heartbeat over more than one NIC, mcast explanation

[Brian Tinsley]

Gregor Goestl wrote:

>I have two questions:
>
>First:
>Is it possible to use more than one NIC for heartbeat signals? Does the
>following setting in ha.cf work:
>
>udp eth0
>udp eth1
>
>to send heartbeats over two different ethernet connections?
>
Yes

>Second:
>Can me someone explain me the functionality of the 'mcast' Setting in ha.cf?
>What can I do with that stuff?
>
the syntax in ha.cf is as follows:

       mcast [dev] [mcast group] [port] [ttl] [loop]

       [dev]           device to send/rcv heartbeats on
       [mcast group]   multicast group to join (class D multicast address
                       224.0.0.0 - 239.255.255.255)
       [port]          udp port to sendto/rcvfrom (no real reason to differ
                       from the port used for broadcast heartbeats)
       [ttl]           the ttl value for outbound heartbeats.  this effects
                       how far the multicast packet will propagate.  (0-255)
       [loop]          toggles loopback for outbound multicast heartbeats.
                       if enabled, an outbound packet will be looped 
back and
                       received by the interface it was sent on. (0 or 1)