Synchronous Ethernet. Silvana Rodrigues, IDT Presentation to WSTS-11, May 10-12, 2010, Westminster, Colorado

Transcription

1 ynchronous Ethernet ilvana Rodrigues, IDT Presentation to WT-11, May 10-12, 2010, Westminster, Colorado 2009 Integrated Device Technology, Inc.

2 Agenda ynchronous Ethernet Features ynchronous Ethernet tandards ITU-T G.803 Clock Hierarchy ynchronous Ethernet interworking with DH Clocks ynchronous Ethernet Operation Modes ITU-T Recommendation G.8262 ynchronous Ethernet Interfaces ynchronous Ethernet ynchronization tatus Message (M) PAGE 2

3 ynchronous Ethernet Concept Packet witched Network Primary Reference Clock (PRC) PRC traceable Reference clock NodeB Ethernet witch supporting ynchronous Ethernet Traditional Ethernet witch (no support for ynchronous Ethernet) NodeB Performance is independent of the network Ethernet link used as a pure point-to-point, layer 1 link (data pipe) where the end points are synchronized to the same network clock (as opposed to separate free running oscillators) Ethernet transmit clock synchronized to a Primary Reference Clock (PRC) at Master node to transport frequency, it does not transport phase or Time of Day (ToD) lave node uses recovered physical layer clock from Ethernet link to derive local clocks traceable to PRC Ethernet IDLE frame symbol is essentially a clock and maintains synchronization when no packets are being transferred In many cases requires both DPLL for Wander filtering and Holdover performance and very high performance Analog PLL to meet Ethernet jitter requirements PAGE 3

4 cope of ynchronous Ethernet Compatible with the current ynchronization Network Compatible with the synchronization hierarchy defined in ITU-T G.823 and ITU-T G.824 Transports high quality reference frequency imilar to ONET/DH Independent of traffic of the network Can interwork with ONET/DH synchronization network Meets requirements of TDM networks Meets mobile backhauling requirements (for Frequency Division Duplex technologies) Does not provide phase alignment neither Time of Day (ToD) Fully compatible with IEEE standards therefore can interwork with traditional Ethernet ynchronization tatus Message (M) is very important for ynchronous Ethernet M is needed to distinguish ynchronous Ethernet from traditional Ethernet PAGE 4

5 ITU-T Recommendation G.8261 Contains the architectural aspects of ynchronous and Network limits Based on G.803 reference synchronization chain ITU-T Recommendation G.8262 ynchronous Ethernet tandards Contains the clock specification for ynchronous Ethernet and it based on G.813 and G.812 Type IV New revision will be consented in June 2010 ITU-T Recommendation G.8264 Contains the ynchronization tatus Message (M) for ynchronous Ethernet Defines 2 modes of operation Non-synchronous Mode ynchronous Mode ITU-T Recommendation G.781 It was updated last year to include ynchronous Ethernet The clock adaptation functions for ynchronous Ethernet were defined ITU-T Recommendation O.174 pecifies test equipment used to generate and measure timing jitter and synchronization wander in digital systems based on synchronous Ethernet network It was consented in October 2009 PAGE 5

6 ITU-T G.803 Clock Hierarchy ynchronization chain is defined in ITU-T Recommendation G.803 Consists of 1 PRC Maximum of 10 Us Maximum of 20 ECs between Us Maximum number of ECs is 60 PRC Primary Reference Clock U - ynchronization upply Unit EC - DH Equipment Clock PAGE 6

7 ynchronous Ethernet interworking with DH Clocks U U U E E E E H H U - ynchronization upply Unit - DH Equipment Clock E ynchronous Ethernet Equipment Clock H Hybrid DH and ynchronous Ethernet Equipment Clock U U U a) b) c) G.8261/Figure D.1 ynchronization chains implemented with different types of NEs ynchronous Ethernet may be part of the ITU-T Clock Hierarchy ynchronous Ethernet synchronization links provide the same behavior as DH synchronization links Hybrid equipment implements both ONET/DH and Ethernet ports PAGE 7

8 Hybrid DH and ynchronous Ethernet Equipment Clock G.8262/Figure I.1 Hybrid NE using TM-N and Ethernet (ETY) interfaces Hybrid Network Elements (NE) offer both TM-N interfaces and Ethernet interfaces (ETY) ETY interfaces are used for timing distribution The use of hybrid NEs do not require modifications of deployed DH NEs or clocks (PRC, U), PAGE 8

9 ynchronous Ethernet Operation Modes Non-ynchronous Operation Mode A ynchronous Ethernet interface can be configured in non-synchronous mode where it does not participate in the synchronization network It is functionally identical to an asynchronous interface as defined in IEEE ynchronous Operation Mode A ynchronous Ethernet interface can be configured in synchronous mode where it can participate in the synchronization network G.8261/Table A.2 Interworking between synchronous Ethernet and Ethernet ports Traffic interworking with Network synchronization interworking with Interface type Ethernet ynchronous Ethernet ynchronous Ethernet Operation mode Nonsynchronous mode Nonsynchronous mode ynchronous mode Interworking is possible Interworking is not possible Ethernet Non-synchronous mode ynchronous Ethernet port ynchronous mode Ethernet Non-synchronous mode ynchronous Ethernet port ynchronous mode PAGE 9

