Managing Networks Network Technologies Operating Systems

Published Date: 02 Nov 2017

Managing Networks

Network Technologies

Operating Systems

Protocols

CSMA

AppleTalk

Token Passing

UDP

802.2

802.3

802.5

802.11

Application Layer Protocols

DNS

DHCP

HTTP

FTP

SMTP

SNMPv3

Internet Control Message Protocol

Why are Network Protocols Important

Physical Network Topologies

Star Network

Bus Network

Ring Network

Mesh Network

Tree Network

Wireless Technologies

Infrared

Bluetooth

3g

Networking Operating Systems

Network Devices

Servers

Interconnecting Devices

Network Card

Networking Tools

Emerging Technologies

Server Virtualization

Video on Demand

Impact of emerging technologies

Network management Functions

Configuration

Fault Management

Account Management

Performance Variables

Other Activities

Network Operations

Reporting

Network management activities

Regular Maintenance Activities

Tools

Documentation

Work Logs

Log Resources Used

System Testing

Configuration Options

User accounts location

Security Features

VPN Access

Firewall Management

Network Technologies

Operating Systems

A network operating system is a computer system that is specifically designed to support workstation, personal computer, and, in some instances, older terminal that are connected on a local area network (LAN).

There are different features that network operating systems provide this includes, providing access to networked printers, managing which users can connect to the printers, at what times and managing how print jobs are queued.

Enabling and managing access to files on a remote system and specifying who can and can’t access that information.

Monitoring the system security, so as to provide proper security against viruses, hackers, and data corruption.

Protocols

Computers need to be able to communicate with each other, if all computers had different ways of communicating then they wouldn’t be able to communicate with any other manufactures machines, this is where network standard protocols come into consideration, this is a set of rules, agreed signals, and codes for data transmission.

The most commonly used protocol is TCP/IP this stands for Transmission Control Protocol/Internet Protocol, these two protocols were developed by the US military in the early days of the internet. TCP/IP software is built into all major operating systems such as UNIX, Windows and Mac OSX.

The above table is a diagram of the standard protocols that are used, and when they are used, so for example if you were to use the internet you would use the entire of the bottom layer the "Host-To-Network-Layer" then you would use the whole of the next layer "Internetwork layer" you would then move up to the next layer and use the "Transport Layer" and when it comes to the application layer you would use the one that applies to you so as we are accessing the internet you would be using the HTTP Protocol.

CSMA

CSMA (Carrier Sense Multiple Access) is a protocol for data transmission in 802.11 networks, what this protocol does is it checks that the network is clear before transmitting data to avoid data collision. If the network isn’t clear it will wait a random amount of time before it tries to resend the data.

AppleTalk

AppleTalk is a multi-layered protocol coming from Apple Computers, it provides internetwork routing and a comprehensive file and print sharing among Apple machines. AppleTalk network can support up to 32 devices and data can be transferred at a rate of 230.4 kilobits per second (Kbps)

Token Passing

Token passing is a method of ensuring that all data that is transferred is secure, so when a connection is established only the people that are included in the token are allowed to access the data, when the connection is closed, you can reopen the token and re access the data.

UDP

User Datagram Protocol is a communications protocol that offers a limited amount of services when messages are exchanged between computers in a network that uses the internet protocol. UDP is an alternative to the transmission protocol TCP, sometimes UPD is referred to as UDP/IP.

802.2

This protocol is the logical link protocol, it is commonly referred to as the LLC or logical link control, this is the top sub-layer in the data link layer of the OSI model, it interfaces with the network layer.

802.3

This protocol provides asynchronous networking using carrier sense multiple access with collision detect (CSMA/CD) sent down coax twisted-pair copper and fibre connections, these speeds range from 10Mbps to 10Gbps.

802.5

This protocol is the token ring, this is the original token-passing standard for twisted-pair shielded copper cables, and this protocol supports copper and fibre cabling ranging in speeds from 4Mbps to 100Mbps.

