[c-nsp] c836 router rfc1483-bridged with NAT / problem every five minutes

[Per Carlson]

On Thu, Jun 29, 2006 at 11:16:00AM +0200, Elmar Pigeaud wrote:
> We have a Cisco 836 ADSL over ISDN router, configured for RFC1483
> bridging, with NAT. It seems to be working fine, however, every five
> minutes (exact) it brings down the ATM0 interface, which brings down
> the bridge (BVI1). After about 20 seconds it comes up again, and
> connection comes back up, no errors logged other than that the
> connection was brought down.
>
> I saw a lot (392) of interface resets for ATM0,
> none for the other (BVI1, ETH0) interfaces. 199 Packet drops...
>
> Has anyone encountered a similiar problem? Any hints for
> more troubleshooting?

I do have the same router with a similar setup (BVI and NAT)
working fine since a long time (several years). It's currently
running 12.3(2)XA4 and ran 12.2(8)YNx previously.

If you have the memory and flash neccesary you could try 12.3(8)YG
(48/12M) or a 12.4T (48/12M or 64/16M). They support 'RBE Client
with QoS', which removes the need for bridgeing (and the use of
BVI).

They also includes the features to do DHCP Release and Renew from
the CLI. These are handy when the BRAS/DHCP-server hickups. I've
had several instances when the lease hasn't expired but my IP and
MAC-address is invalidated by the BRAS/DHCP-server. On those
occasions, the router had an invalid IP-address, and there where
no other options to get a new one than to reload the router... 

-- 
Per Carlson, Sr. Network Developer