Commit Graph

2 Commits

Author SHA1 Message Date
Bill Somerville
662ed0fa7a
Network interface selection for outgoing UDP multicast datagrams
Default  selection  is  the  loop-back interface.  Users  who  require
interoperation  between  WSJT-X   instances  cooperating  applications
running on different hosts should  select a suitable network interface
and  carefully choose  a multicast  group address,  and TTL,  that has
minimal scope covering the necessary  network(s). Using 224.0.0.1 is a
reasonable    strategy    if   all    hosts    are    on   the    same
subnet. Administratively  scoped multicast group addresses  like those
within 239.255.0.0/16  can cover larger  boundaries, but care  must be
taken if the local subnet has access to a multicast enabled router.

The  IPv4  broadcast  address  (255.255.255.255) may  be  used  as  an
alternative  to multicast  UDP, but  note that  WSJT-X will  only send
broadcast UDP datagrams  on the loop-back interface,  so all recipient
applications must be running on the same host system.

The reference UDP Message protocol  applications are being extended to
be configurable  with a list of  interfaces to join a  multicast group
address on. By default they will only join on the loop-back interface,
which is also  recommended for any applications designed  to take part
in the WSJT-X  UDP Message Protocol. This allows full  user control of
the  scope of  multicast  group membership  with  a very  conservative
default  mode  that will  work  with  all interoperating  applications
running on the same host system.
2020-11-10 20:12:33 +00:00
Bill Somerville
0ba5d7e1bf
More flexibility for QDateTime round/truncate routine 2020-08-07 21:31:48 +01:00