This video belongs to the openHPI course A Half Century of Internet: How it works today. Do you want to see more?
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- 00:00In our OpenHPI course, a half-century of internet
- 00:04we want to give now an overview about the various internet applications.
- 00:12What are internet applications, typically we call an application
- 00:16an internet application when we can use
- 00:21application service by means of our computer that is connected to the internet.
- 00:28So for example, what can be done in the world wide web
- 00:33as this is an internet application an email communication,
- 00:40the instant message or check systems file transfer that is
- 00:46possible over the internet. Then the various cloud services
- 00:51are unimaginable without the internet and streaming,
- 00:56to mention here only a few of the important applications, voice over
- 01:01IP is another one, various security questions in the different applications,
- 01:09the online gaming, online shopping, the internet of things
- 01:15with small devices that can interact with each other by means of internet technology.
- 01:22All these are providing internet applications
- 01:35via the world wide web.
- 01:39So, for example, online shopping,
- 01:41Amazon, Thalia, Otto, eBay, Lieferando to mention only a few of its services.
- 01:48Search engines, Google, Bing, Yahoo,
- 01:54Ecosia, DuckDuckGo. Social networks, Facebook, LinkedIn,
- 02:00StayFriends. Another group of internet applications
- 02:07that are accessible via the world wide web are blogs, articles, and communities,
- 02:13to mention Chefkoch, Motor-Talk, GoFeminin.
- 02:17News portals, n-tv, Stern, Tagesschau, Speigel.
- 02:22Travel, Expedia, TUI, FTI, Urlaubspiraten.
- 02:29Price comparison platforms, Check24, Booking.com, Holidaycheck.
- 02:35or offers for digital learning like our OpenHPI.
- 02:41Email with a various different systems Gmail, web.de, Outlook.com
- 02:47GMX. Instant messaging and chat WhatsApp is very famous,
- 02:53Telegram or RocketChat. Entertainment
- 02:57becomes more and more important and although a little bit problematic because of the
- 03:03huge amount of energy that is needed for streaming Netflix
- 03:07online browser games. Navigation systems
- 03:11and services like google maps, TomTom, Lomoot, Tourenfahrer.
- 03:19Online banking from various banks provided, I think meanwhile
- 03:25almost all banks provide these are famous groups of
- 03:30internet applications.
- 03:32And now the question is, how these applications can be used
- 03:37on the internet?
- 03:40What is needed are communication protocols and these are the
- 03:44application protocols in the so-called application layer of
- 03:49the TCP IP protocol stack, which enables the application
- 03:55which does not belong to the stack
- 04:00to make use of the internet to interact with the users to interact with other services.
- 04:06So is the application itself the world wide web, the online shopping, online banking
- 04:14does not belong to the application layer, but for each of this application
- 04:21in the protocol on the application, the layer is necessary that this
- 04:27application can make use of the internet whether it's HTTP, whether
- 04:32it's a worldwideweb, map service, which can use
- 04:37internet by means of the HTTP protocol.
- 04:42So the application layer specifies what's possible communication over the internet,
- 04:49exactly to certain applications.
- 04:53So remember these are different network technologies,
- 04:58are used internet layer provides this internet data package service,
- 05:02then we have the transport layer which guarantees such a a data
- 05:07grams not only reach other computer, but that
- 05:13they also reach a certain application and now for the
- 05:19application layer now this is a transport service that provides
- 05:25the protocols in the lower layers are used
- 05:29to interconnect with the application.
- 05:33So the TCP/IP protocol stack, protocols of the application layer
- 05:40they, of course, use area in the application layer they
- 05:47have to use the protocols of the transport layer, for getting transported
- 05:54inside the data packet service of the IP protocol in the internet layer,
- 06:00to the other. So the application protocols make use of the protocols
- 06:05of the transport layer typically it's TCP or UDP.
- 06:12Some of them use both protocols and TCP and UDP use IP datagram,
- 06:18though we spoke about that already last week,
- 06:21so here are the protocols that make use of TCP protocol.
- 06:28Remember TCP protocol is a protocol in the transmission control layer,
- 06:35which provides a connection-oriented service, which is reliable
- 06:41and various application protocols of TCP layer
- 06:46make use of TCP, for example, DNS the domain name service which
- 06:51converts the domains into IP addresses, we spoke about that
- 06:57or SMTP, simple mail transfer protocol is a protocol
- 07:02which is used to transport emails through the internet and to receive emails,
- 07:08or another example of a protocol of the application layer that
- 07:13make use of TCP is HTTP the hypertext transfer protocol,
- 07:18which enables the transport of website data and of course there are more
- 07:26protocols on the application layer that make use of TCP but also
- 07:33application layer protocols they make use of the UDP.
- 07:39The other, a much more simpler protocol on the transport layer
- 07:44which is connection-less and unreliable,
- 07:48the following protocols of the application layer
- 07:52make use of UDP. So the domain name service makes
- 07:59the values of TCP as values of UDP, it depends on what kind of messages
- 08:06they need to be transported.
- 08:08The SNMP protocols, a simple network management protocol which
- 08:13is necessary and needed for configuration and control of network
- 08:19communication makes use of the simple you UDP protocol. Or DHCP
- 08:24dynamic host configuration protocol, which provides an assignment of IP addresses
- 08:32to individual devices in the network, they make use of UDP.
- 08:38As well as NFS network file system which provides access
- 08:45to remote data storage on other computer systems.
- 08:49This is only a small selection but it should show you that
- 08:53there are some public protocols in the application layer that go with a very
- 08:59a secure and guaranteed connection-oriented TCP protocol
- 09:04and there are other protocols that go with a much a simpler
- 09:10connectionless UDP protocol.
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