• Christoph Paasch's avatar
    mptcp: Use 32-bit DATA_ACK when possible · a0c1d0ea
    Christoph Paasch authored
    RFC8684 allows to send 32-bit DATA_ACKs as long as the peer is not
    sending 64-bit data-sequence numbers. The 64-bit DSN is only there for
    extreme scenarios when a very high throughput subflow is combined with a
    long-RTT subflow such that the high-throughput subflow wraps around the
    32-bit sequence number space within an RTT of the high-RTT subflow.
    
    It is thus a rare scenario and we should try to use the 32-bit DATA_ACK
    instead as long as possible. It allows to reduce the TCP-option overhead
    by 4 bytes, thus makes space for an additional SACK-block. It also makes
    tcpdumps much easier to read when the DSN and DATA_ACK are both either
    32 or 64-bit.
    Signed-off-by: default avatarChristoph Paasch <cpaasch@apple.com>
    Reviewed-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a0c1d0ea
mptcp.h 4.93 KB