Networking Applications Dr. Ayman A. Abdel-Hamid College of Computing and Information Technology Arab Academy for Science & Technology and Maritime Transport Mobility Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications Outline Mobile Computing Mobile IP Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications Mobile Computing Access to data anywhere, anytime, using any means of connectivity Nomadic access Cellular-like access Mobile ad hoc networks Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Host Mobility Problem 1/2 An IP address reflects a host’s point of attachment to the network Example: TCP connection identified by a 4-tuple < source IP address, source TCP port, destination IP address, destination TCP port > if either host move, and acquire a new IP address, the TCP connection breaks Fundamental Problem an IP address serves dual purpose Transport and application layer perspective: end-point identifier Network Layer: routing directive Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Host Mobility Problem 2/2 Subnet 128.82.9 R 128.82.9.60 Packets to Mobile Host routed to home network Mobile Host Stationary Host Subnet 128.80.10 R Internet Mobile Host 128.80.10.50 Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Host Mobility Problem Solutions Network layer solutions -IETF Mobile IP (MIPv4 and MIPv6) uses “Mobility agents” hides a change of IP address, when a mobile host is moving between IP networks. Application layer solutions -Mobility support using “Session Initiation Protocol” used for real-time mobile communications problem with TCP connections, suggests using mobile IP for TCP connections End-to-End Host Mobility support Relies on DNS secure dynamic updates TCP option for connection migration (suspend TCP connection and reactivate it from another IP address) Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Network Layer Solutions Model two-level addressing architecture home address & care-of address key mechanisms address translation map home address to care-of address packet forwarding tunnel packets to care-of address location management update mobile host’s location Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications IETF Mobile IPv4 1/4 Assigned a unique IP address on home network Foreign Network Home Network MH Obtains a co-located care of address in the foreign network MH 3. registration reply HA Foreign Network 4. registration reply MH 2. registration request FA 1. Registration request HA:Home Agent FA: Foreign Agent MH: Mobile Host Provides a care-of address to MH in the foreign network Home Registration Process Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications IETF Mobile IPv4 2/4 Home Network Foreign Network 2. Datagram intercepted by HA (through ARP) and tunneled to care-of address (FA) 3. Datagram detunneled and delivered to MH Triangular Routing tunnel HA FA MH 1. Datagram to MH arrives on home network via standard IP routing 4. Datagrams sent by MH are delivered through standard IP routing. In this case FA is MH's default router CH CH: Correspondent Host Unicast datagram routing to the MH’s care-of address Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications IETF Mobile IPv4 3/4 3. CH caches MH care-of address and uses it for any subsequent datagrams destined to MH 1. Datagram to MH arrives on home network via standard IP routing Home Network Old tunnel CH 2. Binding Update HA informs CH about MH current care-of address FA1 Foreign Network MH HA Route optimization FA2 new tunnel MH Forwarding pointer Previous FA notification inform previous FA of the new care-of address for MH. Previous FA tunnels in-flight packets, and packets from CH with out-of-date location cache entries to new FA. (Handoff) Cache Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications IETF Mobile IPv4 4/4 Problems triangular routing (sub-optimal routing) tunneling overhead use of route optimization solves the triangular routing problem, BUT requires change in the IP stack of CH large signaling overhead (registration) , if movement within the same domain (local-area mobility). MH has to inform the HA whenever it changes its point of attachment. Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications Outline MIPv4 Micro-mobility solutions Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Local-area Mobility Solutions Within the Mobile IP framework Regional Registration Framework (MIP_RR) Local and Indirect Registration Host-based forwarding schemes Cellular IP (Columbia University) HAWAII (Bell Labs) Multicast-based schemes Assign MH a scoped multicast address within the foreign domain Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Regional Registration Framework (MIP_RR) 1/3 Home registration Regional registration 10 GFA HA 4 3 9 FA2 FA3 2 8 6 FA4 FA5 FA6 FA7 Advertises {FA7, FA3, FA1} 7 5 1 MH MH MH {1, 2, 3, and 4}: Home registration when the MH first enters the foreign domain. {5, 6}: Regional registration with a local handoff from FA7 to FA6. {7, 8, 9, and 10}: Home registration involving a local handoff from FA6 to FA5. Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Regional Registration Framework (MIP_RR) 2/3 The old FA relays the BU message, received from the new FA, upwards in the hierarchy (to its father FA) specifying itself as the care-of address of the MH. The father FA performs the following steps delete its MH’s visitor entry, create a binding cache entry for the MH with care-of address the child FA that sent the BU message, relay the BU message upwards in the hierarchy, and send back a binding acknowledge message to its child FA Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Regional Registration Framework (MIP_RR) 3/3 Tunneling consistency mechanism to clear visitor entries in old path Reg. Req. BU Reg. Req. with PFANE Crossover FA MH FA2 FA4 FA5 FA3 FA7 Regional registration request Binding update message GFA FA6 Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Local and Indirect Registration HA:Home Agent FA: Foreign Agent Home Network Secure tunnel Anchor FA Foreign Network MH HA FA 1 4 3 2 Local Registration Home Network Secure tunnel Anchor FA Foreign Network MH HA FA 1 2 3 4 5 6 Indirect Registration Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Cellular IP 1/2 Cellular IP and Mobile IP Global Internet with Mobile IP Mobile IP Global mobility Cellular IP Wireless access network Wireless access network Local handoffs Local handoffs HA Wireless access network model Gateway Router BS FA MH tunnel Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications Cellular IP 2/2 MH: from B MH: from F A, D have paging caches Gateway Router paging update packets A D B E FA G F C Paging update packet (routed hop-by-hop towards the GW) MH paging packet routed to MH using paging caches MH: from B MH: from F Gateway Router A D B E FA MH responds with a route-update packet which configures routing caches along the way to the GW G F C Data packets for MH MH Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications HAWAII 1/2 Handoff-Aware Wireless Access Internet Infrastructure Uses specialized path setup schemes which install host-based forwarding entries in specific routers to handle intra-domain micro-mobility defaults to using mobile IP for inter-domain macro-mobility requires that MH obtains a co-located care of address within a domain, nevertheless MH is required to register with a BS within the domain to be able to better handle handoffs MH sends path setup update messages during power up and after handoffs HR FR MH Home Domain Foreign Domain HA notified of co-located care of address R HA HR: Home Domain Root Router FR: Foreign Domain Root Router domain model within HAWAII Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

© Dr. Ayman Abdel-Hamid, Networking Applications HAWAII 2/2 Router 0 Router 0 (0): 1.1.1.1  B (3): 1.1.1.1  C (0): 1.1.1.1  B (4): 1.1.1.1  C A C B A C B 4 3 4 5 Router 1 Router 2 Router 1 Router 2 ACK (0): 1.1.1.1  B (4): 1.1.1.1  A A C B A C B (0): Default  A (2): 1.1.1.1  B (0): 1.1.1.1  B (3): 1.1.1.1  A A C B A C B (0): Default  A (5): 1.1.1.1  B 2 5 6 6 3 Old BS New BS 2 Old BS New BS A B A B A B A B (0): 1.1.1.1  B (5): 1.1.1.1  A (0): Default  A (1): 1.1.1.1  B (0): 1.1.1.1  B (2): 1.1.1.1  A (0): Default  A (6): 1.1.1.1  B 1 1 7 7 MH IP: 1.1.1.1 MH IP: 1.1.1.1 Non-Forwarding path setup scheme (MH can listen/transmit to multiple BS) Forwarding path setup scheme (MH can listen/transmit to only one BS) Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Multicast and Mobility 1/3 The Deadalus Approach (Berkeley, 1995) maintains the HA concept of Mobile IP MH pre-assigned a multicast address by HA HA encapsulates any packets destined to MH and forwards them over the pre-assigned multicast group MH informs nearby Base Stations about multicast group and controls forwarding/buffering of packets at BSs through a control protocol Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Multicast and Mobility 2/3 A Multicasting-based Mobility Solution (1997) multicast sole mechanism to provide addressing and routing services to MHs each MH is assigned a unique multicast IP address (globally unique) approach affects a number of existing protocols such as TCP, ICMP, ARP, IGMP Mobility © Dr. Ayman Abdel-Hamid, Networking Applications

Multicast and Mobility 3/3 Fast Handoffs for Wireless Networks (1999) foreign domain arranged as a two level hierarchy with a domain FA at the root and base stations as leafs. MH assigned a multicast address within the foreign domain by the domain FA (centralized server) domain FA becomes forwarding agent for all MHs (single point of failure, bottleneck) does not discuss details of multicast address allocation or effects on multicast routing Mobility © Dr. Ayman Abdel-Hamid, Networking Applications