Dear User,
we have a strange problem on our PPPoE network.
Our PPPoE server have an EoIP tunnel with MTU 1500 to our BS.
The BS have a bridge with EoIP and wlans.
For testing purpose we add an ip address to the EoIP tunnel with pppoe-server attached on the server side and note that the cpe could send 1500 packet to the server (ping ip size=1500 do-not-fragment).
We would like to remove fragmentation on CPE side, so we have enabled MRRU that is for us the best choise.
But:
if we set mtu=1480 and mru=1480 and mrru=disabled :we can send 1480 bytes, over need framentation
if we set mtu=1480 and mru=1480 and mrru=1614 :we can send 1475 bytes, between 1475 and 1610 ping reply with timeout , bigger packet need fragmentation
if we set mtu=1450 and mru=1450 and mrru=1614 :we can send at least 1610 bytes [it’s ok]
But i don’t understand why we need to reduce mtu/mru size in order to allow mrru to work.
Thank you