Copyright © 2005 Marconi Corporation plc. All rights reserved Network Timing ATM Switch

Copyright © 2005 Marconi Corporation plc. All rights reserved 2 Objectives  Explain the purpose of network synchronization  Identify the meaning of the Stratum clocking grades  Identify the internal and external timing components associated with the CEC-Plus and ASX-4000 Series TCM  Describe the basic distribution of timing architecture for line timing and external timing sources  Configure the IP interfaces on the CEC-Plus  Configure and verify timing (external timing example) on the CEC-Plus and the ASX-4000 Series TCM

Copyright © 2005 Marconi Corporation plc. All rights reserved 3 Overview Physical Links Primary Reference Source (PRS) Reference Source In Distributed to all ports Used for transmission Port

Copyright © 2005 Marconi Corporation plc. All rights reserved 4 Timing Fundamentals  A timing element (a.k.a., clocking) is a pulse pattern  A timing element can be seen from two perspectives:  Receive timing is derived from the incoming frame rate  Transmit timing controls the outgoing frame rate  Frame rates are universal, even on different interface speeds InterfaceBit rateFrame rate DS Mbps8,000 fps E Mbps8,000 fps DS Mbps8,000 fps E Mbps8,000 fps OC Mbps8,000 fps

Copyright © 2005 Marconi Corporation plc. All rights reserved 5 Timing Precision  The integrity of a timing pulse can be classified by quality  The goal is to have all the devices follow the same reference; hence they are synchronized  Normally the timing signal is derived from the most accurate of clocks (referred to as a Stratum 1 traceable clock) StratumAccuracyTime until first Bit Slip following failure (Holdover) 11 x or less72 Days 21.6 x Days 3E1.0 x Hours 34.6 x Minutes

Copyright © 2005 Marconi Corporation plc. All rights reserved 6 Impact of Timing Problems  When sending and receiving devices use different reference sources, bit slips and frame slips can result  The underlying problem is either buffer overrun or underrun  Synchronized networks minimize these problems buffer Framer ~8,000 fps (8,150 fps) ~8,000 fps (7,920 fps) buffer Framer ~8,000 fps (7,885 fps) ~8,000 fps (8,215 fps) Overrun example Underrun example

Copyright © 2005 Marconi Corporation plc. All rights reserved 7 Timing Structure PRS Secondary Reference Primary Reference Stratum1 S4 S3 S2 S4 S3 Voice or Video Application SRS

Copyright © 2005 Marconi Corporation plc. All rights reserved 8 TCM Types ASX-1000/1200 and TNX-1100  Dual TCMs comprise the CEC-Plus  Supports network timing subsystem and alarm relays  Runs with or without switch fabrics installed ASX-4000 Series  TCM is a daughter card to the SCP  Supports timing functions and alarm relays Daughtercard

Copyright © 2005 Marconi Corporation plc. All rights reserved 9 TCM Features  Hot-swappable  ASX-4000 version is integral to SCP; must remove SCP  Redundant  BITS inputs  Line timing inputs  Hitless reference switching and failover  Timing holdover  Stratum 3 or 4 oscillator and digital phase lock loop  Configurable alarm relay contacts

Copyright © 2005 Marconi Corporation plc. All rights reserved 10 CEC-Plus: TCM Front Panel  25 pin D-sub: Alarm relay connections  Normal open or normal closed wiring  Alarm LEDs: Alarm relay is normal or energized  Ethernet connection to SCPs  Serial port  Status LED  Solid: Active  Flashing: Standby  Amber: Error  External timing signal ports (TX and RX)  Reset button

Copyright © 2005 Marconi Corporation plc. All rights reserved 11 ASX-4000 Series: TCM Front Panel SCP front panel includes:  25 pin D-sub: Alarm relay connections  Normal open or normal closed wiring  Alarm reset button  Returns relays to normal state  Alarm LEDs: Alarm relay is normal or energized Alarm Relay LEDs

Copyright © 2005 Marconi Corporation plc. All rights reserved 12 Timing Distribution Architecture Fabric/Port card PPPSSSSP S S P P BITS-Y BITS-X TCM X TCM Y PLL

Copyright © 2005 Marconi Corporation plc. All rights reserved 13 Line Timing Example Fabric/Port card PPPSSSSP S S P P BITS-Y BITS-X TCM X TCM Y PLL

Copyright © 2005 Marconi Corporation plc. All rights reserved 14 BITS Timing Example Fabric/Port card PPPSSSSP S S P P BITS-Y BITS-X TCM X TCM Y PLL

Copyright © 2005 Marconi Corporation plc. All rights reserved 15 Modes of Operation for TCM Hitless modes move between available clock sources  Line timing – references a network port  CEC-Plus: Automatic mode  ASX-4000 Series: Line mode  BITS timing references an external source  CEC-Plus: BITS mode  ASX-4000 Series: External mode Manual modes do not change sources  FreeRun (internal oscillator)  Primary (CEC-Plus only)  Secondary (CEC-Plus only)

