Local area networks (LANs) is part of computer networking which connects two or more system or network device that is called local area network (LANs) such as floor of building or one building or one office in same floor or other floor of building and campus environment. LANs behave much like people when you have a meeting with three or more people: If you want to say something to someone in particular, you first say that person’s name or at least look at him. Or, if you want to tell everyone in the meeting something, you just say it because they can all hear you. Likewise, LAN or locale Area network is broadcast media in other word that all devices or switches on the media receive the same data. When you are connect your computers or networking devices such as (hub, switch, and router) and we can use various types of topologies.
Figure 1: LAN technologies
Different type of LAN technologies
Figure 2: Different Types of LAN technologies
Ethernet IEEE 802.3
Ethernet: - Ethernet is a physical medium or part of physical technology that is directly connected to PC NIC or Ethernet port of switch or networking device only one PC on a shared Ethernet segment can send a frame at one time, but all stations receive and look at the frame to determine if it is for them. The physical Ethernet specifications up to 100 Mbps. provisioning IEEE 802.3 networks. Of these specifications, 10BASE5 and 10BASE2 are no longer used but are included for completeness. 512 bits is the shortest transmission unit (packet) allowed on an Ethernet network. This is a necessity for collision detection to work correctly. Ethernet is the underlying basis for the technologies most widely used in LANs. In the 1980s and early 1990s, most networks used 10-Mbps Ethernet, defined initially by Digital, Intel, and Xerox (DIX Ethernet Version II) and later by the IEEE 802.3.
The following are specifications for Ethernet, each of which is described in the following sections:
Half-Duplex:-
Half duplex is elements of LAN Technology. Many devices are working with Half duplex for instance HUB or repeater These center points is filling in as multiport repeaters in LAN and they secured the transport topology idea of 10Base2 and 10Base5 and so on by restoring the same electrical sign sent by the first sender of a casing out some other port. Impacts can at present happen, so CSMA/CD access principles keep on being utilized. The operation of NIC cards and the joined center is imperative to have a complete comprehension of the blockage issues and the requirement for full-duplex Ethernet.
As per below outlines the operation of half-duplex 10BaseT with hubs technology.
Figure 3: Half Duplex Operation
Find the below step for hub duplex
Full Duplex:-
Full-duplex performance is allowed when the possibility of collisions is removed. Full- duplex is used to depict correspondence where both sides have the capacity to send and get information in the meantime. In these cases, there is no peril of an impact and accordingly the exchange of information is finished much speedier.
As no collisions possible in full duplex mode, NIC disables the loopback circuitry. In this mode, both devices at the same time can send and receive data. It helps in decreasing congestion in Ethernet and provides the advantages as compared to half-duplex.
Fast Ethernet (100-Mbps)
IEEE introduced the IEEE 802.3u-1995 standard to offer Ethernet speeds of 100 Mbps over the other media of cabling (UTP and fiber etc.). The 100BASE-T standard is similar to 10-Mbps Ethernet in that it uses carrier sense multiple access collision detect (CSMA/CD) runs on the UTP or fiber cable and preserves the frame formats. Connectivity still uses hubs, repeaters, and bridges .100-Mbps Ethernet, or Fast Ethernet, topologies present some distinct constraints on the network design because of their speed.
The following are specifications for Fast Ethernet, each of which is described in the following sections:
100BASE-TX Fast Ethernet
The 100BASE-TX description uses CAT 5 UTP wiring. Fast Ethernet uses only two pairs of the four-pair UTP wiring. If CAT 5 cabling is already in place, upgrading to Fast Ethernet requires only a hub or switch and network interface card upgrades.
100BASE-T4 Fast Ethernet
The 100BASE-T4 specification was developed to support UTP cable at the CAT 3, 4, or 5. This description takes advantage of higher-speed Ethernet without re-cabling to CAT 5 UTP. Fast Ethernet uses three pairs of four-pair UTP wiring|
Gigabit Ethernet IEEE 802.3ab
Gigabit Ethernet was first identified by two standards: IEEE 802.3z (Gigabit Ethernet) invented in year 1998 and second edition of IEEE 802.3ab in year 1999. The IEEE 802.3z for the operation of Gigabit Ethernet over fiber and IEEE 802.3ab coaxial cable and bring together the Gigabit Media-Independent Interface (GMII). These standards are superseded by the latest revision of all the 802.3 standards included in IEEE 802.3-2002.
