Providing time synchronization across store-and-forward communication devices using protocol-enabled switches

1. A communication network, comprising:

a plurality of subnets, wherein each subnet includes a plurality of nodes;

a store-and-forward communication device having a set of subnet ports, wherein each port communicates with a corresponding subnet of the plurality of subnets, wherein one or more of the nodes synchronize a local time using a protocol that includes a set of timing packets that are ignored by the store-and-forward communication device;

a protocol-enabled switch that provides the timing packets for each subnet according to the protocol; and

a plurality of distribution devices, wherein each distribution device is associated with a corresponding subnet, and each distribution device includes a first relay port that is connected to the store-and-forward communication device and a second relay port that is connected to the protocol-enabled switch.

2. The communication network of claim 1 , wherein the store-and-forward communication device is a router.

3. The communication network of claim 1 , wherein each node is selected from the group consisting of:

a computer, a workstation, a control device, a sensor device, a computational device, and an informational server.

4. The communication network of claim 1 , wherein the protocol is the Precision Time Protocol as set forth in IEEE 1588.

5. The communication network of claim 1 , wherein the set of timing packets are multicast packets with a time_to_live=1.

6. The communication network of claim 1 , wherein the protocol-enabled switch operates as a master clock for the communication network.

7. The communication network of claim 1 , wherein each network distribution device is selected from the group consisting of:

a switch, a hub, and another protocol enabled switch.

8. The communication network of claim 1 , wherein the protocol-enabled switch is configured to not relay any packets among the subnets.

9. The communication network of claim 1 , wherein each distribution device includes a plurality of node relay ports, wherein each node relay port is connected to a corresponding node.

10. A communication network, comprising:

a plurality of subnets, wherein each subnet includes a plurality of nodes;

a store-and-forward communication device having a set of subnet ports, wherein each port communicates with a corresponding subnet of the plurality of subnets, wherein one or more of the nodes synchronize a local time using a protocol that includes a set of timing packets that are ignored by the store-and-forward communication device;

a protocol-enabled switch that provides the timing packets for each subnet according to the protocol;

a plurality of hubs, with each hub being connected to the store-and-forward communication device, the protocol-enabled switch, and a respective one of the plurality of subnets; and

a plurality of distribution devices, wherein each distribution device is associated with a corresponding subnet, and each distribution device includes relay port that is connected to the associated hub.

11. The communication network of claim 10 , wherein the a store-and-forward communication device is a router.

12. A communication network, comprising:

a plurality of subnets, wherein each subnet includes a plurality of nodes;

a store-and-forward communication device having a set of subnet ports, wherein each port is associated with a corresponding subnet of the plurality of subnets, wherein one or more of the nodes synchronize a local time using a protocol that includes a set of timing packets that are ignored by the store-and-forward communication device;

a protocol-enabled switch that provides the timing packets for each subnet according to the protocol; and

a plurality of distribution devices, wherein each distribution device is associated with a corresponding subnet, and each distribution device includes relay port that is connected to protocol-enabled switch;

wherein the protocol-enabled switch comprises a first plurality of ports, each of which are connected with a respective one of the subnet ports, and a second plurality of ports, each of which are connected with a respective distribution device.

13. The communication network of claim 12 , wherein the a store-and-forward communication device is a router.

14. The communication network of claim 12 , wherein each node is selected from the group consisting of:

a computer, a workstation, a control device, a sensor device, a computational device, and an informational server.

15. The communication network of claim 12 , wherein the protocol is the Precision Time Protocol as set forth in IEEE 1588.

16. The communication network of claim 12 , wherein the protocol-enabled switch operates as a master clock for the communication network.

17. The communication network of claim 12 , wherein each network distribution device is selected from the group consisting of:

a switch, a hub, and another protocol enabled switch.

18. The communication network of claim 12 , wherein the protocol-enabled switch is configured to not relay any packets among the subnets.

19. The communication network of claim 12 , wherein each distribution device includes a plurality of node relay ports, wherein each node relay port is connected to a corresponding node.

20. The communication network of claim 12 , wherein first and second plurality of ports of the protocol-enabled switch are arranged switch port pairs, where each pair is formed from a port of the first plurality and a port of the second plurality and connects the corresponding subnet port and the network distribution device for the corresponding subnet.