3.2 Understand Transport layer protocols (3.3 Understand Application layer…
3.2 Understand Transport layer protocols
3.3.1 Explain the operation of the Application layer in providing support to end-user applications
Indexes that point to resource locations are stored in a centralized directory.
In a hybrid system, each peer accesses an index server to get the location of a resource stored on another peer.
Some P2P applications use a hybrid system, where resource sharing is decentralized
Common P2P Applications
Many P2P applications allow users to share pieces of many files with each other at the same time.
A small torrent file contains information about the location of other users and tracker computers.
Common P2P networks include: eDonkey, G2, BitTorrent.
Trackers are computers keeping track of the files hosted by users.
This technology is called BitTorrent. There are many BitTorrent clients, including BitTorrent, uTorrent, Frostwire, and qBittorrent.
3.3.2 Identify the protocols names and standards on the OSI and TCP/IP
The International Standards Organization (ISO) has defined a standard called the Open Systems Interconnection (OSI) reference model.
This is a seven layer architecture listed in the next section
This model is sometimes called the DOD model since it was designed for the department of defense.
It is also called the internet model because TCP/IP is the protocol used on the internet.
3.3.3 Explain common Application layer protocols
HTTP and HTTPS
The index.html was specified in the URL and contains the HTML code for this web page.
The browser processes the HTML code and formats the page for the browser window based on the code in the file.
The server sends the requested file to the client.
The browser sends a GET request to the server’s IP address and asks for the index.html file.
3.3 Understand Application layer protocols
The application layer abstraction is used in both of the standard models of computer networking: the Internet Protocol Suite (TCP/IP) and the OSI model.
The application layer only standardizes communication and depends upon the underlying transport layer protocols to establish host-to-host data transfer channels and manage the data exchange
An application layer is an abstraction layer that specifies the shared communications protocols and interface methods used by hosts in a communications network