Procedure 17-2.5: Configure timing for VLNC6x Circuit Emulation Service (CES)
Overview
Use this procedure to configure timing for the VLNC6x providing CES.
The system-timing-source {bits [alternate-source-line]| ptp-1588 | free-running | line | ge | backplane} command is used to specify a common timing source for all the devices on the VLNC6x where:
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bits — Building Integrated Timing Supply This is a timing supply traceable to a common Primary Reference Clock in the network. The shelf has a special T1/E1 input interface associated with each main slot for receiving this timing.
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alternate-source-line — On the VLNC64, when the System Timing is BITS, an alternate source of timing (Line) can be specified, which derives timing from the OC3/STM1 interface on the pack. Specifying an alternate source for System Timing is optional.
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ptp-1588 — Precision Timing Protocol-1588. This option specifies IEEE 1588 version 2, as a choice to drive the system timing. This is useful for remote locations where no high-quality reference clock signal is available.
The IEEE 1588 protocol distributes time and frequency via Ethernet with expected end-point time-alignment time precision measured in nanoseconds. The protocol is designed to synchronize real-time clocks on the nodes of a distributed system that communicate using a network. The protocol uses a master/slave relationship to distribute timestamps from one device to the others.
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free-running — This option specifies that the System clock is in free-running mode. This option is recommended to be used only on the VLNC60/61. The clock is derived from a local SONET Stratum3 or SDH Type III (±4.6 ppm) oscillator in the VLNC60/61.
This option is recommended to be used only when all T1/E1 interfaces offer MLPPP service. By default, VLNC60/61 circuit packs have their System Timing source set as Free Running.
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line — (VLNC64 circuit pack only). This option specifies that the System clock is derived from the optical line (OC3/STM1 interface) on the VLNC64 pack.
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ge — This option specifies that the System clock is derived from SFP based GE (Ethernet interface). This is also known as the SyncE Line timing.
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backplane — This option specifies that the System clock is derived from the backplane 25 Mhz reference. In this mode timing is derived from the adjacent circuit pack. This is also known as the Backplane timing.
The timing-source {system | loop | differential} command specifies the timing source for the T1/E1 interfaces, where:
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system — The source of timing is derived from system timing configured using the system-timing-source command.
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loop — The clocking information recovered from the received signal of the T1/E1 interface is used to drive the transmit side of the same T1/E1 interface.
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differential — The clock is recovered from the real time protocol (RTP) differential timestamps on the incoming Pseudowire packet for the T1/E1. The reference timing for recovery of this clock is System.
Refer to the Alcatel-Lucent 1850 Transport Service Switch (TSS-5) Command Line Interface Guide, for help on using CLI commands.
Step
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Network Timing Distribution for CES using BITS at both ends. See Figure 17-3, Network timing distribution for CES using BITS (VLNC60/61/62s) and Figure 17-4, Network timing distribution for CES using BITS (VLNC6x) for reference. Configure BITS Line Interface Unit (LIU) external timing reference (ref-1 or ref-2) at both Remote and Hub ends. The interface <interface-number> command is used to configure the BITS input. “Interface-number” is either ref-1 or ref-2 corresponding to the BITS input for the Main slot equipped with the VLNC6x. From the Global Config Mode at both the Remote end and Hub end, enter interface ref-1 or ref-2 to enter the Interface Config Mode. From the Interface Config Mode, enter the following commands one at a time:
