I had a few hours to play with a hardware traffic generator today, I wanted to try beating up my OpenBSD setup to see what kind of throughput I could get.
For the curious, I was able to pulverize it with 64 byte packets and it topped out at about 165kpps. Throughput was less than physical interface speed (about 800Mbps). For fun, I cranked the payload size up to 1500 bytes, but I couldn't get the box to exceed 1Gbps, even though I had several gigabit interfaces trunked together. At first, it was a switch problem (the switch was sending all the traffic over a single link). However, after I found out my switches LACP hash algorithm I was able to spread the traffic out by randomizing the port numbers. I then confirmed that 4Gbps of traffic was leaving the switch to the OpenBSD box, but only 1Gbps was coming back. Therefore, I'm guessing that the load-balancing algorithm for OpenBSD does not behave the same way as my Juniper switching gear. Does anybody know the LACP hash that the trunk interface in OpenBSD uses to load-balance the outgoing traffic? I didn't have time to do more than a cursory test with different port numbers and IP addresses, so I'm not sure what I might be doing wrong, or if its even possible to use layer 3/4 info in OpenBSD to hash the traffic. Since I'm using the box as a router, layer 2 hashing doesn't help me very much since the source MAC is always the same. I took a peek at the source, but I'm definitely not a C hacker, so nothing jumped out at me for computing the hash... Thanks, Jason -- Jason Healy | jhe...@logn.net | http://www.logn.net/
