Frequently Asked Questions

How are packet-ins handled when a message is generated through table-miss flow entry?

Faucet adds explicit rules for unmatched packets.

Are group actions supported in Faucet?

Yes, just not by default currently. Set the group_table option to True on a datapath to enable group output actions.

Does Faucet send any multi-part requests? If so, please provide sample use cases

Gauge uses multi-part messages for the stats collection (flow table stats and port stats).

Does Faucet install table-miss entry?


Does Faucet clear all all switch table entries on connection?

Faucet gives all entries a specific cookie, and it clears all entries with that cookie. I.e., it clears entries added by itself but not anyone else.

Does Faucet install fresh set of table entries on connection and re-connection?


Does Faucet installed flows support priority? How is this defined - who get higher priority than the other and why?

Yes, priority is necessary for a number of things. Example: there are higher priority rules for packets with a known source address, and lower ones to send those packets to the controller.

Is there a gui for generating a YAML file?


Should Faucet detect Management, OF controller ports and gateway ports on the switch or pure OF only ports where hosts are connected?

Out of scope for Faucet as it is currently.

If another controller is connected to the switch in addition to Faucet, what happens to Faucet?

Faucet identifies its own flows using a cookie value, if the other controller doesn’t use the same cookie value there shouldn’t be a problem (provided the rules don’t conflict in a problematic way)

If another controller connected to switch changes role (master, slave, equal) on the switch, what happens to Faucet?

Shouldn’t be an issue, if another controller is the master then my understanding is Faucet wouldnt be able to install any flows however?

Does Faucet send LLDP packets?


Some switches always send VLAN info in packet_in messages and some don’t. How does Faucet handle this?

Packets should have VLANs pushed before being sent to the controller.

Is there a event handler registered to detect if flows on the switch change?


Does Faucet use auxiliary connections?


Does Faucet support L2.5 (MPLS, etc.)?


Stats - what does Faucet collect (flow count, etc)?

Gauge collects port stats and takes a full flow-table dump periodically.

How do I use Gauge?

Give Gauge a list of Faucet yaml config files and it will poll them for stats (as specified in the config file).