802.11

This protocol is one of the main network protocols used, it is used in all Wi-Fi certified devices, such as routers. There are many extensions to this protocol as technologies advance without erasing the original protocol it was developed upon to increase the efficiency, such as 802.11b and 802.11g and more recently 802.11N.

Application Layer Protocols

DNS

DNS stands for Domain Name System, this is an internet service that translates domain names into IP addresses, the reason this is helpful is that domain names are usually something that is memorable, whereas if you were to remember an IP address for each website you wanted to visit you would struggle to remember more than 10, for example, www.google.com is translated to: 173.194.66.105, meaning that just using www.google.com is easier to remember.

DHCP

DHCP (Dynamic Host Configuration Protocol) is a communications protocol that lets network administrators centrally manage and automate the process of assigning IP addresses to the organizations network system. Without DHCP the IP address must be entered manually at each computer in the company and a new IP address will need to be entered each time a computer moves to a different location on the network. This is what will give your laptop/mobile device a dynamic IP address so that the IP addresses can be kept free for other users, and DHCP can also set static IP addresses for hardware that needs to keep the same IP address such as network printers and web servers.

HTTP

Hypertext Transfer Protocol is a set of rules defined for transferring files such as, text, images sound, video and other multimedia files across the internet. A web browser is considered a HTTP client which sends requests to server machines, when the browser shows the text, opening it means that the browser is sending a request to the host server to open the data stored at that location and send it to your web browser.

FTP

FTP stands for File Transfer Protocol, FTP is an application protocol that uses the internet’s TCP/IP protocol to transfer files from a host server to the user’s machine, for example when downloading a program from the internet.

SMTP

Simple Mail Transfer Protocol is a TCP/IP based protocol, it is used for sending and receiving email, this protocol doesn’t work alone when sending and receiving email, it is also accompanied by POP3 or IMAP, the reason for this is that SMTP lacks the ability to queue messages at the receiving end of the email, whereas using either POP3 or IMAP the user can periodically download the messages in order of receiving them.

SNMPv3

Simple Network Management Protocol Version 3 (SNMPv3) is an interoperable standards-based protocol for network management. SNMPv3 provides secure access to devices by a combination of authenticating and encrypting packets over the network.

Internet Control Message Protocol

This is used by network operating systems to send error messages indicating that the requested service is not available.

Why are Network Protocols Important

Network protocols are important for many different reasons, the first of which is standardization, this means that manufacturers can all stick to a specific standard, if all of the companies making hardware used their own protocols, only machines created by them would be able to communicate with each other as all machines would have their own set of rules that they abided by, so for example, if you was to follow the rule of CSMA/CD on one machine but another manufacturer decided that they didn’t want to follow this protocol, there would constantly be collisions on the network causing redundant data transfer, causing more unnecessary traffic on the network, if this was a bus network, there would be so much traffic on the network constantly that the network would potentially crash under a high amount of data transmission.

Physical Network Topologies

Star Network

There are several types of networks that a company could use, some have benefits that some don’t have so you need to pick the specific network that is going to be suitable for your situation, if you are going to be using 100 computers then the best network that you could use would be a star network; When using this type of network, it means that there will be less traffic on the network between each machine as there is a switch in-between all of the connections meaning that providing you have the correct network cable. A benefit of using this style of network means that if one of the connections breaks then you will still have access via the other 4 machines, they are easy to set up and expand onto as you only have to connect the one machine to the switch as opposed to join it into another network.

A drawback of this network is that it can be quite expensive to install as you have to purchase extra hardware to connect all of the machines into the network.

Bus Network

A bus network is a simple style of a network that is very easy to set up, and is a cost effective way of setting up your first network a bus network is a network where all of the nodes of the network are connected to a central line also known as the backbone, all of the data transmitted goes through the central cable meaning that you have a lot of data filling the network. There are several disadvantages of using a bus network, one of which is that a failure in the backbone would cause the entire network to go down, and if your cable is 100m long you have got to search down the entire cable to find if there is a break in it, if your cable is broken you would have to replace the entire cable and re run the wires. As there is only one main connection for all of the computers, it means there is only one route for the data to go down, the performance of the network will decrease as more data is transmitted.

