A computer network is a combination of the two or more hardware deceives and with the compatible software which allows the communication between these devices such as data and voice, video etc.
Next section going to deal with the Hardware used to build the network
This is used to connect the transmitter and receiver. It may be guided and unguided medium.
In this type capacity based on the bandwidth rate and the distance it has to cover and type of the link ex: point to point or Multipoint
There are four transmissions medium:
Twisted-pair Cable: These are the most commonly used media generally uses RJ-45 plug. Twisted-pair contains the 4 insulated copper wires and twisted. The twisting pair reduces the effect of the Electromagnetic waves. Twisted pairs restricted in terms of data rate and distance EX: requires amplifiers every 5-6 km for analog signals and 2-3 km for digital signals. These are again divided in to two types called shielded and UN-shielded twisted-pair. STP cables are covered by an additional shield which makes more robust and reduces the electromagnetic interference
consist of two conductors one is inner conductor and other one is shield which is generally metal foil surrounded by the inner conductor with the diameters of 1 to 2.5cm . Outer shield used to reduce the interference and cross talk. These cover more distance than twisted-pair. Generally use in cable TV and to cover long distance telephone lines. It can carry both analog and digital data, supports up to 10000 voice data using FDM.
Optical Fiber cable:
Fiber optic technology uses the light to transmit the data. It has begun in1970s. Fiber technology uses allows higher bandwidth that’s the reason used between the central offices which needs to carry high volumes of voice traffic where copper wire provides limited distance and bandwidth. Optical fiber cable carry thousands time more data than twisted pair , lightweight, low loss of signal, higher reliable and it doesn’t generate the EMI so it is difficult to breach .optical fiber cable consist core and coating buffer, outerjacker, cladding . Core is the part which carry’s the light and which is made of silica and Germanic and the cladding which covers core and is made of silica only cladding has reflective characteristic so which will help the light be in the core . Fiber is two types single and multi-mode .buffer help to protect the core and cladding act as shock absorbent and strength member help to protect from installation damages and outer jacket is for environment protect
Single Mode Fiber
Width of core
Very thin(8 to 10microns) and allows straight line light passing
Light travels in several paths core width is 50 to 65 microns
Longer distance transmission
Short distance transmission
A router is device which divides the network into two parts. The different port of the router comes under different networks. A router is specialized device which routes the packets from the source to destination and also used to connect the different LANS. Routers works on the Network Layer which is the 3rd layer of the OSI model since it uses the logical address (IP address) to do routing decisions, whenever a packet arrives from the data links layer to one of the port in router then router unwrap the data link layer header and attaches the new header to transmit it out. Every router contains the hardware and network operating system. The hardware consisted of Routing processor, ROM, RAM, FLASH Memory and input and output ports, NVRAM, Other interfaces. CPU work along with the routing protocols and creates forwarding tables which is used in transferring the packets to the destination. Input and output interfaces are the physical links which deals with the incoming and outgoing packets generally these are RJ-45 ports and other interfaces such as AUX port and console ports. Console port is used to configure the router which is necessary because router is not zero configuration device. RAM and ROM as same functionality like in normal computers, flash holds the image of the IOS. AUX port is used to connect router from remote access.
HUB: An Ethernet Hub is device for connecting multiple wires (twisted pair, fiber) to connect multiple devices into a single network. Hubs works at layer1 of the OSI model. Hub works at hardware level it receives packets on one port and broadcast to all other ports. If more than couple of devices tries to transfer the data at a time a collision will occur. All the devices which are connected to the hub come under same collision domain. Hubs are two types i.e. passive, active and intelligent. UN-managed are just a hardware just broadcast the incoming signal. Where managed hubs are configured using workstation.
A switch is small hardware device which joints multiple nodes together with in a local area network divides into logical pieces. Switch operates at data link layer (layer 2) OSI model. Switches are similar to hubs but more intelligence than the hub. Switches works on layer 2 so it can interpret the data packets and analyze and send it to appropriate port which leads to destination. Switch consumes the bandwidth and offers the better performance than the hub. Some modern switches operate at layer 3 and layer 4 as well. Each node which is connected to switch gets dedicated link. Switches can provide better security by providing different collision domain means it separate the one port traffic to another port traffic. Switches classified based on the switching it use:
1. Cut-through mode
2. Store and forward mode
Hosts are generally the end devices to which the services are being served or services are being taken.
