line up, protocol down 1

[fadi]

I have the following configuration:

Cisco router-serialModem-serialModem-Ascend router

The encapsulation on the serial ports is ppp.
When both modems are set to loop, both routers can see them going on loop.

On the cisco router I get the following when I issue a show interface serial 0:

Serial0 is up, line protocol is down
Hardware is QUICC Serial
Internet address is 192.168.0.1/30
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation PPP, loopback not set, keepalive set (10 sec)
LCP Listen
Closed: IPCP, CDPCP
Last input 00:07:54, output 00:00:06, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0 (size/max/drops); 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
662 packets input, 9268 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 2 giants, 0 throttles
22 input errors, 0 CRC, 17 frame, 0 overrun, 0 ignored, 0 abort
1159 packets output, 16226 bytes, 0 underruns
0 output errors, 0 collisions, 219 interface resets
0 output buffer failures, 0 output buffers swapped out
110 carrier transitions


and when one of the modems' loop is set i get protocol down (looped)

when i set the debug on the cisco i get the following each 10 secs

serial0: attempt to restart,
and then
reset 0xxxx

reset 0xxxx


please help

thanx

 

[cbum]

Hello, You will not be able to get Protocol Up when running a loopback test when using PPP encapsulation.
For Protocol to be UP, ppp must negotiate with another Device.
To test loopback, first make sure you save a copy of
your current Cisco configuration, change "encapsulation ppp" to "encapsulation hdlc" on your Serial interface. Run "debug serial interface" and
make sure you have the loopback inplace.
IF the Cisco Serial port is good and loopback is good then
the Status of Serial interface should be UP,UP.
Dont forget to "undeb all" on the Cisco when you finish testing.

Hope it helps.

Cbum

 

[fadi]

Thank you very much for your prompt response.
I can't get to my router now, but I will try what you suggested later.
What could be the reason behind this problem anyway?
Both routers can see the loop of both modems (synchronous ones) but they can't get the protocol up.
Bother routers and the modems are brand new, and the configuration on them is kept minimum: ip of serail and ether, enaps of serial.
Another point is that both modems are connected directly in the same room for testing purposes, so line problems are roled out.

THank you very much

 

[cbum]

Hello,
You will need to look at the Cisco Serial interface,
"show interface serial0" and look at the number of packets in and out, your old Email showed that the Cisco serial port received and sent packets ( including error's).
We need to start fresh.
First connect the modems to the Cisco and Ascend routers, do a "clear counters" on the Cisco router,
do a "show interface serial 0" and see if the number of "packets in and out" are increasing, any errors?. If packets are received and sent then you will need to run some debug's.
If you dont see packets input increase, then you may have a
problem with the Modems not sending/receiving, bad Routers inetrface's, bad cabling,etc.
If the number of error's are small compared to the total received then you may have a PPP problem.
If its a PPP problem then you will need to run some debugs.
Before running Debugs, first you will need to configure two items on the Cisco Router.
1)service timestamps debug datetime msec
2)service timestamps log datetime msec
Then exit the configuration and run "debug ppp error", "debug ppp negotiation" and "debug ppp authentication", now shut down the Cisco serial interface (using the Shut command)
then wait a few seconds a then do a "no shut".
Hopefully you will have something on your Cisco console screen if PPP is negotiating between the two routers.
Save the output of the Debugs for further troubleshooting.
Remember to turn OFF the Cisco debugs.
One more thing, we talked about testing Loopback with HDLC,
dont forget to change Encapsulation back to PPP on the Cisco Router when testing with Ascend Router, dont try to use HDLC between the Cisco and Ascend, HDLC is not compatible.

Hope it helps.
Cbum

 

[fadi]

Thank you for your help
The problem is getting complicated.
I switched the v35 cables that are connected to the modems, and the ser0 is up up. Lucent router can now ping me, and even telnet to my ser0. Cisco on the otehr hand is unable to ping its own ser0, nor Lucent's ser0!!!!!!!
why wouldn' tthe cisco see its own ser0?

Thanx again

 

[cbum]

Hello Fadi.

I dont know why the Ping is not working from
Cisco to Lucent. Ping from Cisco to its own
interface may not work, the packet needs to leave the
interface and comeback in for this to work.

I would need to see the configuration to
understand why Cisco cant ping the Lucent.

Note: You can put a loopback on the Cisco Serial port
and change encapsulation to HDLC, put an ip address
on the Serial interface and then you should be able to
ping from Cisco console to Cisco Serial interface's ip address.


If you decide to show your configuration, please remove
passwords, usernames, descriptions, and change ip address.

thanks
Cbum

 

[fadi]

It worked finally
After trying everything for 4 days, I replaced the modem that was connected to the Cisco router, and that did it!!!!

Thank you very much for your help, I really appreciate it.

Regards