IP Multicast Channel


dp_connect ipm -group ipAddr -myport myPort -ttl numHops


IPM is the multicast version of UDP.  It allows any number of machines to join a group and if a message is sent to the group address, all the machines will hear it.

One can add and drop IPM group memberships using the fconfigure -group command. See below for examples and please note the use of the plus and minus symbol to signify add or drop. An IPM channel can be a member of any number of multicast groups (although it is usually limited by the OS to 20) so it is not necessary to drop a group in order to add a new one.


dp_connect ipm -group
dp_connect ipm -group -ttl 3
dp_connect ipm -group -port 1905 -ttl 255
fconfigure $ipmChan -group +
fconfigure $ipmChan -group -