Subject: RE: [bmwg] WGLC on IPv6 Benchmarking

From: [email-masked] (Scott O. Bradner)
Date: Mon, 16 Jul 2007 21:52:53 -0400 (EDT)

David sed:
> One possible solution: For both Ethernet and Sonet, define two short
> lengths -- one that's just the minimum L2 framing+IPv6 header to
> determine throughput and another that includes a signature field to
> measure latency and sequencing.

I'm not sure Ethernet is a problem unless one has a long signature
due to Ethernet's mininum packet size but the concept makes sense to me

Scott

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From: David Newman <[email-masked]>
Date: Mon, 16 Jul 2007 23:00:38 -0700

> due to Ethernet's mininum packet size but the concept makes sense to me

Thanks. I believe signature fields are a problem for v6, even with
minimum-length Ethernet. With 18 bytes of L2 framing plus a 40-byte v6
header we're already at 58 bytes, and the signature fields I'm familiar
with are quite a bit longer than 6 bytes.

I'm not any happier than Chip is about having two lengths but I don't
see any other way to do minimum-length fps tests *and* tests at some
other size to get the signature field in.

If we're going to end up with two lengths, then a 60-byte packet plus L2
framing might be a good choice (and a meaningful one, given that's the
length of an ACK over v6). This would mean a 78-byte frame in Ethernet
and a 67- or 69-byte frame in Sonet depending on CRC length.

dn

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From: Curtis Villamizar <[email-masked]>
Date: Tue, 17 Jul 2007 11:11:37 -0400

In message <[email-masked]>
> due to Ethernet's mininum packet size but the concept makes sense to me

Would it be possible/practical to list a set of very small packet
sizes to test to so as to avoid repeating the recurring argument on
the WG mailing about which tiny packet size to test against?

Let the marketeers argue over which one is most meaningful.

Curtis

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From: "Chip Popoviciu \(cpopovic\)" <[email-masked]>
Date: Tue, 17 Jul 2007 17:35:35 -0400

David,

Currently, major Test Tool vendors (Agilent, IXIA, Spirent) use a 20
bytes long signature field. I did poll them and they don't seem to have
any plans to extend the length of the field (something we should keep in
mind as a possibility in the future). So at this point in time, the
smallest IPv6 packet that would still enable the test tools to capture
all the statistics (delay, jitter, out of order, etc) is 60 bytes.

The minimum frame size that could be proposed for tests that use the
signature field is: 78 bytes for Ethernet and 67 bytes for SONET. Here
are then the lists of recommended frame sizes:

Ethernet: 58, 78, 128, 256, 512, 1024, 1280, 1518 bytes
SONET: 47, 67, 128, 256, 512, 1024, 1280, 1518, 2048, 4096 bytes

Include a note that the first frame size is intended to reach maximum
possible traffic rate for IPv6 for that media type.

Note that the 64 bytes frame size was dropped because it seems less
useful.

That being said, I would like to bring up another point. In IPv6,
testing with extension headers is important. So the note on the lowest
frame size supporting a signature field must also mention that this is
in the absence of extension headers. We end up having recommendations
with many caveats around them.

The alternative would be to keep 64 from 2544 and list:

Ethernet: 58, 64, 128, 256, 512, 1024, 1280, 1518 bytes
SONET: 47, 64, 128, 256, 512, 1024, 1280, 1518, 2048, 4096 bytes

Include note about the first frame size (same as above) and another note
about "for some tests (this to cover those using extension headers), the
smaller frames might not support the signature field ..."

In all of the above I started from the assumption that the WG decides to
go for the minimum possible frame size for IPv6. If this is not the case
then we could list the traditional set (as I said, I am a fan of it
because of the practical perspective, it allows for an upper layer
header as well):

Ethernet: 64, 128, 256, 512, 1024, 1280, 1518 bytes
SONET: 64, 128, 256, 512, 1024, 1280, 1518, 2048, 4096 bytes

Have a note about the smallest possible frame size which would be the
limit performance test case for a given media. Of course a note about
the signature field considerations such as the one we already have.

These are the main options I see. Looking forward to feedback or
alternate suggestions.

Best Regards,
Chip

-----Original Message-----
From: David Newman [mailto:[email-masked]] 
Sent: Tuesday, July 17, 2007 2:01 AM
To: [email-masked]
Subject: Re: [bmwg] WGLC on IPv6 Benchmarking

On 7/16/07 6:52 PM, Scott O. Bradner wrote:
> I'm not sure Ethernet is a problem unless one has a long signature due

> to Ethernet's mininum packet size but the concept makes sense to me

dn

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From: "Chip Popoviciu \(cpopovic\)" <[email-masked]>
Date: Tue, 17 Jul 2007 17:58:17 -0400

This would be the third option mentioned in my earlier e-mail: list the
traditional set and then make a note about the smaller possible size and
the reasons for using it. In fact we could even avoid mentioning the
value but rather mention the way to construct it (use just the IPv6
header). I also like this approach.

Best Regards,
Chip

-----Original Message-----
From: Curtis Villamizar [mailto:[email-masked]] 
Sent: Tuesday, July 17, 2007 11:12 AM
To: Scott O. Bradner
Cc: [email-masked]
Subject: Re: [bmwg] WGLC on IPv6 Benchmarking 

> to Ethernet's mininum packet size but the concept makes sense to me

Would it be possible/practical to list a set of very small packet sizes
to test to so as to avoid repeating the recurring argument on the WG
mailing about which tiny packet size to test against?

