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Analysis of Positive and Negative Features

Positive Features of Desert View LAN

  1. Backbone Speed – The backbone is running at 1Gbps. This should provide plenty of bandwidth for expected growth in the next 7-10 years.
  2. Redundancy of Fiber Cabling – 1 redundant administrative run and 1 redundant curriculum run is provided from the MDF to each IDF in the network, and also between the Maintenance building IDF and the Double Classroom Portable building. If one of the active runs goes down, the network connection can be restored quickly simply by moving a patch cable to another port on the patch panel in the MDF and IDF.
  3. Redundancy of Workstation Outlets – Each curriculum wallplate in each classroom contains 4 active outlets and 1 redundant outlet. Each administrative wallplate contains 1 active outlet and 1 redundant outlet. If one of the active outlets goes down, the redundant outlet can be activated simply by moving a patch cable to another port on the patch panel in the classroom POP.
  4. Use of MTRJ Connectors – These small form-factor fiber connectors are relatively easy to attach compared to ST or SC connectors. They also preserve patch panel space because they only use 1 port rather than the 2 that ST and SC require.
  5. Address Space – With 6 class C networks assigned to each school, the network has enough address space for both the administration and curriculum networks, a management network, and 2 extra networks available for future growth.
  6. Server Fault Tolerance – Both the administrative and the curriculum file servers are RAID 5 enabled, which provides a high level of fault tolerance. In addition, an external tape backup system will help preserve critical data in case of a catastrophic event.
  7. Scalability – By using devices and media which exceed the minimum specifications, much of the existing infrastructure can remain in place during upgrades.
    • Backbone cabling is running at 1Gbps
    • All copper patch cables and horizontal runs are Category 6.
    • The backplanes on the VCC switches range from 6.4Gbps to 13.6Gbps, which should be sufficient even for expected future traffic running at 100Mbps.
    • The LAN switch has an unused module slot which could be used in the future to add fiber ports for more backbone runs, or more ethernet ports for Wing 3 West.
    • The LAN switch has a 64Gbps backplane. Even after each workstation is upgraded to a 100Mbps connection, if 325 workstations (the maximum number of curriculum and administrative workstations expected) and the 6 servers on the network simultaneously sent traffic across the switch, it would only use 33.1Gbps.
  8. Flexibility in Cabling – Use of unloaded modular patch panels allows flexibility in cabling. Fiber and copper ports can be mixed, and new jacks added or removed as needed without having to purchase new patch panels.
  9. Network Manageability – With the exception of the Black Box hubs located in the double portable classrooms, all hubs and switches on the network are manageable and have been assigned IPs on the management network, 192.168.11.0. Two servers, one on each network, will serve as SNMP management stations. The administrative management station will collect and consolidate information from the curriculum management station. The District administrator can then access the administrative management station (via its IP on the Desert View administrative network, since the router will not be configured to route the management network) to collect the data, and can access the management station on either network to perform any management functions required on the hubs and switches.
Negative Features of Desert View LAN

  1. Lack of Free Patch Panel Ports – The network plan places outlets everywhere specified on the site plan, providing for an administrative workstation in each classroom, in the library, and one for each of the school administrators and secretaries, totalling 49. However, if the school wanted to add 26 additional administrative workstations to bring it to the maximum of 75, there may not be enough available patch panel ports in some buildings. Additional patch panels would have to be purchased and installed, and additional copper runs terminated.
  2. Exceeding Capacity of VCC Switches – The network is designed with the intention that most workstations will be laptops that can be moved into classrooms at need, with most likely only 1 or 2 classrooms per building using the laptops at any given time. However, if more than 2 classrooms in Wing 4 West or Wing 5 West, or more than 3 classrooms in Wing 2, Wing 3 East, Wing 4 East, or Wing 5 East are simultaneously attempting to move traffic across the network, this could potentially exceed the capacity of the switch fabric on the curriculum switches in those buildings, resulting in lower bandwidth to each workstation.
  3. Lack of Redundancy in Horizontal Runs – Although there is redundancy in the fiber runs from the MDF to each VCC, and in the runs from each classroom POP to the outlet in each classroom, there is no redundancy in the horizontal runs from the VCC to each classroom POP. The danger of damage to an individual horizontal cable that would not affect all cables is considered minimal, but nevertheless if it were to occur, that network connection would be down until the cable was physically removed and re-run.
  4. Lack of Redundancy to Combo Outlets – Combo outlets containing 3 curriculum outlets and 1 administrative outlet are located in the foyers of Wing 1 and Wing 2 East, in the cafeteria and in the kitchen of Wing 1, in the secretaries' offices in Wing 3 West, and in the P.E. building. No redundant runs were added because it was considered that the 3 existing curriculum runs were already triple redundant, and the likelihood of an administrative user using the combo outlet was extremely low, and therefore did not did not justify the cost or effort of running a redundant run.
  5. IDFs Co-located in Classrooms – Due to the fact that no suitable room could be found to be a wiring closet in their buildings, the IDFs for Wing 2 East, Wing 3 East, and Wing 4 East are co-located in classrooms, and the IDF for Wing 5 East is co-located in the library. While the equipment is locked in cabinets, nevertheless the equipment is less secure than if it had been located in a separate room where physical access and environmental factors such as temperature and humidity could be more tightly controlled.
  6. Lack of Remote Management Capability for Black Box Hubs – The 10 Mbps Black Box hubs being used in the portable classrooms are not manageable via SNMP.