• Numbering System

The number system is a way to represent numbers. We are used to using the base-10 number system, which is also called decimal. Other common number systems include base-16 (hexadecimal), base-8 (octal), and base-2 (binary)


  • Binary

Digit: 0, 1

Base: 2


Digit: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Base: 10


Digit: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Base: 16


8 bit =  1 Byte

1024 Byte = 1 Kilo Byte (KB)

1024 Kilo Byte = 1 Mega Byte (MB)

1024 Mega Byte = 1 Giga Byte (GB)

1024 Giga Byte = 1 Tara Byte (TB)

(b = bit, B = Byte)


  • IP Addressing & Subnet

Class A 1~126 XXX XXX 1~254 Public
10 XXX XXX 1~254 Private
Network Hosts
255 0 0 0 Subnet


Class B 128~191 XXX XXX 1~254 Public
172 XXX XXX 1~254 Private
Network Hosts
255 255 0 0 Subnet


Class C 193~223 XXX XXX 1~254 Public
192 XXX XXX 1~254 Private
Network Hosts
255 255 255 0 Subnet


224~254 Reserved
127 0 0 1 Local Loop Back Test



  • Definitions of Networking

LAN A Local Area Network (LAN) is a high-speed communications system designed to link computers and other data processing devices together within a small geographic area, such as a workgroup, department, or building. Several LANs can also be interconnected within a campus of buildings to extend connectivity
Intranet An intranet is a private network that is contained within an enterprise. It may consist of many interlinked LANs and also use leased lines in the wide area network. The main purpose of an intranet is to share company information and computing resources among employees located in different region
Extranet When part of an intranet is made accessible to customers, partners, suppliers, or others outside the company, that part becomes part of an extranet
Internet A global network connecting millions of computers and decentralized by design. Its operators can choose which Internet services to use and which local services to make available to the global Internet community. The Internet is not synonymous with World Wide Web (WWW).



  • IEEE (Institute of Electrical and Electronic Engineers) Standard

IEEE Std 802.3 Ethernet standard
IEEE 802.3 Fast Ethernet standard
IEEE 802.3ab Gigabit Ethernet
IEEE 802.3z  Gigabit Fiber
IEEE 802.11 Wireless LAN (WLAN)
IEEE 802.16a Wireless MAN® (WiMAX)
IEEE 802.3af Power Over Ethernet (PoE )
IEEE 802.1D Spanning Tree Protocol  (STP)
IEEE 802.1 r Rapid Spanning Tree Protocol (RSPT)
IEEE 802.1 s Multiple Spanning Tree Protocol (MSTP)
IEEE802.1q Virtual Local Area Network (VLAN)



  • Topology

The geometric arrangement of devices on the network. For example, devices can be arranged in a ring or in a straight line. Each LAN has its own unique topology, or geometric arrangement. There are three basic topologies: bus, ring, and star. Most LANs are a combination of these arrangements.

  • OSI Reference Model

Layer Support Example


Application and end-user processes. Tiered application architectures are part of this layer. FTP, SMTP, POP, Telnet


Transform data into the form that the application layer can accept. Formats and encrypts data to be sent across a network, providing freedom from compatibility problems.


Establishes, manages and terminates connections between applications.


End-to-end error recovery and flow control. Ensures complete data transfer. TCP, UDP


Routing and forwarding functions as well as addressing, internetworking, error handling, congestion control and packet sequencing. L3 Switch, Router, IP
Data Link


Data packets are encoded and decoded into bits. Two sub layers: MAC and LLC. Switch


Conveys the bit stream – electrical impulse, light or radio signal — through the network at the electrical and mechanical level Hub, NIC, Cable



  • What Transmission Media?

Devices can be connected by twisted-pair wire, coaxial cables, or fiber optic cables. Some networks do without connecting media altogether, communicating instead via radio waves.


  • What is IP KVM

IP KVM is a Keyboard, Video, Mouse Switch that will allow total control of servers or computers across LANs, WANs over the Internet Protocol (IP).


  •  KVM over IP

KVM Over IP Switches uses a technology that allow the administrators to control those servers using a specialized software or a standard web browser that will give them total access to that machine as though they where setting in front of it.