Why PPPoE Server "AC Name" field not works in Avalanche?
My question about Avalanche PPPoE Server. I configure Enable PPP and Enable PPPoE options in Server->Subnets configuration and AC Name and Service Name. I tried to set up a PPPoE session with third party PPPoE client (not Avalanche port). I checked Wireshark pcap and found that there is no AC-Name tag in PADO from PPPoE Server on Avalanche port. PPPoE AC-Name Tag in PADO must be according to RFC 2516. (The PADO packet MUST contain one AC-Name TAG containing the Access Concentrator's name.) What else should I configure to enable AC-Name tag in PADO from Avalanche PPPoE Server?
Hello Sreerag, thank you for your help. I tried different PPPoE clients (incl. Windows 7 PPPoE client) but I can't configure AC-Name tag in PADI. The same PPPoE clients can set up a PPPoE session with Spirent Test Center L2-L3 application. I'll open a service request, because Avalanche not works according to PPPoE RFC 2516. I also found that Avalanche sends PADO, even if there is no Service-Name tag in PADI. ![alt text] : /storage/temp/4506-pppoe+padi+pado_1.png
Hello Victor, Yes you are correct, PADO is missing the AC-Name tag. That's why I had mentioned that when client PADI has a prefered AC Name tag, Avalanche Server responds with the configured/available AC Name. Session proceeds only for matching AC names, else retries occur before the sessions time out. PADI from your PPPoE client is not having any AC-name tags, hence no answer from server. Could you please try configuring AC-Name at client level so that the PADI contains that? Thanks, Sreerag
Dear Sreerag, thanks. The problem is in PADO answer from Avalanche as PPPoE Server. PADO message is without AC-Name tag. RFC 2516 5.2 says: **The PADO packet MUST contain one AC-Name TAG containing the Access Concentrator's name, a Service-Name TAG identical to the one in the PADI** So Service-Name tag is ok, but where is AC-Name tag? it MUST be in PADO. RFC 2516 5.3 says: **The Host looks through the PADO packets it receives and chooses one. The choice can be based on the AC-Name or the Services offered.** So a PPPoE client can't choose an Access Concentrator = Avalanche and set up a PPPoE session, because there is no AC-Name tag in PADO. There is no PADR message from PPPoE client. ![alt text] Correct me if I am wrong. : /storage/temp/4501-pppoe+service-name+but+no+ac-name.png
Hello Victor, The Techpub link that you attached says (About a Server) "To determine whether it can service a particular client request, the router matches the service name tag received in the PADI packet against the service name tags configured in its service name table. If a matching service name tag is found in the PPPoE service name table, the router sends the client a PADO packet that includes the name of the AC from which it was sent. ***If no matching service name tag is found in the PPPoE service name table, the router drops the PADI request and does not send a PADO response to the client.***" This seems to be the same behavior of Avalanche as well, correct me if I am wrong. Thanks, Sreerag
Sreerag, thank you for the respond. I configued AC-Name and Service-Name tags for the client. PPPoE client sends PADI with Service-Name tag. When PADI has a Service-Name tag Avalanche PPPoE Server responds with PADO only when Service-Name fields match. But according to RFC 2516 and different tech docs PADO must contain AC-Name tag. The same PPPoE client can set up PPPoE session with Spirent Test Center. I still can't set up a PPPoE Session with Avalanche.
Do you have any preferred AC name for the clients? Could you try configuring AC Name at Client level too? I observed that when PADI has a prefered AC Name tag, Server responds with the configured/available AC Name. Session proceeds only for matching AC names, else retries occur before the sessions time out. Thanks, Sreerag