Systems and Network Resources
Operating systems, networking, and security are important aspects in IT career. System administrators, network administrators, and security specialists play critical roles in IT and they are well paid. The following online resources provide information and knowledgebase in systems, networking, and security areas. Read more
Wireless Certification (CWNP) - Where Less is More
In the networking industry, the Wireless segment is growing at lightning speed - an amazing rate of over 40% per year. The astounding wireless journey in IT industry had resulted in huge installations of wireless LAN equipment at home and work place. The future advancement of wireless technology will for sure cut down the cost of manufacturing and thus the cost of purchasing and implementing wireless solutions, that means the wireless installation base will continue to grow. Read more
Cisco Certifications for Successful Career Path on Network
Why Cisco
IT Certifications can not guarantee financial reward, but high level Cisco certifications can help. If your career success is measured by money, you should check out Cisco certifications on your career path. Read more
The 7 Layers of Network
Network administrators, network engineers, and systems administrators should understand the network architecture described as the 7 Layers of the OSI Model. The OSI, or Open System Interconnection, model defines a networking framework for implementing protocols in seven layers. Control is passed from one layer to the next, starting at the application layer in one station, proceeding to the bottom layer, over the channel to the next station and back up the hierarchy.
Layer 7 – Application
This layer supports application and end-user processes. Communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified. Everything at this layer is application-specific. This layer provides application services for file transfers, e-mail, and other network software services. Telnet and FTP are applications that exist entirely in the application level. Tiered application architectures are part of this layer.
Layer 6 – Presentation
This layer provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa. The presentation layer works to transform data into the form that the application layer can accept. This layer formats and encrypts data to be sent across a network, providing freedom from compatibility problems. It is sometimes called the syntax layer.
Layer 5 - Session
This layer establishes, manages and terminates connections between applications. The session layer sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications at each end. It deals with session and connection coordination.
Layer 4 - Transport
This layer provides transparent transfer of data between end systems, or hosts, and is responsible for end-to-end error recovery and flow control. It ensures complete data transfer.
Layer 3 – Network
This layer provides switching and routing technologies, creating logical paths, known as virtual circuits, for transmitting data from node to node. Routing and forwarding are functions of this layer, as well as addressing, internetworking, error handling, congestion control and packet sequencing.
Layer 2 - Data Link
At this layer, data packets are encoded and decoded into bits. It furnishes transmission protocol knowledge and management and handles errors in the physical layer, flow control and frame synchronization. The data link layer is divided into two sublayers: The Media Access Control (MAC) layer and the Logical Link Control (LLC) layer. The MAC sublayer controls how a computer on the network gains access to the data and permission to transmit it. The LLC layer controls frame synchronization, flow control and error checking.
Layer 1 - Physical
This layer conveys the bit stream - electrical impulse, light or radio signal — through the network at the electrical and mechanical level. It provides the hardware means of sending and receiving data on a carrier, including defining cables, cards and physical aspects. Fast Ethernet, RS232, and ATM are protocols with physical layer components.
-
Recent Posts
-
Categories
-
Archives
-
Links
-
Meta
