Subject: [Ioam] Alia Atlas' No Objection on charter-ietf-ioam-00-02: (with COMMENT)

From: "Alia Atlas" <[email-masked]>
Date: Thu, 16 Feb 2017 06:07:50 -0800

Alia Atlas has entered the following ballot position for
charter-ietf-ioam-00-02: No Objection

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The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/charter-ietf-ioam/

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COMMENT:
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1) I share Suresh's question about the difference between SRv6 and IPv6
for this work.

2)  There are common hardware router architecture issues that this work
should at least consider.
This may lead to slightly different requirements and guidelines for
software and hardware.  
For example, a packet is commonly split into a header that is sent to be
processed and the payload
that is stored away and not accessible.  How much data is available for
the header can vary widely
and is not always a power of 2.  This came up significantly during NVO3
discussions about encapsulation
approaches.   This consideration makes me question the practicality of
carrying, for example, lists of
data collected.  The length of the extra information also can impact the
ability to compute flow entropy;
at a minimum this can impact the actual path taken by the selected
traffic. Another example is the issue 
of unordered TLVs being more expensive for hardware processing; given the
possibility of an application 
being able to insert the iOAM data, this could have
negative impacts on router capabilities. 

3) I share Stephen's concerns about security aspects.