Linux – netem for Mac OS X to emulate network latency and dropped packets

There is a tool called qperf that can provide you such statistics. Though, it is bound to OFED/RDMA packages.

# qperf -v xx.xx.xx.xx tcp_lat udp_lat
tcp_lat:
    latency        =  29.2 us
    msg_rate       =  34.2 K/sec
    loc_cpus_used  =    41 % cpus
    rem_cpus_used  =  11.5 % cpus
udp_lat:
    latency        =  24.8 us
    msg_rate       =  40.4 K/sec
    loc_cpus_used  =    34 % cpus
    rem_cpus_used  =     4 % cpus

I've got this working now, here's what I did:

DD-WRT does work: I started with the guide that r.tanner.f linked (http://www.dd-wrt.com/wiki/index.php/Dual_WAN_with_failover) and was able to get things working (on a Asus WL-500w). However, it wasn't particularly great: I'm not good at iptables, and as I added more rules it seemed to actually slow the device down somewhat.

After more research I discovered that the Peplink Balance line does support policy-based routing (see http://www.peplink.com/technology/load-balancing-algorithms/), and I found a used Peplink Balance 20 on eBay for about $200 (they're normally $250-$300). I got it yesterday, it took less than an hour to set it up, and it's wonderful. Here's what the policy-based routing tool looks like:

There's ton more power there I'm not yet using including more complex routing (e.g. "prefer satellite, but fall back to DSL", "prefer DSL but if it's saturated fall over the satellite"), QoS, etc. Another cool feature is that I can tell the device my bandwidth caps for each connection and it'll track and notify me as I start to get close.

So yeah, suffice to say I'm a big fan. Well worth the investment for me.