Ring Network

A ring network is where all of the machines are connected in a loop, the data is transmitted from one machine to the next and the data is only transmitted in a single direction.

There are a few advantages of using this network topology one of which is that as all the data can only travel in direction the transmission of data cannot collide so high speed transfer rates can be achieved. With this style of network there is no need for a central server as all of the machines are connected together so you can access what you need from the next machine.

The disadvantages of this style of network is that when one machine fails or the connection breaks then the data cannot be transmitted to the next machine in the network, it is also harder to add more machines into this network style as you will need to disrupt the current cycle meaning downtime for all of the other machines whilst you put the new machine in.

Mesh Network

A Mesh network is a style of network that all of the workstations are connected to each other so that they all have a direct route to one another, an advantage to a network like this is that it is very reliable as if one of the connections break the data can be sent down another route to get to its destination, also having a dedicated connection to each destination you can achieve a higher transfer rate as there may be less traffic on the network.

A disadvantage to a network like this is that there is a very high cost with the hardware required to set up this network as if you have 5 machines that you are connecting you will have to use 10 Cables instead of 5 to connect all of the machines together.

Tree Network

A tree network is a combination of two or more star networks connected together. Each star is made up of a 1 node and however many machines are needed in the diagram below there is 1 host and 4 machines connected to it. The host is then connected via a bus connection to the main server.

This type of network is ideal when the machines are located in groups for example in a classroom; you have 20-30 machines connected to a switch which is connected to the main server.

A benefit of this network is that if there is a cable fault it is very easy to locate as either a room will be down, a single machine will be down or the entire network will be down. If one machine goes down it doesn’t affect any of the other machines.

Wireless Technologies

Infrared

Infrared is a transmission of data or signals over a visible distance, the signal can be blocked by external factors, depending on the strength of the transmitter; infrared is used in many wireless communications such as, television remote controls, motion detectors, night vision systems and various other pieces of hardware.

Bluetooth

Bluetooth is a telecommunications industry specification that defines how mobile phones and computers can be easily connected using a low range wireless connection, Bluetooth is transmitted on the frequency band of 2.45GHz that is globally available, and data can be exchanged at 1Mbps on first generation technology and up to 2Mbps on second generation devices.

3g

3g is a mobile network that provides download speeds of up to 14.4Mbps and upload speeds of 5.8Mbps, the minimum speed a stationary user can expect is 2Mbps providing that you have a solid 3g connection; a user in a moving vehicle can expect a speed of around 348Kbps.

Networking Operating Systems

Server 2008/10

Linux single user/multi user os

Network Devices

Servers

There are different types of servers that perform different actions there are, web servers, proxy servers, dedicated servers, application servers.

Web servers are servers that provide a web service. Every Web server has an IP address and a domain name. Any computer can be turned into a Web server by installing server software and connecting the machine to the Internet.

Proxy Servers a server that sits between a client application, like a Web browser, and a real server. It intercepts all requests to the real server to see if it can complete the requests itself. If not, it forwards the request to the real server.

Dedicated servers A dedicated server is a single computer in a network reserved for serving the network. For example, some networks require that one computer be set aside to manage communications between all the other computers. A dedicated server could also be a computer that manages printer resources.

Interconnecting Devices

A Bridge is a device which retransmits packets received on one segment onto another segment.

A repeater is a device which regenerates the signal of one segment onto one or more other segments.

A router is a device which receives its instructions for forwarding a packet from one segment to another from a network layer protocol.

Network Card

A network card is a device which can be both wired and wireless, it will give you access to your network Personal computers and workstations on a local area network (LAN) typically contain a network interface card specifically designed for the LAN transmission technology.

Networking Tools

Networking tools are used to manage faults on your network, if you have got a problem on your network, then you can see what faults are occurring. You will be able to remotely see if there are errors with specific pieces of hardware, for example, if you have 20 servers, and only 19 are visible on your software, you would be able to run a diagnostic tool to see if you can see what is wrong with the server that isn't online, and with the tool you may also be able to reboot the system to see if that would fix the fault, meaning that if you fix the server from there, then you won't have to go and physically look at the server, but you may have to go to the server and fix it from there.

