Hi, welcome to this series of lectures on
cloud computing, today we will be discussing on one aspect which is sometime considered
as one of the major prime mover or building block of cloud computing, that is web services
and service oriented architecture. So, we look at that what exactly it means
and try to have a overall a overview of the whole thing. So, that it will help us in understanding
that; how it build up and how things are going on. Now, what are web services there are several
definitions, you will find in the literature and the internet. So, like if you see the W3C web service architecture
requirement specification, it says that software application identified by a URI, whose interfaces
and bindings are capable of being defined described discovered as XML artifacts. So, this is a very versatile definition. So, it is, what it says that the software
applications, which are identified by URI and whose interfaces are bindings are capable
so that you can define, you can describe, you can discover and all is underlining XML
base languages, right. Whereas if you look at the Microsoft define
as a programmable application logic accessible using standard internet protocol right. Other definition an interface that describes
a collection of operation that the network accessible through standardized accessible
messaging and software components that can be spontaneously discovered combined recombined
to provide solution to the users problems and request right. So, from this different sort of definitions
what we can see one thing is there that is a, it is a XML based phenomena, right. So, XML as you know it is a more of a data
transformation language, it helps in interoperability and helps in application talking to each other
right. So, web services are those type of services,
which are available on with can be defined in the, can be accessible through a standardize
URI and it works on a message exchange type of protocol which is based on XML, right. So, what it gives us it gives us a you can
any application can now to application can talk to each other, I am not bothered about
what is at the background of the how things are there, I only bothered about where the
service is available and how I can talk to that services, right I do not bother about
the background processing of the things. This also helps in bringing this legacy application
to talk to other applications, right. So, this is a different way of looking at
the things, those who are costumed with client server type of protocol, which are more tightly
bound this is more loosely bound and can talk to each other very easily and if you look
at the; if I say the genesis of the history of the things. So, there are different aspects which help
or which promoted this web services one is definitely structured programming, which evolved
to a next suggestion of object oriented programming, distributed system as we have discussed in
our previous lectures. So, it is played a important role, there is
another concept of electronic data exchange between two entities primarily to business
entities, when they want to interface that data for some particular purpose. Of course, this World Wide Web which allows
the whole computing phenomena to connect to each other right with backbone internetworking
primarily driven by internet protocol. So, these are this is also a one of the phenomena,
these you know. So, this all this component has all these
components have; now has what we say facilitated that this development of web services or the
evolution of web services. Now, distributed computing we are I am not
going any detail, because there is we have talked in detail talked in length that in
our previous lectures. So, one of the issues; whenever we are doing
distributed computing interoperability right one of the major issues; other than it working
another type of things. So, ability to communicate and share data
with software from different vendors and platform very interesting phenomena and which allows
this whole world of or whole gamut of application to talk to each other that is it allows you
to communicate share data software from different vendors to platforms. Limited among conventional proprietary distributed
computing technologies like in case of interoperability and more, limited scopes, we need to expand
it. There is another major development means in
this area is the EDI or which is popularly known as electronic data interchange, that
computer to computer exchange of business data and documents between companies using
standard formats recognized both nationally and internationally; that means, it is a primarily
a business data or formats, but the formats are recognized by the both the party. So, I understand that the other the organization
A system understand the; what the what type of message is coming from the organization
B and then go was exchanging. The information used in EDI is organized according
to a specific format said by both companies participating the exchange. So, it is important that the format is somewhat
pre known or pre defined that how or exchange that format or the schema exchange previous
to the exchange of the data. So, other party knows that what sort of data
is expecting. There are lot of advantages like one is that
low operating cost because you do not bothered about when exchanging data less data more
accuracy because this data exchange phenomena loop is not there. So, no data entry less human error. So, directly getting the data from the other
things; increase productivity obvious and faster trading cycle if there are multiple
companies are working together that is one aspect. Now all those things have somewhat facilitate
this as we are discussing is that the web services. So, it take the advantages, advantages of
object oriented programming by enabling developers to build application from existing software
component in a modular’s approach, right. So, it helps developer to develop applications
and from the legacy things or the existing thing, and help them to different component
to develop different components in a modular approach. So, transform a network that is internet into
a library of programmatic components available to the developers, to have significant productivity
gains. So, if we look at its a as if the library
of different programming components are there, now you can go on building things to make
your application now, right. So, one if we will take a type of example
that this how this services are exchange, is maybe what we can think of is our this
