[p2p-hackers] Keep Alive and network performance

[Matthew Gertner]

Daniel B. wrote:

> Keep alive is both a missing component in practical P2P and a reason  
> why P2P is also hard to make practical.
>
> The trap is that the keep-alive is between two machines. Imagine  
> hundreds of thousands of machines!!!! Even with small signatures  
> matching each machine, we are talking about a flooded network. A  
> secondary trap is managing reliability. Reliability in P2P is not  
> moving bytes back and forth, but also taking into account the machine  
> may be a laptop or other personal computer that has a pathetic uptime.
>
> The better choice is online/offline signaling and optimistic  
> communications with good error control.

I assume that by "optimistic communications" you mean that we should 
assume a connection exists and confirm this using periodic pings? Isn't 
this basically the equivalent of KA? It seems to me that the fundamental 
tradeoff is speed of notification vs. extra network traffic (i.e. you 
know more quickly when someone's network connection is cut if you ping 
more often), and this is the case both for KA and for a custom 
optimistic approach that uses pings. Am I missing something?

Cheers,
Matt