Subject: [OPSAWG] FW: Re: Last Call: <draft-ietf-opsawg-oam-overview-08.txt> (An Overview of Operations, Administration, and Maintenance (OAM) Mechanisms) to Informational RFC

From: "MORTON, ALFRED C (AL)" <[email-masked]>
Date: Thu, 24 Oct 2013 09:32:02 -0400

OPAWG,

One of the authors asked me to check that my comments on
this draft (below) were resolved. The diff between versions 08 and 09
indicates that they were.

Al

From: MORTON JR., ALFRED (AL)
Sent: Tuesday, January 15, 2013 9:21 AM
To: 'Benoit Claise'; Thomas Nadeau; Monique Morrow; [email-masked]
Cc: Ron Bonica
Subject: RE: Re: Last Call: <draft-ietf-opsawg-oam-overview-08.txt> (An Overview of Operations, Administration, and Maintenance (OAM) Mechanisms) to Informational RFC

Hi Benoit,

Here are some additional comments, just checking a few things
I know a little about.

Al

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

1.1. The Building Blocks of OAM
...
   o Performance Monitoring:
      Consists of 3 main functions

        o Loss Measurement (LM) - monitors the packet loss rate of a
          connection.

        o Delay Measurement (DM) - monitors the delay and delay
          variation between MPs.

        o Throughput measurement - monitors the throughput of a
          connection.

>>> Apparently, no OAM tool currently measures Throughput,
    because no such tool is cited in the memo (and the term "throughput"
    never appears again).  my guess is that there was some reference to
    RFC 2544 that has now been removed. Remove Throughput from the list.

1.3 OAM Toolsets
...
   o OWAMP and TWAMP:
      The One Way Active Measurement Protocol (OWAMP) and the Two Way
      Active Measurement Protocols (TWAMP) are two protocols defined in
      the IP Performance Metrics (IPPM) working group in the IETF. These
      protocols allow delay and packet loss measurement in IP networks.

>>> and Delay variation, duplication, reordering, etc. (all the metrics limited tools
    completely ignore).

1.4 IETF OAM Documents

>>> Expand Table 1 as noted above, to include all the metrics they missed.

3.6.1
...
   TWAMP [TWAMP] is a similar protocol that enables measurement of
>>> both one-way and
   two-way (round trip) characteristics.

>>> sentence below is simply not true, because the authors did not understand
   the one-way measurement capability:
   TWAMP does not require accurate
   time of day, and, furthermore, allows the use of a simple session
   reflector, making it an attractive alternative to OWAMP.
>>> go back and read the memo...

3.7. Summary of OAM Functions

   Table 3 summarizes the OAM functions that are supported in each of
   the categories that were analyzed in this section.

   +-----------+-------+--------+--------+-----------+-------+--------+
   | Standard  |Continu|Connecti|Path    |Defect     |Perform|Other   |
   |           |ity    |vity    |Discover|Indications|ance   |Function|
   |           |Check  |Verifica|y       |           |Monitor|s       |
   |           |       |tion    |        |           |ing    |        |
   +-----------+-------+--------+--------+-----------+-------+--------+
...
   + --------- + ----- + ------ + ------ + --------- + ----- + ------ +
   |OWAMP and  |       |        |        |           |-Delay |        |
   |TWAMP      |  Yes  |  Yes   |        |           | measur|        |
   |           |       |        |        |           | ement |        |
   |           |       |        |        |           |-Packet|        |
   |           |       |        |        |           | loss  |        |
   |           |       |        |        |           | measur|        |
   |           |       |        |        |           | ement |        |
   +-----------+-------+--------+--------+-----------+-------+--------+
                     Table 3 Summary of OAM Functions

>>> Both Continuity Check and Connectivity Verification are tested and
confirmed by establishing the *WAMP Control Protocol TCP connection,
so this should be indicated the table.