code: def request_uplink_info(self, payload):
          
  
          # This request is received from an agent when it run for the first
          # Send the uplink name (physical port name that connectes compute
          #                          node and switch fabric),
          agent = payload.get('agent')
          config_res = self.get_agent_configurations(agent)
          LOG.debug('configurations on %(agent)s is %(cfg)s', (
              {'agent': agent, 'cfg': config_res}))
          try:
              self.neutron_event.send_msg_to_agent(agent,
                                                   constants.UPLINK_NAME,
                                                   config_res)
          except (rpc.MessagingTimeout, rpc.RPCException, rpc.RemoteError):
              LOG.error("RPC error: Failed to send uplink name to agent.")
docs: Get the uplink from the database and send the info to the agent.