Abstract: A processor of a network device receives i) a timing message and ii) a control header corresponding to the timing message. The control header includes information that indicates a timestamping method for communicating timing information corresponding to transmission of the timing message by the network device. The timestamping method is selected from a set of multiple timestamping methods that includes: i) a one-step timestamping method, and ii) a two-step timestamping method. The processor determines whether the two-step timing timestamping method is to be performed based on analyzing the information in the control header. The network device transmits the timing message within a first packet and determines timing information corresponding to the transmission of the first packet. In response to determining that the timestamping method is the two-step method, the processor stores the timing information in a memory for subsequent inclusion in a second packet that is to be subsequently transmitted.

Abstract: A network device transfers packets from a packet memory to one or more network interfaces for transmission by the one or more network interfaces. The transferring of packets includes transferring the packets via one or more respective transmit data paths that correspond to one or more respective network interfaces. The network device measures one or more respective amounts of time required to transmit respective packet data within the one or more respective transmit data paths. The network device uses the one or more respective measured amounts of time to determine when to start transfer of packets from the packet memory to the one or more network interfaces via the one or more respective transmit data paths.

Abstract: A network device includes a first queue for queueing express packets and a second queue for queueing preemptable packets that are to be transmitted via a network interface of the network device. The network device also includes a transmit controller that receives a packet directed to the first queue and determines whether the packet is a type of packet that requires transmission at a specific transmit time from the network interface of the network device. In response to determining that the packet is a type of packet that requires transmission at a specific transmit time, the transmit controller suspends an ongoing transmission of a preemptable packet from the second queue that would prevent transmission of the packet from the first queue at the specific transmit time via the network interface and causes the packet in the first queue to be transmitted at the specific transmit time via the network interface.

Abstract: In a network having at least one slave node including a slave clock, a method of adjusting the slave clock relative to a master clock of a master node includes, at the slave node, correcting a time of day of the slave clock using (a) a slave pulse signal having a known slave pulse rate, (b) a time-of-day counter of the slave node, and (c) a master pulse signal, based on values of the slave clock at nearest corresponding edges of the slave pulse signal and the master pulse signal, and correcting a frequency of the slave clock using the slave pulse signal, a clock signal of the slave node, and the master pulse signal, based on values of the slave clock at nearest corresponding edges of the master pulse signal. No other clock signal from outside the slave node is used for the corrections.

Abstract: Information is shared between switches such as bridges to facilitate efficient forwarding of data. In some embodiments consistency is maintained between information stored in filtering databases for IEEE 802.1D or 802.1Q bridges. When a switch does not have an entry in a filtering database that matches a destination address in a received frame, the switch may send information with the forwarded frame indicating that the switch had no entry for the destination address. When a switch that has an entry for a given destination address receives a frame along with an indication that the sender did not have an entry or has a different entry for the destination address, the switch may send its information corresponding to the destination address to other switches.

Abstract: Information is shared between switches such as bridges to facilitate efficient forwarding of data. In some embodiments consistency is maintained between information stored in filtering databases for IEEE 802.1D or 802.1Q bridges. When a switch does not have an entry in a filtering database that matches a destination address in a received frame, the switch may send information with the forwarded frame indicating that the switch had no entry for the destination address. When a switch that has an entry for a given destination address receives a frame along with an indication that the sender did not have an entry or has a different entry for the destination address, the switch may send its information corresponding to the destination address to other switches.