Partial loss of network connectivity
Customer has an Arris DG3270 (cablemodem/4-port router) with a switch connected to one of the 4 LAN ports on the Arris router. Symptom is occasional (random, a few times per day) the devices connected through the switch lose connectivity (yellow triangle shows). Devices are CC terminal, Win7 POS term, Mac, Win7 PC. Devices connected directly to the router retain connectivity. We can restore connection to switch devices by unplugging the Cat5e cable between the router and switch and reconnecting it. We've tried changing the switch (Netgear, DLink, TPLink), but the symptom persists, so it seems likely the problem originates with a device connected to the switch. I've run RogueChecker to see if there's more than one DHCP source, run IP Scanner to see what it finds on the LAN. Nothing looks out of the ordinary. Any suggestions on what else we can try or check?
dbrunton
Observe the switch when this happens. Might be one port flooding the network/switch with traffic and you might be able to tell by the lights on the port. If you can identify the port then you can identify the computer/device.
Also I have a similar modem. Get a decent Router, call your ISP, have them put it in Bridge Mode, then get the external IP at the router and hook up your stuff to the router.
I do not have any disconnects on my Modem (set up in Bridge Mode).
I do not have any disconnects on my Modem (set up in Bridge Mode).
Since the router-connected devices don't show any problems, I don't think that this is a router issue. I'd use a different port on the router to connect to the switch just to rule out a single bad port on the router.
Set up two switches and connect each to a different port on the router. Divide up the other connections between the two switches. If the problems return, note which devices are affected: switch 1-, switch 2-, or router-connected devices.
Set up two switches and connect each to a different port on the router. Divide up the other connections between the two switches. If the problems return, note which devices are affected: switch 1-, switch 2-, or router-connected devices.
Utilize a network monitor to auto-create a layer-2 map of your network. Then check for any new nodes appearing, as well as the traffic the node(s) is generating. You can use NetCrunch network monitor for that.
I've run RogueChecker to see if there's more than one DHCP source, run IP Scanner to see what it finds on the LAN.Good news is that should discount rogue devices. You never mentioned anything about whether there are devices connected wirelessly to the network.
Move the Mac to a router port and see if you have the same issues. Apple devices to send out a lot of traffic constantly, so it may be at the root of the problem. More ideally, I would say disconnect the Mac and test.
I also agree with Experienced Member in one regard: getting a better router. My reason being that you could more ideally try to break the network into 2: One for most business functions, and one for commerce (POS and CC terminal). I'm assuming that the POS and CC terminal interact with one another. It also makes PCI compliance somewhat simpler. They don't have reason to interact with any other internal systems, do they?
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