How to Build Network Designs
The best network designs consider the users of the network and what information they need in order to do their job. Information might come from data stored on computers or it might mean real time interaction with other people. In the past, real time interaction meant telephone conversations. Modern network designs must consider traditional telephone traffic as well as modern collaboration practices such as video conferencing and data sharing.
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Things You'll Need
- List of users of the network.
- List of applications required by the organization.
- Any available reports on current network usage and application requirements
- Floor plans of buildings to be connected.
- Maps identifying the location of the buildings to be networked.
- Sticky colored label dots.
Instructions
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Defining the Network Requirements
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Network design starts with the user. Examine every application that is needed to support business operations. For each application, estimate the amount of bandwidth required, the acceptable level of network delay and the acceptable level of packet loss. If measurements can be taken based on existing applications, use those figures, otherwise use a best guess
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Security must be planned. Plan the security requirements for each application or service. Be certain to have a policy stating who can access network services and who can access or update data stored on the computers.
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User profiles will drive design Make a user profile for every type of user on the network. For example, sales, management, support staff, research staff. Divide the users into three to five categories, for example, low, medium and high users, and list a maximum bandwidth requirement for each group. Examine what data and voice applications each work position needs and how often they need to access them.
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Use a map and connect the dots. Identify the location of the users. Start by using building floor plans and identify the location of each user, ideally using movable sticky colored dots. Then, using a map of the city, country or world, identify the number of each type of user in each building, city or country.
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Use a floor plan for each building. If the office building is wired according to the EIA/TIA-568 standard, each floor will have enough outlets to wire applications for most business use. If wiring is not installed, contract or connect the wiring for the users on the floor. See the references for the eHow article on how to install voice and data cables.
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Plan the right size of switch. Size the switching equipment. Count one switch port for each user. For security purposes, plan on identifying the hardware address, or MAC address, of the device that will connect.
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Know and monitor traffic levels. Estimate Traffic Flows. Using a spreadsheet, multiply the maximum bandwidth required by each group times the number of users in that group for each location. With the estimates of how much voice usage is required, use an Erlang calculator to find out how many voice channels will be required between each site. See the resources section for information about Erlang calculators.
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8
Use the right size pipes for each link. Size the Data Links. Using the totals from the spreadsheet, you now know how much bandwidth will be required between each site. You will have to negotiate a Service Level Agreement with your Internet provider at each of the sites to guarantee the required bandwidth between the sites. If you prefer a private network, the bandwidth requirements from the spreadsheet in Step 7 will let you know what speed trunk line will be required.
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Ensure the network is private. Decide on using a site to site Virtual Private Network (VPN) or purchasing leased lines for your network. A VPN uses routers at each location to set up encrypted links between each of the sites. VPNs are usually less expensive than private lines, but we have less control over the quality. Price each of the options and decide which best suits your need.
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Tips & Warnings
Use measured data when available.
A bad guess is better than no guess at all.
Test assumptions whenever possible.
Get to know the users and the applications.
Get Service Level Agreements from providers.
Specify penalty clauses for non-performance.
Avoid disrupting users existing systems.
Avoid vendor proprietary solutions--keep your options open.
Do traffic analysis first. Don't design before the needs are understood.
Beware of vendors' claims. Have vendors prove performance with trials.
References
Resources
- Photo Credit global nodes network image by Michael Brown from Fotolia.com boy work on computer image by .shock from Fotolia.com data security image by dinostock from Fotolia.com computer problems image by kuhar from Fotolia.com compass and map image by Marek Kosmal from Fotolia.com blueprint image by Dmitri MIkitenko from Fotolia.com multimedia connections 2 image by JCVStock from Fotolia.com illustration with personal computer and diagram image by Alexander Potapov from Fotolia.com An assortment of different size and shaped pipes at a power plan image by Andrei Merkulov from Fotolia.com computer security concept - usb cable and padlock isolated image by dinostock from Fotolia.com
