Possable Bug in Bridge L2TP

This may be a bug, or a possible way we did not think how it works so let me explain this!

What we have been doing with this client is putting an IPIP tunnel bridging it, in v2.9, and bridging the Ethernet port of a hotspot network. This network gets its DHCP from across the bridge at the hotspot controller (non MT).

So, we have HOTSPOT NETWORK ↔ IPIP BRIDGE ↔ HOTSPOT CONTROLLER

This works fine, as the hotspot controller gets MACs and issues out DHCP.

In version 3 we are trying to standardize with L2TP tunnels. Same as above, but now we are wishing to only use L2TP tunnels. In Version three, what it seams to happen is the MTU is not changed across the bridge between the Ethernet and the L2TP Tunnel. What seams to be happening is packets are entering the MT v3rc5 with a packet size of 1500 bytes as they should, when they are bridged with a IPIP tunnel in version 2.9, it seams the packets are broken up into whatever size is necessary the IPIP Tunnel. Even if we set this size to 1000 bytes, it works fine.

In version 3rc5, it seams it that the L2TP tunnel does not split the packets up, i.e. we get the black hole router effect, as anything above the size of the L2TP tunnel does not get out. i.e. some websites come up, etc.

Is this the way it should work, is there a setting that I am missing? Etc?

Dennis

If you’re able to get this working please let me know as I’ve been having the exact same issues. I’m converting from EoIP tunnel to L2TP. EoIP fragments properly but no luck from the L2TP.

I did email the support and after going back/forth a few times they suggested using Multilink PPP over a single Tunnel. I’m just not seeing the optin via CLI or GUI to enable MLPPP.

What are you using for your LNS? I’m using a Cisco 7200 IOS 12.2(31)SB5.

I wish a clear-dont-fragment-bit option would be added to the mangle chain … been asking for something similiar to that for years now. Maybe there is a technical reason or whatever, who knows.

MrPaul have we talked, just wondering cause I taked with some people about that.

Comon guys - think!

EOIP works with Ethernet Frames
L2TP works with IP Packets.
These are two different things

in L2TP you must concentrate on such thing as MTU and MRU - to work normally in the bridge they must be 1500 byte - it is possible to achieve it only by using Multilink-PPP option MRRU on the bith sides of the tunnel:

http://forum.mikrotik.com/t/multilink-ppp/16030/1

BTW correct way to add PPP interface to the bridge is to specify bridge option in the /ppp profiles menu