Key question

most fundamental questionwe can ask about networks is this: ifwe know the shape of a network, what can we learn about the nature and function of the system it describes? In other words, how are the structural features of a network related to the practical issues we care about?

Metrics

Centrality measures - how important a node is in a network. Deg(V) is a centrality measure. Directed graphs have in-degree and out degree.

Hubs - effects

Hubs are vertices with unusually high degree, analsys shows they effect network resilience and transport phenomena.

basic internet structure

Network backbone providers (NBPs) -> ISP -> Users, BGP negotiation protocol, and traceroute used to analyze structure of the internet.

traceroute - router level

studies on the internets structure ignore end users, focus on internal routers. Degree distribution follows the power law

granularity to see structure

subnets, domains, and autonomous systems. Subnet class C where last octet is variable. Class B last two octets variable, Class A three octets...

Autonmouse systems definition

An autonomous system (or AS) is a collection of routers, computers, or other devices, usually under single administrative control, within which data routing is handled independently of the wider Internet. Mostly coincide with domain-level, BGP routing tables only route between ASs

calc geometric length also really interesting pipeline map on 30

An early example of a mathematical result in this area is the formula for estimating the total geometric length of all edges in such a network by observing the number of times they intersect a regular array of straight lines [345]. This formula, whose derivation is related to the well-known “Buffon’s needle” experiment for determining the value of pi, is most often applied to root systems, but there is no reason it could not also be useful in the study of river networks or, with suitable modification, any other type of geographic network.