3 ms·

>"Another advantage, until recently, was out-of-order delivery." Can you elaborate on this? Which recent development are you referring to? Thanks.

• ncmncm 7y ago
  Doesn't TCP have an ability to re-send dropped packets, now, without sending everything after them? I thought they called it selective re-send, or selective ack, or something. Maybe the receiver could send an ACK with a bitmap of which packets it got, and the sender would fill in the holes?
  • zlynx 7y ago
    I believe it's Selective ACK aka SACK. It allows TCP to ACK ranges of packets so the sender can see that it only needs to resend an earlier block. I've seen rather good speeds over some bad links from my bittorrent server using large window sizes (up to 9), BBR flow control, ECN fully enabled, and SACK.
  • bogomipz 7y ago
    Yes it has had selective acknowledgments(SACK) for quite a long time(RFC 2018.) I thought the OP was referring to something perhaps more recent since I believe SACK might predate Aspera.
    • ncmncm 7y ago
      Most of our customers didn't have SACK-capable network stacks. It used to take a very long time for IETF specs to find their way into deployed systems.