OTN – Lesson 12 – Detailed Discussion of SNC/S Monitoring (Protection Switching)

This blog post presents a video that describes (in detail) SNC/S (Subnetwork Circuit Protection – Sublayer) Monitoring for Protection Switching.

Lesson 12 – Video 7 – Detailed Discussion of SNC/S (Subnetwork Circuit – Sublayer) Monitoring for Protection Switching

This blog post contains a video that presents a detailed discussion of SNC/S (Subnetwork Circuit – Sublayer) Monitoring for Protection Switching purposes, at the ODU Layer.

In particular, this video will discuss the following topics:

  • A Detailed Review of SNC/S (Subnetwork Circuit Protection/Sublayer) Monitoring.
  • This video shows example locations/conditions of where we would use SNC/S Monitoring and why we would use this form of monitoring.
  • This video also highlights similarities of SNC/S with SNC/I Monitoring.
  • It also shows the distinct differences between SNC/S and SNC/Ne or SNC/Ns monitoring.
  • Finally, this video reviews a Multi-Administrative Domain Network (and
    Tandem Connection Monitoring) and describes how SNC/S works within a given “Protect Domain”.

Check Out the Video Below.

Continue reading “OTN – Lesson 12 – Detailed Discussion of SNC/S Monitoring (Protection Switching)”

OTN – Lesson 11 – Tandem Connection Monitoring Multi-Administration Domain Walk-Thru – Part TWO

This post serves as Part TWO (and the Final Part) for the Multi-Administrative Domain Walk Through and Analysis for our study of Tandem Connection Monitoring.

Lesson 11 – Video 9 – TCM Multi-Administration Domain Walk Through – Part TWO

This blog post contains a video that covers the second (and final) part of the Multi-Administrative Domain Walk-Through.

In particular, this video covers the following topics:

  • Part TWO of our Multi-Administration Domain Walk-Through (using our knowledge of TCM-related atomic functions to analyze this network).

In particular, this post covers the following parts of the Multi-Administration Domain Walk-Through.

  • Initializing the Serving Operating Domain (Operator B) – TCM Level 3
  • Terminating the Serving Operating Domain (Operator B) – TCM Level 3
  • Initalizing the Serving Operating Domain (Operator C) – TCM Level 3
  • Initializing the Protect Domain – TCM Level 4
  • Terminating the Protect Domain – TCM Level 4
  • Terminating the Serving Operating Domain (Operator C) – TCM Level 3
  • Terminating the Leased Service Serving Operator Domain – TCM Level 2
  • Terminating the Service Requesting Domain – TCM Level 1

This video serves as Part TWO (and the Final Part) of our Multi-Administration Domain Walk-Through and Analysis.

Check Out the Video Below.

Continue reading “OTN – Lesson 11 – Tandem Connection Monitoring Multi-Administration Domain Walk-Thru – Part TWO”

OTN – Lesson 11 – Tandem Connection Monitoring Controller and Multi-Administration Domain Walk-Thru – Part ONE

This blog post briefly introduces the Tandem Connection Monitoring Controller Atomic Function. This post also serves as Part ONE for the Multi-Administrative Domain Walk Through and Analysis.

Lesson 11 – Video 8 – TCM Controller and Multi-Administration Domain Walk-Through – Part ONE

This blog post contains a video that covers the first part of the Multi-Administrative Domain Walk-Through.

In particular, this video covers the following topics:

  • An Introduction to the TCM (Tandem Connection Monitoring) Controller Atomic Function
  • An Overview of What We Have Covered thus far – In Lesson 11, and Where We’re Going
  • Introduction to Compound (Atomic Functions)
    • Definition/Introduction to the Source Compound Function
    • Definition/Introduction to the Sink Compound Function
  • Part ONE of our Multi-Administration Domain Walk-Through (using our knowledge of TCM-related atomic functions to analyze this network).

In particular, this post covers the following parts of the Multi-Administration Domain Walk-Through.

