Design This page explains rules that apply to all protobuffers, and a bit on how we use them. PBEnvelope All protobuffers are wrapped in the PBEnvelope message, which contains metadata we need in all protobufs. Lost packets & throttling In every line of communications, the packets must be sent periodically. The frequency of sent packets is indicated in their PBEnvelope . If the receiver does not get a packet within given timeout, it means the packet was lost. In most cases this means that the brakes should be engaged for safety.