[sfc] Review comments for : Performance Measurement Architecture for SFC

[Phaneendra manda <[e-mail]>]

Hi,
Please find the below review comments for draft-agv-sfc-performance-measurement-architecture-02
1. In section 2
   Measurement Controller: An entity that controls and coordinates a set
   of measurement functions. The measurement controller is responsible
   for programming the performance measurement instance at measurement
   classifier and updating the same to measurement collector,
   additionally it can inject probe packets in SFP for measurement.

    can be

     Measurement Controller: An entity that controls and coordinates a set
   of measurement functions. The measurement controller is responsible
   for programming the performance measurement instance(PMI) at measurement
   classifier and updating the same to measurement collector,
   additionally it can inject probe packets in SFP for measurement.

   While going through document there is no abbreviation mapped for PMI. Marking this would improve the readability


2. In section 3
   Active measurement : Measurement controller induce probe packets
      with encoded performance measurement data or programs PMI at
      measurement classifier which will in turn induce probe packets
      with encoded performance measurement data. measurement controller
      updates the PMI to measurement collector. Participating
      measurement agents based on received encoded information carry out
      measurements and reports the collected data to measurement
      collector. measurement collector co-relates received data and
      provides measurement results.

   can be

  Active measurement : Measurement controller induce probe packets
      with encoded performance measurement data or programs PMI at
      measurement classifier which will in turn induce probe packets
      with encoded performance measurement data. Measurement controller
      updates the PMI to measurement collector. Participating
      measurement agents based on received encoded information carry out
      measurements and reports the collected data to measurement
      collector. measurement collector co-relates received data and
      provides measurement results.


3. In section 4.1
    "PMF identifier" - PMF is used without providing any abbreviation.

4. In section 4.3.3
    MA identifier has two parts
   1) Node identifier - 24 bit
      a) For SFF: MUST be unique number assigned by controller
      b) For SF: All zero. Context identifier itself identifies SF node.

   I think here it should be Service Index. Context identifier referred nowhere in the draft.

5. In section 4.3.3

  - At MA         : Presence of self service index triggers the
                            PM collection & reporting

  can be

  - At MA         : Presence of self MA identifier triggers the
                            PM collection & reporting

Because of below reasons
   -  A service function does not know its service index
   -  As mentioned in section 5, point 1, it is mentioned Measurement controller programs the MA identifier to MA. So the MA knows the MA identifier not the service index.

6. In section 2
   In the description of Measurement Classifier :  It can also generate probe packet. Need to be updated in description (In section 6 it is mentioned Measurement classifier may generate probe packet based on the instruction by measurement controller.

7. In Section 4.3.3
   A service function can be part of multiple service function chains, In this case the Measurement Agent will have 2 MA ID's configured.  As per the draft in section 4.3.3, there is no consideration for Service Path Index(SPI) while MA Identifier construction. So MA Identifier may have conflict.

8. In Section 4.3.3
  There is no clarity on Measurement Agent Identifier with PM type value on how it is encoded.  Like few bits are used for MA Identifier and few bits are used for PM type. It is just mentioned MA Identifier with PM type. I think more details can be provided here.


Thanks & Regards
Phaneendra Manda.