Designing a LAN

Real Estate Office

Margaret Satsuma is the owner manager of the Satsuma Real Estate Agency. It employs a number of people as administrative staff and real estate agents.

The staff is as follows.

Manager = Margaret
Administrative Assistant = Barry
Accounts Manager = George
Sales/Rentals Manager = Fatima
Reception/Secretarial = Yim, Bradley, Anne, Samantha
Real Estate Agents = Bob, Carol, Ted, Alice
Data Entry/Basic Accounting = Harry, Joan, Yentl

The office deals with private and commercial property sales and rentals.
Margaret has decided that she would like to increase productivity although she is not too sure how to go about it. Essentially what she wants to do is to increase her sales and/or lower her costs.
Currently the office runs using the following equipment in the various information systems.

Margaret doesn’t have a computer on her desk. If she wishes to send a letter she calls in Barry to take shorthand or else writes it on paper and passes it to Barry for typing. Barry has a Pentium IV 1.2 GHz computer running Windows 98 and Office 97 software. He has a laser printer.

The accounts section uses a manual system with a debits and credits book, bank reconciliations book, and individual invoice records for clients. George used a calculator to work out the sums at the end of the month. Harry Joan and Yentl would send out accounts to clients, calculate the amount owing for each client and help enter the figures in the accounts books. Data needs to be entered on more than one ledger (for example the main accounts ledger and individual client records as well as documents tracking real estate agent sales for the calculation of bonuses etc. George also handles the pay for the staff, including taxes and levies such as income tax, payroll tax, superannuation and so on. He does this in the accounts books. Staff are paid fortnightly by cheque. Records are kept in filing cabinets. Staff pays take up to one week to process.

The Sales Rental Manager has a 1.5 GHz Pentium computer running Windows 98 and Office 97. The secretaries share the use of two 2.2 GHz computers with Windows 98 and Office 97. Each computer has an Access database of properties. Sales contracts are also typed up on these computers. A 128M USB FLASH RAM disk is used to back up the database each day.
The Estate Agents have laptop computers each with Windows 98 and Office 97. They have the same Access database as the office staff. They are able to show prospective clients, properties for sale on their laptops. Each day a USB FLASH RAM disk is passed around so they can update their property database, but sometimes an agent will show a client a property which has already been sold by another agent, causing some embarrassment.

Margaret feels that the current system is inefficient and would like to increase the efficiency and effectiveness of the organisation.

You are a systems analyst who has been asked by Margaret to advise her on how to most successfully change her current information systems to improve productivity.

Suggest a network design that would suit Margaret's needs. Include suggestions on: network topology, transmission media (e.g. cables, wireless), device speeds, hardware and software requirements, including recommended operating systems.

Decision 1: P2P or Client-Server?

Do they need a Peer-to-Peer (P2P) or Client-Server network? This decision is affected by a few factors.

1. How many computers will it support? In this case, about 13 (after getting new PCs for Margaret, George, accounts and reception). This is getting rather too large for a P2P setup.

2. Are the users trustworthy? In this case, probably yes. At least their untrustworthiness is not referred to in the case study.

3. How much money do they have to spend? As soon as you decide on Client-Server, you need to buy a server (a cheap one would be about $2500) and a network operating system. The case study does not indicate a budget, but it does say the boss wants to improve profits.

4. How much technical knowledge do they have? Maintaining a network takes skill. In this case, they don't seem to too bright when it comes to IT.

Microsoft Gives 8 Reasons You Need A Server

Mainly considering the potential size of the LAN, I'd opt for Client-Server.

This raises the next decision...

Decision 2: Which Network Operating System?

If you decide to have a server, you'll need a NOS. At least there are not many contenders you have to choose from. It's really a choice between Microsoft Server and Novell Netware.

Factors:

1. How easy it it to get technical support? There are more qualified MS Server technicians around than there are Certified Novell Engineers (CNE)

2. Emma Chizzit? A NOS is not cheap.

3. Which is better? While MS Server is cheaper to start with, it requires extra fiddling with compared to Netware which largely takes care of itself. Novell is harder for a non-tech person to install. Netware lasts longer (e.g. 11 year-old Netware 4 networks still run happily, so its higher initial costs fade away over a longer life. MS needs replacing every 5 years. Netware does not handle internet quite as well as MS, but it runs all the software MS can: more, in fact (like supporting DOS workstations.)

Alas, while Novell was once THE network operating system for many years, it has declined badly because of bad pricing, steep learning curve, poor competition and lack of innovation in response to Microsoft's offerings. It still exists, but is a shadow of what it was. Mind you, there are still many Netware 2 and 3.11 networks still happily chugging away out there nearly 20 years after they were installed!

Most reasonable people (!) believe Netware is superior in most respects to MS, especially when it comes to features and ease of maintenance. But keep in mind that Netware supporters tend to be as passionate as Collingwood supporters.

