Chapter: 07-Mobile Computing 4 G& Mobile IP By: Mr. Abdul Haseeb Khan

 Description of wireless networks  Wireless network evolution  Wireless key technologies  Current researches  Goals Of Network Layer  Terminologies  M-IP Protocol (Discovery, Registration, Tunneling)  Routing  Inefficiencies  MIPv6 Outline

 Motivated by people-on-the-go  PCs availability, Internet usage, Mobile life  Aimed is to establish wide-area voice data communications  Includes mobile systems (cellular telecommunication systems) Wireless Networks

 Otherwise known as NextG, Beyond 3G, 4G, and more!  Motivation  Providing all available services to highly mobile people (anytime anywhere)  Use your wireless device anywhere for listening to music, shopping (m-commerce), downloading (file transfer), watching video (live streaming)  Multiple applications (talk and use Internet services at the same time)  Objectives  Total convergence of the wireless mobile and wireless access communications (developing a broadband wireless network)  Ubiquitous wireless communications and services  Integration of multi-networks using IP technology  Similar technology to the wired Internet where users are freed from their local networks  All-IP based wireless networks  Not just IP end-to-end but over-the-air packet switching  Supporting native wireless IP mode  Highly integrated  High bandwidth / high-speed wireless  Highly compatible with wired network infrastructures  ATM, IP, ATM Forth Generation Wireless Networks

 Supporting heterogeneous multitude of systems  Includes multiple networks:  Cellular telecommunication systems  Digital video broadband  Digital audio broadband  Wireless LAB, Bluetooth-based networks  Open communication network: infrastructure independent which can access to any services and applications (now and in the future!)  Complete compatibility between wireless and wired networks through gateways  Supporting statistical multiplexing of heterogeneous data over-the-air  Latency, noisy environment, unpredictable discontinuities and loss, etc.  High-speed wireless transmission over the air  High performance physical layer  20Mbps (2G: 28Kbps, 3G: 2Mbps)  Scarce bandwidth availability  Efficient frequency spectrum utilization  Efficient hand off  Dynamic bandwidth allocation  Advanced digital transmission technology (modulation, low power devices, etc.) 4G Technology Challenges

 IP Addressing  Mobile IPv6 protocol provides unbroken connectivity between mobile nodes  Architecture  Horizontal communications between different access technologies using gateways  Including local-area access technology (3G only covers wide-area packet switched cellular technology)  Hand off  Fast hand off due to high-speed transmission  High reliability  QoS framework  Interoperability between wireless and wired networks  QoS classes: Conversational (most delay sensitive), streaming, interactive, background (least delay sensitive)  Fair bandwidth allocation  Class-based QoS over the air 4G Key Issues - Research Areas

 Security and billing  Essential in e-commerce  More than just authentication and encryption (as in 3G)  End-to-end security mechanisms between the Internet server (wired) and the mobile terminal  No translation and decomposition of the data at the gateways  Usage fee  Volume based or time-based?  TCP performance in wireless / mobile communications  Research shows unmodified standard TCP is not well aligned with cellular boundaries  New protocols have been developed: Snoop, Split connections, other end-to-end protocol families  Using Snoop agent the exchange of TCP packets and ACKs are monitored and performs local retransmissions as needed (OBS-like!)  Split-connections deals with wireless and wired network inconsistencies (gateways, translations, etc.)  Two separate connections between fixed and mobile hosts  End-to-end protocols deal with retransmission timeout causing the TCP window to shrink too often 4G Key Issues - Research Areas

Goal of Network Layer  Goal of Routing Protocols  decrease routing-related overhead  find short routes  find “ stable ” routes (despite mobility)  Goal of Mobile IP  Supporting end-system mobility while maintaining scalability, efficiency and compatibility in all respects with existing systems.

Mobile IP: Basics  Proposed by IETF (Internet Engineering Task Force)  Standards development body for the Internet  Mobile IP allows a mobile host to move about without changing its permanent IP address  Each mobile host has a home agent on its home network  Mobile host establishes a care-of address when it's away from home

Mobile IP: Basics- Terminology  Mobile Node (MN) - is an end-system that can change the point of connection to the network without changing its IP address.  Home Network (HN) – is the subnet the MN belongs to with respect to its IP address.  Foreign Network (FA) – is the current subnet the MN visits.  Home Agent (HA)  Is a system (or router) located in the home network of the MN,  registers the location of the MN, then tunnels IP datagrams to the COA  Foreign Agent (FA)  system in the current foreign network of the MN, typically a router  typically the default router for the MN

