Pseudo Random Binary Sequence

Pseudo Random Binary Sequence

The Pseudo Random Binary Sequence (PRBS) feature enables data integrity checks between NCS 1014 trunk and client links without generating client traffic.

The PRBS feature must be enabled on both the transmitting and receiving ports to ensure error-free traffic during link bring-up. The transmitting port creates and sends a bit pattern to the peer device. The NCS 1014 device verifies that the correct pattern is received. Additionally, PRBS is supported on the ODU4 controller by the 1.2T card.

You can configure PRBS on a coherentDSP or Ethernet controller of a 1.2T, 2.4T, or 2.4TX cards. PRBS can also be configured on a ODU controller of the 1.2T card. Before enabling PRBS, the secondary admin state of the controllers must be set to maintenance.

PRBS modes

PRBS operates in several modes, each offering unique functionality:

  • Source mode: The NCS 1014 trunk port generates a PRBS signal on the line continuously according to the configured PRBS pattern

  • Sink mode: The NCS 1014 trunk port locks onto the ingress signal according to the configured pattern, analyzes, and reports the errors.

  • Source-Sink mode: The NCS 1014 trunk port acts as both the PRBS transmitter and receiver, meaning it generates a PRBS signal according to the configured pattern, locks onto the ingress signal with the same pattern, and reports the errors.

Configure PRBS on CoherentDSP controller

Use this task to configure PRBS on the trunk port of the coherentDSP controller of a card.

Procedure

Step 1

Run the controller coherentDSP R/S/I/P command to enter the coherentDSP controller configuration mode.

Example:


RP/0/RP0/CPU0:ios(config)#controller CoherentDSP 0/0/0/7

Step 2

Run the secondary-admin-state { normal | maintenance} command to set the secondary admin state.

Example:


RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance

Step 3

Run the prbs mode {source | sink | source-sink} pattern {pn31 | pn23 | pn15 | pn7} command to configure the PRBS mode and pattern.

Example:


RP/0/RP0/CPU0:ios(config-CoDSP)#prbs mode source-sink pattern pn15

Step 4

Commit the changes.

Example:


RP/0/RP0/CPU0:ios(config-CoDSP)#commit

Configure PRBS on ODU controller

You can configure PRBS in these combinations for an ODU controller on a 1.2T card.

The client ports need to have a physical loopback in all the combinations:

  • Near end client and near end trunk ODU4

  • Near end client and far end client ODU4

  • Near end client and far end trunk ODU4

  • Near end trunk and far end trunk ODU4

Use this task to enable PRBS on ODU4 controller's trunk ports of a 1.2T card in configuration mode.

Procedure

Step 1

Run the controller odu4 R/S/I/P command to enter the odu4 controller configuration mode.

Example:


RP/0/RP0/CPU0:ios(config)#controller odu4 0/0/0/7

Step 2

Run the secondary-admin-state { normal | maintenance} command to set the secondary admin state.

Example:

RP/0/RP0/CPU0:ios(config-eth-ctrlr)#secondary-admin-state maintenance

Step 3

Run the opu prbs mode {source | sink | source-sink} pattern {pn31 | pn23 | pn15 | pn7} command to configure the PRBS mode and pattern.

Example:

RP/0/RP0/CPU0:ios(config-eth-ctrlr)#prbs mode source-sink pattern pn23

Step 4

Commit the changes.

Example:

RP/0/RP0/CPU0:ios(config-eth-ctrlr)#commit

Configure PRBS on Ethernet controller

Use this task to configure PRBS on the client ports of an Ethernet controller of the 2.4T and 2.4TX cards.

Procedure

Step 1

Run the controller {fourHundredGigECtrlr} R/S/I/P command to enter the ethernet controller configuration mode.

Example:

RP/0/RP0/CPU0:ios(config)#controller FourHundredGigECtrlr 0/3/0/1

Step 2

Run the secondary-admin-state { normal | maintenance} command to set the secondary admin state.

Example:


RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance

Step 3

Run the opu prbs mode {source | sink | source-sink} pattern {pn31 | pn23 } command to configure the PRBS mode and pattern.