online reservation or booking systems right, I book a train or say flight. So, I have the I gave means when I do when
we use a particular address or URI to access that, and then I then those in-turn say any
that particular travel portal is not having neither having flights, non having hotels
or non having anything right. So, it in-turn talk to the other different
airlines services pull the data showed to the user its selects and then the if the booking
process goes on, then it goes on a it through a credit card debit card, net banking so other
services are called. So, if you see there is a multiple services
are being amalgamated in a proper choreographic way to execute a job. So, my job was to select say a best possible
flight based on my budget and my convenience of time, and I want to do it online. So, I go for a some sort of a travel portal
or what we say some sort of a broker right which allows me to see different airlines
stuffs and then I select my suitable things go on paying through my credit card, debit
card etcetera and then the I get the ticket generative right. So, see neither this airline organizations,
they are directly; I am not directly hooking to them, they are being connected neither
this your credit card or debit card service provider, have any clue that whether you are
buying a ticket, etcetera. So, it what it says that if it gets a request
in a particular form, it will acknowledge it and then replied it one particular form,
right. So; that means, it is some sort of a XML type
of message, exchange going on to the things. So, this allows us to generate different type
of mega applications of using some different type of different software components or different
type of other application. So, I can mix and match and doing the things
and it goes on a choreographic way list minimal involvement of the different service provider
and it goes on like that. So, if you see that improve distributed computing
interoperability by open non-proprietary standard; that can enable theoretically any two or more
software components to communicate; so, it uses a open standard and facilitated interoperability
as you are discussing about XML and type of things. So, it provides capability similar to those
of EDI like exchanging data, but a simpler and less expensive to implement, like I do
not have a any sort of a predefined agreement on the data format etcetera right. Rather somewhere other I should able to know
that where the things have goes on. Configured to work with EDI systems can be
configured to work allowing organizations to use two technologies together or to phase
out EDI while adopting web services right. So, unlike www or World Wide Web, separate
visual from non visual components, right. So, this is important one is that what I visually
see right another is that what goes on the background. So, these two things are separated like if
you look at the XML type of things XML is more of a data transformation language. So, it is not a data visualization language;
in other since html as we know is more of a data visualization or it displays the things,
right. So, XML more work on interoperability type
of issues and how did I will be exchange and so and so forth. So, XML with styling of the XML plus styling
of the data will help in visualize or displaying the data. So, unlike our normal http base things which
displays the thing it is more of a data representation or data transformation type of stuff. So, interaction maybe either through browser
or through desktop client, like can be java swing, python, windows etcetera that can be
there are different type of desktop clients we can interact with the things or the common
interface is the; to the interfacing with the browser. Now, it web service if we look at it tries
to address three major component interoperability, like lack of interoperability standard in
distributed object messaging. So, interoperability between twp software;
between two parties. Firewall traversal. Now, as which as the web service is piggyback
on different Internet or TCP/IP based protocol, primarily http protocol. So, it has a it can basically go over the
firewall most of the our firewalls are http at port 80 are allowed. So, web service can still work on the things. So, CORBA and DCOM used nonstandard ports
web service is use mostly the http. So, it is not only the not only http, it can
use others, but primarily http most firewalls allows post 80 http leading to easier dynamic
collaboration that is one major aspects and complexity web service is it is a more of
a developer friendly service system correct. So, it is the much easier to develop. So, use open text based standards like one
of them is XML which allows components written in different language or different platform
to communicate, right. So, this is important. So, and it can be implemented incrementally
right not on the day one everything has to be done are other deployment also can be done
in incrementally, rather than all at a once which lessens the cost and reduces organizational
disruption from the abrupt switch to the technologies, right. So, these are the different aspects another
major aspect is still organization can run that legacy software and tools if you have
proper web service interface for the external world. So, if we just try to again sum up that communication
via open standard like it can be HTTP it can be SMTP or any type of any other TCP/IP application
layer protocol meant be there. Process of XML messages framed using SOAP,
we will come to that what is SOAP and. So, it is a it is primarily XML based messaging
system and one of the popular thing is the SOAP. Described its messages using XML schema, how
the how my data is organized; I can basically describe is using a XML schema. Provides an endpoint description using WSDL
will again see what is web service description language. So, where my service is launched how it is
configured, I we can do at a WSDL and basically I can publish and discover using a UDDI. So, my web service description discovery and
integration it is facilitated by the UDDI. So, one way of implementing is that we have
XML as the base. And we have three major component SOAP, WSDL,
UDDI, right. So, this is the things all are W3C complaint
and use the de facto XML based things, will just look into that how things works. So, purchase one example. So, as if purchase order goes then credit
check, reserve inventory, credit response, inventory response, consolidate result and
return to the invoice right. So, there are different parties like credit
