Ccna

UNIVERSITI KUALA LUMPUR KAMPUS KOTA
MALAYSIAN INSTITUTE OF INFORMATION TECHNOLOGY

Name of Course | LAN Switching |
Course Code | INB23704 |
Lecturer | SHAHIDATUL ARFAH BT BAHARUDIN |
Semester / Year | JULY 2012 (2/2012) |
Due Date | 2/10/12 |

Assessment | ASSIGNMENT 2 |
Weight age | Report - 10% |
Course Outcome to achieve: 1. CLO 3 - Describe small office homeoffice (SOHO) Wireless LAN (WLAN) with wireless security authentication. |
Assessment Components : 1. Report - minimum of 10 pages (excluding cover page & appendix) 2. Teamwork Skills – lecturer’s observation |

Introduction:
Red Enterprise is having trouble with the wireless section of their network. While the wired portion works fine, the wireless traffic is too slow.

TheScenario:
Red network can be divided in 2 sections: wired and wireless. The 2 sections are connected by Cisco 1811 wireless router (R1) which is also used to route packets to/from The Internet (devices located outside Red’s Network). The wireless traffic is being transmitted clear (no encryption used). The topology is shown below:

Step 1 – High Delays and Packet Loss

You get to Red’s officeand connect to their wireless network using your laptop’s wireless card. The association process (between your laptop and Red’s Access Point – R1) takes longer than usual and you decide to run a few tests.
Once your laptop is associated with Red’s Wireless Access Point (Cisco 1811) you issue a few pings from it. Pings issued from your laptop to any address (inside Red’s network or internetaddresses) have high response time and high loss rate.
You suspect the walls are weakening the signal and decide to move closer to the AP. From a closer spot you issue the pings again and although the shorter physical distance, the loss rate and delay are still very high.

Question 1:
Is physical distance relevant when it comes to wireless traffic throughput?

|

Sitting with your laptop justby the AP and still facing high delays and packet loss, you conclude physical distance is not the main problem.
You disable the wireless card installed in your laptop and, using your laptop’s wired card, you connect it to the wired portion of Red’s network. In this situation everything works fine.
In order to have a better understanding of the problem, you need a wireless tool. From your laptopyou run a wireless diagnose tool.

Note: There are a number of free and non-free wireless diagnose tools available on the Internet, designed to different platforms and different type of Operating Systems.
A wireless diagnose tool is able to scan the medium and provide information about the wireless network.
Wireless diagnose tools usually provide information like a list of open APs, their MACaddresses, SSIDs and their channels of operation.
After running a wireless diagnose tool in your laptop you learn that there are 10 other wireless Access Points running in the same building. Because Red Enterprise’s office is located in a commercial building and other companies also have a wireless structure installed, the proximity of their APs allows your laptop to catch their signal too.
Justfor the record, you name the APs you found as AP1 through to 10 and since your wireless diagnose tool gave out the channels of operation of all APs it has found, you compiled the table shown below:

SSID | Channel |
REDs | 11 |
AP1 | 11 |
AP2 | 9 |
AP3 | 11 |
AP4 | 11 |
AP5 | 9 |
AP6 | 1 |
AP7 | 11 |
AP8 | 9 |
AP9 | 11 |
AP10 | 11 |

As you can see on the table above,many APs are using channel 11 to communicate, including Red’s.
Because so many APs are using the same channel in the same physical area, the channel 11 is congested. Although most wireless Access Points are able to scan and select the best channel automatically, others either don’t have this feature or it is disabled.
Because the way wireless access points channels of operation were split...