End devices are the interface between the user and the network to utilize the services ex: computers, servers, printers, cameras, VOIP phones, and any mobile hand held devices. A server is normal computer or high-end device which provides one or more service over the network where client is another end who request the service. There are several types of servers available. Application, chat server, ftp, mail, proxy servers etc. there are many server software available outside for Ex: Tomcat, Microsoft, IBM HTTP server etc web server has main three computers. Generally server hardware is high end hardware devices and fast processing capable and this system must be robust from the damages and end computers are just desktop of laptops which is used to access the internet and to do the personal work and it can access the server with the specified set of rules, VOIP telephones one of the emerging technology cheaper and faster than normal telephones(PBX).which uses the data network as the medium and any one can make the call to anyone around the world with the cheaper price and better in quality
OSI model is tool from the international organization for standardization which divides the data communication into small parts (Layers). Each layer has its own and unique functionality from other layers and each layer provides service to another layer which is directly connected the bottom three layers operate to send the data from end to end system. The above four layers process the at the end device mostly (software work)
OSI model divides the communication into manageable chunks so every function is specific to the concern layer without OSI model it’s hard to mange network functions in this section going to discus about the Data Link layer and Transport Layer and Network Layer
This provides the end to end logical connection the main functionality of this layer is route handling and data transmission preparation. This layer provides communication with the transport and data-link layer. It encapsulates the data received from the Transport layer and which is called protocol data units and management the connection between the networks. There are several protocols which operate on network layer Ex: IP, ICMP etc… Internet is the principle protocol used to send the data-grams across the network. This is responsible for routing the packets across the network and provides the many functions to send the data grams to the end device
Performance of the network depends on the various factors such as channel capacity, utilization, delay in case of real-time applications and packet loss and conjunction etc
Performance metrics various are two types based on system and service. System performance based on the memory, processor utilization, load and Input/output waiting time etc… Services performance depends on the Delay, Availability etcâ€¦
The router plays very important role routing the packets. Router determines the next hope address forward the traffic then a question raises that which part of the router affects the performance
some people says that software and some people says hard ware but performance depend on the both because as the software works well but hardware haven’t got the proper resources to run that it’s also decreases the performance another side resources available but not utilized properly, also decreases the performance
When comes to the routing is the process of the router and this process happens in the physical, data link and network layers
Routing protocols works at layer three and next hope will be counted at every router and routing is only is based on the destination address without the concern of the routing protocols. MPLS reduces the routing look-up and also need not run a specific protocol on every router. MPLS forwards the packets based on the label. When comes to the IP networks every router decides the next hope address but when comes to the MPLS only edge routers perform the routing look-up core routers sends the packets based on the simple label. When comes to the MPLS layer 2 devices run a layer 3 routing protocol and establish the virtual circuits dynamically so this provides a virtual full mesh topology
IN MPLS only routing look up will be done at edge router means packets processed through the three layers only on edge routers after that the routing will be performed only on the basis of the simple labels attached also provides different forwarding techniques in MPLS forwarding can be done on QOS etc . MPLS with Traffic engineering gives much more performance than the IP based traffic engineering or policy based routing
Hardware Resource Utilization:
Resource issues such as and RAM and CPU and IOS configuration also effects the resource utilization and the bandwidth management is also effects the cables and as well bad circuits. Like PC routers have CPU and RAM extra hardware at the peak time all the router resources will be utilized to the maximum there are some tools which are available to monitor the CPU and interfaces always other than these we can improve the performance. By changing the switching that is used by the router. Generally the default buffer size of the router will be optimized concerning all applications but sometimes need to change when comes to the delay sensitive applications need small buffer size. Disable all the unnecessary applications which run in the back ground and the routing tables has grown up every day using the summarization and turning off the default routing. To resolve the bandwidth problems with the traffic management this is called quality of service, stopping the unwanted traffic also gives the better performance. Some commands available in default Ex: “Show Memory Dead “which shows the memory usage such as free memory, memory failure allocation command shows the Memory allocation failures
Career in Networking:
Career in networking is challenging because every day because its dynamic in nature every day new connections will be added so the network size increases data transfer rate will increase and task of maintaining the network increases. Now a day’s every one using the network starting from web browsing to data transfer. Comparing to software developers network manager has difficult task because it has to connect various number of resources every resource has privileges and connecting this resources not makes the network some other factors need to consider such as security, stability and reliability. Network manager should provide the best protocols that can’t affect the performance of the network
Day to Day Tasks:
1. Handle the maintenance tasks.
2. Upgrade the systems software.
3. Check the hardware and software.
4. Monitor the antivirus
Expectation from the Manager:
1. Provide training on latest technologies.
2. Discuss daily tasks which were done.
3. Good guidance and knowledge
Responsible for installing and managing of networks. This includes installing and maintenance of the network. Future steps to extend the network organization. Monitoring the user activities in the network providing the security to emails, accounts and passwords etc. Able to analyze the network faults from major errors to minor errors. Can able to redesign or modify the network, backups etc..
In this fast changing world, communication is important is important daily life. Lot of advancements has been taken place in the connectivity to have better communication and advancements in standards without exceptions. In this paper i have explained the various hardware and software which has the greatest impact on the networks and the improvements which can optimize the network performance in case of hardware and software and also explained the careers and opportunities in the networking
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