packet generator (computer A) ——> cat 5 ——> Router (GB/s LAN port) ——> 2.4 Ghz network ——> wireshark (computer B)
I’m using Ostinato for mac to generate the packets. I’m giving the packets a source MAC address of computer A and a unicast destination MAC address of the receiving computer (B). The lower layers (IPv4, UDP/TCP, raw data) don’t seem to have any effect on throughput, so as of now for testing purposes my packets only consist of the MAC protocol layer and some arbitrary filler data.
router: netgear nighthawk R7000 (stock firmware, pretty much DD-WRT)
Everything works as it should at low bandwidth (1 mbps and below). Sending and receiving behavior is as expected.
Issue: I seem to have a bandwidth ceiling of about 4 mbps. No matter how high I set the packet generator rate, the receiving end mbps graph levels off. Additionally, the router’s GUI crashes (I can’t even telnet in). The LAN port is capable of GB/s, the 2.4 Ghz network 600 mbps, and the receiving wifi card at least 54 mbps. So why when I try and send packets at a bandwidth anywhere close to 6 mbps do I encounter problems?
Additional info: I’ve gone through every router setting. QoS is disabled, there’s no firewall at any point. I’ve tried 4 different routers (buffalo, netgear, linksys, starry) - all AC “gb/s” routers. I’ve also tried different packet generating software to no avail. I feel like there must be some buffer in the router that’s filling up, but it doesn’t seem to be bufferbloat. I did testing transferring files - got 60 mbps easily, so I don't understand what this issue could be. Clearly the router is capable, the wifi cards are capable... all the hardware should be capable. Could there be some firmware issue where data streams like those from packet generators are recognized as a DoS attack and automatically blocked?