Mobile Ip - NetModule NB3000-Line-Hd User Manual

5.4.4. Mobile IP

Mobile IP (MIP) can be used to enable seamless switching between different kinds of WAN
links (e.g. WWAN/WLAN). The mobile node hereby remains reachable via the same IP ad-
dress (home address) at any time, independently of the WAN link being used. Effectively,
any WAN link switch causes very small outages during switchover while keeping all IP con-
nections alive.
Moreover, NetModule routers also support NAT-Traversal for mobile nodes running behind
a rewall (performing NAT), which makes mobile nodes even there accessible from a central
o ce via their home address, and thus, bypassing any complicated VPN setups.
The home agent accomplishes this by establishing a tunnel (similar to a VPN tunnel) be-
tween itself and the mobile node. WAN link switching works by telling the home agent that
the WAN IP address (called the care-of address in MIP terms) of the mobile node has
changed. The home agent will then encapsulate packets destined to a mobile node's home
address into a tunnel packet containing the current care-of address of the mobile node as
its destination address.
To prevent problems with rewalls and private IP addressing, the MIP implementation al-
ways employs reverse tunneling, which means that all tra c sent by a mobile node is re-
layed via the tunnel to the home agent instead of directly being conveyed to the nal desti-
nation. This fact also empowers MIP to be used as a lightweight VPN replacement (without
payload secrecy).
The MIP implementation supports RFCs 3344, 5177, 3024 and 3519. For applications requir-
ing vast numbers of mobile nodes, interoperability with the Cisco 2900 Series home agent
implementation has been veri ed. However, since NetModule routers implement a mobile
node as well as a home agent, a MIP network with up to 10 mobile nodes can be imple-
mented without requiring expensive third party routers.
If MIP is run as a mobile node, the following settings can be con gured:
Parameter
Primary home agent ad-
dress
Secondary home agent
address
Home address
NB3000-Line-Hd User Manual 4.2
Mobile IP Con guration
The address of the primary home agent
The address of the secondary home agent. The mobile node
will try to register with this home agent, if the primary home
agent is not reachable.
The permanent home address of the mobile node which can
be used to reach the mobile router at any time
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