Vedr.: Re: [cisco-nas] Problems with multilink PPP/ISDN

[Mark Johnson]

At 08:28 PM 1/12/2004 +1100, Darren Ward wrote:
>It looks like one end is sending an ack with a different MRRU to a request.

It's also sending back a different address associated with the
Endpoint Discriminator class "local":

2d22h: Se3/0:0 LCP: O CONFREQ [Listen] id 30 len 36
2d22h: Se3/0:0 LCP:    MRRU 1524 (0x110405F4)
2d22h: Se3/0:0 LCP:    EndpointDisc 1 ao-srv01-dia01
2d22h: Se3/0:0 LCP:     (0x131101616F2D73727630312D64696130)
2d22h: Se3/0:0 LCP:     (0x31)
... snip...
2d22h: Se3/0:0 LCP: I CONFACK [ACKsent] id 30 len 25
2d22h: Se3/0:0 LCP:    MRRU 1500 (0x110405DC)
2d22h: Se3/0:0 LCP:    EndpointDisc 1 Local (0x130601CADFD7)

>This is legal only if the packet is a CONFNACK which means negotiate, a
>CONFACK means or should mean 'I accept these parameters', so the other end
>is rightly saying it's a bad ACK.

Right; the CONFACK should be IDENTICAL to the CONFREQ.

>You'll see it where it send out a CONFREQ for 1524 and the matching CONFACK
>has changed it to 1500.
>
>Later the MRRU's match and the link comes up.

Only momentarily; then the remote sends another LCP CONFREQ, and we
start all over, only to eventually fail.

Your remote ISDN modem (which is likely handling the MPPP - I think
if you disable MPPP on the cisco, things might connect fine) is broke.

mark


>Darren Ward
>CCIE # 8245
>
>-----Original Message-----
>
>-- SNIP -- Mismatched MRRU's
>
>2d22h: Se3/0:0 LCP: O CONFREQ [Listen] id 30 len 36
>2d22h: Se3/0:0 LCP:    AuthProto CHAP (0x0305C22305)
>2d22h: Se3/0:0 LCP:    MagicNumber 0x1F9D41A3 (0x05061F9D41A3)
>2d22h: Se3/0:0 LCP:    MRRU 1524 (0x110405F4)
>2d22h: Se3/0:0 LCP:    EndpointDisc 1 ao-srv01-dia01
>2d22h: Se3/0:0 LCP:     (0x131101616F2D73727630312D64696130)
>2d22h: Se3/0:0 LCP:     (0x31)
>... snip...
>2d22h: Se3/0:0 LCP: I CONFACK [ACKsent] id 30 len 25
>2d22h: Se3/0:0 LCP:    AuthProto CHAP (0x0305C22305)
>2d22h: Se3/0:0 LCP:    MagicNumber 0x1F9D41A3 (0x05061F9D41A3)
>2d22h: Se3/0:0 LCP:    MRRU 1500 (0x110405DC)
>2d22h: Se3/0:0 LCP:    EndpointDisc 1 Local (0x130601CADFD7)
>2d22h: Se3/0:0 LCP: Ignoring bad ACK!
>
>-- SNIP -- Later we request 1524 and get back 1524 and link progresses to up
>and AAA
>
>2d22h: Se3/0:0 LCP: O CONFREQ [ACKsent] id 31 len 36
>2d22h: Se3/0:0 LCP:    AuthProto CHAP (0x0305C22305)
>2d22h: Se3/0:0 LCP:    MagicNumber 0x1F9D41A3 (0x05061F9D41A3)
>2d22h: Se3/0:0 LCP:    MRRU 1524 (0x110405F4)
>2d22h: Se3/0:0 LCP:    EndpointDisc 1 ao-srv01-dia01
>2d22h: Se3/0:0 LCP:     (0x131101616F2D73727630312D64696130)
>2d22h: Se3/0:0 LCP:     (0x31)
>2d22h: Se3/0:0 LCP: I CONFACK [ACKsent] id 31 len 36
>2d22h: Se3/0:0 LCP:    AuthProto CHAP (0x0305C22305)
>2d22h: Se3/0:0 LCP:    MagicNumber 0x1F9D41A3 (0x05061F9D41A3)
>2d22h: Se3/0:0 LCP:    MRRU 1524 (0x110405F4)
>2d22h: Se3/0:0 LCP:    EndpointDisc 1 ao-srv01-dia01
>2d22h: Se3/0:0 LCP:     (0x131101616F2D73727630312D64696130)
>2d22h: Se3/0:0 LCP:     (0x31)
>2d22h: Se3/0:0 LCP: State is Open
>
>-- SNIP --
>
>_______________________________________________
>cisco-nas mailing list
>cisco-nas at puck.nether.net
>https://puck.nether.net/mailman/listinfo/cisco-nas