PPPoE with Jumbo Frame

Hello,

If you want to use MTUs 1500, you need:

• the network interface you use for PPPoE to be jumbo capable 

• any network infrastructure to be jumbo capable 

• the ISP to support RFC 4638 operation. Most UK ISPs using PPPoE on Openreach FTTx support MTU up to 1500.

The patch sets the MTU of parent interfaces where necessary, but will not override explicitly configured interface MTUs. The code attempts to set the PPPoE parent interface's MTU, then checks the MTU of this interface when building the mpd5 configuration file. If your PPPoE interface is not jumbo capable, you will have a maximum MTU of 1500 as before.

The easiest way to get MTU 1500 operation is to set the PPPoE interface to MTU 1500 in Interfaces -> WAN (or whatever interface(s) you use PPPoE on).

Thanks