Copyright © 2005 Marconi Corporation plc. All rights reserved 16 CEC-Plus Address Configuration DB CA Y X DB CA Y X DB CA Y X DB CA Y X 2341 Y X TCMTCM TCMTCM TCM Interface IP Addressing ie ie ie ie ASX-1000/1200/TNX-1100 Fabric 1 ie SCP Addressing Fabric 2 ie Fabric 3 ie Fabric 4 ie

Copyright © 2005 Marconi Corporation plc. All rights reserved 17 CEC-Plus Management Interface - EMI  Extended Management Interface (EMI)  Used to configure the IP addresses for the TCM interfaces ( ie0 and ie1 )  ATM Management Interface (AMI)  Controls the CEC-Plus after IP addresses are configured on the Timing Control Modules (TCMs)  The syntax used for EMI is different than AMI

Copyright © 2005 Marconi Corporation plc. All rights reserved 18 Configure the TCM’s IP Interfaces localhost::> configuration localhost::configuration> ip localhost::configuration ip> address ie localhost::configuration ip> address ie localhost::configuration ip> admin ie0 up localhost::configuration ip> admin ie1 up localhost::configuration ip> show interface stateaddressnetmaskbroadcast ie0up ie1 up lo0 up N/A

Copyright © 2005 Marconi Corporation plc. All rights reserved 19 Addressing the SCPs of the Switch ATM SWITCH:interfaces ip-> mod ie state up ATM SWITCH:interfaces ip-> show Interface State Address Netmask Neighbor Bcast MTU Address Setting lo0 up N/A N/A asx0 down N/A N/A N/A N/A N/A qaa0 down N/A N/A N/A N/A N/A qaa1 down N/A N/A N/A N/A N/A qaa2 down N/A N/A N/A N/A N/A qaa3 down N/A N/A N/A N/A N/A ie0 up N/A

Copyright © 2005 Marconi Corporation plc. All rights reserved 20 Verify Reference Sources Timing Configuration Configure each fabric to listen to the TCM Bus Configure the TCM to listen to the PRS and SRS Configure Automatic Reference Source Line Timing BITS Configure BITS Reference Source (BITS) Configure each fabric to listen to the TCM Bus (CEC-Plus only) Configure the Primary and Secondary Line Timing Sources

Copyright © 2005 Marconi Corporation plc. All rights reserved 21 BITS: Configure Fabrics to Use the TCM Switch Fabric 1:system timing-> modify –timingmode tcmmode Switch Fabric 1:system timing-> show Timing Mode:tcmMode Primary Clock:none Secondary Clock:none Clock Status:tcm (Repeat for each additional fabric) CEC-Plus This is the default for an ASX-4000 Series switch (no action needed)

Copyright © 2005 Marconi Corporation plc. All rights reserved 22 Verify Reference Sources Switch Fabric 2:hardware cecplus timing-> references show Reference Source Status Admin RefQual fabric1_Primary 1 (Down) unavailable up ok fabric1_Secondary 1 (Down) unavailable up ok : fabric4_Primary 4 (Down) unavailable up ok fabric4_Secondary 4 (Down) unavailable up ok tcmX_bits1 BITS1 available up ok tcmY_bits2 BITS2 unavailable up ok ASX-4000:hardware tcm references-> show Reference Source Status Admin RefQual freerun freerun available up ok bits1 BITS1 available up ok bits2 BITS2 unavailable up N/A switchPrimary none unavailable up N/A switchSecondary none unavailable up N/A ASX-4000 Series CEC-Plus

Copyright © 2005 Marconi Corporation plc. All rights reserved 23 Configure Timing Mode ASX-4000:hardware tcm-> show Operational Status: disabled TCM Type: DS1_Stratum_3K TCM Version: 0 TCM PLL Status: acquiring Requested Timing Mode: external Operational Timing Mode: external Primary Timing Reference: bits1 Secondary Timing Reference: bits2 Current Timing Reference: primary : ASX-4000 Series * This is the default for an ASX-4000 (verify with display) Switch Fabric 1:hardware cecplus timing-> modify –mode bits Switch Fabric 1:hardware cecplus timing-> show : BITS interface framing esf line coding b8zs, output level 0.6dB PLL Status: acquiring Current Timing Reference: BITS2 Requested Timing Reference: bits : BITS1 Reference available BITS2 Reference available : CEC-Plus

Copyright © 2005 Marconi Corporation plc. All rights reserved 24 Summary  Explained the purpose of network synchronization  Identified the meaning of the Stratum clocking grades  Listed the internal and external timing components associated with the CEC-Plus and ASX-4000 Series TCM  Described the basic distribution of timing architecture for line timing and external timing sources  Configured the IP interfaces on the CEC-Plus  Configured and verify timing (external timing example) on the CEC-Plus and the ASX-4000 Series TCM