I'm at an APNIC conference in Jakarta, and they demoed a new tool which shows the interconnections (peering + transits) between AS numbers within a given country (will eventually work for regions).
Left-panel is IPv4 and right-panel is IPv6.
Here is the fellow who built it:
For Tor, this tool helps us prioritize the ASs for new relays. To maximize censorship resistance, we would want relays on AS numbers in the middle (lots of interconnections) that do not currently have Tor relays.
We can imagine giving out Roster bonus points depending on the AS-number. The points would go something like:
AS_i_bonus_points = ASweight(i) / #_Tor_relays_on_AS
ASweight(i) = k * \sum_{j=1}^n num_ips_routed_by_edge_i_j
where k is an arbitrary constant (k=1 is reasonable).
This could be very useful for deciding where to put new relays. I'll see if I can access to the raw data that generates these graphs so we have more than just pretty pictures.
Much love,
-V