Networking Tips

Networking Tips

Mesh Topoloy:
In this topology, every node has a dedicated point-to-point connection to every other node on the network. A fully connected mesh network has n(n-1)/2 channels to link 'n' devices. Therefore, every device on the network must have 'n-1' input/output (I/O) ports.
 
In mesh network, each node is directly connected to all nodes on the network. This type of network involves the concept of routes. In this type of network, each node may send message to destination through multiple paths. It means that each node of mesh network has several possible paths to send (or to receive) message, but in Bus, Star, Ring and Tree topologies each node has only one path.

Advantages
Mesh topology has the following advantages:
It has multiple links, so if one route is blocked then other routes can be used for data communication.

Each connection can have its own data load, so the traffic problem is eliminated.

It ensures the data privacy or security, because every message travels along a dedicated link.

Troubleshooting of this topology is easy as compared to other networks.

Its performance is not affected with heavy load of data transmission.
Disadvantages

Mesh topology has the following disadvantages:

It becomes very expensive because a large number of cabling and 110 ports are required.
It is difficult to install.
  Tree Topology:
In tree network, the nodes are connected to each other in such a way that forms a tree like structure. Typically to form a tree network, multiple star topologies are combined together. This type of network has combined features of bus and star topology.

On tree topology the hubs of each star topology are connected to the central hub that controls the entire network. However, some nodes can be directly connected to the central hub. The tree topology configuration is shown in figure below.

The central Hub in the tree network is an active hub. It contains a repeater (a hardware device), which re-generates the received bit patterns. The secondary hubs usually are passive hubs. The passive hub controls the nodes directly connected to it and exchange data to other devices connected to the other secondary hubs (or same hub) through the central hub. The secondary hub may also be active hub if another secondary hub is directly connected to it. The cable TV network is an example of tree topology, where main cable is divided into, branches and each branch is further divided into smaller branches and so on. The hub is used when a branch is created.
 
Advantages
The tree topology has the same advantages as star topology but it has some additional advantages. These are.

It allows more devices to be connected to the central Hub.

Disadvantages
The tree topology also has the same disadvantages as star topology built has some additional disadvantages such as:
It because more expansive because more hubs are required to install the network.
 
Hybrid Topology:
Hybrid network is the combination of different topologies such as star, Ring, Mesh, Bus etc. For example, if a department uses a Bus network, second department uses the ring network, third department uses the Mesh network and fourth department uses the star network. All the networks of different types (of four departments) can be connected together through a central hub.
 
Line Configuration:
Line configuration refers to the way two or more communication devices attached to a link. Line configuration is also referred to as connection. A link is a communication medium through which data is communicated between devices. For communication to occur between two devices, they must be connected to the same link at the same time. There are two possible types of line configurations or connections. These connections are.

Point-to-point connection:

Multipoint connection:

Point-to-Point Connector:
 
The point-to-point connection provides a dedicated link between two communication devices. The entire link or channel is reserved for two devices for data communication, and no other devices can use the dedicated link. Usually, in this type of connection, the two devices are connected together with a cable.

It must be noted that microwave and satellite dedicated links are also possible. Two computers connected together (point-to-point) through microwave link.
When you change the television channel by remote control, you are establishing a point-to-point connection between the remote control and the television’s control system.

Multipoint Connection:
Multipoint connection is also referred to as multidrop connection. This type of connection allows multiple devices (more than two devices) to share a single link.
 
The Telephone Network

The public switched telephone network (PSTN) is the world-wide telephone system and usually this network system uses the digital technology. In the past, it was used for voice communication only but now it is playing very important role for data communication in the computer network such as in the Internet. There are different types of telephone lines that are used for data communication in the network. These are discussed below.

1. Dial-Up Lines
It is a temporary connection that uses one or more analog telephone lines for communication. Modem is used at the sending end as well as at the receiving end. A telephone number is dialed from the sending end through modem and the modem at the receiving end answers the call. In this way, connection is established for data communication between computers or electronic devices. In dial up line connection, the cost of data communication is very low. The mobile users can also access the Internet through this connection.

2. Dedicated Lines
It is a permanent connection that is used to establish connection between two devices permanently. It is better than dial-up line connection because dedicated lines provide a constant connection. These types of connections may be digital or analog. The data transmission speed, of digital lines is very fast as compare to analog dedicated line. The data transmission speed is also measured in bits per second (bps). In dial-up and dedicated lines, it is up to 56 Kbps. The dedicated lines are mostly used for business purposes. The most important digital dedicated lines are described below.

1) ISDN Lines
ISDN stands for Integrated Services Digital Network. It is a set of standards used for digital transmission over telephone line. The ISDN uses the multiplexing technique to carry three or more data signals at once through the telephone line. It is because the data transmission speed of ISDN line is very fast. In ISDN line, both ends of connections require the ISDN modem and a special telephone set for voice communication. Its data transmission speed is up to 128 Kbps.

2) DSL
DSL stands for Digital Subscriber Line. It is another digital line. In DSL, both ends of connections require the network cards and DSL modems for data communication. The data transmission speed and other functions are similar as ISDN line. DSL transmits data on existing standard copper telephone wiring. Some DSLs provide a dial tone, which allows both voice an4 data communication.

3) ADSL
The ADSL (Asymmetric Digital Subscriber Line) is another digital connection. It is faster than DSL. ADSL is much easier to install and provides much faster data transfer rate. Its data transmission speed is from 128 Kbps up to 10 Mbps. This connection is ideal for Internet access.
 4) Cable Television Line

The Cable Television (CATV) line is not a standard telephone line. It is a dedicated line used to access the Internet. Its data transmission speed is 128 Kbps to 3 Mbps.

A cable modem is used with the CATV. it provides a high speed Internet connections through the cable television network. A cable modem sends and receives digital data over the cable television network.
To access the Internet using the CATV network, the CATV Company installs a splitter inside your house. From the splitter, one part of the cable runs to your television and other part connects to the cable modem. A cable modem usually is an external device, in which one end of a cable connects to a CATV wall outlet while the other end plugs into a port (such as on an Ethernet card) in the system unit.
5) T-Carrier Lines
It is very fast digital line that can carry multiple signals over a single communication line whereas a standard dialup telephone line carries only one signal. T-carrier lines use multiplexing so that multiple signals share the line. T-carrier lines provide very fast data transfer rates. The T-carrier lines are very expensive and large companies can afford these lines. The most popular T-carrier lines are:
 
TI Line


T3 Line

i) T1 Line

The most popular T-carrier line is the Ti line (dedicated line). Its data transmission speed is 1.5 Mbps. Businesses often use Ti lines to connect to the Internet. Many ISPs use Ti, lines to connect to the Internet backbone. Another type of TI line is the fractional TI line. It is slower than TI line but it is less expensive. The home and business users use this line to connect to the Internet and share a connection to the Ti line with other users.

ii) T3 Line
Another most popular and faster T-carrier line is T3 line. Its data transmission speed is 44 Mbps. It is more expensive than Ti line. The main users of T3 line are telephone companies and ISPs. The Internet backbone itself also uses T3 lines.
6) Asynchronous Transfer Mode (ATM)
It is very, fast data transmission connection line that can carry data, voice, video, multimedia etc. Telephone networks, Internet and other network use ATM. In near future, ATM will become the Internet standard for data transmission instead of T3 lines. Its data transmission speed is from 155 Mbps to 600 Mbps.