Below is an overview of Gigabit Ethernet scalability constraints.
Gigabit Ethernet Scalability Constraints |
||||
---|---|---|---|---|
Type |
Speed |
Allowed Segment Length (Max) |
Encoding |
Media Used |
1000BASE-T |
1000 Mbps |
100 m |
Five-level |
CAT 5 UTP |
1000BASE-LX (long wavelength) |
1000 Mbps |
550 m |
8B10B |
Single-mode/multimode fiber |
1000BASE-SX (short wavelength) |
1000 Mbps |
62.5 micrometers: 220 m 50 micrometers: 500 m |
8B10B |
Multimode fiber |
1000BASE-CX |
1000 Mbps |
25 m |
8B10B |
Shielded balanced copper |
The following are the physical specifications for Gigabit Ethernet, each of which is described in the following sections:
Wireless LAN
Wireless LAN (WLAN) consists of inside-building access, LAN addition, outside building-to-building infrastructures, public access, and small office/home office (SOHO) communications. The initially standard for wireless LANs is IEEE 802.11, approved by the IEEE in 1997. The current specification is IEEE 802.11-1999, with many amendments thereafter.
IEEE (802.11) implemented wireless LANs at speeds with 1 Mbps and 2 Mbps with Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum which works on physical layer of the Open System Interconnection model.
Quality of service (QoS) configurations or outlines gives special treatment to positive traffic at the expense of others device. This helps make your network presentation more deterministic and probable for this traffic.
QoS in the network addresses the following problems
The main reasons that can affect QoS are:
Latency
In an IP network, latency is defined as the time taken for a packet to enter and leave the network. As shown in Figure packet A enters the network at time = t0 and leaves the network at time = t1. The latency of the network, t2, for packet A, in this case, is t1 t0.
Figure 4: Network Latency Diagram
Note that latency is an end-to-end measurement of network delay. The time, t2, is the total delay introduced from various components of the network. These include transmission technology used, the speed at which packets can be forwarded at each intermediate node, and the various transmission speeds along the way.
Jitter
Jitter is affected by the traffic condition in the network. As a video packet traverses the network, it has to contend with packets from other applications along the way (for example, FTP and web applications). The latter two applications have a very different characteristic from that of the video: They are bursty by nature and may transmit variable-sized packets. The network needs to ensure that the jitter for the voice and video is not affected by these applications. This is when QoS is required.
Loss
Besides solving latency and jitter issues, preventing packet loss in applications such as voice and video is critical. Although losing one packet once every great while might not adversely affect these applications, losing too many might produce undesirable results. A long silence might interrupt a conversation, or a video screen might appear blank. In the case of the bank doing surveillance using an IP camera, losing images might have serious consequences.
Packet loss also results from the traffic condition in the network. A converged network carries different application types of data, video, and voice. These different applications must contend for the resources in the network. If the network is congested, packets are dropped because no resources are available. The network must be able to prevent the loss of packets that belong to voice and video applications. This is an area QoS can help in mitigating the risk of packet loss.
Hierarchical Network Design:
Hierarchical models are using layers to abridge the tasks for internetworking or network environment. Every layer can focus on explicit functions and allowing you to choose the right systems \ device and structures for every layer.
The profits of using hierarchical models for our network design mention below:
Hierarchical design models are used to save operational cost because hierarchical design models do not perform every operation in one routing or switching platform.
A traditional hierarchical LAN design has three layers:
Core Layer
The core layer is backbone of switching in hierarchical design models in other word core layer is bran of network environment that is work on high-speed switching backbone that is vital to corporate communications. The core layer should have below mention characteristics:
Distribution Layer
The distribution layer is the segregation or isolation point between the network's access layer and core layers. The distribution layer is used to implement below functions:
Access Layer
The access layer is responsible for providing access of local system or PC on the network to end users. The access layer is categorized by access switched and shared-bandwidth LAN sectors or segments in a hierarchical design models. Segmentation with the help of LAN access switches provides high bandwidth to workgroups and reduces collision domains on Ethernet\Fast or gigabyte segments. Functions of the access layer include the following:
Network Design Diagram
In this above network design we have used following network resources
2.2.1 Security
Dot.edu College has a security policy in place; it can begin to apply the document and its rules to their particular environment. Dot.edu College with truly comprehensive security policies find that what they have created is a roadmap that helps them implement the correct security appliances, mechanisms, and controls that satisfy their particular security needs. Dot.edu College will also quickly begin to find the weaknesses in their security posture through the process of identifying important resources and associated policies and tying that information to current inadequate security controls. This documentation is sure to change over time as the computing and physical environments change, which should be expected and accepted as normal security policy maintenance. The underlying network provides a perfect place to implement core and advanced security solutions.
