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Query on Mobile IP implementation

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Query on Mobile IP implementation

Hello All,

I was going through the concept of Mobile IP allocation for User device for supporting mobility of User Device.

I have been referring to X.S0011-002-E_v1.0_091116 - 3GPP2 spec and also few RFCs: 5944, 2002 etc.

Coming to my doubt, My main point of concern is about the Visitor list maintained in the Foreign Agent(FA) serving the Mobile Node(MN or User Device).

The Visitor list contains typically, Home Address, Home Agent Address and MAC Address of the MN.

Now when a packet is sent by some node destined for the Mobile Node, the packets arrives at the Home Agent(HA), here HA checks its binding list and gets to know that the device is in foreign location. So, the HA uses the care-of-address for that MN from its binding table and creates and encapsulated packet and sends that encapsulated packet to the FA. Now at the FA, FA decapsulates the packets and gets to know that the packet is for MN. The FA checks its visitor list and finds the MAC address(Link Layer address) for the MN. Then the FA sends the packet to the MN using the MAC address.

1. Why does FA need the MAC address(link layer address) of the MN for sending the packet to MN ?
Why can't the FA use the MN's IP address from the visitor list to route the packet to MN ?
2. During dynamic address assignment for MN, Registration Request(RRQ) message is sent from MN -> FA -> HA. Now, If the MN is booting UP in the foreign area, then it will have no IP address and HA address assigned. So, it sends MN address: and HA address: in the RRQ message.
How does FA know to which HA this RRQ message be forwarded?

I shall be thankful for any input on this topic.

- Regards