Speed issue in only one direction

[Guus Sliepen]

On Tue, Dec 17, 2013 at 05:14:47PM +0100, Florent Bautista wrote:

> More informations :
> 
> root at node1:~# tinc -n coppint info node2
> Node:         sllm2
> Reachability: directly with UDP
> PMTU:         1451
> 
> root at node2:~# tinc -n coppint info node1
> Node:         sllm1
> Reachability: directly with UDP
> PMTU:         1518
> 
> Why PMTU is different ?? They are on a same switch, with same network
> configuration (MTU 1500)...

Indeed, they should both be smaller than 1500 (because of the overhead of
tunneling the packets). If one node thinks the PMTU is 1518 that means packets
will be fragmented, which might very well explain the much lower throughput you
have observed. Could you run tinc with the options "-d5 -D", so you get all
debug messages in a terminal, and then check whether both nodes send PMTU
probes to each other, and whether there really are MTU probes larger than 1500
being sent AND responded to?

-- 
Met vriendelijke groet / with kind regards,
     Guus Sliepen <guus at tinc-vpn.org>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://www.tinc-vpn.org/pipermail/tinc/attachments/20131218/a34e2564/attachment.sig>