Hi there, been working on a strange issue. We have about two dozen cell modems (Sierra GX450s) that we have had deployed for about 4-5 years to provide remote management for our traffic light controllers. Things have been fine until about a month ago when all of a sudden we started getting huge data usage on these devices, upwards of 30GB a month and more than 70GB a month on the worst offenders.
These devices are all on a M2M network through Verizon that tunnel back to a Cisco router at our datacenter. I've checked all of the stuff I can think to do - packet captures on the router outbound interface, ensuring all connectivity to the modems is shut off except the serial port used by the traffic controllers and the cell connection, upgrading firmware, etc.
I'm not a packet capture expert but the traffic I see looks pretty benign, just mostly control traffic between the traffic server and the remote controllers. Is there any easy way to see bandwidth or "big talkers" type stuff? I setup NetFlow in PRTG for the router but again, don't see much.
I'm half wondering if the traffic leaving the modem is split tunnel or something and I'm just not seeing the traffic I'm looking for. We also don't have support with Sierra so I can't really call them for any help. Any advice on how you'd proceed? Thanks so much.
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