Method and system for physical-layer handshaking for timing role transition

Abstract

Aspects of a method and system for physical-layer handshaking for timing role transition are provided. Prior to changing the timing role of a first Ethernet device, the first Ethernet device may communicate over an Ethernet link to a second Ethernet PHY utilizing a first set of one or more PCS code-groups. In response to a determination to change the timing role of the first Ethernet device, the first Ethernet device may communicate one or more IDLE symbols over the Ethernet link to the second Ethernet device. The IDLE symbol(s) may be generated utilizing a second set of one or more PCS code-groups. The first set of PCS code-group(s) may be mutually exclusive with the second set of PCS code-group(s). In response to detecting a received Ethernet physical layer symbol corresponding to the second set of PCS code-groups, the second Ethernet device may make a determination to change its timing role.

1 . A method comprising:
 prior to changing the timing role of a first Ethernet device, communicating over an Ethernet link to a second Ethernet device utilizing a first set of one or more physical coding sublayer (PCS) code-groups; and   in response to a determination to change the timing role of said first Ethernet device, communicating one or more IDLE symbols over said Ethernet link to said second Ethernet device, wherein said one or more IDLE symbol are generated utilizing a second set of one or more PCS code-groups.   
     
     
         2 . The method according to  claim 1 , wherein said first set of one or more PCS code-groups is mutually exclusive with said second set of one or more PCS code-groups. 
     
     
         3 . The method according to  claim 1 , comprising changing said timing role of said first Ethernet device from timing slave to timing master. 
     
     
         4 . The method according to  claim 3 , wherein an Ethernet physical layer connection between said first Ethernet device and said second Ethernet device remains active during said changing of said timing role. 
     
     
         5 . The method according to  claim 3 , comprising upon completion of said changing said timing role from timing slave to timing master, resuming communication over said Ethernet link utilizing said first set of one or more PCS code-groups. 
     
     
         6 . The method according to  claim 1 , comprising making said determination to change the timing role of said first Ethernet device in response to Ethernet Synchronization Message Channel (ESMC) messages communicated to said first Ethernet device. 
     
     
         7 . A method comprising:
 in an Ethernet device:
 receiving Ethernet physical layer symbols via an Ethernet physical layer; 
   and
 in response to detecting that one or more of said Ethernet physical layer symbols correspond to a particular set of one or more physical coding sublayer (PCS) code-groups, making a determination to change a timing role of said Ethernet device. 
   
     
     
         8 . The method according to  claim 7 , comprising changing said timing role of said Ethernet device from timing master to timing slave. 
     
     
         9 . The method according to  claim 8 , wherein an Ethernet physical layer connection between said Ethernet device and a second Ethernet device remains active during said changing of said timing role. 
     
     
         10 . The method according to  claim 8 , wherein said Ethernet device remains IEEE 802.3 master before, during, and after said changing said timing role. 
     
     
         11 . A system comprising:
 one or more circuits for use in a first Ethernet device, said one or more circuits being operable to:
 prior to changing the timing role of said first Ethernet device, communicate over an Ethernet link to a second Ethernet PHY utilizing a first set of one or more physical coding sublayer (PCS) code-groups; and 
 in response to a determination to change the timing role of said Ethernet device, communicate one or more IDLE symbols over said Ethernet link to said second Ethernet PHY, wherein said one or more IDLE symbol are generated utilizing a second set of one or more PCS code-groups. 
   
     
     
         12 . The system according to  claim 11 , wherein said first set of one or more PCS code-groups is mutually exclusive with said second set of one or more PCS code-groups. 
     
     
         13 . The system according to  claim 11 , wherein said one or more circuits are operable to change said timing role of said first Ethernet device from timing slave to timing master. 
     
     
         14 . The system according to  claim 13 , wherein an Ethernet physical layer connection between said first Ethernet device and said second Ethernet device remains active during said changing of said timing role. 
     
     
         15 . The system according to  claim 13 , wherein said one or more circuits are operable to, upon completion said changing said timing role from timing slave to timing master, resume communication over said Ethernet link utilizing said first set of one or more PCS code-groups. 
     
     
         16 . The system according to  claim 11 , wherein said one or more circuits are operable to make said determination to change the timing role of said first Ethernet device in response to Ethernet Synchronization Message Channel (ESMC) messages communicated to said first Ethernet device. 
     
     
         17 . A system comprising:
 one or more circuits for use in an Ethernet device, said one or more circuits being operable to:
 receive Ethernet physical layer symbols via an Ethernet physical layer; 
   and
 in response to detecting that one or more of said Ethernet physical layer symbols correspond to a particular set of one or more physical coding sublayer (PCS) code-groups, make a determination to change a timing role of said Ethernet device. 
   
     
     
         18 . The system according to  claim 17 , wherein said one or more circuits are operable to change said timing role of said first Ethernet device from timing master to timing slave. 
     
     
         19 . The system according to  claim 18 , wherein an Ethernet physical layer connection between said first Ethernet device and said second Ethernet device remains active during said changing of said timing role. 
     
     
         20 . The system according to  claim 8 , wherein said Ethernet device remains IEEE 802.3 master before, during, and after said changing said timing role.