CAPA PRESENTACION

Capa 6 Modelo OSI "Presentación"

 Capa presentación: Se encarga de la representación de la información, de manera que aunque distintos equipos puedan tener diferentes representaciones internas de caracteres (ASCII, Unicode, EBCDIC), números (little-endian tipo Intel, big-endian tipo Motorola), sonido o imágenes, los datos lleguen de manera reconocible. Leer más.

Servicios:

• Data conversion: Is the conversion of computer data from one format to another. Throughout a computer environment, data is encoded in a variety of ways. For example, computer hardware is built on the basis of certain standards, which requires that data contains, for example, parity bit checks.Read more. 
• Compression: Compression is useful because it helps reduce resources usage, such as data storage space or transmission capacity. Because compressed data must be decompressed to be used, this extra processing imposes computational or other costs through decompression, this situation is far from being a free lunch. Read more.
• Encryption and Decryption: Is used to protect data in transit, for example data being transferred via networks (e.g. the Internet, e-commerce), mobile telephones, wireless microphones, wireless intercom systems, Bluetooth devices and bank automatic teller machines.  Read more.

Protocolos:

• Apple Filing Protocol (AFP): Is a proprietary network protocol that offers file services for Mac OS X and original Mac OS. In Mac OS X, AFP is one of several file services supported including Server Message Block (SMB), Network File System (NFS), File Transfer Protocol (FTP), and WebDAV. Read more.

• Independent Computing Architecture (ICA), the Citrix system core protocol: Is a proprietary protocol for an application server system, designed by Citrix Systems. The protocol lays down a specification for passing data between server and clients, but is not bound to any one platform. Read more.

• NetWare Core Protocol (NCP): Is a network protocol used in some products from Novell, Inc. It is usually associated with the NetWare operating system, but parts of it have been implemented on other platforms such as Linux, Windows NT and various flavors of Unix. Read more.

• Telnet: Is a network protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. User data is interspersed in-band with Telnet control information in an 8-bit byte oriented data connection over the Transmission Control Protocol (TCP). Read more.

• eXternal Data Representation (XDR): Is a standard data serialization format, for uses such as computer network protocols. It allows data to be transferred between different kinds of computer systems. Converting from the local representation to XDR is called encoding. Read more.

• X.25 Packet Assembler/Disassembler Protocol (PAD): An X.25 WAN consists of packet-switching exchange (PSE) nodes as the networking hardware, and leased lines, plain old telephone service connections or ISDN connections as physical links.Read more.

Diagrama de red X25.