Example:

RP/0/RP0/CPU0:ios(config-eth-ctrlr)#prbs mode source-sink pattern pn31

Step 4

Commit the changes.

Example:

RP/0/RP0/CPU0:ios(config-eth-ctrlr)#commit

Verify PRBS on controllers

Use this task to verify PRBS details on the controllers.

Procedure

Step 1

Run the show controllers fourHundredGigEctrlr R/S/I/P prbs-details command to display PRBS details configured on an Ethernet controller.

Example:

RP/0/RP0/CPU0:ios#show controllers fourHundredGigEctrlr 0/0/0/4 
Fri Sep 25 09:45:18.222 UTC
Operational data for interface FourHundredGigECtrlr0/0/0/4:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    PRBS: 
      Status: Locked
      Mode: Source-sink
      Pattern: PN31
      Direction: Line
      Framing: Framed
      Configured Time: 25 Sep 09:44:56 (22 seconds elapsed)
      First Lock Established Time: 25 Sep 09:44:59 (19 seconds elapsed)
      Lock Time(in seconds): 19
      Bit errors: 0
      Lock Found count: 1
      Lock Lost count: 0
      Result: PASS
    Laser Squelch: Disabled
    Insert Idle Ingress: Disabled
    Insert Idle Egress: Disabled
    State transition count: 1
    Last link flapped: 00:29:47

Step 2

Run the show controllers coherentDSP R/S/I/P prbs-details command to display PRBS details configured on a coherentDSP controller.

Example:

RP/0/RP0/CPU0:ios#show  controllers coherentDSP 0/0/0/7 prbs-details
Wed Nov 15 18:13:35.210 UTC

----------------------PRBS details------------------
PRBS Test               : Enable
PRBS Mode               : Source-Sink
PRBS Pattern            : PN15
PRBS Status             : Locked

Step 3

Run the show controllers ODU R/S/I/P prbs-details command to display PRBS details configured on an ODU controller where the PRBS status is displayed as Not Applicable, when the mode is Source.

Example:

RP/0/RP0/CPU0:ios#show controllers ODU4 0/3/0/8 prbs-details
Mon Jan 11 05:29:12.436 UTC

 -------------------------PRBS details----------------------------------
PRBS Test                       : Enable
PRBS Mode                       : Source
PRBS Pattern                    : PN7
PRBS Status                     : Not Applicable

---------------------------------------------------

Verify the PRBS performance monitor parameters

Use this task to verify the PRBS performance monitoring parameters on a coherentDSP, ODU, or Ethernet controller.

Procedure

Step 1

Run the show controllers coherentDSP R/S/I/P pm {current | history }{15-min|24-hour} prbs command.

Example:

RP/0/RP0/CPU0:ios#show controllers coherentDSP 0/0/0/7 pm current 15-min prbs
Wed Nov 15 18:19:10.308 UTC

 PRBS in the current interval [18:15:00 - 18:19:10 Wed Nov 15 2023]

 PRBS current bucket type : Valid

 EBC          : 0           Threshold : 0         TCA(enable)  : NO
 FOUND-COUNT  : 0           Threshold : 0         TCA(enable)  : NO
 LOST-COUNT   : 0           Threshold : 0         TCA(enable)  : NO

 FOUND-AT-TS  : NULL
 LOST-AT-TS   : NULL

 CONFIG-PTRN  : PRBS_PATTERN_PN15
 STATUS       : LOCKED

Last clearing of "show controllers OTU" counters never

Step 2

Run the show controllers ODU4 R/S/I/P pm {current | history }{15-min|24-hour} prbs command to view PRBS performance monitoring parameters for a 15-minute sampling interval on an ODU controller.

