I'm getting the impression that you are looking to have computers cache their connections list and then send them instead of passing along pongs...

Clip2 also has something called a reflector... A reflector acts as a super node which passes info along to computers below it... the only problem is that you would always need some central computers that would have higher TTL's inorder for someone out there to have any sort of cache...

What really should be done is query caching that would reduce the network traffic alot... limewire has a proposal on their site about this... I don't think that caching IP's would help because then you would be sending larger pongs less frequently instead of smaller pongs more frequently... and the you'd only be saving some of the header info for bandwidth...

As for standard I think most clients come with them set TTL = 7, some like Limewire have the nice option of keeping others below a certain TTL... so you don't get outragoeus TTL's from some people...

In regards to the connections vs. TTL basically TTLs give you exponential growth on the network and connections are more or less linear... a quick example...

Connection = 5
TTL = 4

Assuming every node has the same settings you would see 5^4 nodes or 625 nodes...

Increase the connection to 6

Connection = 6
TTL = 4

Once again assume all nodes on the network have the same settings this would give you 6^4 or 1296 nodes

now instead increase the TTL to 5 and keep the connections the same

Connection = 5
TTL = 5

Assuming all nodes have the same config... now you see 3125 nodes... increasing the TTL gives you far more of a horizon...

from the example... Connection = 255 and TTL = 1 would give you only 255 people to search from.... a TTL = 51 and 5 connections would give you 4.4 * 10^35 connections... that's more connection than are possible on the current network...

the graph dictates which clients can accept new incoming connections... ie: if you have a Gnucleus it gives you a min and a max connection numbers... the min is how many people Gnucleus will proactively connect to... the max is how many open connections you will accept at one time... so lets say you set min = 5 and max = 7... gnucleus will connect it self to 5 people... then after those are set up it will accept 2 more... once those are full gnucleus stops accepting incoming connections... and then the person running the program drops off the "accepts incoming connections" graph... so really it's not a count of how many people have incoming connections its a count of how many people will accept "new" incoming connections... some other people in the other portion of the graph may have only incoming... after about 1/2 hour most of my connections are incoming anyways...