EF_TCP_ISN_MODE

Onload User Guide (UG1586)

Document ID
UG1586
Release Date
2023-07-31
Revision
1.2 English
Name
tcp_isn_mode
Default
clocked+cache
Scope
per-stack

Selects behavior with which Onload interacts with peers when reusing four-tuples:

  • clocked – Linux compatible behavior (default)
  • clocked+cache – additional cache to avoid failed connection attempts.
    Note: The behavior is relevant to high connection rate use cases with high outgoing data rates.

When in clocked+cache mode, sequence numbers used by closed TCP connections are remembered so that initial sequence numbers for subsequent uses of the same four-tuple can be selected so as not to overlap with the previous connection’s sequence space.