Mobile IP

Definition

Mobile IP is a communication protocol (created by

extending Internet Protocol, IP) that allows the users
to move from one network to another with the same IP
address.
It ensures that the communication will continue
without user’s sessions or connections being dropped.
Mobile Internet Protocol operates in network
layer.

Based on IP.

Allow internetwork mobility for wireless nodes

without them having to change their IP addresses.

Defined by the Internet Engineering Task

Force(IETF).
Evolution of Mobile IP
When mobile node moves from one place to
another, it is assigned a new IP address at the new
hosting subnet to which the service providing
router provides connectivity to the Internet.
Assignment of new IP addresses is impractical due
to the following reasons:
1. Need for enhancing IP network capacity
2. Security Needs –identity of mobile node is
not hidden from another host.
3. Need for non-transparency from layers.
Why mobile nodes using mobile IP instead of the
exsiting IP protocol?

▪ Needs for enhancing IP network capacity.

▪ Need for upgrading the capacity of routers,

datalink and physical layers of IP networks.
Terminology

Router Router
HA FA

HOME MN
NETWORK
FOREIGN
NETWORK

Interne
t

Mobile Node (MN)

system (node) that can change
the point of connection
to the network
without changing its IP address
using mobile IP
Router
CN
Terminology

Router Router
HA FA

HOME MN
NETWORK
FOREIGN
NETWORK

Interne
t

Correspondent Node (CN)

• communication partner
• can be a fixed node or mobile
node

Router
CN
Terminology

Router Router
HA FA

HOME MN
NETWORK
FOREIGN
NETWORK

Interne
t

Home network
Subnet to which MN belongs to
w.r.t its IP
No mobile IP is needed within the
home network

Router
CN
Terminology

Router Router
HA FA

HOME MN
NETWORK
FOREIGN
NETWORK

Interne
t

Foreign network
Current subnet the MN visits.
Not its home network

Router
CN
Terminology

Router Router
HA FA

HOME MN
NETWORK
FOREIGN
NETWORK

Interne
t
Foreign agent
system in the current foreign
network of the MN, typically a
router
forwards the tunneled
datagrams to the MN, typically
also the default router for the
MN
Router
CN
Terminology

Router Router
HA FA

HOME MN
NETWORK
FOREIGN
NETWORK

Interne
t

Home Agent (HA)

system in the home network of the
MN, typically a router
registers the location of the MN,
tunnels IP datagrams to the COA

Router
CN
Terminology

Router Router
HA FA
COA
HOME MN
NETWORK
FOREIGN
NETWORK

Interne
t

Router
CN
Terminologies:
Mobile Node (MN):
It is the hand-held communication device that the user
carries.
e.g. Cell phone.
Home Network: It is a network to which the mobile
node originally belongs to as per its assigned IP
address (home address).
Home Agent (HA): It is a router in home network to
which the mobile node was originally connected.
Terminologies:
Home Address: It is the permanent IP address assigned to the
mobile node (within its home network).

Foreign Network: It is the current network to which the mobile

node is visiting (away from its home network).

Foreign Agent (FA): It is a router in foreign network to which

mobile node is currently connected. The packets from the home
agent are sent to the foreign agent which delivers it to the mobile
node.
Correspondent Node (CN):It is a device on the internet
communicating to the mobile node.
 Working:
Correspondent node sends the data to the mobile node. Data
packets contains correspondent node’s address (Source) and
home address (Destination). Packets reaches to the home agent.

• Now mobile node is not in the home network, it has moved into
the foreign network. Foreign agent sends the care-of-address to
the home agent to which all the packets should be sent.

• A tunnel will be established between the home agent and the

foreign agent by the process of tunneling.
 Tunneling
Tunneling establishes a virtual pipe for the packets
available between a tunnel entry and an endpoint. It is
the process of sending a packet via a tunnel and it is
achieved by a mechanism called encapsulation.