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This command assumes that both the Remote end and Hub end have direct access to the Primary Reference Source (PRS) or BITS. Configure system timing source. The system-timing-source {bits [alternate-source-line]| ptp-1588 | free-running | line | ge | backplane} command is used to specify a common timing source for all the devices on the VLNC6x. From the Global Config Mode at both the Remote end and Hub end, enter system-timing-source bits. If required, at a VLNC64 Hub end, enter an alternate-source of line. Example (VLNC64 only): (ALU 1850TSS-5) (Config)# system-timing-source bits alternate-source line Reference: Procedure 8-1: Configure system timing for circuit pack | ||||||
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Configure Remote end T1/E1 interface Timing source. The timing-source {system | loop | differential} command specifies the timing source for the VLNC60/61/62 T1/E1 interfaces. From the Global Config mode, enter interface <interface-number> to enter the Interface T1/E1 Config Mode. The interface-number specifies the specific T1/E1 interface on the VLNC60/61/62. This command changes the context to the Interface Config Mode and all subsequent configuration in this mode will be applicable to the interface identified by the interface-number. On the VLNC60/61/62, a T1/E1 port is addressed by "T1-Port"/"E1-Port" respectively. On the VLNC64, T1/E1 ports are addressed by "VTDS1-Port"/"VCE1-Port" respectively. See Addressable Entities in the Alcatel-Lucent 1850 Transport Service Switch (TSS-5) Command Line Interface Guide for addresses. If encapsulation has been configured on this interface and you are going to provision “differential” as the timing source for this interface, you must first remove encapsulation using no encapsulation {ppp | satop}. From the Interface Config Mode at the Remote end, enter timing-source differential. If encapsulation has not been provisioned or was removed, enter encapsulation {ppp | satop}. Reference: Procedure 8-3: Configure interface timing for DS1/E1 ports | ||||||
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Configure Hub end T1/E1 interface Timing source. The timing-source {system | loop | differential} command specifies the timing source for the T1/E1 interfaces. From the Global Config mode, enter interface <interface-number> to enter the Interface Config Mode. The interface-number is the specific interface on the VLNC6x. This command changes the context to the Interface Config Mode and all subsequent configuration in this mode will be applicable to the interface identified by the interface-number. On the VLNC60/61/62, a T1/E1 port is addressed by "T1-Port"/"E1-Port" respectively. On the VLNC64, T1/E1 ports are addressed by "VTDS1-Port"/"VCE1-Port" respectively. See Addressable Entities in the Alcatel-Lucent 1850 Transport Service Switch (TSS-5) Command Line Interface Guide for addresses. If encapsulation has been configured on this interface and you are going to provision “differential” as the timing source for this interface, you must first remove encapsulation using no encapsulation {ppp | satop}. From the Interface Config Mode at the Hub end, enter timing-source loop for applications where there is one timing source traceable to a common reference clock for the entire network. Enter timing-source differential for applications where the timing source in each direction (Hub to Remote, Remote to Hub) can be asynchronous to each other. For example: (ALU Switching) (Interface m2-1-1-1-1)# timing-source loop (VLNC64), or (ALU Switching) (Interface a-1-1)# timing-source loop (VLNC60/61/62). For the VLNC64 at the Hub end, configure the differential timing domain for the T1/E1 interface. This command specifies the differential timing domain being used to generate and recover the differential timestamps on the VLNC64. From the Interface Config Mode at the Hub end VLNC64, enter differential-timing-domain <domain-value> where domain-value is in the range 1-28. For example: (ALU Switching) (Interface m2-1-1-1-1)# differential-timing-domain 1. If encapsulation has not been provisioned or was removed, enter encapsulation {ppp | satop}. Figure 17-3: Network timing distribution for CES using BITS (VLNC60/61/62s) 
Figure 17-4: Network timing distribution for CES using BITS (VLNC6x)
Reference: Procedure 8-3: Configure interface timing for DS1/E1 ports | ||||||
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Configure timing distribution using IEEE 1588v2. See Figure 17-5, Network timing distribution for CES using ptp-1588 (VLNC60/61/62) and Figure 17-6, Network timing distribution for CES using ptp-1588 (VLNC6x) for reference. Configure BITS Line Interface Unit (LIU) external timing reference (ref-1 or ref-2) at the Hub ends. The interface <interface-number> command is used to configure the BITS input. “Interface-number” is either ref-1 or ref-2 corresponding to the BITS input for the Main slot equipped with the VLNC6x. From the Global Config Mode at the Hub end, enter interface ref-1 or ref-2 to enter the Interface Config Mode. From the Interface Config Mode, enter the following commands one at a time:
