IPv6 Confusion

Mikael Abrahamsson swmike at swm.pp.se
Fri Feb 20 05:44:08 UTC 2009

On Thu, 19 Feb 2009, Frank Bulk wrote:

> I probably tied CPE to NAT together in my mind....if I peel NAT out from 
> what these CPE are doing, perhaps a PPPoE/A environment is the only 
> place a L3 CPE will be needed with IPv6 anymore.  FTTH, BWA, RFC 
> 1483/RBE, and cable modems can bridge at L2 and each customer host can 
> each have their own IPv6 address.

Do you really want to keep state for hundreds of end user devices in your 

In my mind, IPv6 more than ever requires the customer to have their own L3 
device (which you delegate a /56 to with DHCPv6-PD).

Imagine the size of your TCAM needed with antispoofing ACLs and 
adjacancies when the customer has 100 active IPv6 addresses (remember that 
IPv6 enabled devices often have multiple IPv6 addresses, my windows 
machine regularily grabs 3 for instance).

Mikael Abrahamsson    email: swmike at swm.pp.se

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