Bundling a cross-board Point-to-Point (PPP) Multilink Protocol (MP), according to an example, includes: negotiating with a first device, by a second device, to determine a maximum number of sessions supported by an MP link, when the MP link is established between the first device and the second device, allocating, by the second device, sessions to interfaces board of the second device such that the sessions are distributed among a plurality of interface boards of the second device; when receiving an MP fragment packet from the first device, the second device determines an interface board to which a session is allocated according to a session identification (ID) of the MP fragment packet, and sends the MP fragment packet to that interface board.