Slow AP<=>ZD tunnel WAN performance.

[ms264556]

I have a couple of cross-town WAN links which currently use an OpenVPN tunnel.

LAN <=> OpenVPN <==== 35ms ====> OpenVPN <=> R600

I get basically full wire speed from this setup (>200Mbps).

I'd like to replace the OpenVPN boxes with an LWAPP tunnel from the R600 to my ZD1100.

I did some testing locally...

LAN <=> ZD1100 <=> R600(Tunnel)

...and I get 39 Mbps. This is fine. I only need maybe 16Mbps.

But when I put the R600 at the remote sites...

LAN <=> ZD1100 <=> NAT <==== 35ms ====> NAT <=> R600(Tunnel)

...I get 7.5 Mbps. 

Is there any setting I can tweak to improve throughput? I have ZD1200s and R610s I can swap in if that would help, but obviously don't want to go through the upgrade pain if the root cause is that LWAPP just doesn't like any latency. I don't want to subscribe to SmartZone - I'd rather just keep the OpenVPN boxes.

[eizens_putnins]

Hi,

Also it is  a question what kind of traffic you have -- stated number of 300 Mbps is probably the absolute max, which can be achieved in ideal conditions with optimal (max) packet size. By the way are you sure you use unencrypted tunnel?If you actually use encrypted tunnel, getting 30% of max stated performance is quit normal.

  If you have traffic with short packets, you have a lot of overheads and may be much lower number than with long packets, and efficiency drops again for the same reason, when packets are fragmented. Also -- as much as I understand, you currently have OpenVPN boxes, running encrypted tunnel. This tunnel probably uses different ports -- so make sense to check if there is some firewall or router in between, which  have some rules limiting LWAPP tunnel, but not OpenVPN, or even using different route?

[ms264556]

Thanks for you helpful comments everyone!

Over the weekend, I did a sweep of MTUs from 1500 to 900, testing local performance through the tunnel. Performance increased from ~40 Mpbs at 1500 MTU to ~210 Mbps at 1050 MTU, then started decreasing again.

So I left tunnel MTU at 1050, and went back to the remote site today. Without any further tweaking, I'm now getting 80 Mbps up and down the tunnel.

This is far in excess of what I was expecting/needing, so I'm happy to call it a day.

[eizens_putnins]

Good. So it was mtu, as it often is... Enjoy!

[syamantakomer]

@anthony_rielly glad to hear that performance improved after setting the correct MTU value.