service, inventory service, PO services and so and so forth and those are being can be
choreographed to service the things. It is taken from a resource, but what it tries
to so that, I can provide different type of services, I can compose it and create a larger
application bringing different type of application into the things. This application when choreographs to other
type of things or integrated if other fashion; can give some other type of services. Now looking at this whole thing, it has we
evolved to another this overall architecture what is the web service oriented architecture
SOA. So, IBMs created a model to show web service
interaction, which is referred to as service oriented architecture consisting of a relationship
between three entities. So, with this basic philosophy we have three
entities; one is a service provider, one is a service requestor or service consumer and
there is a service broker right or there is a something which allows this consumer and
provider, requestor or consumer and the broker and to talk to each other to find where the
services are there, etcetera. So, if we look at this figure a very popular
figure, available in you will find in different literature. So, I have the service requestor of the consumer
which wants to get the services to the; from the service provider, but the how the service
requestor find that where it services will be there? So, there is a registry where it can find
out right that which type of services are there. If I try to look at a analogy those who have
seen our, because now a days this is more or less obsolete, our telephone directory
right which comes from telephone exchange. So, there is to be things like at the beginning
that yellow pages, white pages and so and so forth. So, where you find that where to find what? Rather the directory itself is tell you that
by how to search for a particular thing; like suppose you are looking for plumbing or base
or something. So, you go and lift through the thing etcetera. So, it acts as a directory service right or
registry service. So, that type of things is here also require
which basically have a registry service. So, it is there are service description out
here, the service request are finds the this it a required service from this registry service
using that QSDL and UDDI and then basically bind with the service provider it goes for
it can find more than one service provider and so and so forth. A service a provider once a new service is
launched on when say service is updated it is basically it publish the service in the
registry, so that prospective buyer or prospective consumer. Consumer requestor can find that where that
these types of services are there. So, you can find that this is a triangle where
different component works and if anything is developed based on this type of things
what we say that it is a service driven or service oriented architecture. So, if we look at that web service models
that the roles of service architecture this service provider owner of the service, platform
that hosts access to the things, service requestor business that requires or the consumer which
wants consume, and service registry searchable registry of service description where service
provider publish their service description. So, three major operations in the service
web service architecture, one is publish to publish the service provider things, find
the consumer, finds the things consumer find the things and bind once is find and it finally,
binds with the service consumer with the provider. And one of the popular component is there,
there are others also that is one is the which are the component one is the XML, extensible
markup language. I believe all of you know if some of if you
if not you should go through any standard book or even W3C tutorial swearing find a
good tutorial on XML. So, its uniform data representation and exchange
mechanisms it provides. SOAP, Simple object access protocol, right
a standard way for communications over using again XML. WSDL, web services description language, uses
XML and it is a standard meta language to describe the services offered. And UDDI, universal description discovery
and integration specification, its provide its helps in building of the registry service
and a mechanism to register and locate web service applications. So, we can look at other way as we have seen
that the client goes for the client queries the registry to locate services, registry
refers to WSDL document where the description is there, the client access WSDL document
provides data to interact with the web services and client send SOAP message to the SOAP message
request to the provider, and service returns from the SOAP message from the response. So, that is someone binding the things and
these are the different components this underlining thing is the it works on the internetworking
or the our standard network protocol TCP, IP or OSI. So, this is the backbone over that SOAP messaging
the description the UDDI; UDDI can be a static publication or it can be a dynamic publication
and then there are other things like WSFL that is flow management and type of things. So, for other type of aspects and there are
three other component, it goes and in an one is the quality of service that what sort of
service, they are giving a QS management issues that how whole thing can we manage, and then
the security aspects like in doing. So, whether there is a security breach how
to things, what will be the security policies, whom to trust and all those components will
be there. XML, I am not dealing in details; it is a
standard generalized method of a generalized markup language is evolved from. It is a extensible markup language, primarily
used to describe data, and it helps in separation of content from the presentation and XML document
can be optimally refer to a by a DTD the more popular is XSD, that XML schema definition
language schema definitions so that, whether we can the scheme is defined. So, in case of XML tags are not predefined. So, you can define your own tags unlike html
enables cross platform communication in web services. So, this is a typically a XML thing like it
describes. So, sorry, it is a html thing like it basically
shows that how a particular person is address or personal email address etcetera the contact
of a person called John does defined. And if we use these html in standard any browser
so, it will show like this, however if I want to look at the same thing as a XML. So, you see this is more of a data description,