Mobile IP - Mobility: Vocabulary home network: permanent “home” of mobile (e.g., /24) Permanent address: address in home network, can always be used to reach mobile e.g., home agent: entity that will perform mobility functions on behalf of mobile, when mobile is remote wide area network correspondent: wants to communicate with mobile visited network: network in which mobile currently resides (e.g., /24) Foreign agent: entity in visited network that performs mobility functions on behalf of mobile. Permanent address: remains constant ( e.g., ) Care-of-address: address in visited network. (e.g., 79, )

slide by Konidala M. Divyan [3] Mobile IP: Basics-Example:2 Internet Home Agent Home network A Network B Network C Corresp. Node C Foreign Agent Mobile Node

Mobile IP: Basics, Cont.….  Correspondent Node (CN) – is a fixed or Mobile Node act as partner for communication with MN.  Correspondent host is a host that wants to send packets to the mobile host  Correspondent host sends packets to the mobile host’s IP permanent address  These packets are routed to the mobile host’s home network  Home agent forwards IP packets for mobile host to current care-of address  Mobile host sends packets directly to correspondent, using permanent home IP as source IP

Mobile IP: Care-of Addresses  The Home agent uses a registry table to find the care-of address of the mobile host.  address of the current tunnel end-point for the MN (at FA )  actual location of the MN from an IP point of view  can be chosen, e.g., via DHCP  Whenever a mobile host connects to a remote network, two choices:  care-of can be the address of a foreign agent on the remote network  foreign agent delivers packets forwarded from home agent to mobile host  care-of can be a temporary, foreign IP address obtained through, e.g., DHCP  home agent tunnels packets directly to the temporary IP address  Regardless, care-of address must be registered with home agent

slide by Konidala M. Divyan [3] Internet  Mobile Node sends Binding Update  Home Agent replies with Binding Acknowledgement Home Agent Mobile Node   Network B Network C Network A Corresp. Node C Mobile Node registers at its Home Agent Foreign Agent

Protocol  In order to support mobility, Mobile IP includes three capabilities: 1. Discovery 2. Registration 3. Tunneling

Discovery  Mobile Agents send ICMP router advertisements with mobility agent advertisement extension periodically informing mobile nodes of its presence.  Mobile node is responsible for the discovery process.  In order to receive an advertisement, the mobile node may optionally request one from an agent or simply wait for the next advertisement.

Registration  Mobile node recognizes that it is on a foreign network, acquires a Care-of- Address and requests its home agent to forward its data packets to the foreign agent.  The process of registration requires 4 steps: 1. Mobile node request forwarding service by sending registration request to the foreign agent. 2. Foreign agent relays this request to the home agent. 3. Home agent accepts or denies the request and sends registration reply to the foreign agent. 4. Foreign agent relays this reply to Mobile node.

Tunneling  After registration, an IP tunnel is set up between the home agent and care-of-address of the mobile node.  Home agent broadcasts gratuitous ARP request which causes all nodes in the subnet to update their ARP caches to map the mobile nodes IP address to the home agents link level address.  Thus home agent receives packets destined to the mobile node, and forwards the packets to the foreign agent through the IP tunnel.

Tunneling  In the foreign network, decapsulation is done by the foreign agent or by the mobile node itself.  A correspondent node assumes that the reply from the mobile node is coming from its home network and continues to send the packet to the home agent.

Issues in Mobile IP 1. Handoff:  When mobile node changes its point of attachment, a handoff sequence is initiated.  During or immediately after the handoff, packet losses may occur due to delayed propagation of new location information which degrades the quality of service.  Solved by introducing access point probing functionality in the mobile node to identify the current access point it is attached with.

Mobile IP: Security Issues [4] Issues in Mobile IP 2. Replay attacks:  A Bad Guy could obtain a copy of a valid Registration Request, store it, and then “replay” it at a later time, thereby registering a bogus care-of address for the mobile node  To prevent that the Identification field is generated is a such a way as to allow the home agent to determine what the next value should be  In this way, the Bad Guy is thwarted because the Identification field in his stored Registration Request will be recognized as being out of date by the home agent (timestamps or nonce are used for Identification field)

Issues in Mobile IP 3. Redundancy: What if the home agent doesn't answer a registration request?  Registration request to broadcast address  Rejection carries new home agent ID 4. "Ingress" filtering  Routers which see packets coming from a direction from which they would not have routed the source address are dropped

slide by Konidala M. Divyan [3] Internet  Mobile Node sends Binding Updates to Home Agent and all Corresp. Nodes, which already received a previous Binding Update from this Mobile Node Home Agent  Network B Network C Network A Network D Corresp. Node C Mobile IPv6 Roaming