Re: [Rtg-dt-encap-considerations] Added Hardware Friendly to Dallas slides

[Erik Nordmark <[e-mail]>]

On 3/11/15 3:47 PM, Larry Kreeger (kreeger) wrote:
> Hi Erik,
>
> Here are my comments on the slides.  I don't know if the hardware friendly
> slide will stimulate more discussion than several other points in these
> slides, so I don't see why not to have it.
OK, I've added the slide to the NVO3 set for now.
>
> Slide 7: I'm not sure what the bullet "Perhaps optional OAM info modified
> along path?" means.
This was a vague reference to timestamps etc for OAM purposes. I've 
reworded it to be more specific.
> Also, SFC allows not only the service path info to be
> carried (and modified), but the service metadata may also be modified.
Is " *Service meta-data may be modified by service functions" a correct 
state*ment?**
>
> Slide 9: It isn't clear to me whether limiting the source port entropy to
> only use the ephemeral port range is required.  I think in many cases it
> will be fine to use all 16 bits of source port.
The document doesn't even specify exactly why, but has some more text.
If there is some middlebox, it might look at the UDP source port. For 
instance, UDP source ports used by known insecure protocols might be 
blocked by a firewall. If all 16 bits are used that means some flows 
would get blocked. But in other deployments all bits can be used.

How about I have the slide say ">=14 bits" and we can talk to this point?
>
> Slide 13: The bullet "Use some 'discard' next header value?" is one
> option, but it eliminates the possibility of carrying a payload snippet
> before the OAM message.  The other option is an explicit OAM bit (which
> several headers have).
I've reworded as
*Use some “discard” next header value, or OAM bit?

*Note that I'm not sure the discussed OAM bit means the same to everybody.**
>
> Slide 18: Loose -> Lose
Fixed.
>
> Slide 24: Why is there a question mark after "WG document"?  We already
> have a document.  Maybe this is to remind you to put the draft name?
The DT output is a personal document. I don't know (and haven't asked 
Alia) whether her intent was to have the RTGWG pick this up as a WG 
document and review it. Hence asking the question.

I made it a bit more clear:
*RTGWG WG document? Or somewhere else?

*Thanks for your review.

Erik

**
>
>   - Larry
>
>
>
>
>
> On 3/10/15 6:20 PM, "Erik Nordmark" <[e-mail]> wrote:
>
>> See
>> https://docs.google.com/a/aristanetworks.com/presentation/d/1r_LpKB0tV8VJV
>> Jx-t3h3NJagRCtIxqFXS8JesV9BCOo/edit?usp=sharing
>>
>> First question is whether we agree on this summary (I did it from memory)
>> Second question is whether we should add the Hardware Friendly slide to
>> the NVO3 slides for this Friday's presentation?
>> It might raise some discussion.
>>
>>     Erik
>>
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