How this works
The internet is not one network but tens of thousands of autonomous systems wired to each other. This graph draws one ASN's BGP relationships: who it buys bandwidth from, who it exchanges traffic with as an equal, and who buys access from it.
The relationships between AS networks determine how traffic flows, and say a lot about a network's quality and stability:
An ASN's position in the topology affects how its addresses behave. A small ASN hanging off a single upstream with no peering is typically a reseller or a short-term rented facility, and blocks like these get flagged wholesale more often.
Conversely, a carrier-scale ASN with extensive peering carries large volumes of genuine user traffic, so its residential ranges are far less likely to be misclassified.
Tier 1 refers to the handful of operators that reach the entire internet without buying transit from anyone, purely through peering. There are only a dozen or so worldwide. The number of hops from an ASN to a Tier 1 is a rough indicator of where it sits in the hierarchy.
From public BGP routing data. Routing relationships do not change often in practice, barring acquisitions, an upstream switch, or a policy change.
A small ASN genuinely has one or two upstreams and no peering — the sparse graph is an accurate picture. Enterprise-owned ASNs and small hosting resellers usually look like this.
More upstreams mean redundancy, which is good for availability when a link fails. It does not directly translate to cleaner addresses — that depends far more on how the network uses and allocates them.