Networking tools are also used for managing performance of the network, you will be able to see what is using all of the resources on the network, and with different tools you will be able to allow and disallow different tools to run on the network.

Different people use different tools depending on which hardware you are running, if you was running a HP server then you would more than likely be running HP OpenView, HP OpenView allows you to monitor network status and hardware availability, and is vendor specific software as it will only work on HP hardware.

CiscoWorks is a LAN Management Solution, a web-based suite of tools developed in Java by Cisco Systems, with the purpose of helping users manage a Cisco-based computer network. Some of the features that CiscoWorks can manage are; Device management credentials, Grouping Services, Process management, backup and restoration and licensing.

Wireshark is a free open source network protocol analyser, this tools lets users browse through all of the network traffic on a computer network. The program can be used by network administrators to troubleshoot network problems. Network security engineers can also use it to examine security flaws. People can also use it to find out how network protocols work.

Asset management is a good thing to have if you have got a large office, for example you have 150 employees, and they all have a computer, all the peripherals that go with a computer eg (monitor, mouse, keyboard) and they share a printer between 10 people, that works out to 465 pieces of hardware that you need to check to see if they are still all there whereas if you was to use an automated piece of software that will register to see if the hardware will come online on the network, it will be checked via a database of hardware, and you can set it to check to see if something comes online within a certain period of time, if you set it to check every week, then if a piece of hardware isn't registered as it has been used then you can go and check that it is actually still there.

Emerging Technologies

Server Virtualization

Server virtualization is the masking of server resources, including the number and identity of individual physical servers, processors, and operating systems, from server users, There are three types of server virtualization: the virtual machine model, the paravirtual machine model, and virtualization at the operating system layer.

Virtual machines are based on the host/guest paradigm. Each guest runs on a virtual imitation of the hardware layer.

In the OS level model, the host runs a single OS kernel as its core and exports operating system functionality to each of the guests.

Video on Demand

Video on demand is a tool that will let you watch videos, tv programs & films when you want for example like, youtube, BBC iPlayer, 4od. these are free to use, and legal if you have a valid tv licence (BBC iPlayer, 4od)

Impact of emerging technologies

With the advancements of technology you will have more capabilities with the speed of the network, networking speeds are increasing meaning that you are able to handle more traffic on your network giving you the ability to process more data across it without it grinding to a halt.

Another impact of emerging technologies is that network managers have greater control over what happens throughout their systems, meaning that if they don't want a specific user to access something, they can block it, if they want to block certain programs they can, if they want to see what the users are doing, they can. With better controls over the network you can perform actions that wouldn't have been available previously.

Mobile working is another great advancement of technology, mobile working is the ability to leave the office and still be able to continue with the work you have been doing at your desk, this can be done via a VPN and any modern laptop, this will mean that you can access all of your files from anywhere you have a internet connection, be that at home, another office, or tethered to your smartphone.

With the advances in web centric applications this also makes working away from your desk a lot easier too, with websites such as microsoft 365 and google drive, you are able to work on documents, spreadsheets, presentations from the web without having to have software installed on the machine you are working on, meaning that you could go to any computer with a working internet connection and access your documents from either microsoft 365 or google drive.

The ease of use of new technologies is most arguably the best advancement yet, as when technology gets easier to use, more people feel comfortable using it knowing that they can do it, and it isn't going to go wrong, for example touch screens make using a phone easier and simpler, if you want to call someone, you just tap the phone icon and select the person you want to call, without having to press any buttons, this makes it simple to use as you are just touching what you want to do and it is doing it for you.

Network management Functions

Configuration

Configuration is about the devices that will be used and the amount of devices that are going to be needed, the different devices that could be used are hubs or switches, these can be used to connect the computers and components in a network.

Proxy servers can also be configured to make accessing frequently viewed sites faster by caching the website to make sure that it loads faster and if there aren't any changes to the website since last visited then it won't have the be refreshed.

