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Windows Oriented
Mobile IP solution
For transparent routing of IP
datagram's to Windows
oriented mobile nodes.
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Technical adviser:
Danny Zadok
Academic adviser:
Dr. Yuval Elovici
Project team:
Ira Zaitsev
Amir Patoka
Arie Kozak
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Current situation
Public Safety organizations are one of Motorola
biggest consumers which have mobile platform
(cars with Pocket PCs) that travel to the scene of
events (crime scenes, fires …).
In case of a public disaster event the usual provider
infrastructure usually collapse due to
overwhelming demand or damage physical
infrastructure, in those cases there is a need to
switch to the backup Public Safety organization
infrastructure (which is usually slower) without
noticing the change.
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Current situation – (cont.)
Our goal is to facilitate in mobile node
(Pocket PC, Laptop) to roam in the world,
attaching themselves to different points to
the internet while maintaining the
appearance of always being in the home
network.
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Problem domain
IP (Internet Protocol ) requires the location of any
host connected to the Internet to be uniquely
identified by an assigned IP address.
This raises one of the most important issues in
mobility, because when a host moves to another
physical location, it has to change its IP address.
However, the higher level protocols require IP
address of a host to be fixed for identifying
connections.
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Problem domain – (cont.)
Where is 171.68.69.2???
Gateway A
171.68.0.0
171.68.69.2”
Server
Internet
171.68.69.2
“Connect to
Gateway C
140.31.0.0
Client
?
140.31.70.1
Gateway A replies to Host B with an ICMP unreachable •
Proposed solution
The Mobile Internet Protocol (Mobile IP) is an extension to
the Internet Protocol proposed by the Internet
Engineering Task Force (IETF) that addresses this issue.
It is a standard communications protocol that is designed to
allow mobile device users to move from one network to
another while maintaining a permanent IP address.
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System Architecture
Mobile IP introduces the following new functional entities:
Mobile Node - A host or router that changes its point of attachment from one
network or sub network to another.
Home Agent - A router on a mobile node's home network which tunnels
datagrams for delivery to the mobile node when it is away from home, and
maintains current location information for the mobile node.
MN
Database
IP: H
IP: B
MN IP: A
Internet
Client
Home Network
Foreign Network
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System Architecture – (cont.)
Src:A Dest:R
IP: H
Src:B Dest:H Src:A Dest:R
Internet
Remote App
Src:A Dest:R
Home Network
Home IP: A
MN
IP: B
Foreign Network
IP: R
Mobile Node ->Remote Application
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System Architecture – (cont.)
Src:H Dest: B Src:R Dest:A
IP: H
Src:R Dest:A
Src:R Dest:A
Src:H Dest: B Src:R Dest:A
Internet
Remote App
Home Network
Src:R Dest:A
Home IP: A
MN
IP: B
Foreign Network
IP: R
Remote Application -> Mobile Node
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Technologies
NDIS (Network Driver Interface Specification) .
Windows CE API for Mobile Node
implementation.
Win32 API for HA implementation.
DHCP protocol for IP allocation.
ICMP protocol for HA advertisement.
DB for HA using SQLServer.
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Main Functional Requirements
Home Agent Advertisement: In order to
allow Mobile Node to determine whether it
is in Home network or Foreign network.
Our HA will advertise himself by MN
request.
Broadcast or
multicast with
TTL = 1
Mobile
Node
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Main Functional Requirements – (cont.)
Registration: Every Mobile Node that resides in the
foreign network needs to register with HA.
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Main Functional Requirements – (cont.)
Deregistration: when MN returns home, it need to
deregister himself.
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Main Functional Requirements – (cont.)
Datagram tunneling: when MN is in the foreign
networked, in order to hide his real source IP, all
the datagrams from/to him to/from Application
should be tunneled .
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Main Functional Requirements – (cont.)
Home-IP allocation: HA will have a pool of
available Home IP's. Each time HA receives
a registration request with Home IP 0.0.0.0
it assigns one of the available IPs in the
pool to a Mobile Node that sent the
request.
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Non functional requirements Performance constraints
Home Agent recovery (restart) less than 1 minute in case
of failure.
System reliability – works 99.9% of the time.
Registration/deregistration time: 1sec + network latency.
Packet transmission time: 10msec + network latency.
Packet loss is not exceeded more than by 2% the original.
Maximum number of supported Mobile Nodes per Home
Agent is 1000.
