Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Here is the scenario:

A) Desktop openvpn client Thailand B) OpenVPN Server in Singapore C) HTTP Server in London

RTT Latency from A to B is 50ms RTT Latency from B to C is 220ms.

Packet loss (via iperf) on 5mbit between A and B is 2% Packet loss on 5mbit (well even on 20mbit) between B and C is 0%.

As I control the openvpn server and client, I have the option of establishing the openvpn tunnel connection from A to B via UDP or TCP.

The OpenVPN manual tells me that the data channel is dumb, it does not implement its own retran/ack protocol.

So if Im doing TCP/HTTP from A to C my thoughts are that I will be best setting the A to B as an OpenVPN TCP tunnel and let the smaller rtt latency link resolve the packet loss, rather than using openvpn UDP and then letting the longer/higher-level http a-to-c resolve the packet loss?

FYI, I asked in #openvpn IRC on freenode but blanket unqualified statement like "TCP-over-TCP is never a good idea" so hoping for some more informed responses, Im quite happy to accept Im wrong with some substance.

share|improve this question

1 Answer 1

up vote 1 down vote accepted

See the TCP Meltdown Problem section, specifically what it references.

In sum, other than poking holes in a firewall that only allows TCP, it's best to treat the VPN as a point to point "leased line". e.g. your home to ISP doesn't use TCP, treat your OpenVPN connection the same way.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.