Mobile IP Part I IPv4 Raj Jain Professor of Computer Science and Engineering Washington University in Saint Louis Saint Louis MO 63130 Audio Video recordings of this lecture are available at http www cse wustl edu jain cse574 08 Washington University in St Louis CSE574S 16 1 2008 Raj Jain Overview Mobile IP Terminology Processes Registration Advertisements Security Issues Reverse Tunneling Home Networks with Dynamic IP Address Dynamic Home Agent Assignment Network Mobility NEMO Mobile IP and VPN Washington University in St Louis CSE574S 16 2 2008 Raj Jain Mobile IP Features You can take you notebook to any location Your TCP connection can continue TCP connections are from one IP address to another IP address TCP is unaware of the mobility Continuous access to your home resources Access to local resources Printers Finds nearby IP routers and connects automatically Your IP messages are delivered to your new location Only Mobility Aware routers and mobile units need new s w Other routers and hosts can use current IP No new IP address formats Secure Allows authentication Washington University in St Louis CSE574S 16 3 2008 Raj Jain Mr Smith Goes to Washington Mr Smith s office C an yo Can I speak to Mr Smith Jim Taylor u co Hello Senator Taylor nne ct m e to Mr Smi th Mr Smith Call from Taylor Hotel Mr Smith Operator Hello Senator Taylor Washington University in St Louis We need An agent at home office Home Agent An agent at foreign office Foreign Agent CSE574S 16 4 2008 Raj Jain Mobile IP Terminology Home net Mobile Home Node Agent Node moves New Mobile net Node Correspondent Node Foreign Agent Mobile Node MN Home Agent HA Foreign Agent FA Care of address COA Address of the end of tunnel towards the mobile node Correspondent Node CN Home Address Mobile s permanent IP address Washington University in St Louis CSE574S 16 5 2008 Raj Jain Terminology Home Address Long term IP address of the mobile on the home network IP Access Address Local IP address of the mobile on the foreign network Care of Address Address to which the packets are sent by the home agent Destination of the IP tunnel between home agent and the mobile Generally COA IP Access Address Mobility Agent Home agent or foreign agent Agent Advertisement Periodic advertisement from mobility agents Correspondent Node The node communicating with mobile Foreign Network Any network other than the home network Gratuitous ARP Sent by home agent to update other node s ARP cache Washington University in St Louis CSE574S 16 6 2008 Raj Jain Terminology Cont Mobility Binding Binding between home address and COA Tunnel Path followed by an encapsulated packet Mobile Router A router with changing point of attachment Mobile Host A end host not a router Mobile Node Mobile Host or Mobile Router Mobile Network An entire network that changes its point of attachment Mobile Network Node A node in a mobile network May itself be mobile visiting or fixed permanent member of the network Roaming Getting connectivity from a foreign network based on a formal agreement between foreign and home network service providers Washington University in St Louis CSE574S 16 7 2008 Raj Jain Terminology Cont Handover Changing the point of attachment L2 Handover Moving from one access point to another access point in the same IP network same network prefix L3 Handover Moving from one IP network to another Moving from one access router to another access router Horizontal Handover Moving between same technology WLAN to WLAN or 3G to 3G Vertical Handover Moving between different technologies WLAN to 3G Push Handover Previous access router initiates handover Pull Handover New access router initiates handover Washington University in St Louis CSE574S 16 8 2008 Raj Jain Terminology Cont Make Before Break Make a new connection before disconnecting previous Will communicate with both for some time Break before Make Disconnect previous and then connect with next Handover Delay Time between break and make Smooth Handover Minimize packet loss Handover delay not critical Fast Handover Minimize handover delay Packet loss not critical Seamless Handover No change in quality security or capability of service Washington University in St Louis CSE574S 16 9 2008 Raj Jain Terminology Cont Diversity Ability to receive two signals at the same time Micro Diversity Two signals between the same subscriber and base station Macro Diversity Two signals from different base stations IP Diversity Packets from two IP networks Micro Mobility Mobility within a single network No effect outside the network a k a Local Mobility Macro Mobility Mobility between networks Requires Mobile IP type solution a k a Global Mobility Washington University in St Louis CSE574S 16 10 2008 Raj Jain Mobile IP Processes Agent Discovery To find agents Home agents and foreign agents advertise periodically on network layer and optionally on datalink They also respond to solicitation from mobile node Mobile can send solicitation to Mobile agent multicast group 224 0 0 11 Mobile selects an agent and gets uses care of address Registration Mobile registers its care of address with home agent Either directly or through foreign agent Home agent sends a reply to the CoA Each Mobility binding has a negotiated lifetime limit To continue reregister within lifetime Washington University in St Louis CSE574S 16 11 2008 Raj Jain Processes Cont Return to Home Mobile node deregisters with home agent sets care of address to its permanent IP address Lifetime 0 Deregistration Deregistration with foreign agents is not required Expires automatically Simultaneous registrations with more than one COA allowed for handoff Washington University in St Louis CSE574S 16 12 2008 Raj Jain Encapsulation Tunneling Home agent intercepts mobile node s datagrams and forwards them to care of address Care of Address can be the Foreign Agent or it can be colocated in the mobile host Home agent tells local nodes and routers to send mobile node s datagrams to it De encapsulation Datagram is extracted and sent to mobile node Correspondent Home Intermediate Care of Routers Address Agent IP Header To COA Washington University in St Louis IP Header To Mobile CSE574S 16 13 Mobile Host Info 2008 Raj Jain Reverse Tunneling Normally MN sends the packets directly to the correspondent with SA Home Address DA Correspondent Problem Such packets may be dropped by visited network s firewalls since the source address is not on foreign network Solution Reverse traffic is also sent
View Full Document
Unlocking...