[c-nsp] IPv6 on the 877W

[sethm at rollernet.us]

I just went back and forth with TAC regarding IPv6 support on an 877W.
Ultimately, the problem was that there isn't any support for IPv6 IRB, and
IRB is the only way to put the wireless radio on the same segment as the
ethernet ports. Boo. I found a bug id in the c-nsp archives (CSCej50923)
about this from 2005, and I was told it was closed without a fix.

Also of note, I turned the 877W into a brick by doing the following (in
order):

* Assign IPv6 address to int vlan 1
* do "no bridge-group 1" on int vlan 1
* IPv6 works! no IPv4, though
* do "bridge-group 1" on int vlan 1
* ipv6 and ipv4 work! however...
* router locks up after a bit, then never boots again after a power cycle

Seems IPv6 is pretty buggy (and lacking) on this thing.

~Seth