Why are there so many invalid sources in Gnutella? At LEAST 50% of my download requests end in "Awaiting Sources". Of those, probably half are sources that are no longer on-line, while the other half are sources that I see "Waiting 60s for Busy" a handful of times before it dies and goes to Awaiting. Sometimes, I can Force Resume on these files and get back into Waiting mode.

Some specific questions:

1. What can be done to remove invalid sources from the Ultrapeers? Are there certain clients/versions that are particularly guilty of not clearing their disconnected leafs from their source-list?

2. What can be done to reduce premature 'failure' to Awaiting Sources? Does LW fail if just one PING is ignored, or does it pause/retry several times before assuming the source is now off-line?

Some suggestions:

- do a test PING on all source-IPs received and then remove them from the search results if they're off-line. This would delay the display of results, and would contribute to overall Internet traffic (but not Gnutella search-traffic), but would eliminate the first type of Awaiting Source messages.

- change "Awaiting Sources" message to "2 Sources off-line, retrying in 60min". This would give more explanation and would demonstrate to people that LW hasn't just given-up.