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RE: Open issues list? [Re: New (-02) version of IPv6 CPE Router draft is available for review]
The CPE Router will NOT mandate how many LAN ports does the device have
- it's left to a vendor. Further, we have left it to the vendor as well
for LAN interface(s) to be bridged, switched, or routed ports. See the
definition in our Terminology section.
[LAN interface(s) - a set of network interfaces on the CPE Router that
are used to connect hosts in the home. This set of ports could be
switched, bridged, or routed.]
Please rest your case. That's the most the CPE Router will specify.
Please talk to CPE Router vendors, not authors of this draft.
From: firstname.lastname@example.org [mailto:email@example.com] On
Behalf Of Mikael Abrahamsson
Sent: Thursday, July 31, 2008 8:32 AM
Subject: RE: Open issues list? [Re: New (-02) version of IPv6 CPE Router
draft is available for review]
On Wed, 30 Jul 2008, Francois-Xavier Le Bail wrote:
> Significant bandwidth can be wasted by flooding.
I would just like to highlight a scenario that everybody should be aware
of, sorry if this is obvious to everybody here, I know not enough people
in other places are aware of it.
With most ATA/VOIP boxes, the uplink interface is 10/half. A multicast
stream SDTV might be 6-8 megabit/s, so when channel zapping, there might
be a short while (100ms) where two streams are being sent out on the
local segment. If the L2 switch connecting the devices doesn't do
IGMP/MLD snooping, the ATA box port will be take more than 10 meg of
potential traffic for the duration of the burst, which hurts voice
quality (since this will most likely cause packet loss). Since most
cheaper L2 devices also do not have per-port buffers, but instead have
shared buffers, it means that this problem might hurt traffic on other
ports as well, incurring packet loss there also.
So, what I like about IPv6 and DHCPv6-PD is that these kind of low-speed
devices that should never get multicast traffic, can be put on another
L2 domain and have L3 separation from the devices that actually need to
listen to the multicast.
I don't know how this might fit into the CPE router draft, but my
recommendation for CPE router is that it should have at least 4 LAN
ports and it should be possible for these 4 LAN ports to be 4 separate
routed interfaces to enable L3 separation between different devices.
This can also be solved by MLD snooping and personally I'd like to see
both, but it might be cheaper for the CPE manufacturer to implement
routed ports than to get a built in L2 switch that actually does MLD.
Mikael Abrahamsson email: firstname.lastname@example.org