CSUMB Learning Journal (Chris - Group 1)

 This is the final week for this course, next week we'll be starting the next one which is Internet Programming. In this course we learned a lot about network, specifically the different layers of networking such as the application layer, the link layer, and the physical layer. Included in these topic was Ethernet, how devices such as routers and network switches work, the contents of different protocols (such as UDP and TCP) and others. Overall in this course the primary topic that was of interest to me was covering how security is handled in the internet. We use the internet for viewing webpages, transferring data, and communicating with others every day -- but how is our data protected and how is it guaranteed to be delivered to our target host without any alterations. This is accomplished through a variety of methods across multiple network layers such as the application layer for error correction. Security can be accomplished through the use of protocols such as TLS that use k...

 This week focused on the link layer of networking which includes ideas such as network switches, MAC addresses and Ethernet. Modern network switches allow for multiple devices to be hardwired in the same subnet -- normally through a connection such as ethernet. Ethernet is a popular LAN connection that commonly operates through cables containing 4 sets of 2 coiled wires. Ethernet has it's own data packet standard referred to as an ethernet frame. It contains the preamble, destination and source addresses, the payload, a type field, and the CRC (cyclic redundancy check). Ethernet is connectionless and is generally unreliable because the receiving NIC doesn't send any acks or nacks to the sending NIC. All of the normal redundancy must be handled at the application layer. Another topic covered was the idea of access protocols on a network, basically how systems decide when to send data with the intent of minimizing collisions -- which generally make data unusable. Some examples a...

 This week covered topics of the network control plane which heavily deals with how routing tables are managed such as either through per-router methods or logically centralized methods. Along side this we covered some of the forwarding table creation algorithms which included Dijkstra's algorithm and the distance-vector algorithm. Dijkstra's algorithm was super easy to understand due to its generally straight forward workings, but distance-vector algorithm is still a big foggy to me. We also touched on autonomous systems and the way that routers can communicate between them. Some of these protocols that involve it are still a bit vague to me but throughout further coverage on them they will probably make more sense. We also touched on the idea of a traceroute such as the command for it built into windows. A traceroute is similar to a simple ping where it returns the round-trip delay from a host to a target system, but it also keeps track of all of the hops the packet had to ta...