Now, home agent encapsulates the data packets into

new packets in which the source address is the home
address and destination is the care-of-address and sends
it through the tunnel to the foreign agent.
Foreign agent, on other side of the tunnel receives the
data packets, decapsulates them and sends them to the
mobile node.
Mobile node in response to the data packets received,
sends a reply in response to foreign agent.
Foreign agent directly sends the reply to the
correspondent node.
 Key Mechanisms in Mobile IP:
Agent Discovery:
• Agents advertise their presence by periodically
broadcasting their agent advertisement messages. The
mobile node receiving the agent advertisement
messages observes whether the message is from its
own home agent and determines whether it is in the
home network or foreign network.
Agent Registration:
• Mobile node after discovering the foreign agent, sends
registration request (RREQ) to the foreign agent.
• Foreign agent in turn, sends the registration request to the
home agent with the care-of-address.
• Home agent sends registration reply (RREP) to the
foreign agent. Then it forwards the registration reply to
the mobile node and completes the process of registration
Tunneling:
• It establishes a virtual pipe for the packets available
between a tunnel entry and an endpoint. It is the process
of sending a packet via a tunnel and it is achieved by a
mechanism called encapsulation.

It takes place to forward an IP datagram from the home

agent to the care-of-address. Whenever home agent
receives a packet from correspondent node, it
encapsulates the packet with source address as home
address and destination as care-of-address.
Wireless web-Web
services
The wireless web represents the combination of two innovative
technologies— wireless communications and the Internet.

A generic term for untethered access to the Web and other Inter
net services such as email and chat.

Public and private hotspots, Internet access via cellphone and

all other fixed or mobile wireless access services make up the

wireless Web.

Example: Amazon Web Services , Google’s Web service,

Google Cloud Platform.
Wireless web-Web services
On the World Wide Web, a web service is a standardized method for
propagating messages between client and server applications. A web
service is a software module that is intended to carry out a specific set
of functions.
A web service is a set of open protocols and standards that allow data
to be exchanged between different applications or systems. Web
services can be used by software programs written in a variety of
programming languages and running on a variety of platforms to
exchange data via computer networks such as the Internet in a similar
way to inter-process communication on a single computer.
web services include any software, application, or cloud technology that provides
standardized web protocols (HTTP or HTTPS) to interoperate, communicate, and
exchange data messaging – usually XML (Extensible Markup Language) – throughout
the internet.
Web services are XML-centered data exchange systems that use the internet for A2A
(application-to-application) communication and interfacing. These processes involve
programs, messages, documents, and/or objects.
A key feature of web services is that applications can be written in various languages
and are still able to communicate by exchanging data with one another via a web service
between clients and servers. A client summons a web service by sending a request via
XML, and the service then responses with an XML response. Web services are also
often associated with SOA (Service-Oriented Architecture).
Functions of Web Services

It’s possible to access it via the internet or intranet

networks.

XML messaging protocol that is standardized.

Operating system or programming language independent.

Using the XML standard, it is self-describing.
A simple location approach can be used to locate it.
 Components of Web Service

XML and HTTP is the most fundamental web services platform.

The following components are used by all typical web services:
SOAP (Simple Object Access Protocol)
SOAP stands for “Simple Object Access Protocol.” It is a
transport-independent messaging protocol. SOAP is built on
sending XML data in the form of SOAP Messages. A document
known as an XML document is attached to each message. Only
the structure of the XML document, not the content, follows a
pattern. The best thing about Web services and SOAP is that
everything is sent through HTTP, the standard web protocol.
A root element known as the element is required in every SOAP
document. In an XML document, the root element is the first
element. The “envelope” is separated into two halves. The
header comes first, followed by the body. The routing data, or
information that directs the XML document to which client it
should be sent to, is contained in the header. The real message
will be in the body.
UDDI (Universal Description, Discovery, and Integration)
UDDI is a standard for specifying, publishing and discovering a
service provider’s online services. It provides a specification that
aids in the hosting of data via web services. UDDI provides a
repository where WSDL files can be hosted so that a client
application can discover a WSDL file to learn about the various
actions that a web service offers. As a result, the client
application will have full access to the UDDI, which serves as a
database for all WSDL files.
The UDDI registry will hold the required information for the
online service, just like a telephone directory has the name,
address, and phone number of a certain individual. So that a
client application may figure out where it is.
WSDL (Web Services Description Language)
If a web service can’t be found, it can’t be used. The client
invoking the web service should be aware of the location of the
web service. Second, the client application must understand
what the web service does in order to invoke the correct web
service. The WSDL, or Web services description language, is
used to accomplish this. The WSDL file is another XML-based
file that explains what the web service does to the client
application. The client application will be able to understand
where the web service is located and how to use it by using the
WSDL document.
How Does Web Service Work?

