Re: PPPoE drops

[Brad <brad_(_at_)_comstyle_(_dot_)_com>]

On Thu, Nov 25, 2004 at 03:15:04PM +0000, Jason McIntyre wrote:
> On Thu, Nov 25, 2004 at 09:52:15AM -0500, Damian Gerow wrote:
> > 
> > Essentially, the tun interface just stops working.  ppp is still running,
> > the interface is still configured, but nothing traverses the link.  This is
> > the only log I see:
> > 
> >     tun0: Error: ip_Input: deflink: wrote 1496, got Message too long
> > 
> > I /do/ have my MTU/MRU set to 1448, so seeing this note about 1496 is a bit
> > odd.  And to bring the tunnel back up, I just have to kill ppp, destroy
> > tun0, then re-start ppp.  The average session length seems to be in the area
> > of a few hours, which is ridiculously short.  The official termination
> > reason, as seen from my ISPs POV, is "Connection Closed".
> > 
> 
> do you have anything in your setup which is different to that described
> in pppoe(8)? also, why mtr/mru=1448? 1492 should be correct for pppoe.

``If your ISP has an FE crossover to Bell Canada, the optimal MTU is 1448.
This is because of all the tunnelling and packet overhead that's created
-- anything greater than 1448 (actually, it's 1452, but that's on on the
8-byte boundary) will cause some sort of fragmentation in the packet between
you and your ISP.''

> does enabling lqr help?

If anything you should DISABLE LQR. The Juniper ERX routers being used by
Bell Canada do not support LQR.