 So students we have gone through lot of details now we are in almost the middle of the course almost and we discussed about the methodologies we discussed about the modeling we discussed about independence schemas and the list goes on and the design guidelines and many things so we went into less detail we went into more details we looked from a higher level so after whatever has been covered in this course you have developed that excellent web-based database applications and now is the time to put that application to use now is the time for that application to work for you so that now is the time to deploy that application to put it on your web database service provider server the types of servers the type that we have already discussed now there are four basic methodologies for deploying your application okay and actually there are three but the way in the context of load balancing they are considered as four methodologies what are those four methodologies number one is the non-distributed non-distributed means that your different tiers all of them are on the same server except the database okay all are same they are they are not globally distributed anywhere in the world because try you understand because if those tiers are distributed if I have web server in this point application server in this point database server in another location then the network traffic is going to kill the performance so the non-distributed deployment is when we are looking for performance now you would say that if performance is the key if performance is the key okay then why we go for distributed they are reasons for it they are the reasons could be security the reasons could be for example load balancing and of course when we talk of the load instead of having a very very large server which is very expensive to get in the first place we need something called as the web farms what is a web farm web farm is like hundreds and thousands of CPUs okay which provide a tremendous amount of processing power okay and these web farms are usually co-located at a single place right and your application on your tiers they are distributed across the web farms and by virtue of having hundreds and thousands of CPUs in a web farm your application has a very high level of stability because when certain CPUs crash other CPUs take over it's more reliable so you see performance is not everything the point is that whatever is required that is required to be done so for a non-distributed environment performance is the key but you have to ensure that when you have presentation business and all these layers at a web server how do we ensure the concurrency of the users without compromising the security because everything is happening at the same place right so you need to have component based interface you need to have trusted identity and when this data is passing across you need to have it encrypted you need to have digital signing even for a non-distributed environment why because this tier is separate you see the point over here this has to be secured now let's look at the other point distributed this is the keyword over here don't do unless it's necessary because it has its own issues it has its own paradigm and when you divide this you divide it like this for security reason this again is not over here it is not over here you have to secure it so you can do it for security reasons so the point is that to enhance security you use a distributed deployment of your application is at a higher level and over here at these interfaces you are using binary encoding for best performance and you need to protect sensitive data being passed why because now you have that sensitive data being passed at this point and at this point unlike the non-distributed where it was only passing at one position I think you get the picture now let's look at load balancing when we have you when we have this distributed right environment then how do you balance the load you use the windows network load balancing and it has to be stateless design remember when we discussed about the stateless design the stateless design is that when the transactions between the client and the server those transactions are independent of each other the web does not records the relationship as a matter of fact does not considers the relationship between sets of transactions that is stateless so consists consider stateless design you see the point I'm trying to make is that you remember this is not your only work you are working for a company also this is not individual work this is for the company also and finally the web server farms use clustering clustering enhances the performance and partition the database across servers this will give you performance reliability also how it will give you performance because since you have hundreds and thousands of CPUs or servers now when you distribute your data across the server you can access them in parallel that will give you higher performance instead of having data at one server and accessing it over the hardest if you have multiple servers you access in parallel but you need to have proper management also and you have to have certain expertise also so you look for these features these expertise these things in your database service provider because you are deploying an application web based which is drawing a lot of traffic and a lot of processing is going to happen you would not like to compromise the security or the performance of your application that is the key things we should be taking discussing in this module thank you very much