BCP bridging, long frames, packets out of order

RouterOS Beginner Basics
1

I am running a BCP bridge over either L2TP or PPTP (both exhibit the same problems). I have MRRU set to 1600 as recommended.

The BCP bridge runs fine for ethernet frames up to 1432 bytes, with less than 3% packet drop. For frames of 1434 bytes or more, packet loss is about 50%.

In the WinBox PPP screens, both ends of the PPP link show “Rx Drops” and “Rx Errors” counting significantly: about 300,000 per day.

The ISP over which the PPP link runs is notorious for delivering packets out of order. For instance, if the transmitting end sends a large packet followed by a small packet (which I imagine is what happens when the PPP link needs to use multi-link to send a large frame), the receiving end is likely to see the small packet first, followed by the large packet.

Is it possible to configure RouterOS in any way so as to re-assemble the multi-link PPP sub-packets in the correct order, if they arrive out of order?

2

See my post http://forum.mikrotik.com/t/bcp-bridging-over-l2tp-cant-get-over-1437-mtu/51374/1 regarding what sounds like the same issue. I use L2TP with BCP as well. I have a cable conenction and a FIOS connection that connect to a data center where there is a RB1100. The cable works fine with BCP FIOS not so much.

I still can’t figure it out. For now the FIOS L2TP is just running at 1460 MTU with MRRU off but I would like full 1500 byte packets to go through :-/

3

My problem seemed to have solved itself. I was also having packet loss issues. The packet loss went away and now It works great. It seems you need a really stable link to use BCP and MRRU.