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modem shows down in NMS when connecting Lan cable

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smlt_vsat
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Mar 22nd, 2009 at 4:03pm  

I have a strange issue in one site . cystomer informed that link is dwon . imonitor i found that link is down but as per site i came to know that all light are green (Idirect 3100) .  later after many troubleshooting we found that whenever lan cable is removed from the vsat modem , link is up in NMS and when it is connected it suddenly shows down in NMS but status of3 the modem are ok . what could be the problem .
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Reply #1 - Mar 22nd, 2009 at 9:30pm  
Interesting.  I have never seen this. 

Is the modem able to pass traffic in its down status?

What is the latency tab telling you under the two circumstances?  Request timed out?  Or satellite round trip times?

Any chance of an IP conflict with Sat0 or the Lan interface (Eth0)?

When the remote is down, what is the events and conditions tab telling you? UCP or ACQ?

I would also ask what the SAROUTER IP tables look like when the remote is up, and when it is down?  If you intend to telnet to that process, make sure you ID what blade the customer is on before you dig in.



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Reply #2 - Mar 24th, 2009 at 7:46am  
I would guess it s a routing or ip addressing problem.
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Reply #3 - Mar 24th, 2009 at 11:23am  
That is exactly why I asked about a possible IP conflict.  Smiley
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smlt_vsat
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Reply #4 - Mar 24th, 2009 at 3:39pm  


Its never an IP Conflict issue because sometimes i can see that sometimes Modem TX LEd go off while connecting to the switch . Finally after much troubleshooting we found that REDLINE wireless device is creating problem . But what we dont know . when the Wireless device is disconnected from the switch , the modem has no problem (i mean connected to switch) . The same setup was there since 2 years and nothing is changed and this is really wonder what is going with now.
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smlt_vsat
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Reply #5 - Mar 24th, 2009 at 3:48pm  


The issue is now How another device can stop our modem transmission through Ethernet ?
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Reply #6 - Mar 24th, 2009 at 11:44pm  
It is difficult to troubleshoot your situation.  There are many variables...

1. Is the interface (Eth0) on the remote reporting any errors?  

2.  Have the user telnet to falcon and turn on remote messages (xon).   Look for errors and/or odd messages (such as tx queue saturated, etc).  Check for ANY messages both with and without the ethernet (redline) connected.  Often packets received by the remote via the local LAN are not able to be processed due to undefined routes for the packets. Could be anything from spam to possible routing loops....causing a packet flood.  Also check for routing loops or possible duplicate IPs on the local LAN as well.

3. Check the CPU cycle on the remote....if it is low or within tolerance, then the above situation (packet flood) is not likely.
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smlt_vsat
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Reply #7 - Mar 25th, 2009 at 9:02pm  


ok , if this some loop issue or conflict , how it can sop modem transmission ?

after investigation , we found again today that when modem ip address is changed than anything like 192.1.28.1 and 192.1.28.2 , it is workingwell

we had made sure one by one in the remote device that no device is usuing the same IP .

I dont understand anything

How i can check for TX queue in modem ?
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Reply #8 - Mar 27th, 2009 at 1:14am  
How?  CPU cycle being overwhelmed. 

Telnet to falcon and run the xon command. See if the modem is reporting anything out of the ordinairy....(this is a long shot, but frankly your issue is quite difficult for us to troubleshoot due to the amount of variables involved).
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smlt_vsat
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Reply #9 - Apr 6th, 2009 at 3:36pm  


Hello

after all its an issue of virus flooding some continuous packets and made modem busy . device behind the modem establishing sessions and evem modem cannot acknwlodge trasmit updates to the PP , so loosing Even TX . we found some abnormal traffic on upstream and also enables ip accounting omn upstream router to get clear picture to know who is sending such traffic . we isolate those devices and fixed the problem and ok now

Thanks for the information and now everything going smoothly
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Reply #10 - Apr 8th, 2009 at 11:53am  
Glad to hear you isolated the problem.  I figured it was some sort of flood that was keeping the box from its TDMA duties.
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