Upcoming Changes to Overlay Survey

[Brett Boston]

Hi,

As part of the v21.1 release, the SDF stellar-core team is updating the overlay survey to include some additional information. The overlay survey, which we first introduced in v12.3, allows a validator to request connection information from other nodes on the network. For a complete overview of the overlay survey, please see the Overlay Topology Survey section of the admin guide. In the v21.1 release, SDF is adding the following new information to survey responses:

• How well the node is keeping up with the network.

• How well other nodes are keeping up with the network.

• The number of times the surveyed node has lost sync with the network.

• Whether or not the surveyed node is a validator.

• The average latency between the surveyed node and all of its peers, recorded per-peer.

In addition, the surveyed data will only cover a specific window of time (maximum 30 minutes), rather than including data spanning the entire uptime of the node.

This new functionality enables the collection of information vital for understanding network health and will help to better inform future changes to the overlay that aim to improve its scalability.

As before, by default a node will only respond to survey requests from other nodes in its transitive quorum.  You can override this behavior by setting the SURVEYOR_KEYS variable in the config file to a list of nodes you’d like your node to respond to survey requests from. To opt out entirely, set SURVEYOR_KEYS to include only $self or a bogus key.

Best,

Brett Boston

SDF stellar-core engineer