OTN – Lesson 9 – Video 7 – OTUk_TT_Sk Function

This post presents the 7th of the 11 Videos that covers training on Performance Monitoring at the OTUk Layer. This post focuses on the Sink Direction OTU-Layer Atomic Functions.

OTN – Lesson 9 – Video 7 – OTU Layer Sink Direction Circuitry/Functionality – Part 5

This blog post contains a video that starts our discussion of the OTUk_TT_Sk Atomic Function.  

This blog post contains the 5th video that discusses the Sink (or Receive) Direction Atomic Functions at the OTU Layer.  This video is also the 7th of the 11 videos for Lesson 9.  

This video focuses on the following:

  • What is the CI_SSF input pin?
  • Near-End Error Checking  – SM-BIP-8 Verification
  • Sending SM-BEI Information based upon SM-BIP-8 Verification results.  
  • Far-End Error Checking – SM-BEI Monitoring
  • What does it mean to declare or clear the SM-BDI (or dBDI – Backward Defect Indicator) defect condition.  

Continue reading “OTN – Lesson 9 – Video 7 – OTUk_TT_Sk Function”

Lesson 2 – OTU Framing

This post provides a comprehensive review and video training of the OTU frame and its overhead fields.

Lesson 2 – Optical Transport Unit Frame Training

This post includes a video that discusses the OTU (Optical Transport Unit) frames in considerable detail.  

In particular, this video will discuss the OTU frame format and the roles each of its overhead fields plays.

Continue reading “Lesson 2 – OTU Framing”

What is pF_EBC at the OTUk Layer?

This blog post briefly describes the term pF_EBC (Far-End Errored Block Error).

What is the pF_EBC (Far-End Errored Block Count) Performance Monitoring Parameter for the OTUk Layer?

The purpose of this blog post is to briefly define and describe the pF_EBC (Far-End Errored Block Count) Performance Monitoring parameter that the OTN (Sink) STE (or OTUk_TT_Sk Atomic Function) will compute and tally.

The Sink STE (or OTUk_TT_Sk function) will include information on the pF_EBC parameter within each Performance Monitoring report it sends to System Management.

NOTES:

  1. The OTN PTE (ODUP_TT_Sk Atomic Function) also monitors and generates information on the pF_EBC (Far-End Errored Block Count) parameter at the ODUk Layer. Please see the pF_EBC at ODUk Layer Post for more details on this parameter.
  2. Throughout this post, I will use the terms: OTN STE and OTUk_TT_Sk Function interchangeably. In the context of this blog post, these two terms mean the same thing.

Introduction

At the OTUk Layer, the OTN (Sink) STE is the entity that is responsible for detecting and reporting Far-End Errored Block Counts (or SM-BEI errors).

As the Sink STE receives and monitors its incoming OTUk signal, it will check for many things. It will continuously scan the incoming OTUk signal for bit (or symbol) errors (e.g., SM-BIP-8, FEC, etc.). It will also check for Service-Affecting defects (e.g., dTIM, dLOM, dLOF, dAIS, dLOS-P, etc.).

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Definition of Terms:

Before we proceed, we need to define the following terms for this blog post:

  • Block: In this case, we define a block as an OTUk frame.
  • Far-End Errored Block: In this blog post, we define a far-end errored block as any OTUk frame that contains a value for the SM-BEI count that ranges anywhere between 1 and 8. Anytime the OTN STE receives a block with an SM-BEI count value of 0x0, we consider that block to be an un-erred block.

As the Sink STE checks the incoming OTUk signal for errors and defects, it will also record the total number of far-end errored blocks it detects for each one-second period.

At the end of a given one-second period, the Sink STE will load the total number of far-end errored block counts (detected in the most recent one-second period) into the variable pF_EBC.

The Sink STE will then report this value for pF_EBC to System Management as a part of its Performance Monitoring report.

Table 1 presents the number of blocks/second that each type of OTUk signal will transport for each value of k.

Table 1, Number of Blocks/Second for each OTUk Rate.

OTUk TypeNumber of Blocks/Second
OTU120,421
OTU282,026
OTU3329,492
OTU4856,388
OTUCnn x 860,177

So How does the OTN STE tally Errored Blocks for the pF_EBC parameter?

As the Sink STE receives and monitors its OTUk signal, it will continually check the SM-BEI counts within each incoming OTUk frame (or block).

Anytime the Sink STE receives an OTUk frame in which the SM-BEI value is anywhere from 1 to 8, it will increment its internal (pF_EBC Counter) by 1.

NOTE: This means that even if the Sink STE receives an SM-BEI value of “8”, it will still just increment its pF_EBC Counter by 1 (not 8).

Conversely, the Sink STE will not increment its internal pF_EBC Counter whenever it receives an OTUk frame (or block) that contains an SM-BEI value of 0, or 9 through 15. The Sink STE consider these type of OTUk frames to be un-erred.

At the end of each one-second period, the Sink STE will load the contents of this internal counter into the pF_EBC parameter. The Sink STE will then include that information within its Performance Monitor report that it sends to System Management.

Are there any Times or Conditions during which the Sink STE will NOT tally Errored Block Counts for the pF_EBC parameter?

Yes, ITU-T G.798 states that the OTUk_TT_Sk function will stop tallying Errored Blocks for the pF_EBC parameter whenever the upstream circuitry (e.g., the OTSi/OTUk_A_Sk or OTSiG/OTUk_A_Sk Atomic Function) asserts the CI_SSF input of the OTUk_TT_Sk function.

In other words, the Sink STE will not tally any Errored Block Counts (for the pF_EBC parameter) whenever it (e.g., the OTSi/OTUk_A_Sk or OTSiG/OTUk_A_Sk functions) declare any of the following service-affecting defect conditions.

