Cisco 1801W, v6 on wireless, bvi argh.

[Gert Doering]

Hi,

On Thu, Aug 05, 2010 at 10:25:32AM +0200, Daniel Verlouw wrote:
> On Wed, 2010-08-04 at 17:42 +0200, Gert Doering wrote:
> > > "debug ipv6 nd" says everything is fine, RA's are being sent etc.
> > > tcpdump on a directly connected host thinks otherwise. *sigh*
> > > 
> > > This is on 15.0.1(M3) btw.
> > 
> > Well, *this* is the old "IPv6 on BVI does not work right" bug.
> 
> really? Mmm, my understanding always has been that this "bug" [1]
> affected IPv6 on wireless, not on wired as in this case.

In my tests, it affected both.  You could configure IPv6 on the BVI, but
the box would get all confused about it, and would not recognize the
network as "directly connected" and send packets to it.

Bridging IPv6 packets from *other* nodes ("Node A on WiFi, node B on
wirde LAN") worked fine, just talking to the Cisco's BVI didn't work.


> [1] was it really a bug or just a missing feature? Since 15.1T now
> specifically mentions IPv6 on BVI:
> <http://www.cisco.com/en/US/docs/ios/15_1/release/notes/151TNEWF.html#wp1063071>

Well, since you could configure it, and it didn't work, it's a bug in
my book.  Of course one can always relabel bugs as "missing features".

> Note that the 887W wireless architecture is much different from let's a
> 877W. It uses a seperate wifi AP subsystem running its own IOS
> connecting to the main router subsystem using a GigE switchport. The
> main router simply sees the AP as "another switchport" and doesn't use
> BVI's anymore.

Ah.  I didn't know that.  (I long lost track on the plethora of 8xx 
ciscos that are all weird in their own way, like the 861 that is said
to never ever get IPv6 support in any way "because it is not powerful
enough").

> > Try 15.1T or whatever the original poster reported that worked for his
> > 1800 :-)
> 
> actually, it turned out the end-user had a semi-smart-but-braindead
> switch connected that dropped some multicasts and hence the RA's were
> not making it all the way through :/ Problem solved, works fine on
> 15.0 :)

Glad that it works now - and annyoing to learn that there is now some
more L2 gear that breaks IPv6...

Gert Doering
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