2.2.2 Scalability
Scalability point of view network is setup in this manner so that we do IOS up gradation of switch without any outage and downtime or other word it can refer to the ability of a system to increase its total output under an improved load when resources are added. For instance we are using UTP cat 3 cables and now we need to upgrade it to UTP cat 6 cable.
2.2.3 Availability
It is signified as a percentage of periods. How many days, hours, and minutes is the server electrical infrastructure operational and supplying power over a given time period? Server availability suffers whenever the electrical infrastructure fails to provide power to the room.
Most companies want extremely high availability for their server, because downtime affects their ability to be productive and perform business functions. How high, though, can vary significantly and is represented by the concept of nines. The more nines of availability, the closer to 100% uptime a system or device has reached. For example, that your company brings the DC electrical system offline for one hour of maintenance every month. Assuming there are no additional outages of any kind, which means that the DC is running for all but 12 of the 8760 hours in the year. That's 99.863% of the time, or two nines of availability.
The college will be using 192.168.0.0/16 within LAN and we will user same ip pool for accessing outside network or WAN network.
Subnet allocation |
Site |
Bit |
192.168.0.0 Start Host 192.168.0.1 End Hot 192.168.1.255 Subnet Mask 255.255.254.0 |
Edinburgh |
192.168.0.0/23 |
192.168.2.0 Start Host 192.168.2.1 End Hot 192.168.3.255 Subnet Mask 255.255.254.0 |
Birmingham |
192.168.2.0/23 |
192.168.4.0 Start Host 192.168.4.1 End Hot 192.168.5.255 Subnet Mask 255.255.254.0 |
Liverpool |
192.168.4.0/23 |
192.168.6.0 Start Host 192.168.6.1 End Hot 192.168.7.255 Subnet Mask 255.255.254.0 |
Manchester |
192.168.6.0/23 |
192.168.8.0 Start Host 192.168.8.1 End Hot 192.168.9.255 Subnet Mask 255.255.254.0 |
Glasgow |
192.168.8.0/23 |
192.168.10.0 Start Host 192.168.10.1 End Hot 192.168.11.255 Subnet Mask 255.255.254.0 |
NEW HO in CP |
192.168.10.0/23 |
For Example
Now we are configure new head office in Central London with subnet mask 192.168.10.0/23
192.168.10.0 /23
Start Host 192.168.10.1
End Hot 192.168.11.255
Subnet Mask 255.255.254.0
Library department
Address: 192.168.10.0
Subnet mask: 255.255.255.0 = 24
Wildcard: 0.0.0.255
=>
Network: 192.168.10.0/24
Broadcast: 192.168.10.255
Starting Host: 192.168.10.1
End Host: 192.168.10.254
Hosts: 254
Finance department
Address: 192.168.11.0
Subnet mask: 255.255.255.192 = 26
Wildcard: 0.0.0.63
=>
Network: 192.168.11.0/26
Broadcast: 192.168.11.63
Starting Host: 192.168.11.1
End Host: 192.168.11.62
Hosts: 62
Customer Service:
Address: 192.168.11.64
Subnet mask: 255.255.255.192 = 26
Wildcard: 0.0.0.63
=>
Network: 192.168.11.64/26
Broadcast: 192.168.11.127
Starting Host: 192.168.11.65
End Host: 192.168.11.126
Hosts/Net: 62
Server ip address:
Address: 192.168.11.128
Subnet mask: 255.255.255.192 = 26
Wildcard: 0.0.0.63
=>
Network: 192.168.11.128/26
Broadcast: 192.168.11.191
Starting Host: 192.168.11.129
End Host: 192.168.11.190
Hosts: 62
Work Station |
IP Address |
Subnet Mask |
Broadcast ID |
PC1 |
192.168.11.10 |
255.255.255.192 |
192.168.11.63 |
PC2 |
192.168.11.11 |
255.255.255.192 |
192.168.11.63 |
PC3 |
192.168.11.12 |
255.255.255.192 |
192.168.11.63 |
PC34 |
192.168.11.44
|
255.255.255.192 |
192.168.11.63 |
Printer |
192.168.11.50 |
255.255.255.192 |
192.168.11.63 |
Customer Service has only five work station. 192.168.11.64/26
Work Station |
IP Address |
Subnet Mask |
Broadcast ID |
PC1 |
192.168.11.70 |
255.255.255.192 |
192.168.11.127 |
PC2 |
192.168.11.71 |
255.255.255.192 |
192.168.11.127 |
PC3 |
192.168.11.72 |
255.255.255.192 |
192.168.11.127 |
PC4 |
192.168.11.73 |
255.255.255.192 |
192.168.11.127 |
PC5 |
192.168.11.74 |
255.255.255.192 |
