• Current needs
• Immediate future needs
• Strategic needs (that is, long term, eg three to five years, out to seven to ten years)

2. COSTS

• Cable - from 10s of cents to a few $ per metre.
• Connectors - between cables (cents to a few $), patch panels (10s to 100s of $), housing frames and cabinets (10s to 100s of $)
• Labour - the greatest cost component (10s of $/hr). There are economies of scale: the installer does not spend double the time to install two cables from point A to B as they spend to install one cable from point A to B. eg a double point $200, a single point $140.

3. PLANNING

• Wherever a single connection point exists today, is it prudent to provide a double point?
• Wherever a computer connection point is needed, is it prudent to allow for a phone connection point?

4. EXPANDABILITY AND FLEXIBILITY

• An Ethernet LAN network, using a 10BaseT architecture that can run at up to 100 megahertz (Mhz) speed, in a star topology (a star pattern layout of the cables each computer has its own cable, coming from a central point). This system typically uses Cat 5 cable. This upper limit of 100Mhz is far above current needs, but current needs are regularly surpassed as the technology progresses (a 1[omega] - 2 year lifecycle).
• Category 5 (Cat 5 in slang) cable, comprising Unshielded Twisted Pair (UTP) of four pairs (eight wires). Telephone systems Telstra (1 pair) or PABXs such as the Telstra Commander system (3 pair) use UTP cable. Cat 5 cable may be used for telephone lines as well as computer lines (legally used if installed by an Austel-approved installer).
  • By installing more-than-expected cabling, expandability and flexibility are covered cost-effectively:
  • ß Where one connection point is used now, often a second point is needed later.
  • ß Where a computer connection is needed, often a phone connection is also required.
  • ß Where a computer or phone connection is needed or envisioned, extra connection points than originally envisioned are often shortly later found to be needed or desired (scenario I wish we put in that extra connection point when we were upgrading).

5. FUTURE OPTIONS AND DEVELOPMENTS

• If we are upgrading because capacity is full (using n), double what we use now (2n).
• To allow for unseen technology developments, expandability and flexibility, double the expected figure within need and cost common-sense (4n), especially if the organisation is uncertain of its future situation re expansion. Eg 8 connections now, need 13 now, so double 8 to 16. For a stable situation, stay at 16. For a dynamic situation, somewhere between 16 (3n) and 32 (4n) connections as 3-year allowance for both computer and phone usage, for (a) growth (b) flexibility.

Disclaimer

Mark Dowling, Program Officer, Information Management/Information Technology Program