  • Initializing the Service Requesting Domain – TCM Level 1
  • How We Initialize the Leased Service Serving Operator Domain – TCM Level 2
  • Initializing the Serving Operating Domain (Operator A) – TCM Level 3
  • Terminating the Serving Operating Domain (Operator A) – TCM Level 3

This video serves as Part ONE of our Multi-Administration Domain Walk-Through and Analysis.

Check Out the Video Below

Continue reading “OTN – Lesson 11 – Tandem Connection Monitoring Controller and Multi-Administration Domain Walk-Thru – Part ONE”

OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 5

This blog post includes a video that discusses both the ODUTm_TT_Sk (Non-Intrusive Monitoring) Function and the ODUT/ODU_A_Sk Atomic Function. This is the last blog post to describe and define the TCM-related Atomic Functions.

Lesson 11 – Video 7 – Tandem Connection Monitoring – ODUTm_TT_Sk and ODUT/ODU_A_Sk Atomic Functions

This blog post contains a video that covers the fifth part of the Sink Direction Tandem Connection Monitoring (TCM) related Atomic Functions.

In particular, this video covers the following two atomic functions:

  • ODUTm_TT_Sk (Atomic Function for Non-Intrusive Monitoring – TCM Applications), and
  • ODUT/ODU_A_Sk

More specifically, this video covers the following aspects of each of these Atomic Functions.

  • ODUTm_TT_Sk Atomic Function
    • Applications in which we would use the ODUTm_TT_Sk Atomic Function (e.g., Non-Intrusive Monitoring for TCM Subnetworks)
    • A brief overview of this function’s capabilities and attributes
    • How this function differs from the ODUT_TT_Sk Atomic Function.
      • When the ODUT_TT_Sk Function is operating in the OPERATIONAL Mode
      • If the ODUT_TT_Sk Function is operating in the MONITOR Mode, and
      • When the ODUT_TT_Sk Function is operating in the TRANSPARENT Mode
  • ODUT/ODU_A_Sk Atomic Function
    • Where this function fits into the Tandem Connection Monitoring Network
    • The Architecture/Functionality of the ODUT/ODU_A_Sk Function
      • Operation in the various TCM Modes (e.g., OPERATIONAL and MONITOR/TRANSPARENT).
      • The Protection Port (for Automatic Protection Switching support).
      • The Removal Block – How this function terminates the “Selected TCMOH and APS/PCC field”.
      • Replacing the Normal ODU signal (carrying client data) with either the ODU-AIS or ODU-LCK Maintenance Signals.
      • Asserting CI_SSF and CI_SSD in response to upstream defect conditions.

This video completes our discussion/review of the TCM-related Atomic Functions.

Check Out the Video Below.

Continue reading “OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 5”

OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 4

This blog post presents the fourth and final video of the ODUT_TT_Sk Atomic Function. This video discusses how the ODUT_TT_Sk function supports Performance Monitoring at TCM Level i.

Lesson 11 – Video 6 – Tandem Connection Monitoring – ODUT_TT_Sk Atomic Function, Part FOUR

This blog post contains a video that covers the fourth part of the Sink Direction Tandem Connection Monitoring (TCM) related Atomic Functions.

In particular, this video covers the fourth part of the ODUT_TT_Sk Atomic Function.

More specifically, this video covers the following Performance Monitoring parameters, that the ODUT_TT_Sk Atomic Function generates.

  • TCMi-pN_DS (TCM Level i, Near-End Defect Seconds)
  • TCMi-pF_DS (TCM Level i, Far-End Defect Seconds)
  • TCMi-pN_EBC (TCM Level i, Near-End Error-Block Count)
  • TCMi-pF_EBC (TCM Level i, Far-End Error-Block Count)
  • pN_delay – TCM Level i, Round-Trip Subnetwork Delay

This video also briefly describes the functionality of the ODUT_TT_Sk Atomic Function, whenever it has been configured to operate in both the:

  • Monitor Mode, and
  • Transparent Mode

This video completes our discussion of the ODUT_TT_Sk Atomic Function.

Check Out the Video Below.

