Transparent auto-negotiation of ethernet
A system for negotiating Ethernet link settings between interconnected nodes in a network having an Ethernet protocol stack that includes a PCS sub-layer with an auto-negotiation function. The system comprises connecting an intermediate device coupled between two network nodes via optical or copper interfaces, with the link settings between each node and the connected intermediate device being the same, thereby bypassing the auto-negotiation of the PCS sub-layer in the intermediate device. The intermediate device may transparently send negotiation messages from each node to the other during the link negotiation phase without interacting with those messages. Instead of the intermediate device, a single form pluggable (SFP) device may be connected between the two network nodes via optical or copper interfaces on the network side and via an SFP slot on the device side.
1. A method of negotiating an Ethernet link setting between a first device and a second device, said first device and said second device coupled via an intermediate device in a network, said first device and said second device each having an Ethernet protocol stack that includes a physical coding sub-layer with an auto-negotiation function, said intermediate device having a protocol stack that includes a physical coding sub-layer with a function that acts as a switch, and comprising a management module coupled to said switch, said method comprising:
programming, said management module to configure said switch into a configuration mode;
negotiating the Ethernet link setting identically between said first device and said intermediate device and between said second device and said intermediate device wherein said intermediate device communicates via said switch, while said switch is in said configuration mode, a first auto-configuration code received from said first device to said second device and a second auto-configuration code received from said second device to said first device without modification of the received first and second auto-configuration codes and bypassing an auto-negotiation function of the physical coding sub-layer of said intermediate device;
said management module monitoring said first auto-configuration code and said second auto-configuration code to determine an auto-negotiation phase status between said first device and said second device;
said management module, when determining that said auto-negotiation phase status is complete, programming using said management module said switch into a data mode, and configuring said protocol stack of the intermediate device to be compatible with said first auto-configuration code and said second auto-configuration code, wherein said intermediate device communicates via said switch, while said switch is in said data mode, data received from said first device to a MAC layer and data received from said second device to said MAC layer.
2. The method of claim 1 wherein said intermediate device is a small-form factor pluggable transceiver (SFP).
3. The method of claim 2 wherein said SFP has one port connected in the first device and the other port connected to the network.
4. An intermediate device for negotiating Ethernet link settings in a network, said intermediate device having a protocol stack that includes a physical coding sub-layer with a function that acts as a switch, said intermediate device comprising:
a first network interface and a second network interface, said first network interface and said second network interface both comprising an Ethernet protocol stack;
said switch coupled between said first network interface, said second network interface, and a management module;
said management module receiving auto-configuration codes from said first network interface and said second network interface, said management module monitoring said auto-configuration codes to determine an auto-configuration status of a first device coupled to said first network interface and a second device coupled to said second network interface, said first and second devices each having an Ethernet protocol stack that includes a physical coding sub-layer with an auto-negotiation function;
said management module, upon detecting that said auto-configuration status is incomplete, programming a mode of said switch in a configuration mode;
wherein said intermediate device communicates via said switch, while said switch is in said configuration mode, said auto-configuration codes received from said first device back to said second device and said auto-configuration codes received from said second device to said first device without modification of the auto-configuration codes and bypassing an auto-negotiation function of the physical coding sub-layer of said intermediate device; and
wherein said management module, upon detecting that said auto-configuration status is complete, programming a mode of said switch into a data mode and configuring said protocol stack of the intermediate device to be compatible with said auto-configuration codes; and
wherein said intermediate device couples, while said switch is in said data mode, said first network interface and said second network interface with a MAC layer of said Ethernet protocol stack of said intermediate device via said switch.
5. The device of claim 4 wherein said intermediate device is a small-form factor pluggable transceiver (SFP).
6. The system of claim 5 wherein said SFP has one port connected in the first device and the other port connected to the network.