Switch vs Hub on Level 2 protocol layer

Sandman · October 7, 2019

I work with an embedded ethernet system. It uses a KSZ8081RNA PHY chip that can do the 10/100Mbps negotiation and RX/TX Straight-through and crossover detection. When I use a 10Mbps Hub (Netgear 10 BASE-T EN104TP) the client PC system can send and receive signals to the embedded system. Everthing looks and operates great on the client PC using wireshark. But when I use a switch (Netgear Fast Ethrenet Switch FS105 10/100Mbps), the embedded system can receive signals (verified by wireshark on the client PC) but the "embedded to PC" traffic isn't making it to the PC. Does the embedded system need to do anything special to setup the switch on the Level 2 protocol layer?

VioletChepil · October 7, 2019

Thanks for your question! Lets see if some of our experts can help on this one. @Pooh @TheCustomCave @Hronos @kltaylor @Marc @SimoneSpinozzi anything to add on this one?

TheCustomCave · October 7, 2019

What sort of traffic are you testing? Hubs tend to be fairly dumb devices and just push all traffic out to all ports. Switches are more direct, they know what's located at each port and will direct the traffic to the intended recipient.
Is the switch set to drop any type of traffic (e.g. multicast)? Is the device showing up within the switch's admin console (i.e. is it pickig up the 10 base connection)?

Sandman · October 7, 2019

The Ethernet traffic I'm using is IPv4. The embedded system is using the LWIP (Light Weight Internet Protocol) stack. My cables to the switch & hub are the same cables, I'm just swapping out the hub & switch. I use the hub so that I know the embedded system is "seeing" all the traffic, I.E. no funny stuff. I didn't know the Netgear Prosafe 5 port 10/100 Switch FS105 v2 needed to be setup. Its got a serial number, but no discernible switches or buttons.

TheCustomCave · October 7, 2019

They're generally good to use out of the box, but there's a chance that something's just not quite right for the setup.

Granted there's nothing in what you've told me that's a red flag in any way/shape/form - but you never know.

I'm not directly familiar with the FS105 but in general Netgear switches have a web interface or can be connected to via a Windows application to manage/monitor.

Sandman · October 7, 2019

The Netgear Manual talks about flow control. Maybe its a flow control issue with my stack? I should try another switch.

From the manual:

<b>Technical Specifications
</b>

</code><code><b>Standards Compatibility:
</b>

</code><code><b>IEEE 802.3i 10BASE-T Ethernet, IEEE 802.3u,100BASE-TX Fast Ethernet
</b>

</code><code><b>IEEE 802.3x Flow Control; compatible with Windows®, Mac® OS, NetWare®, Linux®
</b>

</code><code><b>Data Rate:
</b>

</code><code><b>100 Mbps with 4B/5B encoding and MLT-3 physical interface for 100BASE-TX
</b>

</code><code><b>10 or 100 Mbps half-duplex
</b>

</code><code><b>Network Interface:
</b>

 

RJ-45 connector for 10BASE-T or 100BASE-TX Ethernet interface

kltaylor · October 7, 2019

TheCustomCave said:

They're generally good to use out of the box, but there's a chance that something's just not quite right for the setup.

Granted there's nothing in what you've told me that's a red flag in any way/shape/form - but you never know.

I'm not directly familiar with the FS105 but in general Netgear switches have a web interface or can be connected to via a Windows application to manage/monitor.

Can you definitely say that the switch that you're using is/isn't a 'Smart Switch' at all?

kltaylor · October 7, 2019

Sandman said:

The Netgear Manual talks about flow control. Maybe its a flow control issue with my stack? I should try another switch.

From the manual:
Technical Specifications 
</code><code>Standards Compatibility: 
</code><code>IEEE 802.3i 10BASE-T Ethernet, IEEE 802.3u,100BASE-TX Fast Ethernet 
</code><code>IEEE 802.3x Flow Control; compatible with Windows®, Mac® OS, NetWare®, Linux® 
</code><code>Data Rate: 
</code><code>100 Mbps with 4B/5B encoding and MLT-3 physical interface for 100BASE-TX 
</code><code>10 or 100 Mbps half-duplex 
</code><code>Network Interface: 
RJ-45 connector for 10BASE-T or 100BASE-TX Ethernet interface

The last time that I had to worry about Flow Control (Xon/Ooff) was back in my modem/BBS days where you had to configure flow control for the serial port that your modem was connected to.

If you feel that this is a flow control problem, enter into the Properties of the network adapter, then 'Advanced' and see if there is a means to toggle/select that.

Save the changes and test again, let us know what the results are, please.