192.168.11.127 |
Library department -: 200 workstation are installed in Library so we require /24 subnet IP address. 192.168.10.0/24
Work Station |
IP Address |
Subnet Mask |
Broadcast ID |
PC1 |
192.168.10.10 |
255.255.255.0 |
192.168.10.255 |
PC2 |
192.168.10.11 |
255.255.255.0 |
192.168.10.255 |
PC3 |
192.168.10.12 |
255.255.255.0 |
192.168.10.255 |
PC4 |
192.168.10.13 |
255.255.255.0 |
192.168.10.255 |
PC5 |
192.168.10.14 |
255.255.255.0 |
192.168.10.255 |
PC10 |
192.168.10.19 |
255.255.255.0 |
192.168.10.255 |
PC200 |
192.168.10.209 |
255.255.255.0 |
192.168.10.255 |
Printer 1 |
192.168.10.220 |
255.255.255.0 |
192.168.10.255 |
Printer 2 |
192.168.10.221 |
255.255.255.0 |
192.168.10.255 |
Server ip address: 192.168.11.128/26 File Server, Web Server, Domain Controller
Server ip |
IP Address |
Subnet Mask |
Broadcast ID |
Web Services |
192.168.11.140 |
255.255.255.192 |
192.168.11.191 |
File Server |
192.168.10.141 |
255.255.255.192 |
192.168.11.191 |
Creating the baseline of LAN network in Dot.edu College we have to pull the presentation data of college traffic, BW (bandwidth) use and errors. We know there was no change done after setup. We need to pull daily or weekly performance reports from monitoring tools PRGT and EMC Smart so that we can check how much BW has been used during the working day and also we will check on different monitoring tool whether we get any errors on the interfaces or not.
All useable port where user systems are connected; those were put in monitoring tool which helps us to identify or find how much system data have been used.
Network devices (switch, router etc.) which we configured during the time of setup, are these using all features of new technology. We applied on network LAN segment like port security policy or mac binding are those working or not. We ping router IP from switch continuously to check latency and drops. We also keep checking ports and make sure that ports are proper VLAN according to department.
Below is the baseline parameter which was configured.
Dot.edu College we are using two monitoring tools PRTG, EMC smart. Monitoring tools are the key for network stability. EMC smart software helps us to identify any link failure and device down. PRTG checks the devices, link performance. If any irregularity occurs on the network, proactively send the alert. It helps us to the action in advance so that we can take quick action.
Below are the key advantages of the monitoring tools.
We need to replace one computer with new computer in library so please find the below step
First, we have to check system device IP address it is defined static or DHCP. If here we configure IP address through DHCP server.
Second, we have to check the device is connected to switch port that has port security configured or not. If the port security is enabled we have to disable it once and again configure Mac address of new device on this switch ports.
Now we will check on the system whether cross sign has been disappeared. Now system will be able to connect on the network and will be able to access intranet and internet based application
Now we have to take these following step of configure network in device.
Now test network connectivity, first ping default gateway if it take reply time 1 and show packet drop 0, it means our network connection is good.
Building and configuration of devices and services within the LAN and Implementation of specialized configuration and security mechanisms within the LAN
I am configuring New HO location in Central London so first I will configure Router and connected with Core switch mention below.
We have configure host name of router with command
router#configure terminal
Router (config) #hostname CD-NEW-HO-RT
We are configuring new HO location LAN segment so first we will configure switch and we can create 4 VLAN in core switch mention below.
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