Mobile IP (RFC 3344) by Charles PerkinsPresented by: Roberto GarciaWhy Mobility?✦When you move to a new subnet you get a new IP address.✦Don’t want to close connections if possible.✦Not compatible with TCP/UDP as packets are routed by IP address (no other real solutions exist)✦Don’t want to miss traffic if possible (other solutions exist). Again packets are routed using the IP of the host.Two Solutions (bad)✦Change routing such that routing decisions are made based on hosts.✦Dismiss the connections by merely changing the IP address and nothing else. Force the application layer to deal with the problem.Another Solution?✦Mobile IP!✦But first...Some Terms✦Home Network - Where the mobile node has a long lasting IP address.✦Foreign Network - Where the mobile node moves to temporarily✦Home Agent - A router/host responsible for intercepting and tunneling packets to the mobile node in the foreign network.✦Foreign Agent - A router/host on the foreign network that provides “routing services when registered” (many functions are optional!)Basic Protocol✦Mobile Node leaves the home network and appears in the foreign network.✦Attempts to get a new IP address (think DHCP). This address is called a care-of-address.✦The foreign agent sends an Agent Advertisement possibly giving the node a default route.✦The mobile host will then register either with the home agent or with the foreign agent (who registers with the home agent)Basic Protocol cont...✦Upon an affirmative reply, the home agent is prepared to deliver packets to the mobile host in the foreign network.✦Packets sent from the corresponding host are then re-encapsulated at the home network and sent to the mobile host.✦Packets sent from the mobile host to the corresponding host are sourced with the care-of address in the foreign network.Mobility in ActionMobility in ActionHome NetworkMobile HostForeign NetworkForeign AgentHome AgentCorresponding NodeMobility in ActionHome NetworkForeign NetworkForeign AgentHome AgentCorresponding NodeMobile HostMobile IP is 3 Things✦Discovery - Mechanism that allows mobile computers to determine where they are and how they will communicate.✦Registration - Mechanism that tells the mobility agents how to communicate with the mobile host.✦Delivery - Mechanism to deliver messages to the mobile host.Discovery✦Like ICMP Router Discovery (RFC 1256)✦The mobile hosts finds itself on the a network.✦The Foreign Agent sends a periodic Agent Advertisement, which the mobile host heres. Interval can be no longer than 1/3 advertised lifetime of care-of address.✦The mobile host can either use the advertised care-of address or obtain one externally (DHCP)✦ Agent Solicitation✦Mobile host can send an ICMP Router Solicitation request if it does not hear any Agent Advertisements.Discovery✦Like ICMP Router Discovery (RFC 1256)✦The mobile hosts finds itself on the a network.✦The Foreign Agent sends a periodic Agent Advertisement, which the mobile host heres. Interval can be no longer than 1/3 advertised lifetime of care-of address.✦The mobile host can either use the advertised care-of address or obtain one externally (DHCP)✦ Agent Solicitation✦Mobile host can send an ICMP Router Solicitation request if it does not hear any Agent Advertisements. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Registration Lifetime |R|B|H|F|M|G|r|T| reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | zero or more Care-of Addresses | | ... |Discovery✦Like ICMP Router Discovery (RFC 1256)✦The mobile hosts finds itself on the a network.✦The Foreign Agent sends a periodic Agent Advertisement, which the mobile host heres. Interval can be no longer than 1/3 advertised lifetime of care-of address.✦The mobile host can either use the advertised care-of address or obtain one externally (DHCP)✦ Agent Solicitation✦Mobile host can send an ICMP Router Solicitation request if it does not hear any Agent Advertisements.Registration✦Request forwarding services✦Inform the home agent of the mobile agents care-of address✦Renew expired registered bindings✦De-registering bindings.Registration continued...✦Done either using the Foreign Agent (which basically just relays the message) or directly with the Home Agent✦Two types of messages sent over UDP (port 434) ✦Registration Request✦Registration ReplyRegistration continued...✦Done either using the Foreign Agent (which basically just relays the message) or directly with the Home Agent✦Two types of messages sent over UDP (port 434) ✦Registration Request✦Registration Reply 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type |S|B|D|M|G|r|T|x| Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Agent | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Care-of Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identification + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+-Registration continued...✦Done either using the Foreign Agent (which basically just relays the message) or directly with the Home Agent✦Two types of messages sent over UDP (port 434) ✦Registration Request✦Registration ReplyRegistration continued...✦Done either using the Foreign Agent (which basically just relays the message) or directly with the Home Agent✦Two types of messages