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Configure system timing source. The system-timing-source {bits [alternate-source-line]| ptp-1588 | free-running | line | ge | backplane} command is used to specify a common timing source for all the devices on the VLNC6x. From the Global Config Mode at the Hub end, enter system-timing-source bits. If required, at a VLNC64 Hub end, enter an alternate-source of line. From the Global Config Mode at the Remote end, enter system-timing-source ptp-1588. Reference: Procedure 8-1: Configure system timing for circuit pack | ||||||
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Configure ptp-1588 parameters. Reference: Procedure 17-2.6: Configure Precision Timing Protocol - 1588ver2 parameters | ||||||
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Configure Remote end T1/E1 interface Timing source. The timing-source {system | loop | differential} command specifies the timing source for the T1/E1 interfaces. From the Global Config mode, enter interface <interface-number> to enter the Interface T1/E1 Config Mode. The interface-number specifies the specific T1/E1 interface on the VLNC60/61/62. This command changes the context to the Interface Config Mode and all subsequent configuration in this mode will be applicable to the interface identified by the interface-number. On the VLNC60/61/62, a T1/E1 port is addressed by "T1-Port"/"E1-Port" respectively. On the VLNC64, T1/E1 ports are addressed by "VTDS1-Port"/"VCE1-Port" respectively. See Addressable Entities in the Alcatel-Lucent 1850 Transport Service Switch (TSS-5) Command Line Interface Guide for addresses. If encapsulation has been configured on this interface and you are going to provision “differential” as the timing source for this interface, you must first remove encapsulation using no encapsulation {ppp | satop}. From the Interface Config Mode at the Remote end, enter timing-source differential. If encapsulation has not been provisioned or was removed, enter encapsulation {ppp | satop}. Reference: Procedure 8-3: Configure interface timing for DS1/E1 ports | ||||||
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Configure Hub end T1/E1 interface Timing source. The timing-source {system | loop | differential} command specifies the timing source for the T1/E1 interfaces. From the Global Config mode, enter interface <interface-number> to enter the Interface Config Mode. The interface-number is the specific interface on the VLNC6x. This command changes the context to the Interface Config Mode and all subsequent configuration in this mode will be applicable to the interface identified by the interface-number. On the VLNC60/61/62, a T1/E1 port is addressed by "T1-Port"/"E1-Port" respectively. On the VLNC64, T1/E1 ports are addressed by "VTDS1-Port"/"VCE1-Port" respectively. See Addressable Entities in the Alcatel-Lucent 1850 Transport Service Switch (TSS-5) Command Line Interface Guide for addresses. If encapsulation has been configured on this interface and you are going to provision “differential” as the timing source for this interface, you must first remove encapsulation using no encapsulation {ppp | satop}. From the Interface Config Mode at the Hub end, enter timing-source loop for applications where there is one timing source traceable to a common reference clock for the entire network. Enter timing-source differential for applications where the timing source in each direction (Hub to Remote, Remote to Hub) can be asynchronous to each other. For example: (ALU Switching) (Interface m2-1-1-1-1)# timing-source loop (VLNC64), or (ALU Switching) (Interface a-1-1)# timing-source loop (VLNC60/61/62). For the VLNC64 at the Hub end, configure the differential timing domain for the T1/E1 interface. This command specifies the differential timing domain being used to generate and recover the differential timestamps on the VLNC64. From the Interface Config Mode at the Hub end VLNC64, enter differential-timing-domain <domain-value> where domain-value is in the range 1-28. For example: (ALU Switching) (Interface m2-1-1-1-1)# differential-timing-domain 1. If encapsulation has not been provisioned or was removed, enter encapsulation {ppp | satop}. Figure 17-5: Network timing distribution for CES using ptp-1588 (VLNC60/61/62)
Figure 17-6: Network timing distribution for CES using ptp-1588 (VLNC6x)
Figure 17-7: Network timing distribution for CES using ptp-1588 with two masters
Reference: Procedure 8-3: Configure interface timing for DS1/E1 ports End of steps |