The diagram depicts a very simplified version of how a web

service would function. The client would use requests to send a
sequence of web service calls to a server that would host the
actual web service.
Remote procedure calls are what are used to make these
requests. Calls to methods hosted by the relevant web service
are known as Remote Procedure Calls (RPC). Example: Flipkart
offers a web service that displays prices for items offered on
Flipkart.com. The front end or presentation layer can be written
in .Net or Java, but the web service can be communicated using
either programming language.
The data that is exchanged between the client and the server,
which is XML, is the most important part of a web service
design. XML (Extensible markup language) is a simple
intermediate language that is understood by various
programming languages. It is a counterpart to HTML. As a
result, when programs communicate with one another, they do
so using XML. This creates a common platform for applications
written in different programming languages to communicate with
one another.
For transmitting XML data between applications, web services
employ SOAP (Simple Object Access Protocol). The data is sent
using standard HTTP. A SOAP message is data that is sent
from the web service to the application. An XML document is all
that is contained in a SOAP message. The client application that
calls the web service can be created in any programming
language because the content is written in XML.
Features/Characteristics Of Web Service

Web services have the following features:

(a) XML Based: The information representation and record
transportation layers of a web service employ XML. There is no
need for networking, operating system, or platform binding when
using XML. At the middle level, web offering-based applications
are highly interoperable.
(b) Loosely Coupled: A customer of an internet service
provider isn’t necessarily directly linked to that service provider.
The user interface for a web service provider can change over
time without impacting the user’s ability to interact with the
service provider. A strongly coupled system means that the
patron’s and server’s decisions are inextricably linked, indicating
that if one interface changes, the other should be updated as
well.
A loosely connected architecture makes software systems more
manageable and allows for easier integration between different
structures.
(c) Capability to be Synchronous or
Asynchronous: Synchronicity refers to the client’s connection
to the function’s execution. The client is blocked and the client
has to wait for the service to complete its operation, before
continuing in synchronous invocations. Asynchronous
operations allow a client to invoke a task and then continue with
other tasks.
Asynchronous clients get their results later, but synchronous
clients get their effect immediately when the service is
completed. The ability to enable loosely linked systems requires
asynchronous capabilities.
(d) Coarse-Grained: Object-oriented systems, such as Java,
make their services available through individual methods. At the
corporate level, a character technique is far too fine an operation
to be useful. Building a Java application from the
ground, necessitates the development of several fine-grained
strategies, which are then combined into a rough-grained
provider that is consumed by either a buyer or a service.
Corporations should be coarse-grained, as should the interfaces
(e) Supports Remote Procedural Call: Consumers can use an
XML-based protocol to call procedures, functions, and methods
on remote objects utilizing web services. A web service must
support the input and output framework exposed by remote
systems.
Enterprise-wide component development Over the last few
years, JavaBeans (EJBs) and.NET Components have become
more prevalent in architectural and enterprise deployments. A
number of RPC techniques are used to allocate and access both
technologies.
A web function can support RPC by offering its own services,
similar to those of a traditional role, or by translating incoming
invocations into an EJB or.NET component invocation.
(f) Supports Document Exchanges: One of XML’s most
appealing features is its simple approach to communicating with
data and complex entities. These records can be as simple as
talking to a current address or as complex as talking to an entire
book or a Request for Quotation. Web administrations facilitate
the simple exchange of archives, which aids incorporate
reconciliation.
The web benefit design can be seen in two ways: (i) The first
step is to examine each web benefit on-screen character in
detail. (ii) The second is to take a look at the rapidly growing
web benefit convention stack.
Advantages Of Web Service