10 ITU-T Recommendation G.8262 Outlines the minimum requirements for timing devices used in synchronizing network equipment that supports synchronous Ethernet It specifies 2 types of Ethernet Equipment slave Clock (EEC) EEC-option 1 based on G.813 EC option 1 EEC-option 2 based on G.812 type IV (equivalent to tratum 3 in North America) Frequency accuracy 4.6 ppm for both EEC option 1 and 2 Pull in and pull out range of 4.6 ppm for both EEC option 1 and 2 Wander Generation and Tolerance Based on G.813 for EEC-option 1 and 2 Jitter Generation and Tolerance ITU has agreed to include wideband jitter tolerance and generation in G.8262 consented in June 2010 High frequency jitter has been defined by IEEE 802.3, therefore synchronous Ethernet equipment must meet that specification PAGE 10

11 ITU-T Recommendation G.8262 cont d Noise Transfer (Loop Bandwidth) Based on G.813 for EEC-option 1 and 2 The minimum bandwidth requirement for EEC-option 1 is 1 Hz and the maximum is 10 Hz The maximum bandwidth requirement for EEC-option 2 is 0.1 Hz hort and long term phase transient Based on G.813 for EEC-option 1 and G.812 type IV (stratum 3) for EEC-option 2 Phase response to input signal interruptions Based on G.813 for EEC-option 1 and 2 Phase discontinuity Based on G.813 for EEC-option 1 and G.812 type IV (stratum 3) for EEC-option 2 PAGE 11

12 ynchronous Ethernet Interfaces Appendix III of G.8262 includes a list of Ethernet physical interfaces applicable to ynchronous Ethernet Ethernet interfaces must have a constant signal This signal must be coded so that there is a guarantee of transitions to allow the clock to be recovered OTN was updated at ITU to support ynchronous Ethernet ynchronous Ethernet works with Fast Ethernet, Gigabit Ethernet, 10Gigabit Ethernet (LAN and WAN), 40 Gigabit Ethernet and 100 Gigabit Ethernet PAGE 12

13 List of Ethernet interfaces applicable to ynchronous Ethernet PHY Description IEEE Clause 100BAE-BX10 100Mb bidi fiber 58, BAE-FX 100Mb fiber 24, BAE-LX10 100Mb fiber 58, BAE-TX 100Mb TP copper 24, 25 PHY Description IEEE Clause 1000BAE-BX10 1Gb bidi fiber 59, BAE-CX 1Gb twinax BAE-KX 1Gb backplane BAE-LX 1Gb fiber BAE-PX 1Gb PON BAE-X 1Gb fiber BAE-T 1Gb TP copper 40 PHY Description IEEE Clause 40GBAE-KR4 40G 4x backplane 84 40GBAE-CR4 40G 4x twinax 85 40GBAE-R4 40G 4x fiber 86 40GBAE-LR4 40G 4λ fiber 87 PAGE 13 PHY Description IEEE Clause 10GBAE-CX4 10Gb 4x twinax 54 10GBAE-ER 10Gb fiber 49, 52 10GBAE-EW 10Gb fiber 50, 52 10GBAE-KR 10Gb backplane 72 10GBAE-KX4 10Gb 4x backplane 10GBAE-LR 10Gb fiber 49, GBAE-LRM 10Gb fiber 68 10GBAE-LW 10Gb fiber 50, 52 10GBAE-LX4 10Gb 4λ fiber 50, 52 10GBAE-R 10Gb fiber 49, 52 10GBAE-W 10Gb fiber 50, 52 10GBAE-T 10Gb TP copper 55 10/1GBAE-PR 10G/1G PON 76 10GBAE-PR 10G PON 76 PHY Description IEEE Clause 100GBAE-CR10 100G 10x twinax GBAE-R10 100G 10x fiber GBAE-LR4 100G 4λ fiber GBAE-ER4 100G 4λ fiber 88

14 ynchronization tatus Message (M) ITU-T Recommendation G.8264 pecifies the M transport channel which is named Ethernet ynchronization Messaging Channel (EMC) pecifies the protocol behavior pecifies the Message format M is intended to be used with the synchronization selection algorithms specified in ITU-T Recommendation G.781 M messages carry the quality level (QL) of the system clocks G.8264/Table 10.1: M messages for ynchronous Ethernet Clock message EEC1 QL-EEC M code EEC2 QL-EEC For existing DH based M, the M message is carried in fixed locations within the DH frame In the case of Ethernet, there is no equivalent of a fixed frame IEEE slow protocol is used to transport M in ynchronous Ethernet PAGE 14

15 Ethernet ynchronization Messaging Channel (EMC) EM uses an IEEE Organization pecific low Protocol (OP) IEEE has provided ITU-T with an Organizational Unique Identifier (OUI) and a low Protocol subtype G.8264/Table : IEEE assigned OUI and low protocol subtype Organizational pecific Identifier 0x0019A7 low Protocol ubtype 0X0A Two types of messages are defined in order to meet G.781 requirements for reference switching Heart-beat message sent once per second - provides a continuous indication of the clock quality level Event message with new M message is sent upon detection of a clock quality level change If no M messages are received after a 5 second period then the M value is set to DNU (Do Not Use) Current G.8264 defines one QL TLV (Type Length Value) to transport the clock quality level G.8264 has provision for extensions of the EMC Protocol Data Unit New TLVs can be defined in future revision of the Recommendation Future extensions to the EMC PDU are for further study PAGE 15

16 QUETION??? THANK YOU! PAGE 16