21-11-2012, 01:49 PM
Mobile IP
mobile.ppt (Size: 51 KB / Downloads: 44)
We’re not quite done with IP
You’re probably sick and tired of hearing about all things IP
Forwarding, routing, multicast, etc…
One last topic we must cover because it’s going to be important in the future – mobile networking
Examples of mobile networking today?
Examples of mobile networking tomorrow?
Mobile networking should not be confused with portable networking
Portable networking requires connection to same ISP
Portable Networking Technology
Cellular systems
Cellular Digital Packet Data (CDPD)
3G
Bluetooth
Low cost, short range radio links between mobile devices
Wireless Ethernet (802.11)
Widely used wireless MAC layer technology
Mobility and Standard IP Routing
IP assumes end hosts are in fixed physical locations
What happens if we move a host between networks?
IP addresses enable IP routing algorithms to get packets to the correct network
Each IP address has network part and host part
This keeps host specific information out of routers
DHCP is used to get packets to end hosts in networks
This still assumes a fixed end host
What if a user wants to roam between networks?
Mobile users don’t want to know that they are moving between networks
Why can’t mobile users change IP when running an application?
Mobile IP
Mobile IP was developed as a means for transparently dealing with problems of mobile users
Enables hosts to stay connected to the Internet regardless of their location
Enables hosts to be tracked without needing to change their IP address
Requires no changes to software of non-mobile hosts/routers
Requires addition of some infrastructure
Has no geographical limitations
Requires no modifications to IP addresses or IP address format
Supports security
Could be even more important than physically connected routing
IETF standardization process is still underway
Mobile IP Entities
Mobile Node (MN)
The entity that may change its point of attachment from network to network in the Internet
Detects it has moved and registers with “best” FA
Assigned a permanent IP called its home address to which other hosts send packets regardless of MN’s location
Since this IP doesn’t change it can be used by long-lived applications as MN’s location changes
Home Agent (HA)
This is router with additional functionality
Located on home network of MN
Does mobility binding of MN’s IP with its COA
Forwards packets to appropriate network when MN is away
Does this through encapsulation
Security in Mobile IP
Authentication can be performed by all parties
Only authentication between MN and HA is required
Keyed MD5 is the default
Replay protection
Timestamps are mandatory
Random numbers on request reply packets are optional
HA and FA do not have to share any security information.