(a) Business Functions can be exposed over the Internet: A

web service is a controlled code component that delivers
functionality to client applications or end-users. This capability
can be accessed over the HTTP protocol, which means it can be
accessed from anywhere on the internet. Because all apps are
now accessible via the internet, Web services have become
increasingly valuable. Because all apps are now accessible via
the internet, Web services have become increasingly valuable.
That is to say, the web service can be located anywhere on the
internet and provide the required functionality.
(b) Interoperability: Web administrations allow diverse apps to
communicate with one another and exchange information and
services. Different apps can also make use of web services. A
.NET application, for example, can communicate with Java web
administrations and vice versa. To make the application stage
and innovation self-contained, web administrations are used.
(c) Communication with Low Cost: Because web services
employ the SOAP over HTTP protocol, you can use your
existing low-cost internet connection to implement them. Web
services can be developed using additional dependable
transport protocols, such as FTP, in addition to SOAP over
HTTP.
(d) A Standard Protocol that Everyone Understands: Web
services communicate via a defined industry protocol. In the
web services protocol stack, all four layers (Service Transport,
XML Messaging, Service Description, and Service Discovery)
use well-defined protocols.
(e) Reusability: A single web service can be used
simultaneously by several client applications.
Sample Questions

Question 1. What exactly do you mean when you say you’re

going to upload a file on the internet? The name of the
protocol that was utilized for it.
Answer:
Uploading a file to a server is the process of transferring a
file from your computer to a server through the Internet.
FTP(File Transfer Protocol) is the protocol that is used for
this. An FTP client application allows a user to
communicate with an FTP server program in order to gain
access to data and services on the server machine. Users
must be able to connect to the Internet or communicate
with an FTP client application in order to use the FTP server
program.
Question 2. Why do we need a web service?
Answer:
Web-based apps are developed using a range of
programming platforms in today’s corporate world. Some
applications are written in Java, others in .Net, and still
others in Angular JS, Node.js, and other frameworks. Most
of the time, these diverse programs require some form of
communication to work together. Because they are written
in separate programming languages, ensuring accurate
communication between them becomes extremely difficult.
Web services have a role in this. Web services provide a
common platform for several applications written in
different programming languages to connect with one
another
Question 3. For web services, what kind of security is
required?
Answer:
Web services should have a higher level of security than
the Secure Socket Layer (SSL) (SSL). Entrust Secure
Transaction Platform is the only way to attain this level of
security. This level of security is required for web services
in order to assure dependable transactions and secure
confidential information.
API vs. Web Services
Web services and APIs are often mistaken for each other, which
isn’t all that surprising since there is some distinct common
ground.
Most web services provide an API, which, with its set of
commands and functions, is used to retrieve data. Here’s one
example: Twitter delivers an API that authorizes a developer
access tweets from a server and then collects data in JSON
format.
Differences between APIs and Web Services
APIs can be hosted within an app or IIS (Internet Information
Services), but a web service can only be hosted on IIS.
Web services are not an open source and are used to
understand JSON (JavaScript Object Notation) or XML, whereas
APIs are an open source and only used for XML.
API is a light-weight architecture (best for limited bandwidth
devices (e.g. smartphone). Web services are not lightweight
architectures since they require SOAP to send and receive
network data.
APIs can use any form of communication, but a Web service
only uses SOAP, REST, and XML-RPC.
APIs support URL, request/response headers, caching,
versioning, content formats. Web services only support HTTP.
Similarities between APIs and Web Services
Similarities between APIs and Web Services
Both are accessed through HTTP/HTTPS to enable
communication between services providers and customers.
Both call a function, process data, and receive a response