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

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: Vocabularyhome network: permanent “home” of mobile(e.g., 128.119.40/24)

Permanent address: address in home network, can always be used to reach mobilee.g., 128.119.40.186

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., 79.129.13/24)

Foreign agent: entity in visited network that performs mobility functions on behalf of mobile.

Permanent address: remains constant (e.g., 128.119.40.186)

Care-of-address: address in visited network.(e.g., 79,129.13.2)

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. Discovery2. Registration3. 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