right. So, it is a name, it is a address, this is
the country phone, email and type of things, right. So, this is a XML type of things this not
any presentation. So, for representing we need to do a something. So, as we were discussing three major component
one of the thing is SOAP, is a more of a messaging protocol, like simple object access protocol
format for sending messages over the internet it is XML based, W3C complaint and stateless
and one way uses mainly http as the what we say transport protocol. This this transport protocol should not be
mix up with our TCP/IP transport protocol, this is transporting this web services. So, a here the http access the carrier protocol. So, there are different building block I am
not going to the nitty-gritty of the things, how a SOAP building blocks are there. So, transport protocol is over all envelope,
then the MIME header is there then SOAP envelop SOAP header and SOAP body and there are fault
and deification scenarios, but all are XML base. So, message structure it goes on a SOAP envelope
and goes through this its piggyback on this transport, basically become a envelope and
become a pay load for this transport protocol in this case http, again I am repeating this
transport protocols do not be mix up with our TCP/IP or OSI protocols. The SOAP request goes like that if you see
this is a post message in our http stuff and the SOAP message in this case its goes for
a get a particular stock price and stock name particular may be the IBM and so and so forth
and the response is again. Again if you see that http response, and it
response with a again a value. Since this is more of a structured way of
exchanging data, it does not say out can be displayed for the display unit to have a html
type of a stuff. So, why soap? It is are there are other technologies which
are not could not do this type of application to applications, SOAP is a platform neutral
choice simple XML wire format, places no restriction on endpoint implementation of the technology,
that you can run your legacy things, etcetera. There are major three characteristics this
is extensible, neutral and independent. So, this is exactly suited for our distributed
applications talking to each other and type of things. And there are different usage models, one
can be RPC like message exchange or SOAP specification allows any kind of body content so and so
forth. And there as other security aspects we are
not going to that we will talk about these when you talk about out security. The other one is the WSDL, web service description
language. So, it allows to it is again XML base W3C
complaint allows to describe the language. So, it has different structure that what will
be port type where the how can be defined that where the particular services will be
enabled and a web things will be there; the message types of message and so and so forth. How this binding process will go on between
the service provider and the consumer. So, it is a sample WSDL message, it is a binding
see that it is a SOAP message with the WSDL the SOAP message is bind with these things;
that means, the description over that the messaging of the SOAP message how the data
is transferred over that things is bind between the source destination or any like from requestor
to the registry to the consumer and so and so forth. Finally we have the UDDI, universal description
discovery and integration, it is a registry service right. So, a frame work to define XML based registries. So, that all these metadata informations are
there, where from the this consumer or the requestor look for that particular bases and
how to binding with that particular provider and so and so forth. So, it is service provider registry and requestor,
just if you remember the previous couple of slides before. So, you little bit what we say that orientation
is different. So, the registries the service provider publish
it, requestor finds it and binds with things. So, it plays extremely important role for
keeping the whole things working together. So, if you the same thing, it basically publish
another thing the consumer search and go on binding with the provider. There are several benefits any registry service
gives a very benefits of keeping the data in a particular format. So, there it can be search, making it possible
discover right business from the millions of currently online. So, you can finding how to enable say connectivity
with the preferred business and so and so forth. We will not go to the detail of the things
this security will work. So, in security becomes a another important
aspect of soap, a aspect of web services it works on a vertical line as we have seen in
our previous some of the one of the previous figure, and it has different components right
like web service policy, trust, privacy, secure conversation, federation and authorization
and different type of components. So, this becomes a integral one there are
other things like management and QoS which also works. So, what we are try to see in this particular
lecture is that this web services and service oriented architecture, is a plays a important
role in setting up this cloud. The whole cloud process if you see that IaaS,
PaaS or SaaS say XaaS or anything as a service. So, it its basic building block is the web
services the all this phenomena of web services of publish, bind and find bind and publish
find and bind, this also is true for the things whenever we have cloud services. So, I need to basically look at the, who is
the service provider and consumer, I need to know that where the service is launched
and type of things, right. So, this is a extended in a appropriate way
to realize this cloud services. So, it plays; this development of web services
and service oriented architecture, has played a important role in bringing this cloud computing
as a viable things. So, we will stop here today and we will continue
in our future lecture with other aspects of cloud computing. Thank you.

Cloud Computing Web Services, Service Oriented Architecture
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4 thoughts on “Cloud Computing Web Services, Service Oriented Architecture

  • February 20, 2018 at 3:08 pm

    sir,i want ppt's that you are showing in the veidos.
    Is that avilable for us…….

  • September 18, 2018 at 5:20 pm

    not clear explanation

  • November 21, 2018 at 12:43 am

    we want ppt's,please provide ppt's at description.

  • February 2, 2019 at 2:53 pm

    the explanation is very poor


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