Example:

RP/0/RP0:ios#show controllers ODU4 0/3/0/1 pm current 15-min prbs
Mon Jan 11 00:58:48.327 UTC 
 
PRBS in the current interval [00:45:00 - 00:58:48 Mon Jan 11 2021] 
PRBS current bucket type : Valid 
EBC                      : 40437528165 
FOUND-COUNT              : 1 FOUND-AT-TS : 00:51:22 Mon Jan 11 2021
LOST-COUNT               : 1 LOST-AT-TS  : 00:52:52 Mon Jan 11 2021
CONFIG-PTRN              : PRBS_PATTERN_PN7
Last clearing of "show controllers ODU" counters never

Step 3

Run the show controllers ODU4 R/S/I/P pm {current | history }{15-min|24-hour} prbs command to view PRBS performance monitoring parameters for a 15-minute sampling interval on an Ethernet controller.

Example:

RP/0/RP0/CPU0:ios#show controllers fourHundredGigEctrlr 0/0/0/4 pm current 15-min prbs
Wed Nov 15 18:48:19.114 UTC

 PRBS in the current interval [18:45:00 - 18:48:19 Wed Nov 15 2023]

 PRBS current bucket type : Valid

 EBC          : 0           Threshold : 0         TCA(enable)  : NO
 FOUND-COUNT  : 0           Threshold : 0         TCA(enable)  : NO
 LOST-COUNT   : 0           Threshold : 0         TCA(enable)  : NO

 FOUND-AT-TS  : NULL
 LOST-AT-TS   : NULL

 CONFIG-PTRN  : PRBS_PATTERN_PN23
 STATUS       : LOCKED

Last clearing of "show controllers ETHERNET" counters never

This table describes the fields of PRBS PM parameters.

Table 1. PRBS PM parameters

PM parameter

Description

EBC

Cumulative count of PRBS bit errors in the sampling interval (15-minute or 24-hour). PRBS bit errors are accumulated only if PRBS signal is locked.

FOUND-COUNT

Number of state transitions from signal unlocked state to signal locked state in the sampling interval. If state change is not observed in the interval, the count is 0.

LOST-COUNT

Number of state transitions from signal locked state to signal unlocked state in the sampling interval. If state change is not observed in the interval, the count is 0.

FOUND-AT-TS

Latest timestamp when the PRBS state moves from unlocked state to locked state in the sampling interval. If state change is not observed in the interval, the value is null.

CONFIG-PTRN

Configured PRBS pattern on the port.

STATUS

Displays the PRBS status.

Clear PRBS bit errors and lock time

Lock time refers to the duration elapsed since the last PRBS lock was detected.

Use this task to clear the bit errors and lock time.

Procedure

Step 1

Run the show controllers ODU4 R/S/I/P prbs-details command to show that bit errors are observed during the PRBS test.

Example:


RP/0/RP0/CPU0:ios#show controllers odu4 0/2/0/5 prbs-details
Fri Nov 13 03:21:44.191 UTC

-------------------------PRBS details----------------------------------
PRBS Test : Enable
PRBS Mode : Source-Sink
PRBS Pattern : INVERTED PN31
PRBS Status : Locked
PRBS Direction : Line
PRBS Lock Time(in seconds) : 28
PRBS Bit Errors : 23776

---------------------------------------------------

Step 2

Run the clear controller ODU4 R/S/I/P prbs details command to clear the lock time and bit errors before the PRBS test.

Example:


RP/0/RP0/CPU0:ios#clear controller odu4 0/2/0/5 prbs-details
Fri Nov 13 03:21:50.726 UTC
PRBS bit errors cleared
This sample shows the removal of bit errors and lock time.

RP/0/RP0/CPU0:ios#show controllers odu4 0/2/0/5 prbs-details
Fri Nov 14 03:21:44.191 UTC
-------------------------PRBS details----------------------------------
PRBS Test : Enable
PRBS Mode : Source-Sink
PRBS Pattern : INVERTED PN31
PRBS Status : Locked
PRBS Direction : Line
PRBS Lock Time(in seconds) : 2
PRBS Bit Errors : 0

Trunk PRBS

Table 2. Feature History

Feature Name

Release Information

Description

Cumulative PRBS on CoherentDSP controllers

Cisco IOS XR Release 24.3.1

The cumulative PRBS (Pseudo-Random Binary Sequence) on CoherentDSP controllers enhances troubleshooting capabilities between the trunk ports.

