J The mobile receiver sends a Rm_out message to the old LMR (oLMR).
J oLMR starts a procedure of updating the DBT if this mobile receiver is the
last receiver attached.
J The mobile node sends Rm_in message towards the new LMR (nLMR).
J The nLMR starts a DBT update procedure if this mobile receiver is the first
receiver attaching to the nLMR.
J The nLMR starts the registration procedure for the mobile node; the
registration procedure is similar to join/leave procedure in SReM except that
this registration will not be sent to the source node.
Depending on the MDT state of x’oLMR and the x’nLMR, two scenarios will be found.
The first scenario is that the mobile receiver is not the last receiver attached to the oLMR
and it is not the first mobile receiver attached to the nLMR which means that there will
not be any DBT update. The second scenario is when either the mobile receiver is the last
receiver attached to the oLMR case or it is the first mobile receiver attached to the nLMR
case or both cases which means that there will be a DBT update.
In the first scenario, the mobile receiver, say x must be not the last one attached to the
oLMR and not the first one attached to the nLMR. x will send a Rm_out message towards
its oLMR. Upon receiving this message, the MDT for the x’s oLMR will be updated by
removing the x’s entry. No changes will happen to the existing DBT regarding this
mobile node roaming out. Similarly, x will send a Rm_in message towards its nLMR
when x in the domain covered by its nLMR. Upon receiving the roaming in message, the
nLMR MDT will be updated by adding an entry for the mobile receiver x. Similar to the
previous case no multicast DBT session update will happen. As mentioned previously,
nLRM is able to be aware of the x’s membership belonging to multicast groups.
Therefore, from then on, mobile receiver is able to receive multicast packets directly
from its nLMR.
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