-----Original Message-----
From: Sri Gundavelli (sgundave)
Sent: Friday, August 13, 2010 4:22 PM
To: Suresh Krishnan
Cc: Hemant Singh (shemant); IPv6 WG Mailing List; Brian Haberman
Subject: Re: Consensus call on
adopting:draft-krishnan-6man-rs-mark-06.txt
>I don't understand either. Why is it an issue for a sender node to
transmit a packet on the link-layer as a unicast message, if its known
there is only one receiver. I've not seen a single valid >argument and
so its fine, one is entitled for their opinions.
This is the email I sent out to Fred on 8/3/2010 in regards to your
draft - in double quotes below. See my one reason for why your
document's rule will break MLDv2 protocol. Ole agrees with me that yes,
MLDv2 sniffing will not work with your document's rule. Further since
RFC 4862 uses MLDv2 for ND control messages such as an NS(DAD). So now
the router node also fails to get an NS(DAD). My summary is that IPv6
address auto configuration in RFC 4862 and RFC 4861 ND control is so
tied to MLDv2 and RFC 3810 that if MLDv2 breaks for L2 sniffing as
mentioned below, we just broke other IPv6 control.
Hemant
"Fred,
Snipped from RFC 3810, section 7 is the following text.
[For each interface over which the router operates the MLD protocol, the
router must configure that interface to listen to all link-layer
multicast addresses that can be generated by IPv6 multicasts. For
example, an Ethernet-attached router must set its Ethernet address
reception filter to accept all Ethernet multicast addresses that start
with the hexadecimal value 3333 [RFC2464]; in the case of an Ethernet
interface that does not support the filtering of such a multicast
address range, it must be configured to accept ALL Ethernet multicast
addresses, in order to meet the requirements of MLD.]
I can program such a L2 multicast filter in the CAM (Content Addressable
Memory) of Ethernet hardware with CAM. So if this router directly
receives a multicast message with multicast destination but unicast L2,
the sniffing on 3333.xxxx.xxxx fails to capture this packet and the
router just failed MLDv2 gleaning of this message. One may also note
that MLD is used by ND as specified in RFC 4862 and RFC 4861.
So what text do we add to the Sri document to exclude MLDv2 protocol
from their proposal?
Hemant"
--------------------------------------------------------------------
IETF IPv6 working group mailing list
ipv6@ietf.org
Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------
