OTN – Lesson 10 – Video 5N – ODUk_TT_Sk Atomic Function

This post presents the 5th of the 7 Videos that covers training on the Peformance Monitoring of the ODUk Layer (for Non-Multiplexed Applications). This post focuses on the Sink Direction ODU-Layer Atomic Functions. More specifically, this post presents a video that discusses how the ODUk_TT_Sk Atomic Function declares and clears the PM-dDEG defect condition.

OTN – Lesson 10 – Video 5N – The ODUk_TT_Sk Atomic Function

This blog post presents a video that continues our discussion of the ODUk_TT_Sk Atomic Function.  

This video covers the following features within the ODUk_TT_Sk Atomic Function.

  • How the ODUk_TT_Sk function declares and clears the dDEG (Path Signal Degrade) defect condition?
  • What does the ODUk_TT_Sk function do with its AI_TSF Output pin whenever it declares a Service-Affecting defect condition?
  • What does the ODUk_TT_Sk function do with its AI_TSD Output pin whenever it declares the dDEG (Signal Degrade) defect condition?  
  • Defect Correlation Equation Analysis
  • Consequent Equation Analysis 
  • Performance Monitoring Equation Analysis

Continue reading “OTN – Lesson 10 – Video 5N – ODUk_TT_Sk Atomic Function”

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.).

New Comprehensive OTN Training…Available Now. Click on the Banner Below to Learn More!!!

Discounts Available for a Short Time!!!

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.

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