1. AW01 Introduction to WANs Case Study

2. Objective Identify the appropriate WAN technology given specific requirements

3. Scenario Yoko Inc. just opened a branch office in Chicago and needs to connect it to the Main office (located in New York City). They have called you for help. Yoko’s network ◦ Each office has a router, NYC at the Main office and CHG at the Branch office. ◦ Branch traffic headed to the Internet must pass through Main (NYC), which has a connection to the Internet.

4. Choosing the type of WAN Link Since NYC and CHG are far apart, it is not possible to run cables to interconnect them. To use 802.11x wireless is also not possible because of the range. A WAN link is necessary.

5. Requirements 1. Yoko Inc. is a financial company. Therefore, the 2 offices require an always-on connection. Stock information and rates must be available 24 hrs per day. 2. The amount of traffic will also be high, which requires high bandwidth. 3. The information travelling through the link is very sensitive. Security is a big concern. For this reason, Yoko Inc. prefers a private infrastructure. 4. Only 2 sites need to be connected: New York and Chicago. 5. Yoko Inc. is prepared to pay for all the requirements. Money is not an issue.

6. Your Suggested Solution Based on item (3) listed above and on cost/benefit, you chose not to use any Cable or DSL WAN links and aim for the private WAN options. Items (1) and (4) lead to a dedicated leased line and since a reasonable bandwidth is also required – as stated in item (2) – you decide to go for a private leased T1 line WAN link. The only possible disadvantage would be the higher cost but according to item (5) this is not an issue for Yoko Inc. who is prepared to pay the high monthly fees for this type of link. You contact a few ISPs to get quotes. All ISPs offer similar services with different prices. You hire ISP3 because they offer the lowest price (about $800/month). Some of the considered ISPs also had other flaws: ◦ ISP1’s prices are too high, ISP2 does not offer dedicated T1 links, and ISP4 doesn’t support the Chicago area.

7. Questions What are the most common WAN links known as public WAN? What were the biggest flaw disadvantages of such WAN links in the past?