Sorry for not being of much help here, but I thought at least I should tell you that I see the same behavior for quite some time now.A large network that is running VPLS has been working quite well. We currently are not worried about packet fragmentation, however, we can not push the 1500 byte MTU packets though the VPLS in some instances.
VPLS circuits are set to 1508 in MTU in case of VLAN information, the VPLS tunnels do come up. In most cases, we have had the VPLS tunnels up for several weeks or longer, then in the morning, we come in and have calls about customer issues. We check, the VPLS circuit is up, but the largest ping we can get though is 1442. In many cases we can simply remove the MPLS interfaces, and readd them, upon readding the VPLS comes back up and we can ping 1500 byte packets across the link.
The question is WHY does this stop working? We have tried BGP VPLS as well, but still 1442 pings only. Whats even more confusing, is we have another VPLS tunnel that goes THOUGH the affected site, and it does not have the MTU issue!
saw this post and thought I would throw my two pesos in as I do a lot of MPLS work in Cisco and Mikrotik.
Not sure if any of you guys have tried this, but if you want to do EoMPLS/VPLS and pass a 1500 byte IP packet between the two connected hosts on the CE routers, then the MPLS MTU (and hence the max L2MTU) has to be at least 1526 for untagged frames and 1530 for tagged frames. You should be able to ping with the fragment bit set at 1472 bytes to test passing a full 1500 byte packet (you lose 20 bytes for the IP header and 8 bytes for ICMP hence 1472)
Basically with VPLS you have to have additional mtu overhead because you are encapsulating a Layer 2 frame inside of an MPLS packet and it has to have an ethernet header to deliver once it gets there so there's 14 bytes plus a 4 byte VPLS header and the standard 8 bytes for MPLS....which gets you to 1526. So whatever the max L2 MTU is on your interface is, subtract 26 bytes and you will get the VPLS payload
Also, if you're setting different MPLS mtus on each router, then you can potentially run into issues. it's better to set them all to the lowest common denominator in the path.
Does that network card report an L2MTU in Mikrotik?Yes we are running vpls circuits between data centres. Each vpls tunnel is carrying vlan tagged packets. We are running RouterOS on Dell R210-II with Pro1000 quad port NIC and booting from Kingston 8GB SSD.
We have a lot of these in production all doing MPLS/VPLS with no issues.
The cards do not report L2MTU and it cannot be manually set. The values are greyed out in winbox, and at the command line you can enter the command, but it does nothing.If the card does not report L2MTU you must set MTU to desired value.
Yea, but when I do that, and I try to put a larger packet thru that interface with MPLS and a VPLS tunnel, the router crashes.Again if L2MTU is not detected you must set MTU (Layer3 MTU) to desired value.Code: Select all
/interface set ether1 mtu=1530
Is beta 3 out? Can I get a copy?It is a driver problem. Try v6beta3 there should be newer drivers. If it crashes on beta3 too then get better ethernet card.
Ok thanks emailed support.You can get beta3 if you contact support. Well the card is not bad, but it is quite new and drivers are not optimized in older kernel.
Haha, fair enoughI couldn't get the PCI-e card in the PCI slot, lol
I think I might have to do this, further testing of a realtek card shows it can just quit working, only a disable and re-enable fixes it, I dont like that.Get a Dell R210-II with Xeon E3 CPU, Intel Pro1000PT Quad Port NIC (I350 should work in later 5.x), then just add a small 8GB SSD for RouterOS.
You should be able to get this configuration from Dell Direct for around USD $800 - $1000 depending on where you are located you can probably get same day warranty on it too.
This is known working config and is being deployed by quite a few people on these forums with success.
I would probably go for the new RouterBoard RB44Ge http://routerboard.com/RB44Ge instead of an Intel NIC on any new builds. This way if you encounter any issues Mikrotik will be more obliged to support you since you are using their hardware
Maybe email firstname.lastname@example.org and see if they will do a licence transfer (doubtful, but worth a try)I think I might have to do this, further testing of a realtek card shows it can just quit working, only a disable and re-enable fixes it, I dont like that.
There is a local r210-II for sale here, more than I need (dual SAS 300 gig raid, core i3 chip, DRAC 6 enterprise), new for 800 bux no tax, I can probably strip out the drives and raid controller and sell them and stick in a small sata drive, but I just bought a controller level 6 license and it sits on an IDE drive, that was only a couple months ago and I dont want to buy a new one again