I main­tain an OpenPGP key server in a pub­lic server pool and reg­u­larly re­ceive peer­ing re­quests from other server op­er­a­tors. To help me bet­ter un­der­stand the net­work and make more in­formed de­ci­sions about which re­quests to re­spond to, I’ve com­piled a net­work graph us­ing the mon­i­tor­ing data col­lected by Kristian Fiskerstrand.

A pre­lim­i­nary look at its de­gree dis­tri­b­u­tion re­veals that most servers are well con­nected, and sev­eral are very much so:

Degree distribution of SKS key server network

While this is good news re­gard­ing the health of the pool, it does pose a chal­lenge to ef­forts at vi­su­al­iza­tion; the graph is a hair­ball. In that light, I’ve taken con­sid­er­able artis­tic li­cense to make the net­work’s fea­tures more dis­tin­guish­able:

Hover over a node to clar­ify its con­nec­tions.

The size of a node de­notes its close­ness cen­tral­ity, a rough pre­dic­tor of how quickly data might be able to prop­a­gate from that server to the rest of the net­work.

Color is de­ter­mined by a server’s pri­or­i­ties in the three re­gional pools, Europe (EU), North America (NA), and Oceania (OC):

From this graph I can see that my server is rel­a­tively well bal­anced across re­gions and has a high pri­or­ity, but has few con­nec­tions com­pared to other servers.

I’d hoped that it would be more vi­su­ally ap­par­ent which new con­nec­tions I should make to strengthen the net­work, but the graph has turned out to be too com­plex for me to fol­low by eye.

I’ll have to take a more an­a­lyt­i­cal ap­proach—to be con­tin­ued.