Dense wavelength division multiplexing (DWDM) is a technology that puts data from different sources together on an optical fiber, with each signal carried at the same time on its own separate light wavelength. Using DWDM, up to 80 (and theoretically more) separate wavelengths or channels of data can be multiplexed into a lightstream transmitted on a single optical fiber. Each channel carries a time division multiplexed (TDM) signal. In a system with each channel carrying 2.5 Gbps (billion bits per second), up to 200 billion bits can be delivered a second by the optical fiber. DWDM is also sometimes called wave division multiplexing (WDM).

Since each channel is demultiplexed at the end of the transmission back into the original source, different data formats being transmitted at different data rates can be transmitted together. Specifically, Internet (IP) data, Synchronous Optical Network data (SONET), and asynchronous transfer mode (ATM) data can all be travelling at the same time within the optical fiber.DWDM promises to solve the “fiber exhaust” problem and is expected to be the central technology in the all-optical networks of the future.

digital crossconnect system (DCS or DXC) is a piece of circuit-switched network equipment, used in telecommunications networks, that allows lower-level TDM bit streams, such as DS0 bit streams, to be rearranged and interconnected among higher-level TDM signals, such as DS1 bit streams.

RAD’s DXC-8R, DXC-10A and DXC-30 provide digital access and cross-connect functionality for multiple services, supporting a wide range of applications for carriers, cellular operators, ISPs, utilities, transportation, campus networks, and enterprises.

A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.

Fiber optics has several advantages over traditional metal communications lines:


  Fiber optic cables have a much greater bandwidth than metal cables. This means that they can carry more data.

  Fiber optic cables are less susceptible than metal cables to interference.

  Fiber optic cables are much thinner and lighter than metal wires.

  Data can be transmitted digitally (the natural form for computer data) rather than analogically.


The main disadvantage of fiber optics is that the cables are expensive to install. In addition, they are more fragile than wire and are difficult to splice.

Fiber optics is a particularly popular technology for local-area networks. In addition, telephone companies are steadily replacing traditional telephone lines with fiber optic cables. In the future, almost all communications will employ fiber optics.


Optical fibers have a wide number of applications. They are used as light guides in medical and other applications where bright light needs to be shone on a target without a clear line-of-sight path. In some buildings, optical fibers route sunlight from the roof to other parts of the building (see non-imaging optics).

We are also in optical fiber installation. Fault rectification supply and laying of ofc and fusion splicing, testing and characterization of ofc.

In packet-switched networks such as the Internet, a router is a device or, in some cases, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination.

The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to. A router is located at any gateway (where one network meets another), including each point-of-presence on the Internet. A router is often included as part of a network switch.Routers are located at gateways, the places where two or more networks connect.

Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.

Very little filtering of data is done through routers.

A router may create or maintain a table of the available routes and their conditions and use this information along with distance and cost algorithms to determine the best route for a given packet. Typically, a packet may travel through a number of network points with routers before arriving at its destination. Routing is a function associated with the Network layer (layer 3) in the standard model of network programming, the Open Systems Interconnection (OSI) model. A layer-3 switch is a switch that can perform routing functions.

An edge router is a router that interfaces with an asynchronous transfer mode (ATM) network. A router is a network bridge combined with a router.

Cisco 1861 and Cisco 2800, 3800, 2900, 3900, and 3900E Series unified communications routers communicate directly with Cisco Unified Communications Manager, allowing for the deployment of unified communications solutions that are ideal for small and medium-sized businesses, large enterprises, and service providers that offer managed network services. The Cisco 1861 and Cisco 2800, 3800, 2900, 3900, and 3900E Series Routers provide a highly flexible and scalable solution for small and medium-sized branch and regional offices.

SDH (Synchronous Digital Hierarchy) is a standard technology for synchronous data transmission on optical media. It is the international equivalent of Synchronous Optical Network. Both technologies provide faster and less expensive network interconnection than traditional PDH (Plesiochronous Digital Hierarchy) equipment.

In digital telephone transmission, “synchronous” means the bits from one call are carried within one transmission frame. “Plesiochronous” means “almost (but not) synchronous,” or a call that must be extracted from more than one transmission frame.SDH uses the following Synchronous Transport Modules (STM) and rates: STM-1 (155 megabits per second), STM-4 (622 Mbps), STM-16 (2.5 gigabits per second), and STM-64 (10 Gbps).

There are many companies where SDH are used so those who want to learn SDH technology can contact us for the training. We provide best practical training on SDH.

In networks, a device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs.

We are working onCisco catalyst 2690 series SI, Cisco catalyst 3560 series switches.

The Cisco Catalyst 3560 v2 Series are next-generation, energy-efficient, Layer 3 Fast Ethernet switches. These new switches support Cisco EnergyWise technology, which helps companies manage power consumption of the network infrastructure and network-attached devices, thereby reducing their energy costs and their carbon footprint.

Consider the newer model Catalyst 2960-X Series Switch which offers more intelligent features, higher performance, and at a similar price. Easy to use and upgrade, these fixed configuration Fast Ethernet access switches offer superior Layer 2 threat defense capabilities and basic Layer 3 static routing with 16 routes. They also offer:

  • 2x1GE uplink
  • 24, and 48 Fast Ethernet port configurations
  • Advanced QoS, rate-limiting, Access Control Lists (ACLs), IPv6 management, and multicast services
  • IEEE 802.3af PoE with up to 15.4W per port for up to 48 ports