[nsp] 3640 DSL question

jp at pour.midcoast.com jp at pour.midcoast.com
Fri Aug 29 13:44:28 EDT 2003

For about a good six months, we've been doing DSL over ATM flawlessly 
without any problems whatsoever on a 3640 with an NM-4t-ima on the ATM 
side. (C3640-IS-M), Version 12.1(5)T15 is what's used. This is the latest 
update for the IOS plus upgrade I bought that is protected from the 
vulnerability last month. The prior version also had the same trouble. I 
don't think it's a cisco problem but I'll try anything.

What happens, DSL customer all of a sudden can not surf/ping/etc.. 
Restarting DSL modem doesn't fix a thing. If we remove the customer's 
subinterface and static route, then put it back in, the customer works 
again. Nothing in the arp table with their IP before the problem.

The setup is:
us        indy telco         customers

The ATM switch is a psax which I presume would be a lucent one, but it's 
carefully guarded at the telco. The DSL system is all paradyne. Paradyne 
is generally great stuff.

The problem started last weekend with this style of DSL hookup, as well as
our older DSL customers who are hooked up via ATM, which the psax converts
to frame relay before going to IPCs going ethernet to the DSLAMs. We have
no configuration-per-customer on the cisco for these people, so we
couldn't do anything about that. Telco denies any involvement of course.
Nothing showed up in the syslogs when the big problem happened affecting
about half our customers. Rebooting the cisco didn't fix things. Telco
points finger saying it's either cisco or the customers. I don't know a
thing about a psax, and I'm figuring they know a minimum.

Anyone else had problems where DSL customers just dissapear off the ATM 
network? (And re-entering them fixes it) Any suggestions?

bridge irb
interface ATM1/1
 no ip address
 atm uni-version 4.0
 no atm ilmi-keepalive
 no scrambling-payload
 cablelength short 133
 bridge-group 2
interface ATM1/1.2103 point-to-point
 description of customer
 ip unnumbered BVI2
 rate-limit input 384000 8000 8000 conform-action transmit exceed-action drop
 rate-limit output 384000 8000 8000 conform-action transmit exceed-action drop
 atm route-bridged ip
 pvc 2/103 
interface BVI2
 ip address x.x.x.x secondary
 ip address x.x.x.x
ip route x.x.x.x ATM1/1.2103
bridge 2 protocol ieee
 bridge 2 route ip

Jason Philbrook   |   Midcoast Internet Solutions - Internet Access,
    KB1IOJ        |  Hosting, and TCP-IP Networks for Midcoast Maine
 http://f64.nu/   |             http://www.midcoast.com/

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