Continue reading “OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 4”

OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 3

This blog post includes a video that serves as the 3rd (of our 4 Videos) that discusses the ODUT_TT_Sk Atomic Function. This video focuses on the TCMi-dDEG (Signal Degrade) defect condition, Defect Correlation and Consequent Equations.

Lesson 11 – Video 5 – Tandem Connection Monitoring – ODUT_TT_Sk Atomic Function, Part THREE

This blog post contains a video that covers the third part of the Sink Direction Tandem Connection Monitoring (TCM) related Atomic Functions.

In particular, this video covers the third part of the ODUT_TT_Sk Atomic Function.

More specifically, this video covers the following operations (within the ODUT_TT_Sk Atomic Function).

  • How the ODUT_TT_Sk Atomic Function declares and clears the TCMi-dDEG (Signal Degrade) defect condition
  • Defect Correlation within the ODUT_TT_Sk Atomic Function. This video reviews the following Defect Correlation Equations:
    • cSSF <- CI_SSF or dAIS;
    • cLTC <- dLTC and (NOT CI_SSF);
    • cOCI <- dOCI and (NOT CI_SSF);
    • cLCK <- dLCK and (NOT CI_SSF);
    • cTIM <- dTIM and (NOT CI_SSF) and (NOT dAIS) and (NOT dLTC) and (NOT dOCI) and (NOT dLCK);
    • cDEG <- dDEG and (NOT CI_SSF) and (NOT dAIS) and (NOT dLTC) and (NOT dOCI) and (NOT dLCK) and (NOT(dTIM and (NOT TIMActDis)));
    • cBDI <- dBDI and (NOT CI_SSF) and (NOT dAIS) and (NOT dLTC) and (NOT dOCI) and (NOT dLCK) and (NOT dTIM) and (NOT TIMActDis)));
  • Consequent Equations within the ODUT_TT_Sk Atomic Function. This video review the following Consequent Equations:
    • aBDI <- (CI_SSF or dAIS or dLTC or dOCI or dLCK or dTIM) and TCMCI_Mode != TRANSPARENT;
    • aBIAE <- dIAE and TCMCI_Mode != TRANSPARENT;
    • aTSF <- CI_SSF or ((dAIS or (dLTC and LTCAct_Enable) or dOCI or dLCK or (dTIM and (NOT TIMActDis))) and TCMCI_Mode == OPERATIONAL;
    • aTSD <- dDEG and TCMCI_Mode == OPERATIONAL;
    • aAIS <- (dOCI or (dLTC and LTCAct_Enable) or dLCK or (dTIM and (NOT TIMActDis))) and TCMCI_Mode == OPERATIONAL;
    • aBEI <- nBIPV and TCMCI_Mode != TRANSPARENT;

Check out the Video Below.

Continue reading “OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 3”

OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 2

This blog post contains a video that serves as Part TWO of our discussion of the ODUT_TT_Sk Atomic Function. In this video, we discuss how this function declares and clears the TCMi-dTIM, TCMi-dAIS, TCMi-dLCK, TCMi-dOCI, TCMi-dIAE and TCMi-dBIAE defects.

Lesson 11 – Video 4 – Tandem Connection Monitoring – ODUT_TT_Sk Atomic Function, Part TWO

This blog post contains a video that covers the second part of the Sink Direction Tandem Connection Monitoring (TCM) related Atomic Functions.

In particular, this video covers the second part of the ODUT_TT_Sk Atomic Function.

More specifically, this video covers the following functions (within the ODUT_TT_Sk Atomic Function).

  • How the ODUT_TT_Sk Atomic Function declares and clears the following defect conditions
    • TCMi-dTIM (Trail Trace Identification Mismatch Defect for TCM Level i)
    • TCMi-dAIS (Alarm Indication Status Defect for TCM Level i)
    • TCMi-dLCK (Locked Status Defect for TCM Level i)
    • TCMi-dOCI (Open Connection Indicator Defect for TCM Level i)
    • TCMi-dLTC (Loss of Tandem Connection Monitoring Defect for TCM Level i)
    • TCMi-dIAE (Input Alignment Error Defect for TCM Level i)
    • TCMi-dBIAE (Backward Input Alignment Error Defect for TCM Level i)

Check out the Video Below

Continue reading “OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 2”

OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 1

This blog post contains video training that covers Introductory Material and the First Portion of the discussion of the ODUT_TT_Sk Atomic Function.

