What is the most typical implementation of the hierarchical star? Specifically, where are the horizontal cross-connection and workgroup switches typically placed?
To reduce the cost of a hierarchical star, the network designer has the option to locate network elements closer to equipment outlets. What is this called and what are the benefits?
In certain situations it makes sense to install all network equipment in a central location. What is this implementation of the hierarchical star topology called and what are the pros and cons?
Solution
The typical implementation of the hierarchical star topology involves placing the horizontal cross-connection and work group switches in a telecommunications room(s) on each floor of a building. This allows equipment to be located in a room separate from the equipment outlets. Typically, the utilization of switch ports is low and can lead to higher costs compared to other implementations of the hierarchical star.
Placing horizontal cross-connections and work group switches closer to equipment outlets is called FTTE (fiber-to-the-telecommunications enclosure). The benefits include savings of 25 percent or more through better port utilization and lower building costs of telecommunications rooms.
This is called centralized cabling, or FTTD (fiber-to-the-desk). On one hand this provides the greatest port utilization and reduces the size and load of telecommunications rooms. On the other hand it can be more expensive since it requires the use of media converters or optical NICs near the equipment outlets to convert from optical to electrical. For examples of situations where cost savings were obtained, visit TIA's Fiber Optics LAN Section:
