PASSIVE NETWORK DEVICES

A Wired Computer Network (LAN) is basically a combination of various Active and Passive Network Components. In this article, we explore the salient points on the important Active and Passive Components that are required for building a basic wired computer network.

Wired Computer Network – Architecture Diagram:

Architecture Diagram - Active and Passive Components in an IP Network
Architecture Diagram – Active and Passive Components in an IP Network

In the above diagram, let us assume that there are basically three departments in an organization that wants to have a LAN across all the departments – IT Department, Department 1, Department 2. So, if we are to plan for the network components department wise, for the IT department, we could plan for,

Network rack,

Router, Core switch

Edge Switches (if required)

UTP Patch panel, UTP Patch Cords

Fiber Patch Panel, Fiber Patch Cords

Cat 6/ Cat6A UTP cables

I/O Box with Face Plate, UTP Patch Cords

PVC Channel – Casing Caping/ Conduits

Fiber Cables (Single Mode or Multi Mode)

The components required in the other two departments would also be similar with the exception of router/ core switch being replaced by distribution/ edge switches.

The above mentioned network components can be broadly divided in to two categories – Active Components and Passive Components. Active Components are those devices which required to be supplied with external power (AC/DC/POE etc) in order to function. They also boost the power of the signals. Passive components do not require to be provided with any electrical power to work – They just plug on to active components and transmit/ carry the information (electrical / optical signals).

 

Passive Network Components:

Structured Cabling has become quite common for inter-connecting the various active devices in an IP network. So the following passive components are commonly utilized in an IP Network for Structured Cabling:

  • Cat 6 UTP (Un-shielded Twisted Pair) Copper Cables – These are the network cables that connect a PC/ endpoint to a network switch. Some times, they are also used to provide inter-connectivity between switches as long as the distance is not greater than 90 meters, which is the distance they support for transmitting data without using any repeater (repeater function is provided by using network switches).
  • Cat 6 UTP Patch Cords – These are one meter/ 2 meter factory crimped cables with RJ-45 connectors installed at both ends. Actually, the Cat 6 Cables are not recommended to be directly terminated in either the network switch or the PC/endpoint. Only the patch cords terminate on both devices and connect to the Cat 6 Network cable through an I/O Box and UTP patch panel.
  • Network Rack – Network Racks are either wall mounted or Floor Standing types depending upon their size. Common sizes of network racks range from 6U to 42U. All the network equipments are designed in multiples of 1U so as to be accommodated in to these racks with standard fittings. They generally have a width of 19”. The network racks come with a glass door, lock and key, fans required for cooling, trays, power supplies, cable managers and all other accessories.
  • I/O Box and Face Plate: The I/O Box and Face Plate are kept near the computers and a UTP patch cord is used to connect the Face Plate with the network port in the PC. The Cat 6 UTP cable which comes from the switch terminates in to a permanent connection behind the I/O Box.
  • UTP Patch Panel: The UTP Patch Panel is used for terminating all the Cat 6 Cables that come from various PC’s/endpoints in the network (Actually I/O Box) to the rack. These Cables are permanently connected behind the UTP Patch Panel and UTP Patch Cords connect from the respective ports in front to the network switches. This allows for flexible moves, adds and changes without disturbing the switch ports. All the ports in the patch panel are labelled for easy identification of which node they are connected to.
  • Optical Fiber Cables: For carrying data over 90 meters, Optical Fiber Cables are used. These cables use light for transmission of data instead of the electrical signals used by the UTP cables. They can carry data for longer distances – even to a few kilo meters without having to repeat the signals in between. There are two types of cables – Single Mode (Used for higher bandwidth requirements for longer distances) and Multi Mode (Used for shorter distances). They connect directly to the Fiber Patch Panel at either end. Usually they come in multiples of 6 Cores – 6 Core, 12 Core, 24 Core being common. For each connection, two cores are used – one for transmit and another for receive.
  • Fiber Patch Panel/ Patch Cords: The Optical Fiber Cables are terminated on either end using the Fiber Patch Panel, Pigtails and Coupler assembly. Actually each core of the Fiber Cable is spliced to fit in to the Fiber Patch Panel. A Fiber Patch Cord connects to the Patch Panel and the Fiber interface of the Network Switch. The Fiber interface is usually an SFP Port over which a Fiber Module is inserted (Mini-Gbic interface). This Fiber Module can connect to the fiber patch cord directly.