Savings are notable in those cases where routers disseminate data as far as the scope allows, even if no participants exist at that distance. This is differentiated from the mobile machine problem in that users, not machines, are mobile.
Users migrate from machine to machine, or are engaged in computations on multiple machines at once.
A ttl of 0 is also legal but is only used among processes local to a single machine, e.g., this technique has been used for audio device arbitration. Ttls above 127 are typically used for bandwidth constrained distributions. The user directory's multicast address is presently 224.2.127.254. Data is only distributed to disinterested regions if multicast pruning is not available. It is not our intent to solve mobility at an IP level, but instead to try to support application-level mobility.