Nodes should reconnect to peers once they are online

[weiihann]

Given the following scenario:

• Node A is a feeder node.
• Node B is a regular P2P node.
• Node A is online first. Node B syncs successfully from Node A.
• Node A goes offline. Node B no longer syncs from Node A.
• Node A goes online again. Node B should automatically detects that Node A is online again, and attempts to resync from it.

However, that's not the case currently as Node B wasn't able to detect that Node A is online.

Not sure where the root cause is, but have some ideas for solution:

1. Persists the peer information somewhere and loads it whenever the node is started. In this way, Node A could notify Node B that it is online.
2. Regularly ping peers if they are online.

[IronGauntlets]

LIbp2p automatically detects when an old nodes come back online but it does take some time. This is probably due to how often the DHT table is refreshed. I would recommend to wait a little while longer.

[CodeMongerrr]

I want to try this one out, with the first way.