Curtis

---

From: David Newman <[email-masked]>
Date: Tue, 17 Jul 2007 14:59:45 -0700

> all the statistics (delay, jitter, out of order, etc) is 60 bytes.

agree

> signature field is: 78 bytes for Ethernet and 67 bytes for SONET. 

Agree. Per my email yesterday, a 60-byte IP packet also has the nice
feature of being the size of a TCP-over-v6 ACK.

Here
> Ethernet: 58, 78, 128, 256, 512, 1024, 1280, 1518 bytes

A 58-byte frame is not valid Ethernet. See 802.3-2002, sections 4.4.2.[1-4].

As proposed, this test SHOULD trip the undersize counters of every
Ethernet device out there. I do not believe that was your intention...

> Note that the 64 bytes frame size was dropped because it seems less

Disagree, if for no other reason than it allows useful comparisons
between v4 and v6 test results. Testing with 64-byte frames is a VERY
common practice.

> Ethernet: 58, 64, 128, 256, 512, 1024, 1280, 1518 bytes

did you mean 64 here?

> SONET: 64, 128, 256, 512, 1024, 1280, 1518, 2048, 4096 bytes

I do not understand 64 for Sonet, unless the goal is simply backward
compatibility with Ethernet. In my opinion this is not a good option,
since we're not doing our job of describing the limits of a given device
that supports a given medium.

> These are the main options I see. Looking forward to feedback or

I agree with you conceptually; you have min-length frames and you can
accommodate signature fields and you allow for extensions, all of which
is to the good IMO.

If we can resolve the 58/64 thing I think we're all set.

dn

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From: "Chip Popoviciu \(cpopovic\)" <[email-masked]>
Date: Tue, 17 Jul 2007 18:16:06 -0400

David,

The 58 issue is a non-issue, I got carried away in math :)

So what do you think would be the best way to present this? I just
responded to Curtis with the option I vote for which is to list the
traditional frame sizes and then separately discuss explicitly the
smallest frame size test. The discussion would include an explanation of
the scope of the test, the recommended size and any things to consider.
What do you think?

As for accommodating the signature field, we can stay with the note and
there mention as an example the minimum size which would be able to
include the commonly used signature.

Best Regards,
Chip

-----Original Message-----
From: David Newman [mailto:[email-masked]] 
Sent: Tuesday, July 17, 2007 6:00 PM
To: [email-masked]
Subject: Re: [bmwg] WGLC on IPv6 Benchmarking

On 7/17/07 2:35 PM, Chip Popoviciu (cpopovic) wrote:
> bytes long signature field. I did poll them and they don't seem to 
> have any plans to extend the length of the field (something we should 
> keep in mind as a possibility in the future). So at this point in 
> time, the smallest IPv6 packet that would still enable the test tools 
> to capture all the statistics (delay, jitter, out of order, etc) is 60
bytes.

agree

Here
> Ethernet: 58, 78, 128, 256, 512, 1024, 1280, 1518 bytes

A 58-byte frame is not valid Ethernet. See 802.3-2002, sections
4.4.2.[1-4].

did you mean 64 here?

> Include note about the first frame size (same as above) and another 
> note about "for some tests (this to cover those using extension 
> headers), the smaller frames might not support the signature field
..."
> 
> In all of the above I started from the assumption that the WG decides 
> to go for the minimum possible frame size for IPv6. If this is not the

> case then we could list the traditional set (as I said, I am a fan of 
> it because of the practical perspective, it allows for an upper layer 
> header as well):
> 

dn

>> due

> header we're already at 58 bytes, and the signature fields I'm 
> familiar with are quite a bit longer than 6 bytes.
> 
> If we're going to end up with two lengths, then a 60-byte packet plus 
> L2 framing might be a good choice (and a meaningful one, given that's 
> the length of an ACK over v6). This would mean a 78-byte frame in 
> Ethernet and a 67- or 69-byte frame in Sonet depending on CRC length.
> 
> dn
> 
>

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From: David Newman <[email-masked]>
Date: Tue, 17 Jul 2007 15:35:28 -0700

> include the commonly used signature.

I'm glad we agree on the two-size approach.

Personally, if we have to pick one I would prefer either:

a. to make the minimum length the standard, with optional tests at
slightly larger, signature-field-accommodating sizes if desired; or

b. to require both lengths

Mandatory inclusion of min-length tests is in line with benchmarking's
general goal of determining the limits of device performance.

dn

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From: "Chip Popoviciu \(cpopovic\)" <[email-masked]>
Date: Tue, 17 Jul 2007 21:52:55 -0400

To recap, the proposal is to have the following frame size
recommendations:

Also to include a note for each of the following topics:
- 47 was chosen as the limit case
- how to select a minimum frame size if one wants to use the signature
field

We agree in general terms so lets see if there are other opinions within
the WG in case we missed something.

Best Regards,
Chip

-----Original Message-----
From: David Newman [mailto:[email-masked]] 
Sent: Tuesday, July 17, 2007 6:35 PM
To: [email-masked]
Subject: Re: [bmwg] WGLC on IPv6 Benchmarking

On 7/17/07 3:16 PM, Chip Popoviciu (cpopovic) wrote:
> smallest frame size test. The discussion would include an explanation 
> of the scope of the test, the recommended size and any things to
consider.
> What do you think?
> 
> As for accommodating the signature field, we can stay with the note 
> and there mention as an example the minimum size which would be able 
> to include the commonly used signature.

dn