Abstract: Methods, systems, and apparatus, including computer programs, providing resilient SCTP stack operation. One method includes having a master and slave for a gateway, the master checkpointing key protocol state, including: for transmissions over an SCTP connection from an application to a peer, checkpointing the message payload when a message is received from the application and before it is pushed to the SCTP protocol; after transmitting data to the peer, checkpointing a stream ID, stream sequence number, and transmission sequence number (TSN) of each chunk; and on receiving a selective acknowledgement (SACK) that a chunk was received, deleting the chunk and checkpointing this deletion; and for receptions of data: on receiving a chunk from the peer, checkpointing a message payload, stream ID, stream sequence number, and TSN before sending a SACK; and upon delivery of a message to the application, deleting the message from the SCTP stack and checkpointing the deletion.