[ppml] IPv6 flawed?

briand at ca.afilias.info briand at ca.afilias.info
Thu Sep 6 13:51:58 EDT 2007

"Mack" wrote:
> In the most relevant products from Cisco (sup32 and sup720) the IPv6 is
> stored in a TCAM with a different architecture from the IPv4 TCAM.
> Specifically the Sup32 and Sup720-3B both have 256000 IPv4 slots and
> 128000 IPv6 slots.


A closer inspection of the literature, you will find, says *or*, not *and*.

Meaning, 256k IPv4 *only*, or 128k IPv6 *only*.

And the default set-up is a mix of 192k IPv4 and 32k combined

> An argument can be made that it will be cheaper for some organizations to
> switch to IPv6 shortly due to the impending limit of the FIB TCAM on their
> routers.

Organizations at the edge, maybe, who don't do content or services.
Who can deploy IPv6 to IPv4 NAT gateways at their upstream edges.

Not content players, and not DFZ players, for sure.

> In any case the most relevant Cisco products are going to run out of IPv4
> TCAM space before IPv6 even makes a dent.

... which is all the *more* reason why paying close attention to IPv6
allocation, aggregation, and usage, is so important.


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