Horizontal cabling
The current horizontal cabling will not suffice for the new network design and hence a different cabling is anticipated. In this case, a larger network is designed and the appropriate cable is fiber. Fiber is most preferred because it has long distance capability and high bandwidth. According to TIA 568, two multimode fibers are preferred. The first one is 62.5/125 (OM1) fiber cable which is suitable until network speeds exceed 1Gb/s. The second one is 50/125 OM2 or OM3 laser optimized cable with a higher bandwidth compatible with all fiber equipment. OM3 50/125 will be used for gigabit networks within the departments while single mode fiber is preferred for longer backbone links such as in this multiple-building campus where high speed connection exceeding OM3 capability is required.
Fiber optic cabling will be installed and not terminated as a future proofing for the future higher speed network. In this case, higher bitrates and future upgrades are inevitable due to increasing enrollment and the requirement for fiber connection is unavoidable. With respect to cost, a centralized fiber network that connects the desktop directly to the computer room without the need for intermediate electronics will be designed.
Using the cost differentiation model, it is found that fiber offers a cost effective solution for horizontal cabling than copper cabling. A cost saving is achieved when fiber network implemented is based on SG SFF connector and the less expensive 100Base-SX technology. A sizeable saving will be realized in the tune of thousands of dollars. Horizontal fiber cable cost is assumed at $0.50/meter for two fibers while vertical cable is averaged at $0.50/fiber/meter for 100 feet two fibers. These are starting point costs and since the fiber network will have a longer useful life than UTP network, it is economical in the long run.
Network devices for access layer
The access layer comprises of the devices that allow workgroups and users to utilize the services provided by the distribution and core layers. A switch, a repeater, database server, workstation, email server, laptop, and a hub are present at this layer.
Network requirement for a distribution layer
At the distribution layer is routers based at the LAN and layer three switches. Other devices include bridges, firewall, and VPN access router. Distribution layer is where routing between subnets and VLANs are conducted in an enterprise. Other than router, other functions such as policy definition, access list, QoS, CPU-intensive routing among others occurs. The core and distribution layer can be collapsed to create a two-tier design as compared a three tier design.
Network devices at the core layer
The core layer is the backbone of the network where consideration for speed and reliable delivery of the packet is undertaken. The devices at the core layer include high-end switches, high-speed cables such as fiber cables, PBX, VoIP, Multiplexer and high-speed enterprise WAN router.
Redundancy in a local area network is designed at the distribution layer. It is at the distribution layer that high availability can be provided by using redundant switches linking to the end user or equal cost paths to the core. Example of a switch that provides redundancy at the distribution layer is dell 5424 gigabit switches.
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References
Koonen, T. V. (2010). Designing in-building optical fiber networks. . National Fiber Optic Engineers Conference (p. JThA46). Optical Society of America.
Szigeti, T. H. ( 2013). End-To-End QoS Network Design: Quality of Service for Rich-Media and Cloud Networks. Pearson Education.
