Subject: sequence num. synchronisation

From: Sabrina Minshall <[email-masked]>
Date: Mon, 17 Jan 2000 19:52:18 -0800 (PST)

How does one handle sequence number synchronisation or recovery
when the user space l2tp daemon dies and comes backup? Or, does 
it reset all the sessions?

Thanks,

sabrina

---

From: "John Bourke" <[email-masked]>
Date: Tue, 18 Jan 2000 13:26:15 -0000

Folks,

If I have many LACs and many LNS's, I may want to keep the shared secrets on
a Radius server.

Is there any provision in the current drafts to have the LNS pass shared
secret exchanges off to a Radius server ?

Has anyone implemented this ?

Once a L2TP  tunnel and session are up, and a ppp session has started,
during PPP authentication at the LNS, the LNS can use a Radius server to
check PPP user/password details.  Is there anything in this radius
interaction whihc allows me to identify the tunnel and session ?

The LNS then sends accounting information to the Radius server during the
PPP session.  The accounting information contains a reference to the L2TP
tunnel and session carrying the PPP session :-

4.1.  Acct-Tunnel-Connection
   Description
      This Attribute indicates the identifier assigned to the tunnel
      session.  It SHOULD be included in Accounting-Request packets
      which contain an Acct-Status-Type attribute having the value
      Start, Stop or any of the values described above.  This attribute,
      along with the Tunnel-Client-Endpoint and Tunnel-Server-Endpoint
      attributes [3], may be used to provide a means to uniquely
      identify a tunnel session for auditing purposes.
[...]
      The format of the identifier represented by the String field
      depends upon the value of the Tunnel-Type attribute [3].  For
      example, to fully identify an L2TP tunnel connection, the L2TP
      Tunnel ID and Call ID might be encoded in this field.  The exact
      encoding of this field is implementation dependent.

From the accounting information I could potentially have tunnel and session
is, but I cannot tie these back to the PPP authentication.

Should a mapping between the AVP's in the L2TP ICRQ and LNS Radius
interactions be defined ?

john