[nsp] Connecting Max6000 with Cisco 2500 over HDSL: "line protocol is down"

Bruce Pinsky bep at whack.org
Mon Jun 21 15:37:19 EDT 2004


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Mehmet Ali Suzen wrote:

| Dear List,
| We are trying to establish a connection between Cisco 2509 over a
| serial line and HDSL modems to Ascend Max 6000, but frustrated
| to get "line protocol is down" status.
|
| Set up is :
|
|   Cisco2509--serial 0
|     <----over DTE Cable--V35>
|   Alcatel HDSL
|      <----telco over line L1 L2 ---->
|   Alcatel HDSL
|     <---G703---RJ48--->
|   E1 port Ascend Max 6000
|
|
| But we can not ping to serial 0 even modem lights indicates
| connection is OK? Shall We assigned an IP address to
| serial 0 and WAN interface of Ascend Max 6000 as we did?
| What could be the reason to get "line protocol is down"?
|
| Many thanks for any comments or suggestions
|
| Best,
| -Mehmet
|
| PS:
| Encapsulation has set to be PPP, here is the running conf for
| serial 0:
| !
| interface Serial0
|  ip address 192.168.1.60 255.255.255.224
|  encapsulation ppp
|  ppp authentication chap
|  ppp chap password 7 1248574446
| !
|
| Here is the status of interface
| # sh int ser 0
| mahir-r2#sh interfaces serial 0
| Serial0 is up, line protocol is down
|   Hardware is HD64570
|   MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
|      reliability 255/255, txload 1/255, rxload 1/255
|   Encapsulation PPP, loopback not set
|   Keepalive set (10 sec)
|   LCP Listen
|   Closed: CDPCP
^^^^^^^^^^^^^^^^^^^^^^^^

You have not successfully negotiated the PPP connection.  LCP is still in
listening state so no other CPs will be negotiated until LCP is successful.

I suggest that you check out
http://www.cisco.com/en/US/tech/tk713/tk507/technologies_tech_note09186a008019cfa7.shtml
for tips on troubleshooting and look at the output of these commands:

	debug ppp authentication?To see if a client is passing 				authentication.
If you are using a version prior to Cisco IOS 			software Release 11.2, use
the debug ppp chap command instead.

	debug ppp negotiation?To see if a client is passing Point-to-Point 	
Protocol (PPP) negotiation; this is when you check for address 			negotiation.

	debug ppp error?To display protocol errors and error statistics 	
associated with PPP connection negotiation and operation.

My guess is an authentication problem.  You may need the "callin" option
for "ppp authentication chap" so that the cisco is not challenging the
Ascend for outgoing calls, only incoming ones.

|   Last input never, output 00:00:08, output hang never
|   Last clearing of "show interface" counters 00:09:36
|   Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
|   Queueing strategy: weighted fair
|   Output queue: 0/1000/64/0 (size/max total/threshold/drops)
|      Conversations  0/1/256 (active/max active/max total)
|      Reserved Conversations 0/0 (allocated/max allocated)
|   5 minute input rate 0 bits/sec, 0 packets/sec
|   5 minute output rate 0 bits/sec, 0 packets/sec
|      0 packets input, 0 bytes, 0 no buffer
|      Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
|      0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
|      119 packets output, 2261 bytes, 0 underruns
|      0 output errors, 0 collisions, 31 interface resets
|      0 output buffer failures, 0 output buffers swapped out
|      0 carrier transitions
|      DCD=up  DSR=up  DTR=up  RTS=up  CTS=up
|



- --
=========
bep

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