[lwip-users] LwIP 1.3.2 -> 1.4.0: Huge RAM increase for PPP use

[Marco Jakobs]

Dear all,

updating a project from LwIP 1.3.2 to 1.4.0 without the use of PPP did a 
minor increase of the used RAM of a few hundret bytes, which is no 
problem on my limited microcontroller environment.

But a project which is using PPP (PPPoS) with LwIP did a jump up of 
around 3kByte and more by the update from LwIP 1.4.0 to 1.3.2. This 
really killed my free memory.
What are the changes which uses this huge amount of memory in LwIP 1.4.0 
while using PPP? Is there any way to get this down again without hurting 
the PPP functionality?