NetModule NB2710 User Manual page 71

If MIP is run as a home agent, you will have to set up a home address and network mask for the
home agent first. Then you will need to add the configuration for all mobile nodes which is made
up of the following settings:
Parameter
SPI
Authentication type
Shared secret
NB2710 User Manual 4.0
Figure 5.23.: Mobile IP
Mobile IP Node Configuration
The Security Parameter Index (SPI) identifying the security context
for the tunnel between the mobile node and the home agent.
This is used to distinguish mobile nodes from each other. Therefore
each mobile node needs to be assigned a unique SPI. This is a
32-bit hexadecimal value.
The used authentication algorithm. This can be prefix-suffix-md5
(default for mobile IP) or hmac-md5.
The shared secret used for authentication of the mobile node at
the home agent. This can be either a 128-bit hexadecimal value
or a random length ASCII string.
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