Subject: [bmwg] draft-ietf-bmwg-mcastm-11.txt

From: "Hickman, Brooks" <[email-masked]>
Date: Wed, 16 Apr 2003 17:43:31 -0700

There are a couple of editing changes that I would like to get
comments/feedback.

Section 3.1 Test Considerations

In the second paragraph it states:

     "An actual flow of test traffic may be required to prime related 
     mechanisms, (e.g., process RPF events, build device caches, etc.) 
     to optimally forward subsequent traffic.  Therefore, before an 
     initial, measured forwarding test trial, the test apparatus MUST 
     generate test traffic utilizing the same addressing characteristics 
     to the DUT/SUT that will subsequently be used to measure the 
     DUT/SUT response.  The test monitor should ensure the correct 
     forwarding of traffic by the DUT/SUT. The priming action need only 
     be repeated to keep the associated information current."

The sentence:

"Therefore, before an initial, measured forwarding test trial, the test
apparatus MUST 
 generate test traffic utilizing the same addressing characteristics to the
DUT/SUT
 that will subsequently be used to measure the DUT/SUT response."

implies priming is only needed when performing forwarding rate tests. This
would also apply for latency or throughput testing as well. My suggestion
would be to change the sentence to:

"Before an initial, measured test trial, the test apparatus MUST generate
test traffic utilizing the same addressing characteristics to the DUT/SUT
that will subsequently be used to measure the DUT/SUT response."

Note that while the Join/Leave Delay tests are not a forwarding rate test
and would not actually apply, the procedure in both cases requires that the
same multicast addressing characteristics be generate for
validation purposes prior to the actual test traffic being generated.
Basically you need to do the same thing, but for a different purpose.
Alternative would be to specify "throughput, forwarding and latency test
trials".

Second Item

Section 5.1 Multicast Latency

Seventh Paragraph States:

     "The test apparatus MUST record the time of the successful detection 
     of a tagged frame from a tested egress interface with a timestamp, 
     Timestamp B.  A set of Timestamp B values MUST be collected for all 
     tested egress interfaces of the DUT/SUT.  See RFC 1242 [Br91] for 
     additional discussion regarding store and forward devices and bit 
     forwarding devices."

The goalposts which are being referenced will be dependent upon what type of
measurement(Store and Forward or bit forwarding) is being made. I think that
it would provide clarity by replacing the last sentence with the following: 

"Note that the nature of the latency measurement(i.e., "store and forward"
or "bit forwarding"),
 defined in section 26.1 of RFC1242 impacts the bit that Timestamp A and
Timestamp B references."

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