CST 311 - WEEK 5

This week we delved deeper into learning about the Network Layer. The primary role of the network control plane is to coordinate the local, per router actions so that datagrams are ultimately transferred end-to-end, along paths of routers between source and destination hosts. 

So, again, the primary role of the network layer is to move packets from a sending host to a receiving host. The two important network-layer functions are:

1) Forwarding. When a packet arrives at a router's input link, the router must move the packet to the appropriate output link. 

2)Routing. The network layer must determine the route or path taken by packets as they flow from a sender to a receiver. (The algorithms that calculate these paths are referred to as routing algorithms.)

A key element in every network router is its forwarding table. A router forwards a packet by examining the value of one or more fields in the arriving packet's header, and then using these header values to index into its forwarding table. 

The two photos below show the purpose of forwarding tables: 

I learned a bunch more in this week's textbook readings from the network service model, to learning on what's inside a router, input port processing, and destination-based forwarding, switching, where queueing occurs, packet scheduling, IPv4 and IPv6, and much more. 

Overall, this week went well especially finishing up PA#3 and doing this week's labs and assignments. I look forward to ending the course well and studying hard!

Until next time~