Asus AXE1600 PPPOE MTU 1500

[le_florin]

Hello,

I have set in nvram on Asus AXE1600:

nvram set none_wan_mru=1508
nvram set none_wan_pppoe_mru=1500
nvram set none_wan_mtu=1508
nvram set none_wan_pppoe_mtu=1500
nvram set wan0_mtu=1508
nvram set wan0_pppoe_mru=1500
nvram set wan0_pppoe_mtu=1500
nvram set wan_mtu=1508
nvram set wan_pppoe_mru=1500
nvram set wan_pppoe_mtu=1500

but the PPPOE is made with 1492.

ISP supports PPPOE with MTU 1500.

I have the latest Asus official firmware.

What can be the problem?

 

[bbunge]

MTU of 1500 is the Ethernet frame size. With the PPoE encapsulation of 8 bytes this lowers the MTU to 1492. Setting the MTU higher will result in fragmentation and thus lower speed. Setting the MTU to 1492 or lower can improve performance. Does not seem right but it is.