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Monthly Archives: December 2010
Final exam grades available
If you wanted to, you can take a look at your graded exam tomorrow (Wed) in my office; 10-11:30am, and 2-4pm. CSE 589: mean = 136, median = 147, min = 67, max = 172 CSE 489: mean = 93, … Continue reading
Final exam solution posted
There might be a couple of typos in it. Didn’t have time to proof-read thoroughly, let me know if you found any serious ones.
Sample final & solution to assignment 4 posted
You can find them here.
Wikileaks, Comcast vs Level 3
The past week was pretty exciting from a … networking point of view. The Hydra’s (i.e. Wikileaks’) diversification of DNS and hosting resources was fascinating technically. And then, there was the dispute between Comcast and Level 3 which generated lots … Continue reading
Wireless (In)Security
In the beginning (around 1997-1999), 802.11′s security mechanisms include … suppressing the SSID broadcast (called “SSID hiding”), allowing only a white-list of MAC addresses, and WEP. SSID hiding is completely ineffective because the SSID is sent in plaintext anyhow in … Continue reading
Posted in Lectures
Tagged Authentication, Encryption, security, WEP, WLAN, WPA, WPA2
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Mobile Networking
For simplicity, we use mobile networking to refer to the situation where one wants to maintain, say, TCP connections while moving a large distance. If we move only within the same access network then smart switches can handle this limited … Continue reading
Hubs, Bridges, Switches, VLANs
To build large LANs, there are a few hurdles. First, electrical signals get weaker when they travel longer distances. Second, the collision domain of a CSMA/CD type of protocol becomes larger. Repeaters and hubs operate at the physical layer. They … Continue reading
Ethernet basics
Ethernet is one of the most successful pieces of technologies out there. It is inexpensive, and it was able to keep up with the speed race: 10Mbps, 100Mbps, 1Gbps, and 10Gbps, 100Gbps. Metcalfe designed the Ethernet protocol based on his … Continue reading
Multiple Access Control
On a single broadcast channel (wireless channel, shared link, etc.), two or more simultaneous transmissions lead to interference. We thus need a distributed algorithm coordinating accesses to the channel. This distributed algorithm is realized by a multiple access control (MAC) … Continue reading
