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lec3
Connecting Networks
Instead of having every network to every other network, we have global ISP's which connect and close the gaps between varying networks. On top of this there are IXP's(internet exchange point) where each of these global ISP's connect to each other. Sometimes links from one Global ISP to another may be referred to as a perring link.
Delay, loss Throughput
Delay
For delay there are 4 main sources of delay: processing delay, queueing delay, transmission delay, propagation delay. All of this combined results in the nodal processing delay.
Loss
Loss of packets in the network isn't something we should ever be surprised about since it happens all the time. This is especially true when you have one node with too much traffic being pushed onto it. Typically we have some methods of telling the sender that some sent packet was dropped. These packets are usually tiny enough where they shouldn't get dropped but then if those get dropped we can keep stacking the dropped information along the network.
Throughput
Rate at which bits are exchanged from sender to receiver. It's not uncommon to have to links connected which have different throughput rates which means in these scenarios we have a bottleneck link.
Layering Network Protocols
Application Layer
Software that usually manipulates data the most on a particular machine.
FTP, SMTP, HTTP
Transport
Protocols here setup for what kind of data we have and essentially package the data to be ready to be sent.
TCP UDP
Network
Here we are actually sending things around from machine ot machine along some physical network, be it wirelessly or in a wired fashion.
IP routing protocols
Link
Data transfer bewtween machines in a physical network.
Ethernet, 802.11x
Physical
Wires yo