Enhanced sequenced packet exchange (SPXII) protocol

How SPXII works
    Backward compatibility with SPX
    Large packets
    Large packet negotiation
    Windowing protocol

SPXII packet structure

SPXII header fields

SPXII data flow
    Data packet format
    SPXII ACKs
    SPXII NAKs
    Sequence of data packets without a NAK
    Sequence of data packets with a NAK

SPXII connection management
    Connection establishment packets
    Session termination packets
    Watchdog
    Renegotiation
    Negotiating other values between endpoints

SPXII windowing algorithm
    Positive and negative acknowledgments
    Variable window size
    Error recovery
    Data packet timeout

SPXII programming interface