I try to setup a MPLS / VPLS on a existing network to have a full 1500 byte on VPLS tunnels to make PPPoE centralize.
And I stuck in a problem on packet fragmentation that packets not going trough VPLS with more than 1500 byte
I've checked all the things , and not resolved yet , anybody know ?
Here is my check list :
R1 is 1036 , R2 is RB1100 .
Two routers are connected with a direct patch cord cable .
RouterOS version are 6.39.3 and firmwares are last .
VPLS is running between two routers and works , MTU IS 1508 and I try it by 1520 too .
Interface L2MTU on R1 is 1580 , R2 is 1598 .
I've changed L2MTU on both interfaces with 1600 too .
MPLS interface MTU is 1550 at first and I tried with 1590 too .
R1 Loopback = 172.16.0.1 , R2 = 172.16.0.2
interface address is = 172.16.1.0/30 . (R1=1 , R2=2) .
Problem is :
Maximum ping byte to 172.16.0.2 from R1 is 1500 and got error on even on 1501 .
I've setup this configs on LAB
devices and works well .
If ping 172.16.1.2 (interface address) from R1 , maximum byte will be 1500.
If ping 172.16.0.2 (loopback address) from R1 ,maximum byte will be 1546 (when MPLS interface is 1550) and works well .