Hi Scott,

Assuming you are referring to this thread: 
http://forum.mikrotik.com/viewtopic.php?f=14&t=78755

We have run into many issues with MPLS on x86 boxes, related to MTU, and found 
a few workarounds (none ideal)...

Placing a 'shim' VLAN, or two, between the physical ethernet interface and MPLS 
often seems to help. This does impact performance, but not as badly as running 
MPLS directly on the ethernet. This only ever seems to be necessary at the 
interfaces of x86 boxes, and whatever they attach to.

Using only L2VPN/VPLS (no IP-over-MPLS or L3VPN), setting the MPLS MTU at 1492 
or lower, and letting VPLS FAR handle fragmentation (it does a much better job 
than IP fragmentation, and is almost transparent to the end user). Again, this 
impacts performance, as it nearly doubles the number of frames that your 
transport links must carry.

Move the MPLS boundary back, so that the x86 boxes are not participating. For 
us, this often required extra hardware.

Also, make sure you are testing from and to boxes that are not participating in 
MPLS. I.e. test CE to CE, not PE to PE, or PE to CE; also, test UDP in addition 
to TCP. For some reason x86 boxes acting as PE routers often show far worse TCP 
performance than their actual forwarding performance. I've had some paths with 
x86 PEs that are easily able to move 300+Mbps CE to CE; but when testing 
between the PEs, the test maxes out at 5-6Mbps.

Good luck.

--Eric

From: [email protected] [mailto:[email protected]] On Behalf 
Of Scott Carullo
Sent: Monday, November 11, 2013 7:45 AM
To: [email protected]; [email protected]
Cc: Carullo, Scott
Subject: [WISPA] MPLS / Mikrotik Assistance Needed

Good morning.
We are in need of anyone who has deployed MPLS  across a WISP network of decent 
size to help us resolve a few issues we are having with our MPLS 
implementation.  We have about 50 routers / towers involved, fairly meshed.

I love and appreciate free advice that can help.  I am willing to pay 
consultant(s) as well.  My only problem to date - I can't seem to entice anyone 
into helping us - paid or otherwise.

If you know how to implement MPLS on Mikrotik routers or know someone who does, 
please contact me, we would really appreciate some assistance.
Scott Carullo
Technical Operations
855-FLSPEED x102

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