hello,
I have bonded two eth ports at each end (RB750G) and set vpls tunnel through bonding1, but web pages fails to open. I think there is mtu problem, because small packets (until 1450 or so) goes normally. MPLS MTU set to 1526, didn’t help. How can I fix that?
Correction: this is not mtu problem. When I disconnect one of two bonding slaves, everythink goes well… Then WTF? 
I can confirm that. I’ve made a wireless bonding and bridged the bonding interface to the local ethernet. You can ping between sites with 1500 ok no frag, but you get only 1478 bytes via any VPLS over the bonding.
I didn’t got further investigations why that happens tho. Also, I didn’t tried awesomes “VPLS over EOIP over bonding” techniques. But it may deceive MPLS thus possibly work out the VPLS.
Increase the MTU on the bonding interface to at least 1508bytes, the default 1500 is not large enough to pass a full size ethernet frame as well as the MPLS + VPLS headers.
I did a presentation on MTU requirements at the Australian MUM, the presentation has some good slides showing the required MTU’s for various configurations, check it out Here
Hi I have the same problem, i already increase the mtu of bonding interface but doenst work, this is my configuration
router1
captive portal
vpls1 router4 ( mtu 1500 )
Router2
Trunk radio1/2 ( mtu 1524 )
radio1 (ubnt) mtu 1524
radio2 (ubnt) mtu 1524
radio1 (ubnt) mtu 1524
radio2 (ubnt) mtu 1524
router3
trunk radio1/2 ( mtu 1524 )
router 4
vpls1 router 1 mtu ( 1500 )
bridge vpls with ether 2
the trunk is working normaly, but when i try to use the vpls interface i can get the dhcp and ping so i can use some thinks with low mtu but when try to open pages doesnt work, if i stop the second interface off the trunk all works, the problem for sure is in the bonding mtu, but i already increase and dont change anythink, the radios are ubnt with 5.5 firmare and amd mtu set to 1524 ( max )
tks for any help.
Romualdo
Same problem here as well, If i put the VPLS on a normal interface or a VLAN, it works OK, though the moment i change it to a bonding interface (with same interface as before), it doesn’t work.
MPLS MTU on ALL routers should be a minimum:
1526 -if using untagged VPLS
1530- if using tagged VPLS
That will allow you to pass a standard 1500 byte IP packet over the L2 handoff without having to adjust MSS