Unanswered Question
Feb 26th, 2009


I cannot ping my connected device on the STM1 link. My configs are as below


interface ATM5/0

ip address

atm clock INTERNAL

no atm ilmi-keepalive

pvc 1/200

encapsulation aal5snap



interface ATM1/0

ip address

atm clock INTERNAL

no atm ilmi-keepalive

pvc 1/200

encapsulation aal5snap


please check my configs and advice why can't ping ping .2 addresses.

I have this problem too.
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marikakis Fri, 02/27/2009 - 00:18


1) It is not typical for routers to supply the clock (atm clock internal). The default is to derive clocking from the line (some ATM switch which has better clock stratum levels). Even if this is just two routers connected back-to-back, still only one side should provide the clock.

2) The IP addresses you have on the interfaces are not on the same subnet (unless you changed those to post your config and this is a typo).

3) Check that both your interfaces are in up/up status. If not, you need to check your cables (inverted tx/rx in fiber strands is common error) and any intermediate devices between the routers.

4) You might consider using the "oam-pvc manage" command in pvc configuration mode so that you have PVC failures propagated by the network to the endpoints.

Kind Regards,


Paolo Bevilacqua Fri, 02/27/2009 - 03:06

To add to excellent Maria's advice, you also must configure a point-to-point subinterface, and put ip address and pvc there.

An ATM main interface is always point-to-multipoint and not suited for sane an simple networking.

Giuseppe Larosa Fri, 02/27/2009 - 12:07

Hello Lawrence,

the ip addresses have to be in the same subnet as noted by Maria

point-to-point subintefaces are to be preferred as noted by Paolo


pvc 1/200

protocol ip broadcast

Hope to help


marikakis Fri, 02/27/2009 - 13:33


We were lucky enough to have the same very simple ATM setup everywhere across the network. That is point-to-point subinterfaces, and we never needed to use "broadcast" keywords or anything else. It just worked. We had something like this:

interface atm2/0

interface atm2/0.1 point-to-point

ip address ...

mtu ...

pvc 1/200

oam-pvc manage

This was just it. I don't know when the command you mentioned is required. I don't have time to explore this right know, so if you could explain further, I would be grateful.

Kind Regards,


Paolo Bevilacqua Fri, 02/27/2009 - 14:20

The wonderful things of this type of threads is that often times they end in a nice conversation among the usual suspects, while the OP never bothers to peep in again to say, "thanks", or "they sent me back to drive the repairs truck".

marikakis Sat, 02/28/2009 - 02:15

Paolo, this is probably the case because after some silence, which can be expected as is very common, we kind of forget the volunteer feeling and try to get the best of the conversation mostly for ourselves (either in the point format or in the knowledge format :-)

marikakis Sat, 02/28/2009 - 02:36

When I see the silence thing, I sometimes wonder if person is still alive. And then I say to myself: if they are still alive, that's ok, at least nothing bad happened!

mailaglady2 Sat, 02/28/2009 - 13:24

Hi sorry for the late response, my adsl was down so that was the reason I could not access the net and my lab. I have changed my network physical layout but will revert back on monday and will be able to provide feedback then after exercising all your advises or technical assistance.

Thanks for all your efforts and I really appreciate your help, I'm back on line again and enjoying my time again.

Hope everybody is emjoying his/her's too.

marikakis Sat, 02/28/2009 - 17:06

I can't help myself from saying that I am truly glad you are still alive! :-) In many cases there is a very simple explanation for late or no response. People sometimes forget or resolve their issues and they soon have to face more issues, and they just don't have the time to respond. I have to say here that when Paolo didn't post for some time in the forum I was quite worried, but he eventually came back and I felt quite better!


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