Lesson 11 – Video 3 – Tandem Connection Monitoring – ODUT_TT_Sk Atomic Function, Part ONE

This blog post contains a video that covers the initial part of the Sink-Direction Tandem Connection Monitoring (TCM) related Atomic Functions.

In particular, this video covers the first part of the ODUT_TT_Sk Atomic Function.  

More specifically, this video covers the following functions (within the ODUT_TT_Sk Atomic Function).

  • The Interfaces of the ODUT_TT_Sk Atomic Function
  • Near-End Error Checking – TCMi-BIP-8 Error Checking/Verification
    • TCMi-BEI Generation (in response to TCMi-BIP-8 Errors)
  • Far-End Error Checking – TCMi-BEI Checking
  • Defects
    • TCMi-BDI (Backward Defect Indicator) Defect Condition

Check Out the Video Below.

Continue reading “OTN – Lesson 11 – Tandem Connection Monitoring – Sink Atomic Functions – Video 1”

What is an Atomic Function for OTN?

This post briefly introduces the concept of the Atomic Functions that ITU-T G.798 uses to specify the Performance Requirements of OTN systems.


What is an Atomic Function for OTN Applications?

If you have read through many of the ITU standards, particularly those documents that discuss the declaration and clearance of defect conditions, you have come across Atomic Functions.

For OTN applications, ITU-T G.798 is the primary standard that defines and describes defect conditions.

If you want to be able to read through ITU-T G.798 and have any chance of understanding that standard, then you will need to understand what these atomic functions are.

I will tell you that you will have a tough time understanding ITU-T G.798 without understanding these atomic functions.

Therefore, to assist you with this, I will dedicate numerous blog postings to explain and define many of these atomic functions for you.

NOTE:  I also cover these Atomic Functions extensively in Lesson 8 within THE BEST DARN OTN TRAINING PRESENTATION…PERIOD!!!

OK, So What are these Atomic Functions?

You can think of these atomic functions as blocks of circuitry that do certain things, like pass traffic, compute and insert overhead fields, check for, and declare or clear defects, etc.

These atomic functions are theoretical electrical or optical circuits.  They have their own I/O, and ITU specifies each function’s functional architecture and behavior.

It is indeed possible that a Semiconductor Chip Vendor or System Manufacturer could make products that exactly match ITU’s descriptions for these atomic functions.  However, no Semiconductor Chip Vendor nor System Manufacturer does this.  Nor does ITU require this.

ITU has defined these Atomic Functions such that anyone can judiciously connect a number of them to create an Optical Network Product, such as an OTN Framer or Transceiver.

However, if you were to go onto Google and search for any (for example) OTUk_TT_Sk chips or systems on the marketplace, you will not find any.  But that’s fine.  ITU does not require that people designing and manufacturing OTN Equipment make chips with these same names nor have the same I/O as these Atomic Functions.

OK, So Why bother with these Atomic Functions?

The System Designer is not required to design a (for example) OTUk_TT_Sk function chip.  They are NOT required to develop chips with the same I/O (for Traffic Data, System Management, etc.).

However, if you were to design and build networking equipment that handles OTN traffic, you are required to perform the functions that ITU specified for these atomic functions.

For example, if you design a line card that receives an OTUk signal and performs the following functions on this signal.

  • Checks for defects and declare and clear them as appropriate, and
  • Monitors the OTUk signal for bit errors and
  • Converts this OTUk signal into an ODUk signal for further processing

Although you are NOT required to have OTUk_TT_Sk and OTUk/ODUk_A_Sk atomic function chips sitting on your line card, you are required to support all of the ITU functionality defined for those functional blocks.