Show coherentDSP R/S/I/P prbs-details command output now includes the newly supported fields.

The trunk PRBS feature performs data integrity checks between trunk links without generating actual client traffic.

NCS 1014 trunk port supports these PRBS patterns:

  • PRBS31: Sequence length is from 2^31 -1 bits.

  • PRBS23: Sequence length is from 2^23 -1 bits.

  • PRBS15: Sequence length is from 2^15 -1 bits.

  • PRBS7: Sequence length is from 2^7 -1 bits.


Tip

It is recommended to use these patterns for higher datarates like 100G and 400G:

  • high sequence length PRBS patterns

  • PRBS inverted pattern

Note

The ethernet PRBS PN23 pattern interoperability is not supported on the 2.4T and 2.4TX cards.


Note

In case of muxponder configuration, PRBS is not supported on the split ports of the 2.4TX card.

Configure the trunk PRBS

Use this task to configure PRBS trunk mode on the NCS1K4-2.4T-K9 card.

Procedure

Step 1

Run the controller coherentDSP R/S/I/P command to enter the coherentDSP controller configuration mode.

Example:


RP/0/RP0/CPU0:ios(config)#controller CoherentDSP0/0/0/7
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance
RP/0/RP0/CPU0:ios(config-CoDSP)#prbs mode source-sink pattern pn15
RP/0/RP0/CPU0:ios(config-CoDSP)#commit
Wed Nov 15 18:11:55.450 UTC

Step 2

Run the show controllers coherentDSP R/S/I/P prbs-details command to display PRBS details configured on a coherentDSP controller.

Example:

RP/0/RP0/CPU0:ios#show controllers coherentDSP 0/0/0/7 prbs-details
Wed Nov 15 18:13:35.210 UTC

----------------------PRBS details------------------
PRBS Test               : Enable
PRBS Mode               : Source-Sink
PRBS Pattern            : PN15
PRBS Status             : Locked
PRBS Lock Time(in seconds)      : 37
PRBS Bit Errors                 : 0
PRBS Found Count                : 1
PRBS Lost Count                 : 0
PRBS Configured Time            : 11 Feb 00:20:43 (719 seconds elapsed)
PRBS First Lock Established Time: 11 Feb 00:32:05 (37 seconds elapsed)
Result Summary                  : PASS

The Result Summary will display PASS if the PRBS bit errors are 0 and the PRBS elapsed lock time is equal to the elapsed first lock established time.

Step 3

Run the clear controllers coherentDSP R/S/I/P prbs-details command to clear the counters.

Example:

clear controller coherentDSP 0/0/0/7 prbs-detailsentDSP

Step 4

Run the show controllers coherentDSP R/S/I/P prbs-details command to display cumulative count of PRBS bit errors in the 15-min sampling interval.

Example:

RP/0/RP0/CPU0:ios#show controllers coherentDSP 0/0/0/7 pm current 15-min prbs
Wed Nov 15 18:19:10.308 UTC

 PRBS in the current interval [18:15:00 - 18:19:10 Wed Nov 15 2023]

 PRBS current bucket type : Valid

 EBC          : 0           Threshold : 0         TCA(enable)  : NO
 FOUND-COUNT  : 0           Threshold : 0         TCA(enable)  : NO
 LOST-COUNT   : 0           Threshold : 0         TCA(enable)  : NO

 FOUND-AT-TS  : NULL
 LOST-AT-TS   : NULL

 CONFIG-PTRN  : PRBS_PATTERN_PN15
 STATUS       : LOCKED

Last clearing of "show controllers OTU" counters never

Client PRBS

Table 3. Feature History

Feature Name

Release Information

Description

New PRBS Counters on Ethernet Controllers

Cisco IOS XR Release 24.4.1

The new Pseudo-Random Binary Sequence (PRBS) counters on Ethernet controllers collect statistics in a cumulative manner.

The output of the show controllers controller-type R/S/I/P command now includes these counters:

  • Configured Time

  • First Lock Established Time.

