ccna peiod 6-7 10/26/11

I believe what went wrong in today's activity was that we had a lack of communication. We all assumed separate positions instead of working as an united body we all pursued different tasks. I think if we had some sort of guidance that the end result would be more successful. 

UDP

UDP, or User Datagram Protocol enables computer applications to send messages, or in this case referred to as datagrams. These datagrams can be sent to other hosts on an Internet Protocol network without requiring prior communications to set up special transmission or data paths. UDP is most effective in small servers that have an enormous client population. UDP is cohesive to the Transport Layer due to the fact that it is time sensitive and the UDP ensures no delay when packets are dropped. UDP is a minimal message Transport Layer Protocol, unfortunately UDP offers no guarantee to the upper layers of message delivery or retaining the state of any messages that have been sent. Examples of applications that use UDP include real time multiplayer games, voice over IP as well as streaming media

Transport Layer Problems

Playstation Network Problems
On April 17, 2011 the Playstation Network was hacked exposing the personal account information of 77 million users. This prevented users of the Playstation 3 as well as PSP from online activity. This problem lasted for approximately 23 days. Sony claimed that the playstation users data was compromised long before they were able to detect a breach. Credit Card information is encrypted over the Playstation Network, but other personal details are not and therefore were vulnerable.

The attack on the network was in accordance to the Sony servers being taken offline the previous day, and therefore the Network was susceptible to a hack. George Hotz is the alleged hacker and he was able to do this by enabling himself read and write access as well as having hypervisor level access to the processor. He used a Playstation 2 emulator which had been removed by Sony from the current console. In addition he also created a custom firmware. It requires the OtherOS function of the machine, and consists of a linux kernel model and gaining control of the systems hyperdriver via bus glitching.

Playstation 3 had a feature that would update firmware and delete the OtherOS function but this was absent from the newer, slimmer models. Due to the fact that Linux is foreign to the PS3 network it made it more difficult to resolve and remove the custom firmware. Hotz had run a "homebrew" application on his own PS3 similar to the Iphone jailbreaking technique by reviewing the jailbreak of the Iphone, Sony gained assistance in solving the problem. They also hired various experts to set up firewalls and basically abolish the custom firmware. 

DHCP

DHCP is an acronym for Dynamic Host Configuration Protocol, is a network configuration protocol for hosts on Internet Protocol (IP) networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. DHCP eliminates the manual task by a network administrator. It also provides a central database of devices that are connected to the network and eliminates duplicate resource assignments. Other than IP information the DHCP also provides info on service hosts in general but particularly network boot servers.

Peer-Peer vs Client-Server

The Client-Server model is more centralized, due to the fact that all the clients revolve around one figure. In this case as more clients join the system fewer resources are available. In a client-server model your information gets channeled directly to the source/destination while in a peer-peer it has to go through each figure in the network. Some advantages of peer-peer are that it allows the pc's in the network to pool resources, as well as applications only need to be installed in one of the computers and their is no need for a dedicated server. On the other hand with a client-server model network access speeds are usually faster than those found on peer-to-peer networks, also it’s more secure because if a client wants to communicate with another client he/she has to message to he/she and then it will first sent to the file server, where it is then routed to its destination. But the disadvantages are that network congestion can be created by the amount of users as well as maintenance problems and the fact that if the main server goes down none of the clients will be able to operate. Peer-peer also has some disadvantages like being less secure than client-server networks, especially so because the files have to shared and no password is required.