So - bottom line decision for today? While my heart is with Novell, I'd have to choose MS Server 2003 for the real estate agency. Sigh. :-(

Decision 3 - What sort of server should they have?

Powerful servers get really expensive really quickly. A good one can be $10,000 or more. (See why here). A smallish LAN like Satsuma's probably would not need RAID or redundant power supplies etc, so they might get away with a cheapish server with a gigabit NIC, perhaps 2 x 80G SATA HDDs, 2G or more of RAM (servers love RAM!), and probably a modest DAT tape drive. Cost - about $3000.

Decision 4 - Choice of Topology

Never choose bus nowadays - you can't get NICs with BNC (coaxial) connectors. It's also prone to congestion and cable break. Always go for star or tree. This LAN is small enough to be a simple star with about 13 nodes. They'd need UTP cable, probably CAT5e or CAT6.

Decision 5 - Speeds

For a simple network like this, workstations with inbuilt NICs of 10Mbps would do just fine... no use spending money on faster NICs to replace the ones you already have. But, if you had to buy NICs, get 10/100 for workstations. When the price of gigabit NICs gets down to the same as 10/100, you'd opt for gigabit.

Always get gigabit NICs for servers. You need maximum bandwidth at the heart of the network.

Remember: if you have existing equipment, consider whether it will perform adequately in the new or changed system. If it will hamstring or degrade the new system, replace it. If it will cope, keep it.

SIDEBAR: Re-using existing equipment in a new or changed system, and designing with this in mind, is the core of bottom-up design strategy. If you ignore all existing equipment and design from scratch starting with the "big picture" and only getting to details at the end of the process, that is top-down design.

Decision 6 - New computers?

The computers they have are not exactly state of the art, but they will suffice for what they use them for. They could be given extra RAM if the need arose, but there seems to be no need to replace them. They should buy Margaret a computer of her own (making sure it's compatible with their existing hardware and software), the accounting department needs a couple of more PCs and the receptionists need an extra PC too so they don't have to share it and work inefficiently.

Their current OS (Win 98) will probably manage, but might warrant updating to Win XP. This, however, could well require RAM upgrades to help them cope with the greater system demands of the newer OS. They could perhaps do a pilot installation of Win XP on one PC and see how it copes.

The agents' laptops may or may not have wireless NICs and antennae already in them if they are relatively new. If not, they would need to purchase a PC Card slot wireless NIC for each laptop.

Decision 7 - Internet

It would be silly to network the organisation and not get the benefits of internet access. Giving them access to email, the web and perhaps their own website would be great bonuses for their efficiency and effectiveness. See here for a page discussing the options for internet access. Dialup would be slow and awkward, requiring a second phone line and frequent connections and disconnections. A cheap ADSL plan (if available where they are) would be fast, always-on, and would not interfere with their phone line. Cable, if available, would be even faster than ADSL, but perhaps a little more expensive. I'd probably opt for a 128 or 256Kpbs ADSL plan for them, using a combination ADSL modem/router/switch/print server/USB hub.

Putting it together

When you sketch your LAN, remember to make it detailed. Do not endlessly repeat yourself (e.g. drawing 24 PCs with tiny keyboards and their NICs all labelled the same way, draw a few rough PCs with a note indicating how many there are, and what features they all share. If one deviates from the others, put in a blanket statement covering the majority and add a note explaining how the odd one out is different (e.g. "All NICS will be 10/100 except the server which is gigabit"). All important defining features should be labelled, particularly:

• topology name (though its drawn shape will make it clear, it's wise to show you know what it's called)
• cable types
• component speeds
• vital software (e.g. NOS, workstation OS)
• key features of equipment

If in doubt, put it in the picture! Remember, the picture should be a logical description of the LAN, not a work of art. Do not spend an hour with your Mathomat drawing perfectly-scaled PCs and keyboards and drawing all 24 ports in your switch!

Finally - the printer

How to share a printer used to be difficult to decide.

Option 1 was to plug the printer into any of the workstations and it would run File and Printer Sharing in Windows. That software would handle the printer sharing. The problem was that the computer that was hosting the printer had to be left turned on if anyone was going to print.

Some home routers have a built-in printer server and USB port into which a normal printer could be plugged. The print server circuitry in the router box handled the incoming print jobs. Only the computer sending the print job had to be turned on. The drawback is that not many routers have the inbuilt printer server.

The third alternative was to buy a networked printer: it has a NIC built into it and will plug in to the switch like any other computer does. The drawback was these printers were usually heavy-duty and expensive: the NIC option alone could cost $300-$400! Not good for a little organisation. I always advised against this option for small networks.

Now (2007), however, networked printers are on the market for only a few hundred dollars and are worth considering as an option.