Mobile IPv4 White Paper

HP-UX Mobile IPv4 White Paper 6
HP-UX Mobile IPv4 runs on HP-UX 11i and provides mobility
support for mobile devices as they roam about from one
network to another on the Internet. Version A.02.01 is designed
for a wide-ranging commercial deployment of Mobile IP that
requires AAA (Authentication, Authorization, and Accounting)
services and support.
HP-UX MOBILE IPv4
Product Features
The following are the salient features of the HP-UX Mobile IPv4
product.
IP Mobility Support for IPv4 [RFC 3344]
HP-UX Mobile IPv4 provides mobile nodes, the ability to roam
through the Internet while maintaining their home address and
network connection. HP-UX Mobile IPv4 allows transparent
routing of IP datagrams to these mobile nodes as they migrate
from their home network to other networks.
IP Encapsulation and Tunneling
When the mobile node is away from its home network, the
Home Agent receives all packets destined for the Mobile Node's
home address. The Home Agent encapsulates each packet in a
new packet. The destination address of this encapsulated packet
is set to the Mobile Node’s Care-of Address. This is called IP
Encapsulation.
This encapsulated packet is then routed to the Mobile Node’s
Care-of Address. When this encapsulated packet arrives at the
Mobile Node’s Care-of Address, the original IP packet is
extracted (or decapsulated) and the original packet is routed to
the Mobile Node.
This use of encapsulation and decapsulation of a datagram is
frequently referred to as tunneling the datagram, and the
encapsulator and decapsulator are then considered to be the
endpoints of the tunnel.
Reverse Tunneling [RFC 3024]
A Mobile Node, when communicating with a Correspondent
Node, typically sends packets directly back to the
Correspondent Node. With reverse tunneling, the IP packet is
encapsulated in a new packet with the destination address set to
the Home Agent. The Home Agent decapsulates the tunneled
datagram and routes it to the original destination.