As far as I can tell, neither Foundry Bigiron, nor Cisco 65xx
support IPV6 (I could be wrong).
It is rumored that Cisco has software for the 6500 that does IPv6,
albeit "in software" on the MSFC. And I'm sure they have plans to
support IPv6 in hardware on this platform at some point.
Foundry has something like "protocol-specific VLANs", which allows you
to bridge IPv6 traffic, while (Layer-3-) routing IPv4.
While they probably aren't the most popular routers, they are very
popular, and im sure plenty of cisco's smaller routers don't support
The smaller routers are generally not a problem as long as they have
enough memory to run recent IOS releases, and I think the bloat is
mainly due to new functions other than IPv6.
An interesting question is what it would take to support IPv6 on
appliance-like routers such as IP-over-Cable or -xDSL CPE. In the
retail space I actually see some interest in running IPv6, because it
makes it much more feasible to operate a small network at home, and I
have the impression that home users now lead enterprises in terms of
IPv6-enabled OS deployment (Windows XP and Linux in particular).
How ready is the 'net to transit to IPV6 in the future?
Let's say that most ISPs could satisfy the current demand
Even though there are relatively few high-performance implementations
(read: ASIC-based IPv6 forwarding as Juniper has) out there, a modest
amount of IPv6 traffic could be carried "natively" on most networks.
If you need higher performance and don't have hardware forwarding for
IPv6, you can always tunnel in IPv4 (or, shudder, MPLS) at the edges.
You may also want to do this if you don't really need the IPv6
performance, but would like to protect the control plane of your
production (IPv4) service from the additional CPU load (IPv6 traffic
as a DOS on your RPs :-).
Should everyone be factoring in replacing big routers with IPV6
being the only reason?
Sure, provided everyone has infinite amounts of money, or the
additional revenue from IPv6 justifies the investment. Honestly I
don't think either is the case today for most of us, except where some
form of public funding exists, for example through innovation/research
subsidies or tax breaks for enterprises using IPv6.