Sandman · October 7, 2019

While trying out another switch, a Netgear Prosafe FVS318G, I noticed that the PC was on the 10M/100M and the WLAN was on the5 port side. I hooked up the WLAN to WLAN and ports to ports, and my PC wouldn't log on to my domain anymore. The FVS318G was configured to some setup that confused the companies WLAN system. Aggh. I put everything back to the way it was and my PC wouldn't log on anymore. Created a ticket on another PC with our IT, then after about 10 minutes, it finally logged back on again. IT still hasn't gotten back to me. SO, anyway the hub/switch thing is on the back burner, got other fires to put out.

kltaylor · October 7, 2019

Sandman said:

While trying out another switch, a Netgear Prosafe FVS318G, I noticed that the PC was on the 10M/100M and the WLAN was on the5 port side. I hooked up the WLAN to WLAN and ports to ports, and my PC wouldn't log on to my domain anymore. The FVS318G was configured to some setup that confused the companies WLAN system. Aggh. I put everything back to the way it was and my PC wouldn't log on anymore. Created a ticket on another PC with our IT, then after about 10 minutes, it finally logged back on again. IT still hasn't gotten back to me. SO, anyway the hub/switch thing is on the back burner, got other fires to put out.

Welcome to IT ...

One of the companies that I worked for in my previous life was a Franchisor, one of the franchise locations resided inside of a military defense location so they had a similar 'good time' in keeping their MIS system connected to the web, everything was insanely locked down.

What ails me though is that they are only providing to you 10/100Mbps speed and not Gigabit. Makes me wonder if there is an issue with that translation since most, if not all modern technology for networking is running 10/100/1000 and soon to be faster than that.

SimoneSpinozzi · October 7, 2019

Last i checked the netgear FS105 is a "smart" switch, which means it's got its own IP and you can login to change settings inside. (base settings are "admin" as user and either "password" or "1234" as thew password)

Since nobody mentioned it.

Is there (by any chance) an IP conflict between the "smart" switch and the PC? Because that would explain why traffic can get out of the PC... but not in. 😅👍

Yes, it's a stupid question, but worth exploring. Nowhere in this thread i see mentioning the IPs of the machines in the net.

Sandman · October 7, 2019

Well.... IT did finally get back to me. They said that my machine (Windows 7) is in need of an update. It will take about 8 hours..

??? (!). SO, when I leave after work, he will remotely do his thing.

The Netgear FVS318G has a three color LED for speed on each jack. Green is 1000M, Amber is 100M and off is 10M. When I had the WLAN hooked up, that connection was green (1000M), then in the ports, my PC was Amber (100M) and my embedded system was off (10M).

I will check to see if I can find the FS105 web IP for the settings page.

My PC and embedded system are on the same subnet. The embedded client DHCP talks to the company DHCP server ok and gets an IP assigned.

Maybe after my PC is "Upgraded" things will work better.

Perhaps I should convince the IT guys to get a FING box into the LAN here at work, maybe it would help more?

My Fing box at home hasn't missed a beat.

Thanks for everyones input.

Hronos · October 7, 2019

As you said "Windows 7" it could be a matter of update network drivers / protocols, because W7 is quite old now...
Keep us posted if this update help you.

kltaylor · October 8, 2019

Hronos said:

As you said "Windows 7" it could be a matter of update network drivers / protocols, because W7 is quite old now...
Keep us posted if this update help you.

...and with it residing on a 10/100 network, 8 hours for a patch updates doesn't surprise me. Do you have an upgrade plan for Windows 7 since it reaches end of life in mid-January 2020?

Sandman · October 8, 2019

Most people here have been given new machines with windows 10. They put an Ethernet phone in series between the WLAN and

my PC. Yet another variable that I haven't ruled out. Haven't had time yet to see if the upgrade fixed anything. When they replaced the hard drive with a SSD, the PC performance was tolerable, so I haven't complained.

kltaylor · October 8, 2019

Sandman said:

Most people here have been given new machines with windows 10. They put an Ethernet phone in series between the WLAN and
my PC. Yet another variable that I haven't ruled out. Haven't had time yet to see if the upgrade fixed anything. When they replaced the hard drive with a SSD, the PC performance was tolerable, so I haven't complained.

Just as a helpful hand, not saying that you're going to run into this situation, however, it sounds like your desktop systems are jumped through one Ethernet cable, which connects to the VOIP device and from that device to the computer.

In my work with the franchise stores, we found that to be an issue and had mandated that each workstation have two data 'drops', one for VOIP (which can surpass the router because you really don't need or want to restrict voice data, especially for QoS) and Data.

This will help with removing one of the niches where you could feasibly spend a lot of time troubleshooting a situation of intermittent connectivity issues.

It may not be related to your specific situation, but its a personal experience of mine that I am passing along to hopefully be a 'lookout' piece for you.

Switch vs Hub on Level 2 protocol layer

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