Switch for clock synchronization over a switched fabric

A method, comprising:

• a switch performing:
• receiving a request packet from a device over a memory-mapped fabric;
• transmitting a completion packet to the device over the memory-mapped fabric, wherein the completion packet comprises a counter value from a counter of the switch;
• determining an in-switch delay related to the receiving and the transmitting;
• and
• storing the in-switch delay.

A switch, comprising:

• at least one I/O port, configured to couple to a memory-mapped fabric;
• and
• a processing element, coupled to the at least one I/O port;
• wherein the switch is configured to:
• receive a packet via the at least one I/O port from a first device over the memory-mapped fabric;
• and
• forward the packet via the at least one I/O port to a second device over the memory-mapped fabric;
• and
• wherein the processing element is configured to:
• determine an in-switch delay of the packet related to the receiving and forwarding of the packet;
• and
• store the in-switch delay.

A method, comprising:

• a switch performing:
• receiving a packet from a first device over a memory-mapped fabric;
• forwarding the packet to a second device over the memory-mapped fabric;
• determining an in-switch delay of the packet;
• and
• storing the in-switch delay.