IPv6 support by wifi systems

Tue Feb 12 20:36:58 UTC 2013

On Tue, 2013-02-12 at 13:49 -0500, Brandon Ross wrote:
> > MLD Snooping and IPv6 ACLs are a must.
> 
> MLD Snooping only seems important to me if you are actually going to do 
> multicast outside of the local broadcast domain

MLD snooping allows the switch to send multicast traffic only to those
listeners wanting to receive it. Witout MLD snooping, the switch floods
multicast to all ports. May be a security issue, is definitely a traffic
issue, though in a small network, it may make no difference.

For example, multicast is used by ND, the IPv6 equivalent of ARP. MLD
snooping means only a few hosts (typically only one, in fact) in the
subnet see any given ND request. Without MLD snooping, every port in the
subnet sees it. Or DHCPv6 - without MLD snooping, every port sees all
client traffic for all DHCP requests; with MLD snooping only the
routers/relays in the subnet see it. "See" with MLD snooping means "see
it at all", not "see and ignore it" as in the broadcast world. 

Regards, K.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au)
http://www.biplane.com.au/kauer
http://www.biplane.com.au/blog

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