Methods and apparatus for communicating IP datagrams efficiently within communication links employing variable frame sizes bundles IP datagrams into data payloads. The number of datagrams that can fit within a current frame size is determined, a bundle header indicating that the bundle header is associated with a bundled IP datagram is generated that includes information for unpacking bundled IP datagrams. The bundle header is joined to one or more IP datagrams to form a data payload that is communicated as a frame payload without indicating in a frame header that the frame includes bundled IP datagrams. Information in the bundle header enables a receiver processor to extract the IP datagrams from the frame payload without requiring modifications to the frame header. A bundle header may precede each IP datagram, or one bundle header may include a map IP datagrams in the frame payload.