Subject: Re: [bmwg] WGLC on IPv6 Benchmarking

From: "Poretsky, Scott" <[email-masked]>
Date: Sat, 24 Feb 2007 02:56:46 -0500

When we state a 64 bute Ethernet frame, that includes the ethernet header.  Likewise we should require a minimum Sonet frame size that includes the POS header - 48 bytes.  Also we should be discussing the maximum size since RFC 2544 goes up to 1500 byte packets and Carrier Sonet links often transport Jumbo frames.
         
Scott

----- Original Message -----
From: David Newman <[email-masked]>
To: [email-masked] <[email-masked]>
Sent: Fri Feb 23 18:48:18 2007
Subject: Re: [bmwg] WGLC on IPv6 Benchmarking

On 2/23/07 7:59 AM, Chip Popoviciu (cpopovic) wrote:

> Has this approach been considered within the WG in the past? Looking for
> opinions on this topic. I think that in the case of Ethernet and SONET
> this correlation is logical.

bmwg scope is limited both explicitly and historically to testing boxes
in the lab, not on live production networks.

For that reason I do not think it makes sense to rule in or out given
packet lengths because of where boxes *might* be used in production
today or at some future point. We can't predict the future. We can
design tests so they stress the technology in front of us right now.

For example: When 1242 and 1944/2544 were written 10-15 years ago,
Ethernet boxes weren't flinging packets over distances of 40 km or more.
Instead, the notion was that Ethernet supported a 64-byte minimum frame,
so that's what should be tested.

I would hope the same approach would apply here. Sonet supports 40-byte
packets, the shortest length possible for IPv6. Ergo, that length should
be included in any methodology, regardless of where a Sonet device
ultimately gets deployed.

dn

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---

From: David Newman <[email-masked]>
Date: Sat, 24 Feb 2007 21:26:13 -0800

On 2/23/07 11:56 PM, Poretsky, Scott wrote:
> When we state a 64 bute Ethernet frame, that includes the ethernet
> header.  Likewise we should require a minimum Sonet frame size that
> includes the POS header 

Include a CRC too, and I agree.

- - 48 bytes.  Also we should be discussing the
> maximum size since RFC 2544 goes up to 1500 byte packets and Carrier
> Sonet links often transport Jumbo frames.

Not a bad idea either, but it's a moving target.

There's no standard for jumbo frames. Some boxes support 9000-byte
frames, while it's 9216 on others. And it only gets worse over
Sonet/SDH. Different cards from one popular vendor have MTUs ranging
from 4474 to 9192.

While I'd agree that it's useful to test with jumbo frames, I don't
believe it's possible yet to define a general case.

dn

---

From: "Romascanu, Dan \(Dan\)" <[email-masked]>
Date: Sun, 25 Feb 2007 08:19:54 +0200

> -----Original Message-----
> From: David Newman [mailto:[email-masked]] 
> There's no standard for jumbo frames. Some boxes support 
> 9000-byte frames, while it's 9216 on others. And it only gets 
> worse over Sonet/SDH. Different cards from one popular vendor 
> have MTUs ranging from 4474 to 9192.
> 
> While I'd agree that it's useful to test with jumbo frames, I 
> don't believe it's possible yet to define a general case.
> 

I agree about jumbo frames which are not standardized at this point in
time. I would observe at the same time that RFC 2544 is out of synch by
two generations in what Ethernet standard (non-jumbo) maximum frame
length is concerned. The figure of 1518 mentioned all over RFC 2544 was
replaced long time back by 1522 in order to accommodate the IEEE 802.1Q
VLAN header, and 1522 was more recently replaced by 2000, as per IEEE
802.3as. 

Dan