Method for distributing time within synchronous ethernet and SONET/SDH domains
The embodiments of the present invention pertain to a method for distributing time between a first and a second Synchronous Ethernet “SyncE” domain, the first and second domains being interconnected by a third, Synchronous Optical Networking/Synchronous Digital Hierarchy “SDH-SONET” domain in which a time-associated reference parameter is distributed, through Synchronous Ethernet “SyncE” domains, by means of at least one additional Type Length Value “TLV” field of an Ethernet Synchronization Messaging Channel “ESMC” message and a corresponding time-associated reference parameter is distributed, through the Synchronous Optical Networking/Synchronous Digital Hierarchy “SONET-SDH” domain by means of at least one additional Type Length Value “TLV” field within a message of the IEEE 1588 V2 protocol.
1. A method for distributing time between a first and a second Synchronous Ethernet “SyncE” domain, said first and second domains being interconnected by a third, Synchronous Optical Networking/Synchronous Digital Hierarchy “SONET/SDH” domain, comprising the steps of:
distributing a time-associated reference parameter, through SyncE domains, by means of at least one additional Type Length Value “TLV” field of an Ethernet Synchronization Messaging Channel “ESMC” message; and
distributing a corresponding time-associated reference parameter through the SONET/SDH domain by means of at least one additional Type Length Value “TLV” field within a message of the IEEE 1588 V2 protocol.
2. A method for distributing time according to claim 1 wherein the IEEE 1588 V2 protocol message is a SYNC message.
3. A method for distributing time according to claim 1 wherein the IEEE 1588 V2 protocol message is an ANNOUNCE message.
4. A method for distributing time according to claim 3 wherein the time-associated reference parameter distributed through SyncE domains comprises a master clock value of the SyncE domain.
5. A method for distributing time according to claim 4 wherein the corresponding time-associated reference parameter distributed through the SONET/SDH domain comprises an offset value between a master clock of the SyncE and a master clock of the SONET/SDH domain.
6. A method for distributing time according to claim 4 , wherein the master clock value of the first Synchronous Ethernet “SyncE” domain is retrieved within the destination border hybrid node based on the master clock value of the SONET/SDH domain and on the offset value transmitted by the ANNOUNCE message.
7. A method for distributing time according to claim 1 , wherein the time-associated reference parameter distributed through Synchronous Ethernet “SyncE” domains comprises a master clock value of the SyncE domain.
8. A method for distributing time according to claim 1 , wherein the corresponding time-associated reference parameter distributed through the SONET/SDH domain comprises a timestamp value.
9. A method for distributing time according to claim 1 , wherein a mapping from at least one additional TLV field of the received ESMC message to the IEEE1588V2 protocol's message is carried out within a source border hybrid node by a synchronization network manager so as to allow an alteration to the value of said at least one additional TLV field of the IEEE1588V2 protocol's message by the SONET/SDH domain.
10. A method for distributing time according to claim 9 , wherein a mapping from at least one additional TLV field of the received IEEE1588V2 protocol message onto the ESMC is performed within a destination border hybrid node by the synchronization network manager.
11. A method for distributing time according to claim 1 , wherein the message of the IEEE 1588 V2 is encapsulated within a Multiprotocol Label Switching “MPLS” tunnel.
12. A source border hybrid node comprising means configured to:
receive an Ethernet Synchronization Messaging Channel “ESMC” message comprising at least one Type Length Value “TLV” field associated with a master clock value of a Synchronous Ethernet “SyncE” domain,
map the TLV fields of the EMSC message, at least one of which is associated with a master clock value, with additional Type Length Value “TLV” fields of a SYNC or ANNOUNCE message of the 1588V2 protocol,
encapsulate and transmit the SYNC or ANNOUNCE message comprising said additional TLV fields within a tunnel through a Synchronous Optical Networking/Synchronous Digital Hierarchy “SONET-SDH” domain.
13. A destination border hybrid node comprising means configured to:
receive and unencapsulate a SYNC or ANNOUNCE message of the 1588V2 protocol comprising Type Length Value “TLV” fields, at least one of which is associated with a master clock value, said message having been transmitted within a tunnel through a Synchronous Optical Networking/Synchronous Digital Hierarchy “SONET-SDH” domain,
map the TLV fields of the transmitted SYNC or ANNOUNCE message, at least one of which is associated with a master clock value, with Type Length Value “TLV” fields of a Ethernet Synchronization Messaging Channel “ESMC” message,
transmit the ESMC message comprising the TLV fields, at least one of which is associated with a master clock value, through a Synchronous Ethernet “SyncE” domain.
14. A source border hybrid node comprising means configured to:
receive an Ethernet Synchronization Messaging Channel “ESMC” message comprising Type Length Value “TLV” fields, at least one of which is associated with a master clock value of a Synchronous Ethernet “SyncE” domain,
determine the offset between the master clock value of the received SyncE domain and a master clock value of a Synchronous Optical Networking/Synchronous Digital Hierarchy “SONET-SDH” domain,
encode and insert the offset value within a field of an ANNOUNCE message of a 1588V2 protocol,
encapsulate and transmit the ANNOUNCE message comprising a field associated with a clock offset value within a tunnel through the SONET-SDH domain.
15. A destination border hybrid node comprising means configured to:
receive and unencapsulate an ANNOUNCE message of a 1588V2 protocol comprising a field associated with a clock domain value transmitted within a tunnel through a Synchronous Optical Networking/Synchronous Digital Hierarchy “SONET-SDH” domain,
retrieve the master clock value of the Synchronous Ethernet “SyncE” domain based on the master clock value of the SONET-SDH domain and the received clock offset value,
transmit an Ethernet Synchronization Messaging Channel “ESMC” message comprising a Type Length Value “TLV” field associated with the master clock value of the retrieved SyncE domain.