Configuration also includes the accounts that are going to be on the network and the account settings that are going to be applied to each account, this includes having access to files, folders, locations, hardware, software.

Fault Management

Fault management is the method in which faults on a network are managed, this includes how faults are reported to the network managers, this can be done via, email, phone, fax or face to face if you work in a small office/building

Fault management is a very important part of keeping a network running smoothly in a business as if you keep having downtime due to faults then your company is going to start losing money as a result of the network being down.

Account Management

Account management is the detailing of all of the user accounts that are going to allowed access to the network, these details include personal information about the users such as, Forename, surname, department and other various details about the employee.

When managing users accounts you need to take into account a user's security, this can be done via the use of an automatic password reset, this is that every 30 days a users password will have to be changed, this means that if someone is trying to access your account they will have a harder time doing so as your password is constantly changing.

Performance Variables

Network throughput is the amount of data passing through a network, the amount of data can be tracked to make sure that no one user is exceeding their allocated data limits, as this could have an adverse effect on the network causing it to slow down dramatically.

User response times is the amount of time the computers in a network take to respond to a users request for something, for example, if 30 people tried to log onto a network all at the same time, this would take a longer amount of time as the amount of data passing through the network will be large.

Line utilization is how much of the line is utilized, if the capacity of the line is exceeded then it will need to be planned on how to increase the capacity of the line so that the network runs smoothly, this can be done by increasing the amount of cabling that is available to users, or replacing the switch to one that can handle more traffic.

Other Activities

Planning needs to be carried out by network managers to see what needs to be replaced, what needs to be upgraded, the reason it needs to be planned is that there is a financial aspect of what you’re upgrading, and there is a time scale that you will need to adhere to, for example at a college if a room full of 30 computers needs to be replaced, you firstly need to decide when is going to be the best time to do it (half term, summer holidays) then you need to decide what units you are going to use, this is where the financial side of the planning comes into action, and then you need to physically go and install the machines in this room, this isn't a task that you can do just on a whim, it needs to be carefully planned with a backout procedure in place to ensure that nothing goes wrong.

Designing needs to be done to decide what components of your network need to be changed, whether or not it be just a single piece of hardware inside the machine or the entire tower or the operating system as the current one isn't allowing you to do a specific task. This needs to be decided whether or not the change is going to be beneficial and cost effective.

Installing is a very important activity as you need to decide when you are going to complete the install, is it going to be a night where there is no one on the network or is it going to be whilst staff are on holiday, as you cannot install new software or hardware whilst the network is still being used. You will need to predict how long the install will take so that you can let the users know roughly how long their network will be unusable.

Network Operations

Security is a very important part of a network, there should be alerts setup for when something goes wrong, or when something is happening on the network that is out of the ordinary, for example a user logging on at 9am is not unusual, but a user logging in at 3am would be unusual for a company or organisation that only works 8am-6pm. Alerts would need to be setup to notify the network managers as someone could be trying to hack the system.

Data logging should be done for both security and fault finding reasons, if someone is trying to access something illegal on your network, Torrents, pornographic images/videos, racist derogatory material, then with the data logged that it was them trying to access it, you can either give the member of staff a disciplinary or sack them.

Checking performance and traffic is important as you can see where there are flaws in your network causing you to slow down what you are doing, if you can see that there is room for a performance increase then you will need to decide whether or not it will be cost effective to carry out this change.

Reporting

The network manager should constantly be reporting to the managing director of the company to ensure that everyone is up to date with how the network is running, performing and what needs to be updated and why, if you don't keep the managing director informed of what you are doing, and then you go and spend £1000 on new hardware they are going to want to know why you have just gone and spent that money without telling them that it was a necessary upgrade to your servers to ensure that the network continues to run smoothly with the increase of users/traffic on there.

Network management activities

Regular Maintenance Activities

Regular maintenance must be carried out on a network to ensure that you have minimal downtime or data loss in the event of a failure of hardware/software/natural disaster. The ways in which you can prevent this is by regularly backing up all of the data that is stored on the servers, storing them in a secure location, and ensuring that they also work, by restoring the data back onto the system, there is no point in taking a backup every day and finding that the backup didn't actually successfully complete and there is no data on the backup media.

