As a network administrator, we are primarily concerned with the first three layers of the OSI model to be concerned - but for the CCENT and CCNA exam, we need all seven concerned!
The OSI layers are often defined by numbers, with the application layer as a Layer 7 (L7), where the level 6 presentation layer, and so on up to level 1, the physical layer. To you, I will refer to levels with their names and numbers in thisTutorials.
The Application Layer
This is the level where consumers interact with the network. Authentication services also operate on Layer 7
Protocols and services that belong to L7:
E-mail protocols SMTP and POP3
Telnet
HTTP
File Transfer Protocol (FTP)
Simple Network Management Protocol (SNMP)
The presentation layer
This layer responds to a simple question: "How should this information be presented?" Additionallycorrect formatting of data, encryption occurs at this level.
Session Layer
Level 5 is the "manager" of two-way communication between two remote computers. This is the level that are the creation, maintenance and teardown of communication between two hosts.
Transport Layer
TCP and UDP is executed in transportation, and we need to know these two protocols in and out, to pass the CCNA and CCENT exams. We look at these protocols in a futureTutorial.
The network layer
E 'level 3 of the OSI model, it's me and you start as a network administrator, a high degree of interaction with the network. Internet Protocol (IP) runs at this level, and because this router operate at L3, this layer is often defined as the level of routing.
In brief, routing is a two-question
What valid paths consist of the local router to a specific destination?
What is the best way to get there?
Data LinkShift
Switches operate at Layer 2, as well as wireless access points (WAP). We have four main characteristics that are running here, some of which you may already know:
Ethernet
High Data Link Control (HDLC)
Point-to-Point Protocol (PPP)
Frame Relay
Physical layer
When things go a little 'complicated networking, I remember that it is "all ones and zeros it!" As always, the data also provide our end users, and sooner or later"translated" into a series of 1 and 0. Once this is done, is the physical layer that deals with actually transferring data. All you need to do is run with a cable - the pins, the connectors, the electrical current in itself - a physical level.