i connect to verizon dsl using windows xp pro with pppoe (network connections software). my westell dsl modem doesnt have any pppoe firmware. pppoe further encapsulates the ethernet frame. windows xp pppoe ip mtu is 1480. The 20 bytes of overhead consist of the PPPoE header (6 bytes), the largest possible outer PPP header (4 bytes), the largest possible Multilink PPP header (4 bytes), the largest possible PPP header for compression and encryption (4 bytes), and the PPP header that identifies the actual packet being sent (2 bytes).
do i also have to add an addtional 20 bytes for pppoe when calculating an icmp packet?
56(default)+14(ethernet)+20(pppoe)= 90 bytes outgoing