[Mobile IP] MN behaviors to uplink data packets during a handoff

Hi all,

Could anybody offer me some instructions on the behaviors of a Mobile Node
to
uplink (MN-->FA) data packets during a handoff?

For example,
1. when the MN loses link contact with the old FA (before getting an agent
advertisement), are all uplink data packets stored up at the link layer?
2. when the MN is aware of agent advertisements are missing, at the same
time it sends an agent solicitation, should it stop sending data packets
until
it gets an agent advertisement (or even until the registration is
successful)?

Many thanks,
Jee