I was hoping someone could help me understand why my PPPoE connection keeps “flapping” in my lab I am using the dialer persistent, dialer idle-timeout 0 and, no cdp enable commands.
(idk why i would need to disable cdp but I seen it in another post, it does not seem to matter whether I have cdp enabled or not)
Everything works like normal but after some time my PPPoE link breaks and then re-establishes. I have the configuration of the clients dialer and fast ethernet interface below.
Also i am using 7200 routers in gns3 with the image: c7200-adventerprisek9-mz.152-4.S3
interface Dialer1 mtu 1492 ip address negotiated encapsulation ppp dialer pool 1 dialer idle-timeout 0 dialer persistent ppp chap hostname CUSTOMER ppp chap password 0 CISCO no cdp enable interface FastEthernet0/0 no ip address duplex full pppoe enable pppoe-client dial-pool-number 1
If someone could explain to me why this is happening or teach me what I can do to prevent this from happening I would greatly appreciate it. Also I can provide the Server config if you like but I dont think it is necessary (but then again what do I know i am asking for help lol)
Your configuration appears to be completely correct. Seeing the "server" side configuration (the PPPoE access concentrator) would be useful! Can you share that configuration as well?
Either way, the reason for the PPPoE session flap is not obvious from here. I wonder if you could run the following debugs:
debug ppp negotiation
debug pppoe errors
debug pppoe events
debug pppoe packets
on both the client and the server till the flap occurs, and then share the outputs. This should allow us to tell better what had caused the PPPoE session to go down. I personally suspect some kind of LCP timeout, perhaps due to high CPU on your GNS3 machine (just a guess), but the debugs should tell us more. Obviously, we would need to have the debugs logged, so make sure to configure both the client and the server with logging buffered 10000000 debugging to make sure these logs get recorded in their entirety.
Thanks a lot!
Sorry I was not been able to respond sooner. I was at work and can't work on this problem there.
However while turning debugs on I believe I have found the issue but not the root cause.
The first debug error I seen is below
*Jun 7 19:54:10.751: Vi1.1 PPP: Missed 5 keepalives, taking LCP down
*Jun 7 19:54:10.751: Vi1.1 PPP DISC: Missed too many keepalives
*Jun 7 20:08:26.359: Vi1 LCP: I TERMREQ [Open] id 4 len 4
*Jun 7 20:08:26.363: Vi1 PPP DISC: Received LCP TERMREQ from peer
So it seems the access concentrator is not getting keepalives
I believe this could be a GNS3 issue but I am not sure if it is CPU related as my CPU never gets taxed.
I have pasted in the concentrator and client configs like you have asked. Sorry If I didn't give you enough debug information but I seen the missed keepalives and that seemed obvious to me why the connection was flapping.
bba-group pppoe global
ip address 192.168.12.2 255.255.255.0
peer default ip address pool CLIENT
ppp authentication chap callin
ip local pool CLIENT 192.168.12.1
username CUSTOMER password 0 CISCO
no ip address
pppoe enable group global
ip address negotiated
dialer pool 1
dialer idle-timeout 0
ppp chap hostname CUSTOMER
ppp chap password 0 CISCO
no ip address
pppoe-client dial-pool-number 1
Please let me know your thoughts on this. I would be more than happy to get you more debugs/logs. Thanks for any help you can provide!