Subject: Re: updated PIM for IPv6 draft

From: JINMEI Tatuya / 神明達哉<[email-masked]>
Date: Wed, 22 Dec 1999 01:39:35 +0900

>>>>> On Fri, 19 Nov 1999 16:07:05 -0500, 
>>>>> "Brian Haberman" <[email-masked]> said:

>      The following was just submitted to the I-D editor.  Comments to
> the authors
> or the mailing list.

I have a question (comment) about PIM for IPv6. I'd apologize in
advance since the question is not directly related to the draft, but I
think it is important for the specification of IPv6 PIM and its
interoperability.

(Actually I sent the question to the PIM mailing list two months ago,
 but unfortunately I could get few answers and the issue was not
 clear. So I'll resend this here, but if there's more appropriate
 place to discuss it, please let me know.)

The comment is about the checksum field of IPv6 PIM
packets. The PIM specification in draft-ietf-pim-v2-sm-01 defines how
to calculate the checksum as follows:

        Checksum
             The checksum is the 16-bit one's complement of the one's
             complement sum of the entire PIM message, (excluding the
             data portion in the Register message).  For computing the
             checksum, the checksum field is zeroed.

i.e. the checksum is calculated without a pseudo-IP header. However, I
believe it should be calculated *with* a pseudo-IP header for IPv6 PIM
packets, because IPv6 does not have an IP layer checksum and because
PIM depends on some fileds of received IP packets (e.g. the source
address field).

If it's reasonable, I hope it will be described in a future version of
the pim-ipv6 draft and/or the pim-v2 draft.

What do you think? I'd appreciate any answers. Thanks,

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					[email-masked]
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---

From: "Brian Haberman" <[email-masked]>
Date: Tue, 21 Dec 1999 12:44:53 -0500

Your approach would be consistent with what OSPF for IPv6 does.
The draft could be changed to require that change, but I would like
some input from the working groups.

Brian

--
Brian Haberman
Advanced Network Research
Nortel Networks
[email-masked]