Simplest installation: any configuration values with
default values won’t participate in installation process and
will be set to default.
Maximum number of network interfaces per Mobile Node
supported by system is 4.
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Non functional requirements - SE
Project Constraints
The Mobile node might not run on the university
network due to firewall limitations.
Home Agent will not run on the university
network due to NAPT and Firewall limitations
during final presentation, but on the remote
network.
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Major Use-Cases
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Major Use-Cases – (cont.)
Installation of the system on Mobile Node:
Primary Actor: Administrator.
Precondition: Windows Mobile/XP, support for
NDIS.
Post condition: the host now supports Mobile IP.
Main scenario:
1.
2.
3.
4.
Running the installation program for the driver.
Installing the service.
Configuring the service (Use Case 2).
Registering the Mobile Node to the Home Agent.
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Major Use-Cases – (cont.)
Configuring the service :
Primary Actor: Administrator.
Precondition: configuration/installation program is running.
Post condition: the service is configured.
Main scenario:
1.
Configuration of networks’ priorities.
2.
Configuration of encapsulation method (optional).
3.
Configuration of Home Address (default automatic).
4.
Configuration of Home Agent IP, Home Network IP address and
ports.
5.
Security configuration (keys, SPI, algorithms, etc).
6.
Networking configuration: delays, rates, etc. for each network.
Note: sometimes the configuration of service will require reconfiguration
of Home Agent (for the associated information).
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Major Use-Cases – (cont.)
Configuring Home Agent :
Primary Actor: Administrator.
Precondition: Home Agent is installed/installing.
Postcondition: Home Agent is configured.
Main scenario:
1.
Configuring registration table of supported Mobile Nodes (Home
Address, Security data, networking, etc.).
2.
Defining range of IP’s for supplying Home IP to Mobile Nodes
3.
Provide possibility to allocate/free each Home IP.
4.
Defining logging level.
5.
Configuration of different delays, rates, networking parameters.
Note: sometimes the configuration of Home Agent will require
reconfiguration of Mobile Node (for the associated information).
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Major Use-Cases – (cont.)
Displaying current state of Home Agent :
Primary Actor: Administrator.
Precondition: Home Agent is installed and running.
Post condition: User receives the information of current
network state.
Main scenario:
1. User prompts for type of information he wants: which
mobile nodes currently connected (registered), with
what care-of-address, registration life-time, different
statistics and logging.
2. Requested information is displayed.
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Major Use-Cases – (cont.)
Forward tunneling :
Primary Actor: Remote Application.
Secondary Actor: User Application.
Precondition: System is installed and configured and there is
a network link for both Home Agent and Mobile Node.
Postcondition: The packet arrives at the destination (User
Application).
Main scenario:
1. Remote application sends a packet.
2. The packet is intercepted by the Home Agent
encapsulated and tunneled to the Mobile Node.
3. Finally, the packet is decapsulated by the Mobile Node
and passed to the User Application.
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Major Use-Cases – (cont.)
Reverse tunneling :
Primary Actor: User Application.
Secondary Actor: Remote Application.
Precondition: System is installed and configured there is a network link
for both Home Agent and Mobile Node.
Post condition: The packet arrives at the destination (Remote
Application) with source IP equal to Home Address.
Main scenario:
1.
User application sends a packet.
2.
The packet is intercepted by the Mobile Node encapsulated and
tunneled to the Home Agent.
3.
Finally, the packet is decapsulated by Home Agent and sent to
destination.
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Major Use-Cases – (cont.)
Attachment Notification :
Primary Actor: Internet Service Provider.
Precondition: System is installed.
Post condition: Mobile Node has a virtual network
with his home network.
Main scenario:
1. Internet Service Provider notifies on a new
address or a new gateway.
2. Mobile Node registers himself with the Home
Agent.
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Risks
In case we don't find an open UDP port in the university
network we will need two cellular provider modems.
Availability of a Pocket PC with four network interfaces
questionable. Capacity test will be done in worst case on
laptop.
Testing the system inner network communication with
inputs outside the specification (Robustness testing) is
difficult due to non existing tools to feed the system with
improper inputs, which will require changing working
system components to faulty ones. Robustness testing
could be done with recording inputs through sniffer
programs and sending a modified recorded datagram.
Failing to live up to nonfunctional performance
requirement on common platforms will demand adding
constraints on components running platform to high end
ones.
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