Subject: IPv6 over GigE

From: Ran Atkinson <[email-masked]>
Date: Thu, 21 Jun 2001 17:48:38 -0400

Folks,

	The IS-IS WG has a draft out on how IP over GigE jumbograms
should work.  This is online at:
	http://www.ietf.org/internet-drafts/draft-ietf-isis-ext-eth-00.txt

	As this does have implications for IPv6 over GigE jumbograms,
folks over here in IPv6-land might want to look over that document
and participate in the discussions over on the IS-IS mailing list.

	Because all IS-IS WG documents are published as Informational 
RFCs (because ISO is the standards-body for IS-IS), many folks treat 
Informational RFCs from the IS-IS WG as carrying equal weight
as a standards-track document.  While it might not precisely *be*
a standards-tack document, this tends to be the reality of output
from that particular WG.

	For reference, one issue is how big an Ethernet Jumbogram
is.  The IEEE position is that there is only one Ethernet MTU size.
Widely available GigE products support a frame size of ~9K bytes.
The IS-IS WG, with its folks on POS interfaces that have been designed
for FDDI MTU (4470 bytes) for historical reasons, might end up
picking 4470 as their spec for Ethernet Jumbogram MTU.  There is
also the matter of how the IP packet is encapsulated into Ethernet/
802.3 for the case of an Ethernet jumbogram and several opinions
there also.

	If none of this matters to folks, fine.  If it does matter, 
the discussion is occurring over on the IS-IS list and the time 
to review and comment is now...

Cheers,

Ran
[email-masked]

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From: "Herbert, Howard C" <[email-masked]>
Date: Fri, 29 Jun 2001 16:26:33 -0700

Ran:

We have reviewed your referenced draft including the appendices at:

Intel concurs with the analysis that there is no increase in undetected
errors using a jumbo frame size of 9018 bytes.  Intel believes that frames
as large as 16K bytes are feasible and in fact our current gigabit products
support frames sizes up to 16132 bytes (although we are not aware of any
switches that support jumbo frames this large).  Intel believes that frames
larger than 16K are not feasible because of clock resolution issues.

Is the IS-IS WG planning to get this proposal standardized through the IEEE
802.3 committee?  If not, why not?

Intel believes that the best way to proceed in this area is to have these
issues (MTU and encapsulation formats) worked in conjunction with the IEEE
802.3 committee.

Howard C. Herbert

Product Architect
Intel Corporation
LAN Access Division
480-554-3116