switches support double tagging of frames. The idea is that the untagged ethernet frames from this device will be tagged first in our management VLAN and then again in the outer VLAN. This works but... It only works from a remote site. The management server on the same site is unable to connect with the untagged device.

• Management VLAN: 40
• Outer VLAN: 1500
• Uplink to remote site is connected to: GigabitEthernet0/0/1
• Server is connected to: GigabitEthernet0/0/2
• Untagged device is connected to: GigabitEthernet0/0/3

​

vlan 40
 management-vlan
#
interface Vlanif40
 ip address 10.0.0.1 255.255.255.0
 undo icmp host-unreachable send
 qinq stacking vlan 1500
#
interface GigabitEthernet0/0/1
 description uplink-to-remote-site
 port link-type hybrid
 qinq vlan-translation enable
 undo port hybrid vlan 1                  
 port hybrid tagged vlan 40 1500
 port vlan-stacking vlan 40 stack-vlan 1500
#
interface GigabitEthernet0/0/2
 description management-server-tagged-40
 port link-type hybrid
 qinq vlan-translation enable
 undo port hybrid vlan 1
 port hybrid tagged vlan 40
 port hybrid untagged vlan 1500
 port vlan-stacking vlan 40 stack-vlan 1500
#
interface GigabitEthernet0/0/3
 description untagged-device
 port link-type hybrid
 qinq vlan-translation enable
 undo port hybrid vlan 1
 port hybrid untagged vlan 1500
 port vlan-stacking untagged stack-vlan 1500 stack-inner-vlan 40
#

No response from the untagged device when the management server on the same site is trying to connect or send a ping. But the funny thing is that a management server from the remote site is able to get a response. What am I missing here?

I finally built my freenas box with 10gbe, but in my windows 10 pc I can't enable 9000mtu because the jumbo frame config doesn't exist. So, is max ethernet frame size the same as MTU? The nic is a HP NC523SFP.

Has anyone else noticed this? The formatting of the solved pages when arranged by artwork tie in quite well to the format of an ethernet header and trailer , which in turn sometimes use encrytion on the contents of the frame (athough a number of technologies make use of frames).

For anyone who hasn't seen one:

https://study-ccna.com/ethernet-frame/

If you look at the ratio of text in each section, it matches up roughly to the ratio of each header field. Even the areas that could be considered Destination/Source MAC has a nice little tie in - as well as being almost exactly the same length, the artwork itself reflects this - the source pages being of a young woman with a womb like symbol at the bottom of the page, whereas the destination is of an old man on a tombstone like background.

My thinking is that the reason liber primus han't been solvable using previous methods is that there could be a double layer of encryption? Many transmission frames use encryption between nodes (I would be looking at Tor cells too), and I have a feeling that if this got cracked then the usual subtitution ciphers would apply using a key found in the text.

Cicada threw in a little bit of networking homework when they asked for a small TCP server to be built, so it could make sense that this could also be an option.

The only thing that threw me was that the "Preamble" and "Start frame delimiter are back to front - but then, wasn't the gematria primus reversed to translate this section?

In the section that corresponds to the FCS at the end, a more mathematical cipher is used, ie, the totient function - this again makes sense given the area that it comes in. Some frames also come with a delimiter at the end.

Perhaps this theme will run through the networking layers, until the "data and pad" is reached after both the "IP" and "TCP/UDP" heaers have been removed? Perhaps the "Data and pad" involves the stream of plaintext characters near the end of the unsolved pages?

Also, the part that corresponds to the "type" field will likely have an impact on the next section of it if it is indeed following this format. IPv4 or IPv6?

EDIT: here is the design PDF for physical Tor transmissions, the most likely culprit.... I am having a look right now but the lazy bit of me hopes that someone else nails it first.

[https://svn.torproject.org/svn/projects/design-paper/tor-design.pdf](https://svn.torproject.org/svn/projects/design-paper/tor-desig

I'm confused as to why the headers are decreasing the MTU size, rather than increasing it?

I meant to say packet, not frames. But forgot to backspace frame.

Interesting blog post from the Internet Storm Center today.

OP wants to capture invalid Ethernet frames, but although his NIC allows for that feature, tcpdump and everything else on Linux that uses it doesn't. Windows doesn't have the driver setting for said capture (he already tried.)

Can an Illumos distribution save the day here?

Not sure if this is the correct subreddit for this but - Regarding MII spec, I have a question about the RX_DV signal that I'm not able to find elsewhere: From the perspective of the Ethernet MAC, when sending a frame to a PHY over MII, does the RX_DV (Data Valid) signal have to stay HIGH/asserted for the entire frame, or can it go LOW and back HIGH again on the same frame (and still be interpreted as 1 frame by the PHY)?

I guess another way of asking is: does an MII PHY use the RX_DV as a delimiter for individual frames, or does it check the SOF byte of something else to distinguish frames?

Any help is appreciated

I was reading scapy 3.0.0 documentation and saw this line of code.

>>> Ether()/IP()/IP()/UDP()
 <Ether type=0x800 |<IP frag=0 proto=IP |<IP frag=0 proto=UDP |<UDP |>>>>

This seems to mean that there are two IP packets nested in one E-frame. Can anyone explain this behaviour for me? Why are there two? I thought the standard of an ethernet frame is dest mac/ src mac/ type/ one ip packet?

Capturing packets from Wirshark, I noticed that a device close to me is constantly broadcasting Ethernet II frames repeating the same data. (Screenshot: https://i.postimg.cc/V6FMrhfq/image.png)

192.168.1.3 is me.

My question is why would a device do that ? What does it expects to gain from broadcasting frames like that constantly ?

It's a Huawei device with mac address 10:51:72:24:b1:25

Hehey, because of the difficulty to search with the term dlang -> "did you mean golang" ... and the possibility of unknown for most ppl.

I asking here;

Exists a lib out there, for handle ethernet frames and interfaces, without to handle it with raw c libs..

extern c {
   all the c stuff 
}

?

Like libpnet for Rust, or Packet for Go.

Happy greetings :)

Hey guys,

I’m studying hard and I’m confused.

I found that the Ethernet frame :

Preamble SOF Destination Source Type Data FCS

Is different than the IPv4 packet

Version IHL dscp Ecn Total length Identification Flags Fragment offset ( IPv4 only) Ttl Protocol Header checksum Source Destination Options

IPv6 Version traffic class ECN Flow label Payload length Next header Hope limit Source Destination.

So I found the IPv4 chart online, while I found the IPv6 and Ethernet charts on boson test prep. Is my Ipv4 packet structure correct?

Also one of the test prep questions says frame offset is only on IPv4. But from the charts it seems there is many more differences, no?

And then to my most confusing question. How is Ethernet packets different from IPv4 packets? I thought Ethernet was the same as IPv4 packets or even IPv6 packets. I thought IPv4 and v6 were Ethernet packets. Please help.

Interesting blog post from the Internet Storm Center today.

OP wants to capture invalid Ethernet frames, but although his NIC allows for that feature, tcpdump and everything else on Linux that uses it doesn't. Windows doesn't have the driver setting for said capture (he already tried.)

Could FreeBSD save the day here?