PPP over ATM not working with Cisco 877

[Youenn Rivoallan]

Hi,

I have a Cisco 877 CPE connected to a Huawei 5300 DSLAM via the adsl interface. On the other end of the DSLAM I have a Roaring ¨Penguin PPPoE server connected via FE2/0/0. I want the 877 to use PPPoA to connect to the PPPoE server and get an IP configuration (address, dns, Gateway,...). The DSLAM is configured to make the translation between PPPoA and PPPoE and it will only accept PPPoA on adsl interfaces.

When I use a Netgear CPE it all works fine, the point-to-point connection is created and the CPE get IP configurations from the rp-pppoe server.

But I can't make it work with Cisco 877 router. I used wireshark on the server and I saw no packets coming from the 877 (or from the DSLAM). So my guess is that the configuration on the router is wrong. Based on what I found on the internet, PPPoA should be possible on Cisco 877 but none of the configurations suggested did the trick. You'll find attached a file with the running-config, the version, the interface description and a part of the PPP packet debug of the 877. I also attached screens from the Netgear working configuration. If you need any other info I'll be glad to provide.

Any help to get PPPoA working on Cisco 877 router would be much appreciated.

Regards.

[Georg Pauwen]

Hello,

on the 877, try the adjustments below (in bold):

interface ATM0
 no ip address
 no atm ilmi-keepalive
 no shutdown
 pvc 8/35
 encapsulation aal5mux ppp dialer
 dialer pool-member 1

interface Dialer0
 ip address negotiated
 encapsulation ppp
 ip mtu 4470
 dialer pool 1
 dialer-group 1
 ppp authentication chap
 ppp chap hostname test
 ppp chap password 0 test

Also, post the output of 'show controllers dsl 0'...

[Youenn Rivoallan]

Hello,

Thank you for your answer.

I think pvc 0/35 is correct. You'll find attached a screen of the adsl line-profiles of the DSLAM, as you can see, it is configured to work with pvc 0/35 (the CPE is connected to adsl 0/0/1 by the way).

Interesting thing about the mtu size : in dialer 0 interface, it can't be more than 1500 bytes but on the atm 0 interface I can set it to 4470. I've tried with max on both but it did not work.

You'll also find attached the "show controllers atm 0" output.

[Youenn Rivoallan]

Problem solved !

I tried again with a basic config from the internet and this time it worked. I think I forgot to reload the CPE last time.

I attached the working-config just in case.

Once the CPE came back up, I had to shutdown atm0 and turn it back up and it worked.

I'm now trying to get the rp-pppoe server to give a specific address based on the client's MAC. Here is a link to the post I created on Ubuntu (french) : https://forum.ubuntu-fr.org/viewtopic.php?id=2010290

Thanks for your help.

Bye.