NOTE: (*) – Indicates that one must have a membership to THE BEST DARN OTN TRAINING PRESENTATION…PERIOD!!!, to access this information.

Additionally, the OTUk_TT_Sk function is not supposed to increment any pF_EBC counts whenever it declares the dBIAE (Backward Input Alignment Error) defect condition.

Is there such a thing as Near-End Errored Block Counts?

Throughout this post, we have used the term Far-End Errored Block Count. Does this mean that there is another parameter called Near-End Errored Block Count?

Answer: Yes, there is such a parameter. Please see the Near-End Errored Block Count post at the OTUk Layer for more details.

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What is pN_EBC at the OTUk Layer?

This blog post briefly describes the Performance-Monitoring parameter or term pN_EBC (Near-End Errored Block Count) for the OTUk-Layer.

What is the pN_EBC (Near-End Errored Block Count) Performance-Monitoring Parameter for the OTUk Layer?

This blog post aims to briefly define and describe the pN_EBC (Near-End Errored Block Count) Performance Monitoring parameter that the Sink STE (or OTUk_TT_Sk Atomic Function) will compute and tally.

The Sink STE (or OTUk_TT_Sk function) will include information on the pN_EBC parameter within each Performance Monitoring report it sends to System Management.

NOTES:

  1. The OTN PTE (or ODUP_TT_Sk Atomic Function) also monitors and generates information on the pN_EBC (Near-End Errored Block Count) parameter at the ODUk Layer. Please see the pN_EBC at ODUk Layer Post for more details on this parameter.
  2. Throughout this post, I will use the terms: Sink STE and OTUk_TT_Sk Function interchangeably. In the context of this blog post, these two terms mean the same thing.

Introduction

At the OTUk Layer, the OTN (Sink) STE is the entity that is responsible for detecting and reporting Near-End Errored Block Counts (or SM-BIP-8 Errors).

NOTE: We refer to SM-BIP-8 errors as Near-End errors because these are errors that the Near-End Sink STE is detecting on its end. In contrast, we refer to the SM-BEI parameter as Far-End errors because that parameter reflects errors that a remote (or Far-End) Sink STE is detecting and reporting.

As the Sink STE receives and monitors its incoming OTUk signal, it will check for many things. It will continuously scan the incoming OTUk signal for bit (or symbol) errors (e.g., SM-BIP-8 errors, FEC errors, etc.) as well as Service-Affecting Defects (e.g., dTIM, dLOF, dLOM, dLOS-P, dAIS, etc.).

Definition of Terms:

Before we proceed, we need to define the following terms for this blog post:

  • Block: In this case, we define a block as an OTUk frame.
  • Errored Block: In this blog post, we define an errored block as any OTUk frame (or block) that contains at least one SM-BIP-8 error.

As the Sink STE checks the incoming OTUk signal for errors and defects, it will also keep a count of the number of errored blocks it detects for each one-second period.

At the end of a given one-second period, the Sink STE will load the total number of errored block counts (detected and tallied in the most recent one-second period) into the variable pN_EBC.

Since each type of OTUk signal (for a given value of k) transmits a different number of OTUk frames than does another OTUk signal (with a different value for k), each OTUk type will transmit a different number of blocks/second, as we show below in Table 1.

Table 1, Number of Blocks/Second for each OTUk Rate

OTUk TypeNumber of Blocks/Second
OTU120,421
OTU282,026
OTU3329,492
OTU4856,388
OTUCnn x 860,177

So How does the OTN STE tally Errored Blocks for the pN_EBC parameter?

As the Sink STE receives and monitors its OTUk signal, it will continually check for SM-BIP-8 errors.

Anytime the Sink STE receives an OTUk frame that contains at least one SM-BIP-8 error, then it will increment its internal (pN_EBC Counter) by 1.

Conversely, the Sink STE does not increment its internal pN_EBC Counter whenever it receives an OTUk frame that contains 0 SM-BIP-8 errors.

At the end of each one-second period, the Sink STE will load the contents of this internal counter into the pN_EBC parameter and include that information within its Performance Monitor report that it sends to System Management.

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Are there any Times or Conditions during which the OTN STE will NOT tally Errored Block Counts for the pN_EBC parameter?

Yes, ITU-T G.798 states that the OTUk_TT_Sk function will stop tallying Errored Blocks for the pN_EBC parameter whenever the upstream circuitry (e.g., the OTSi/OTUk_A_Sk or OTSiG/OTUk_A_Sk Atomic function) asserts the CI_SSF input of the OTUk_TT_Sk function.

In other words, the OTN STE will not tally any Errored Block Counts (for the pN_EBC parameter) whenever it (e.g., the OTSi/OTUk_A_Sk or OTSiG/OTUk_A_Sk functions) declares any of the following service-affecting defects conditions.

NOTE: (*) indicates that you must have a membership with THE BEST DARN OTN TRAINING PRESENTATION…PERIOD!!!, to be able to access these lessons.

Additionally, the OTUk_TT_Sk function is not supposed to increment any pN_EBC counts whenever it declares the dIAE (Input Alignment Error) defect condition.

Is there such a thing as Far-End Errored Block Counts?

Throughout this post, we have used the term Near-End Errored Block Count. Does this mean that there is another parameter called Far-End Errored Block Count?

Answer: Yes, there is such a parameter. Please see the Far-End Errored Block Count post at the OTUk Layer for more details.

Clueless about OTN? We Can Help!!! Click on the Banner Below to Learn More.

Discounts Available for a Short Time!!

And Finally, Click on the Following Image for More OTN-Related Topics in this Blog

OTN Related Blog

OTN Related Topics within this Blog

OTN Related Topics within this Blog General Topics Consequent Equations - What are they and How can you use them? ...
Read More