10. VPN Tests

I've hinted at the SL1000's VPN tunnel performance and now it's time to deliver the results. Figure 14 and 15 pretty much speak for themselves!

Figure 14: SL1000 / SL500 Site-to-Site tunnel performance
(click on the image for a full-sized view)

Figure 14 shows Remote-to-Local and Local-to-Remote throughput for a site-to-site tunnel between an SL1000 and SL500. Both tests were run with no other activity in either router. Integrating by eye shows an average throughput around 30Mbps, but there are regular temporary pauses in transmission in both direction that brings the calculated averages down to 22-25Mbps.

You'll also note a curious upward drift in speed over the 30 second test period for the remote-to-local test (blue trace) that I have no explanation for.

Figure 15: SL1000 / SSH Sentinel client tunnel performance
(click on the image for a full-sized view)

Figure 15 shows Remote-to-Local and Local-to-Remote throughput but this time using my Dell Inspiron 4100 notebook running WinXP and SSH's Sentinel (Version 1.3.2 build2). Throughput in both directions is much more consistent, though there are still occasional pauses causing dropouts on the plots.

ASUS' literature says the SL1000's throughput is "80Mbps for VPN, 100Mbps for Firewall, and 90Mbps for NAT". Like any other manufacturer's throughput specs, I suspect that these are raw data rates and maybe even internal packet processing rates. No matter. The 30Mbps rates shown in the Chariot plots above are simply the highest I've seen in any VPN endpoint to date and amazing when you consider they are coming from a box that you can buy for around $150 (the SL500)!

By the way, running a quick Qcheck Response time check revealed virtually no latency through the tunnel. I also tried some web browsing and email checks while running other Chariot tunnel tests and found no noticeable effects in the Chariot results or pauses in browsing.

NOTE: Details of how we test can be found here.