Therefore, you must understand the following:

  1. Which atomic functions apply to your system (or chip) design, and
  2. What are the requirements associated with each of these applicable atomic functions?

If you understand both of these items, you fully understand the Performance Monitoring requirements for your OTN system or chip.

What type of Atomic Functions does ITU-T G.798 define?

ITU-T G.798 defines two basic types of Atomic Functions:

  • Adaptation Functions and
  • Trail Termination Functions

I will briefly describe each of these types of Atomic Functions below.

Adaptation Functions

Adaptation Functions are responsible for terminating a signal at a particular OTN or network layer and then converting that signal into another OTN or network layer.

For example, an Adaptation function that we discuss in another post is a function that converts an ODUk signal into an OTUk signal (e.g., the OTUk/ODUk_A_So function).

Whenever you read about atomic functions (in ITU-T G.798), you can also tell that you are dealing with an Adaptation atomic function if you see the upper-case letter A within its name.

For example, I have listed some Adaptation functions that we will discuss within this blog below.

  • OTSi/OTUk-a_A_So – The OTSi to OTUk Adaptation Source Function with FEC (for OTU1 and OTU2 Applications)
  • OTSi/OTUk-a_A_Sk – The OTSi to OTUk Adaptation Sink Function with FEC (for OTU1 and OTU2 Applications)
  • OTSiG/OTUk-a_A_So – The OTSiG to OTUk Adaptation Source Function with FEC (for OTU3 and OTU4 Applications)
  • OTSiG/OTUk-a_A_Sk – The OTSiG to OTUk Adaptation Source Function with FEC (for OTU3 and OTU4 Applications)
  • OTUk/ODUk_A_So – The OTUk to ODUk Adaptation Source Function
  • OTUk/ODUk_A_Sk – The OTUk to ODUk Adaptation Sink Function
  • ODUkP/ODUj-21_A_So – The ODUkP to ODUj Multiplexer Source Atomic Function
  • ODUkP/ODUj-21_A_Sk – The ODUkP to ODUj Multiplexer Sink Atomic Function

Another Way to Identify an Adaptation Function?

ITU in general (and indeed in ITU-T G.798) will identify the Adaptation Function with trapezoidal-shaped blocks, as shown below in Figure 1.

OTUk/ODUk_A_Sk Function - Adaptation Atomic Function

Figure 1, A Simple Illustration of an Adaptation Function (per ITU-T G.798)

Now that we’ve briefly introduced you to Adaptation Functions let’s move on to Trail Termination Functions.

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Trail-Termination Functions

Trail Termination functions are typically responsible for monitoring the quality of a signal as it travels from one reference point (where something called the Trail Termination Source function resides) to another reference point (where another thing is called the Trail Termination Sink function lies).

When you read about atomic functions (in ITU-T G.798), you can also tell that you are dealing with a Trail Termination atomic function if you see the upper-case letters TT within its name.

The Trail Termination functions allow us to declare/clear defects and flag/count bit errors.

I’ve listed some of the Atomic Trail-Termination Functions we will discuss in this blog below.

  • OTUk_TT_So – The OTUk Trail Termination Source Function
  • OTUk_TT_Sk – The OTUk Trail Termination Sink Function
  • ODUP_TT_So – The ODUk Trail Termination Source Function (Path)
  • ODUP_TT_Sk – The ODUk Trail Termination Sink Function (Path)
  • ODUT_TT_So – The ODUk Trail Termination Source Function (TCM)
  • ODUT_TT_Sk – The ODUk Trail Termination Sink Function (TCM)

Another way to Identify a Trail-Termination Function?

In general (and indeed in ITU-T G.798), ITU will identify Trail Termination Function with triangular-shaped blocks.  I show an example of a drawing with a Trail-Termination below in Figure 2.

OTUk_TT_Sk Function - Trail Trace Atomic Function

Figure 2, A Simple Illustration of a Trail Termination Function (per ITU-T G.798)

We will discuss these atomic functions in greater detail in other posts.

 

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