You should also ensure that you are regularly deleting user accounts that are no longer in use as they take up resources, being that it may only be hard drive space, if the account is no longer going to be used, then it is no longer needed and should be deleted.

Virus scans should be ran regularly on all of the machines connected to the network, as if there is a virus on one of the machines, it could quite easily spread to all of the others as they are all connected via the same switch/hub and all connected to a server. If you was to get a virus on a system it could potentially be a large disaster as it could wipe all of the data on just one computer, or it could find its way to the server and delete everything.

File cleanup is also important to do as when you are doing anything on your computer, files are cached and put into temporary folders, which take up space, which can be quite valuable if you are a large company.

Tools

Performance tools are a set of tools used for error trapping and problem solving, they are usually a monitoring tool that uses little resources, that scan the network and look for errors so that the fault log can be sent to the network technician so the fault can be fixed. Tools such as HP Openview will perform these actions for you as an automatic system, but they are vendor specific, this means that they will only run on HP Servers and machines.

SNMP (Simple Network Management Protocol) is an application layer protocol, this provides a minimalistic protocol for retrieving network performance data and setting network device parameters. This tool does not process or analyse the network traffic it simply collects it and sends it to the network manager.

Documentation

Work Logs

Below is an example of a ticket system that could be used for recording when a customer has a problem with one of their machines. It is used to log what the problem is, when the problem occured, who reported the problem, and how high of a priority the problem is.

Log Resources Used

Network resources are logged as resources for a company can be an important asset, if you are a small company, with a small bandwidth on your network for example, and you have got a user on a laptop / wireless device, downloading non work related items, such as music / video etc, then this is going to take a lot of bandwidth from the network slowing every other user down, and possibly causing the network to crawl to a halt as wireless uses a lot more bandwidth than a wired connection.

System Testing

When you are testing your system, it is a good idea to make documentation stating what is/was working when you installed / upgraded it, what isn't working and what your next step is going to be on improving the system, this means that if you are at a clients office, and you are working on a machine that has sensitive data on the hard drive, and you have come in for an upgrade of software, and once you have installed the software the system is running perfectly fine, the upgrade worked without any hiccups, and then 2 days later you get a call to say that the hard drive has been wiped and its not working since you have upgraded the software, you would have taken logs on what you did, and even screenshots as a form of evidence that the computer was working fine when you left it.

Also another reason for keeping logs of system testing is that if you are working on setting up an entire office for a client, and one day you are unwell, you will be able to send another engineer in to continue with the installation as you would have documented where you are up to with the installation and what will need to be done next for the install to be completed.

Configuration Options

User accounts location

Security Features

VPN Access

Virtual private network is a network that uses public connections such as the internet to provide a remote connection to offices, or individual users with secure access to the companies network.

A VPN is a good idea for businesses to set up as they are able to work from anywhere around the world with an internet connection, meaning that you are able to continue with your work and access all of your files.

Firewall Management

A firewall will have to be managed carefully, as this is what is protecting the network from unwanted traffic accessing the servers and the data on them, a firewall will have to be set to screen certain bits of data from entering the network, this could be known viruses, or unknown data / previously used data, this is to prevent an attack being made towards the system. One tool that could be used to perform such tasks could be Cisco Security Manager, this tool will allow you to manipulate the firewall into whatever protection you need to keep your network safe.

Access Control List

An access control list is a list of pre-approved users that will have access to certain files and folders, the access control list specifies which users of system processes are granted access to objects as well as commands.

Networking Accessing control lists refer to the rules that are applied to IP Addresses and port numbers that are available on a host. Access control lists are protecting both individual users and servers.

Device Hardening

Hardening a device requires you to know what security vulnerabilities will need to be eliminated or reduced. A vulnerability is any weakness or flaw in either the software design, implementation or administration of a system.

The purpose of system hardening is to eliminate as many security risks as possible. This is typically done by removing all non-essential software programs and utilities from the computer.