On 12/11/2014 04:18 PM, Roy Hirst wrote:
Confidently based on no knowledge at all -
*Roy Hirst* | 425-556-5773 | 425-324-0941 cell
XKL LLC | 12020 113th Ave NE, Suite 100 | Kirkland, WA 98034 | USA
- We have noticed that in some instances that if a user is on a low
speed connection that their VPN speed gets cut by about 1/3.
This doesn't
seem normal that the VPN would use this much overhead
No, sure, but are you sure that congestion is not dropping a packet
somewhere in the end-to-end? If you offend TCP it will likely cut the
sender's packet transmit rate, even if the "possible" VPN rate is much
higher.
- We do not have the issue when connecting to VPN directly on
our own
network, only connections from the Internet
Internet would mean maybe a proxy or firewall then, with too-small
buffers or an old-time TCP/IP stack? Just a thought.
If you have any ideas on what we could try net, please let me know!
- Zachary
What OS builds? At one point the code had an 8 packet hard coded
window per tcp flow, which capped ssl over tcp window size to about
5mbps depending on RTT. Recent 8 branches raised this to
something more reasonable that capped around 20 mbps. DTLS over udp
and IPSEC tunnels did not have this issue.
UDP traffic does not have this problem but TCP does? Hmmm...
UDP transport with DTLS or IPSEC in UDP Encapsulation doesn't need to
deal with tcp window size scaling and the associated packet buffers.
-James