  • Lock Time (in seconds)

  • Bit Errors

  • Lock Found Count

  • Lock the Lost Count

  • Result

The client PRBS feature performs data integrity checks without generating client traffic on client links.

The NCS 1014 client port supports these PRBS patterns:

  • PRBS31: Sequence length is from 2^31 -1 bits.

  • PRBS23: Sequence length is from 2^23 -1 bits.

Configure the client PRBS

Use this task to configure PRBS client mode on the NCS1K4-2.4T-K9 card.

Procedure

Step 1

Run the controller {fourHundredGigECtrlr} R/S/I/P command to enter the four hundred gigabit client controller configuration mode.

Example:

RP/0/RP0/CPU0:ios(config)#controller fourHundredGigECtrlr 0/2/0/4
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#prbs mode source-sink pattern <pn31|pn23> direction system <line|system> 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#commit

Step 2

Run the show controllers fourHundredGigEctrlr R/S/I/P prbs-details command to display four hundred gigabit client controllers details.

Example:

RP/0/RP0/CPU0:ios#show controllers fourHundredGigEctrlr 0/0/0/4            
Fri Sep 25 09:48:03.959 UTC
Operational data for interface FourHundredGigECtrlr0/0/0/4:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    PRBS: 
      Status: Locked
      Mode: Source-sink
      Pattern: PN31
      Direction: Line
      Framing: Framed
      Configured Time: 25 Sep 09:44:56 (187 seconds elapsed)
      First Lock Established Time: 25 Sep 09:47:52 (11 seconds elapsed)
      Lock Time(in seconds): 11
      Bit errors: 0
      Lock Found count: 0
      Lock Lost count: 0
      Result: PASS
    Laser Squelch: Disabled
    Insert Idle Ingress: Disabled
    Insert Idle Egress: Disabled
    State transition count: 1
    Last link flapped: 00:32:32

The Result displays PASS, only if the First Lock Established Time and Lock Time (in seconds) are same, and Bit errors is 0.

Step 3

Run the clear controllers fourHundredGigEctrlr R/S/I/P prbs-details command to clear four hundred gigabit client controller PRBS statistics.

Example:


RP/0/RP0/CPU0:ios#clear controller fourHundredGigEctrlr 0/0/0/4 prbs-stats 
Fri Sep 25 09:47:52.678 UTC
Operational data for interface FourHundredGigECtrlr0/0/0/4:
State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    PRBS: 
      Status: Locked
      Mode: Source-sink
      Pattern: PN31
      Direction: Line
      Framing: Framed
      Configured Time: 25 Sep 09:44:56 (179 seconds elapsed)
      First Lock Established Time: 25 Sep 09:47:52 (3 seconds elapsed)
      Lock Time(in seconds): 3
      Bit errors: 0
      Lock Found count: 0
      Lock Lost count: 0
      Result: PASS
    Laser Squelch: Disabled
    Insert Idle Ingress: Disabled
    Insert Idle Egress: Disabled
    State transition count: 1
    Last link flapped: 00:32:24

Step 4

Run the show controllers fourHundredGigEctrlr R/S/I/P prbs-details command to display four hundred gigabit client controller PRBS bit errors in the 15-min sampling interval.

Example:

RP/0/RP0/CPU0:ios#show controllers fourHundredGigEctrlr 0/0/0/4 pm current 15-min prbs
Wed Nov 15 18:48:19.114 UTC
 PRBS in the current interval [18:45:00 - 18:48:19 Wed Nov 15 2023]
 PRBS current bucket type : Valid
 EBC          : 0           Threshold : 0         TCA(enable)  : NO
 FOUND-COUNT  : 0           Threshold : 0         TCA(enable)  : NO
 LOST-COUNT   : 0           Threshold : 0         TCA(enable)  : NO
 FOUND-AT-TS  : NULL
 LOST-AT-TS   : NULL
 CONFIG-PTRN  : PRBS_PATTERN_PN23
 STATUS       : LOCKED

Last clearing of "show controllers ETHERNET" counters never