On Tue, Apr 13, 2010 at 1:09 AM, Abhijit Bhopatkar <[email protected]> wrote: >> 1. Even though I understand that the VPN server adds headers and hence the >> need to lower the MTU, I cannot understand why communication stalls when I >> talk to CVS in such a situation, and it does not stall with regular internet >> traffic. > > The cvs will have a huge bulk traffic going in and out. The main > problem with MTU is not at server or client side, but is usually in > the middle, the routers. The problem is that some routers on the > network are not able to handle large packets very well. They start > building up huge chains of backlog packets and eventually cause TCP > retransmissions.
Usually, routers will drop packets that they cannot handle on the fast path (on the line cards' switching fabric). This causes TCP to timeout, causing retransmissions. That apart, I would guess that since only the CVS traffic is affected, there is something wrong/badly configured at the router/server at the CVS end. A MTU of 1200 (which solves the problem, as Parag stated) is ridiculously low. Kaustubh -- Kaustubh Gadkari kaustubh [dot] gadkari [at] gmail [dot] com _______________________________________ Pune GNU/Linux Users Group Mailing List
