© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Examining Mobility Examining Mobile IPv4

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Mobile IPv4 Model Subnet Prefix C Visited link Subnet Prefix B Subnet Prefix A

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Link A is the home link of the mobile node that has moved to link B. Another node is connected to link C. Mobile IPv4 Devices Mobile IPv4 Model (Cont.) Mobile Node Correspondent Node Home Link Home Agent Foreign Agent Subnet Prefix C Visited link Subnet Prefix B Subnet Prefix A

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v A node moves from a link with prefix B to a link with prefix C. On link C, the node gets an additional, temporary address on the network of C, referred to as a care-of address (CoA). Care-of Address Mobile IPv4 Model (Cont.) Address B Address B and Address C Home Agent Subnet Prefix C Subnet Prefix B Foreign Agent

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Types of CoA Mobile IPv4 Model (Cont.) Two types of CoA exist: CoA acquired from a foreign agent Colocated CoA

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Mobile IPv4 Process Mobile IPv4 Model (Cont.) Home Link Foreign Link Subnet Prefix B Mobile Node Home Agent Foreign Agent

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Mobile IPv4 Process (Cont.) Mobile IPv4 Model (Cont.) Home Address: Foreign Agent CoA: Home Link Foreign Link Subnet Prefix B Mobile Node Home Agent Foreign Agent

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Mobile IPv4 Process (Cont.) Mobile IPv4 Model (Cont.) Home Address: Foreign Agent CoA: Home Link Visited Link Subnet Prefix B Mobile Node Home Agent Foreign Agent

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Mobile IPv4 Process (Cont.) Mobile IPv4 Model (Cont.) Subnet Prefix C Visited link Subnet Prefix B Home Link Mobile Node Home Agent Foreign Agent Home Address: Foreign Agent CoA: Correspondent Node

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Mobile IPv4 Process (Cont.) Mobile IPv4 Model (Cont.) Subnet Prefix C Visited link Subnet Prefix B Home Link Mobile Node Home Agent Foreign Agent Home Address: Foreign Agent CoA: Correspondent Node

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Summary The Mobile IPv4 model creates a CoA whenever a node changes its point of attachment to a new network or subnet. The Mobile IPv4 process includes the following: –Mobility agents advertise their presence via agent advertisements. –Datagrams to the home address of the mobile node are intercepted by the home agent, tunneled to the CoA, received at the tunnel endpoint, and delivered to the mobile node. –In the reverse direction, datagrams sent by the mobile node are delivered to their destination using standard IP routing, not necessarily via the home agent.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v