Winbox access problem when set MPLS

Hello folks, I’m with a problem by accessing via winbox. Everytime I add an interface in “mpls interface tab” I lose my connection via winbox, but I have ssh and telnet connection yet, only using winbox that I’m having trouble.

does anyone here can help me?

winbox requires 1500 byte packets to go through. If you loose access it means that configured MTUs are not correct.

[admin@MikroTik] /interface> pri
Flags: D - dynamic, X - disabled, R - running, S - slave

NAME TYPE MTU L2MTU MAX-L2MTU

0 R ether1 ether 1526 1526 1526
1 R bridge1 bridge 1500 1500
2 R MNGT vlan 1520 1496
3 R wlan2 wlan 1540 2290
4 R vpls1 vpls 1500 1500
But winbox not working, only telnet. Web access not working too.

It’s an MTU problem! Try to reset to factory default your configuration and the reconfigure mpls layer:
specify in mpls interface only interfaces that partecipate in the mpls and set mpls-mtu value to 1526

bye

Dears..

When there is Luciano.. I cant say much …!!!

Just want to share some tuning..

for vpls mtu should set on MTU and L2MTU :
MTU + vlan + ether header
1500(MTU) + (vlan)4 + (ether)14 = 1518 byte

for MPLS MTU should set:
MTU +vlan + ether + vpls
1518 + (vpls) 4 = 1522 byte

for ether interface full L2MTU should be not less than 1530.. by default its 1600byte..

If you use QinQ that mean move some vlan into vlan need to add more 4 byte for sub vlan

So you have to set the VPLS MTU and L2MTU 1522 byte and for MPLS MTU 1526

And the ethernet L2MTU will need at least 1534byte that is no need to be worry its already 1600


thanks a lot

Ali Sami