27/WAKU2-PEERS: Peer selection recommendations

[jm-clius]

Currently 27/WAKU2-PEERS recommends a minimal method for peer storage and management in Waku v2, including keeping track of the libp2p protocols supported by each peer.

It does not, however, recommend a way to select a suitable peer for a given protocol. As it stands there could be multiple connected peers supporting the same protocol. A node wishing to select a specific peer for, say, store protocol could do so:

1. at random
2. by selecting the first available peer from the peer store, or
3. by applying some ranking mechanism to select the best store peer. Currently most client implementations follow (2).

The spec should make clear the different options and recommend a way to perform peer selection, preferably based on a reasonable ranking mechanism.

Ties in with https://github.com/vacp2p/research/issues/89

cc @richard-ramos

[oskarth]

While this is useful, is this something we need to specify now? As opposed to something that grows out empirical usage and experience.

[jimstir]

Issue moved here.