Data Communications HW 4: LAN, ATM vs Ethernet

Sunday, February 8, 2009

I have decided to post my homework for publishing online. I write about 6 pages of homework per week and I find it educational so here is homework 4 for my data communications class:

Develop a cost-effective cable plan for a scientific R&D organization. Criteria:
• Five-story building
• 1st floor: lobby and administrative offices
• 2nd and 3rd floor: labs for heavy equipment requiring high bandwidth.
• 4th floor – offices for lab personal
• 5th floor – executive offices
In developing the cable plan for the new five-story building I will use a structured cabling system. Each floor will have a fiber optic switch, which will connect all of the floors together with the quickest media available. This is the backbone LAN of the building. We will not have two switches in each floor for redundancy to keep the price low and as research shows these fiber switches do not malfunction often. Instead we will keep only one spare fiber switch in the lab with all the backup configurations for the others. If one switch goes bad, we simply load the configuration on the spare fiber switch and install it on the floor.
The fiber switch on each floor will connect with a Cat5e/Cat6 switch. Depending on the floor this switch will be different. We will be using managed Cisco switches for security and manageability for VLANs and access lists in the future. The 1st, 4th, and 5th floor will have 10/100mb switches as those workstations and laptops do not require such fast connections. The 2nd and 3rd floor will have gigabit Cisco switches for the extra speed requirements for the equipment and future needs.
These switches will connect to a patch panel in a centralized location on each floor. Cables will then be ran from the patch panel to each room and labeled accordingly. The user will simply need to connect to the wall connection. Each room will have 2 network connections an A and a B. A connections will go to the A patch panel and connect to the A switches, while B connects to the B patch panel and connects to the B switches. This is for redundancy and future expansion opportunities into VoIP.
Furthermore the 1st and 5th floor will have wireless access points in the executive and administrative offices. This media will be available for our executives who have wireless devices such as laptops and smart phones. This will allow the user to walk to other offices and have connectivity always available.
Just because the solution needs to be cost-effective does not mean that we will forfeit usability for pricing. Cost reduction is seen with only have one fiber switch in each floor instead of 2 for redundancy. The 1st, 4th, and 5th floor will save on costs by only having up to 100mbps switches instead of gigabit. Money is also saved by only deploying wireless to the 1st and 5th floors.

Develop and overview of Network Virginia paying particular attention to networking strategy in reference to LAN Support.
Network Virginia is an outreach program initiated by Virginia Tech to develop universal access of digital communication services for all of Virginia. The project has been in service since 1996 and currently serves and estimated 1.3 million people. The main contractors for the network are Verizon and Sprint. The legacy backbone is still operational with three ATM switches located around the state to provide interconnection points. Recently, Sprint deployed a newer high-speed backbone gateway at OC12 capacity for Internet access. Sprint also has a backbone to the National LambdaRail and Internet2 gigaPOP facility in Virginia Tech.
This concept of providing a centralized universal access to an entire region has many advantages as some disadvantages. Some of the advantages and benefits according to are:
* Universal access with level prices statewide.
• Capability to support interactive, multimedia applications.
• Range of access options with very high capacity available.
• Capability to support very high performance computing applications with guaranteed quality of service objectives.
• Scales to match increasing demands.
• Advanced digital communications services at reasonable cost.
• Inherent Internet access.
• Founded upon public network services owned and operated by the communications industry:
o Lever for economic development
o Promotes competition
o Ubiquitous availability of advanced digital services to serve all sectors
I had never heard of this networking strategy before but think it is fascinating. The advantages outweigh the disadvantages by far. A disadvantage I saw right away is that the backbone network is provided by Verizon and/or Sprint. This does not give you many choices especially if you are moving to a datacenter. However if the fastest and most reliable backbones are those then you might not want anything else. Another issue that I can identify is security as essentially the entire project is a huge WAN.
I would be interested in seeing a project like this for Florida or the entire United States. I know other regions outside the USA like the United Kingdom and Korea have extensive WAN’s as their networking strategy. I am sure users would surely enjoy the must faster broadband speeds that are currently being offered in our regions.

ATM vs. Gigabit Ethernet - Compare two technologies and formulate a position paper outlining a potential scenario for each technology might constitute the optimal solution.
ATM is currently the biggest competitor to Gigabit Ethernet. Like most technology decisions there is not right or wrong answer for choosing one over the other, everything depends on your scenario.
Gigabit Ethernet
Gigabit Ethernet is the obvious solution for upgrading and existing network infrastructure. It has the power to deliver lots of bandwidth to any current device with an Ethernet network card. Upgrading would require changing the NIC card but most new laptops, and servers come with gigabit capabilities. Also 10/100-Mbps NIC’s can be plugged into gigabit switches and work fine, just at a slower speed. Gigabit Ethernet is much cheaper than ATM so if a company is upgrading from 10/100-Mbps and wants to go to gigabit speeds upgrading to Gigabit Ethernet is the correct solution.
Some disadvantages of Gigabit Ethernet to be considered is that it is an upgrade to Ethernet which was never truly designed for anything other than data. Furthermore, Ethernet cannot prioritize traffic for good Quality of Service or Class of Service. So if voice and video is a huge concern for the network, Gigabit Ethernet might need to be reconsidered.
If you are asked to design a new network from the ground up and the main requirements are a single network to integrate telephony, data, voice, and video, ATM might be the correct choice. ATM can accommodate different bit rates and allows support for real-time traffic for excellent Quality of Service and Quality of Class connections. Therefore VoIP traffic will be flawless as well as Video Teleconferencing, data, and any other transmission required.
ATM does have its drawbacks, as it is more expensive than Gigabit Ethernet. Another issue, which won’t be faced if it is a new network, would be that ATM is connection-oriented. If you are integrating with a current Ethernet LAN you will experience issues.
If you are creating a new network from the group up and need all types of traffic to work nicely on a quick network then ATM is the correct choice. If you are upgrading a current Ethernet network to faster speeds and video and voice are not requirements then upgrading to Gigabit Ethernet is the answer. As stated previously and like most technological decisions, the true answer of which is better between ATM and Gigabit Ethernet needs to be analyzed in each specific scenario.


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Placing 2 jacks per room may not be needed. Many VoIP phones, specifically Cisco, have a 10/100 Ethernet switch port on the back of the handset.

Also, ATM vs. Ethernet. You have to consider devices that wont work properly with it. (e.g. printers)

February 9, 2009 at 8:23 AM