CISCO SYSTEMS 16-Port Gigabit Switch (SG11016NA) - connectivity issues

[internet_down]

Just purchased this switch to replace an old netgear 16 port switch. We have 16 computers/VOIP phones/printers connected to this switch, all had internet connectivity on the old switch, before we installed the one new, and got rid of the old.

Now, one of our computers is losing its internet connection once per day. The computer has to be restarted in order to get internet back. This computer had no issues getting on the internet, or losing connection, before the new switch was installed.

I am not exactly sure which CAT5 cable goes to that specific computer, but I did notice that 2 of the ports on the switch have an amber (red) LED lit up steady on the left, and the light on the right is off.

Can anyone help?

[Richard Burts]

If I am understanding your post correctly you had an old 16 port switch which you replaced with a new 16 port Cisco switch. Of the 16 ports 15 are working ok but one computer, connected to some port but you are not sure which one, is having issues. If I have something not correct please clarify.

Without knowing more about your environment it is difficult for us to figure out the problem. Can you tell us what this switch connects to for Internet access? Can you tell us when this computer is having problems with Internet access is it able to access other devices that are connected to this switch?

It would help us if you could determine which port on the switch this computer connects to. And it would help if you could tell us about the configuration of this switch, especially about the configuration of the port that the computer connects to.

HTH

Rick

[internet_down]

Hi Rick,

Thanks for your post.

The switch is connected to a Linksys WRT 3200ACM router with a Cat5 cable. The router is connected to our Cox Modem via Cat5 cable.

I am not sure if the affected computer is able to communicate with other devices when the internet goes down on that machine. What would be the best way to test that? I am not very skilled in networking, and unfortunately Cisco does not offer phone support without paying a premium.

Everything worked perfectly fine with the Netgear switch, All we did was unplug everything from that switch, and plug it all into the new one.

Thank you again

[luis_cordova]

Hi @internet_down,

As Richard said, the reason for the problem can be varied, so it would be useful if you could identify to which port of the switch the PC is connected.
In addition, you could show us the configuration of the switch to try to find the reason of the problem.

Regards

[Pedro Arrieta]

Hi,
You can validate on which port your computer is, desconnecting it and looking which port turned down, when you have the port try changing the cable or using other port for the computer, if the problem persist maybe the port has a problem, but if not, the problem is the cable or the computer.

[internet_down]

Thank you for your responses. I determined that the affected computer was plugged into port #5 on the switch. The lights on either side of the network cable were green.

I switched the cable to port #13, and moved the cable from 13 to 5 (the port that was giving the computer issues). The device connected to port 5 is a weather station console, so it is not that big of a deal if internet is lost.

I will post if the internet loss is still an issue on the new port. I highly doubt its the cable or computer that is the issue, because both have been working fine for 2 years, and the only change was the new 16 port switch.

Thank you

[Pedro Arrieta]

Hi @internet_down,

As I mentioned, change the port and try again to valite if the port is the problem, please keep us informed.

[Richard Burts]

Moving the computer and cable to a new port is a good test. Please let us know the results as you get some experience with the computer on the new port.

If the problem does occur again you could open a command window and attempt ping to the IP address of some of the other devices. The output of arp -a to show the arp table of the computer might also be helpful.

Do you know anything about the configuration of the Netgear switch?

HTH

Rick

[internet_down]

The same computer lost internet again, even after changing ports. 

As far as the configuration of the old netgear switch, there was no configuration. Both the netgear switch and this new cisco switch are just "dumb" switches as far as I can tell. There is no way to change settings (as far as I know). With the netgear switch, which functioned for 5+ years, all we did to set it up was run a cable from the router to it, and then plug all computers into it. It worked fine for 5+ years like this until we switched to the cisco switch.

[Richard Burts]

It is interesting that the computer lost Internet again. So that indicates that it was not related to the switch port to which it connected. 

You are correct that this switch is an unmanaged switch. So there is no configuration for us to check. And I am not sure that there is any way to troubleshoot on the switch. So we need to concentrate on the computer. When it lost Internet were you able to attempt to ping anything? Did you get the output of arp -a? It might also be helpful to get the output of route print from the computer while it is having the issue.

Are there other similar computers connected to this switch? If so is it true that they are not having the same problem?

HTH

Rick

[paul driver]

Hello

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@internet_down wrote: but I did notice that 2 of the ports on the switch have an amber (red) LED lit up steady on the left, and the light on the right is off

Is it possible this device has itself hard coded speeds/duplex settings? - or that for some reason the device and the switchport cannot agree in a negotiated setting and as such has defaulted to half duplex

can you check the interface status of the switchport this device is connected to and also the device nic settings itself 

From the switch:

sh interface x/x status 

sh interface x/x