PPPoE 1500 Issue

[Lappy]

Hey,
I’m currently using an RB850Gx2 for my routing and a Draytek Vigor 130 for my modem, when I first configured the modem RouterOS managed to establish a 1500 MTU PPPoE connection just fine (with ether1 MTU being set to 1508), after a reboot it’s no longer going above 1492, I have tested the modem using my Macbook as the PPPoE client with the ethernet interface set to 1508 and ppp0 set to 1500 via terminal, that allowed 1472 pings to be sent without fragmentation just fine.

Is there any way to force RouterOS to use a 1500 MTU instead of it assuming or being told by the far end what to use?

(My ISP does support baby jumbo frames for the VDSL connection)

[mducharme]

@Lappy

Hey,
I’m currently using an RB850Gx2 for my routing and a Draytek Vigor 130 for my modem, when I first configured the modem RouterOS managed to establish a 1500 MTU PPPoE connection just fine (with ether1 MTU being set to 1508), after a reboot it’s no longer going above 1492, I have tested the modem using my Macbook as the PPPoE client with the ethernet interface set to 1508 and ppp0 set to 1500 via terminal, that allowed 1472 pings to be sent without fragmentation just fine.

Is there any way to force RouterOS to use a 1500 MTU instead of it assuming or being told by the far end what to use?

(My ISP does support baby jumbo frames for the VDSL connection)

You shouldn’t force it. It should work automatically by setting both “Max MTU” and “Max MRU” to 1500 in the PPPoE client settings.

[Lappy]

@mducharme

@Lappy

Hey,
I’m currently using an RB850Gx2 for my routing and a Draytek Vigor 130 for my modem, when I first configured the modem RouterOS managed to establish a 1500 MTU PPPoE connection just fine (with ether1 MTU being set to 1508), after a reboot it’s no longer going above 1492, I have tested the modem using my Macbook as the PPPoE client with the ethernet interface set to 1508 and ppp0 set to 1500 via terminal, that allowed 1472 pings to be sent without fragmentation just fine.

Is there any way to force RouterOS to use a 1500 MTU instead of it assuming or being told by the far end what to use?

(My ISP does support baby jumbo frames for the VDSL connection)

You shouldn’t force it. It should work automatically by setting both “Max MTU” and “Max MRU” to 1500 in the PPPoE client settings.

I have them both set to 1500, it still refuses to work (yet worked when I initially connected the modem, just not since rebooting the router.)