Advertisment: Broadband via satellite
Advertisment: Planet Earth rotating animation

www.satsig.net

Satellite Internet Forum.

Welcome, Guest.        Forum rules.
      Home            Login            Register          
Pages: 1

Warning: TRAFFIC_HUB_MODEM_CRC

(Read 8342 times)
Gomes
Member
★★
Offline



Posts: 12
Bangladesh
Oct 28th, 2007 at 8:25am  
Since last few days I'm getting WARNING on my ULC "Line card’s traffic CRC xxx above high limit of 10 within
15 seconds"
Can anyone tell me how to resolve this ?
Back to top
 

Gomes&&
WWW  
IP Logged
 
TDMAMike
Senior Member
★★★
Offline



Posts: 826
Reply #1 - Oct 28th, 2007 at 1:11pm  
1. How many line cards are you running in that network?

2. Are they configured for Carrier groom or Freq hop?

3. If you have more than one HLC in your network are any of your other HLCs in warning?  

If not, you need to put a specan on the MHz that is configed into the line card and run a minimum trace against it and look for energy under the TDMA.  

You can also run a Line card stats query against all of the cards and look for Traffic CRC errors (compare your other cards with the card taking errors). You can view all of your line cards stats by right clicking the network level (in iMonitor) and select LINE CARD STATs.  Query ONLY your Rx cards and look for CRC errors.  

If the errors are coming from a specific remote (which they may be)...there is a procedure you can use to find the suspect VSAT.  I will wait to give you that procedure until I hear feedback on the above questions.

Back to top
« Last Edit: Oct 28th, 2007 at 3:59pm by TDMAMike »  

Regards, &&&&M
 
IP Logged
 
Eric Johnston
Senior Member
★★★
Offline



Posts: 2109
Reply #2 - Oct 28th, 2007 at 5:46pm  
With the spectrum analyser tuned to the return link frequency you might also try zero span and look out for any abnormally shaped bursts, low level bursts, two bursts overlapping or low level cross-pol bursts.

Make tests of every remote and record the return link quality and burst timing of each.

Use a sweep time of a few seconds and single sweep manually triggered.  Keep clicking till you get a picture of something interesting.

A normal spectrum analyser display on the return link with max hold, will build up the overall envelope of your return link bursts.  Look for spectral regrowth in case one of your remote BUCs is overdriven.  Look for interference in the gaps between the return links. Follow Mike's advice regarding min hold which will find in band steady interference.

Parallel up another receiver and see if that detects the same problem but be careful that the traffic so received does not duplicate all the packets into your ethernet router system. ( been there - done that ! )

Best regards, Eric.
Back to top
« Last Edit: Oct 29th, 2007 at 10:33am by Eric Johnston »  
 
IP Logged
 
Gomes
Member
★★
Offline



Posts: 12
Bangladesh
Reply #3 - Oct 29th, 2007 at 4:02am  
1. I've TWO ULC, TxRx - ULC1 & Stdby - ULC2
2. Configured for Carrier Grooming
3. ULC2 is Standby
Back to top
 

Gomes&&
WWW  
IP Logged
 
TDMAMike
Senior Member
★★★
Offline



Posts: 826
Reply #4 - Oct 29th, 2007 at 11:01am  
Run that minimum trace and look for energy underneath. 

also

Are any of the other remotes in that (carrier groomed) inbound taking CRC errors? 

If not, then the issue is with a specific remote. 

If that is the case, I am guessing that one of the users is off peak and needs to re-aim.  If you run a Network Data Snapshot at the Network level you should be able to find the culprit.  Pull the stats and look at downstream and upstream SNRs. 

Back to top
 

Regards, &&&&M
 
IP Logged
 
Gomes
Member
★★
Offline



Posts: 12
Bangladesh
Reply #5 - Oct 30th, 2007 at 5:30am  
Warning shows most of the time (at pick hour) when one of my Remote Tx Power close to "Max. Power".
But downstream and upstream SNRs are good through out the day!
With SpecAn we found little Intermittent at HUB end!
Back to top
 

Gomes&&
WWW  
IP Logged
 
TDMAMike
Senior Member
★★★
Offline



Posts: 826
Reply #6 - Oct 30th, 2007 at 10:52am  
1. When you run a network data snapshot against the network level (by right clicking the network level and selecting network data snapshot) do you see anyone taking any errors? 

2. What is the size of your FWD (Tx) carrier on that line card?
3. What is the size of the Upstream (Rx) carrier also on that line card?

4. If your upstream and downstream snrs look good, why is your remote getting close to its max power?  Off peak? 

That remote may be very close to saturating its BUC when it is working that hard.  Something has to be causing it.

Additional questions:

What kind of remote is it? 
What is its max power setting?
What is your UCP sweet spot set to (Nominal C/N)?
Back to top
 

Regards, &&&&M
 
IP Logged
 
Gomes
Member
★★
Offline



Posts: 12
Bangladesh
Reply #7 - Oct 30th, 2007 at 11:18am  
1. Yes, sometimes that remote have TDM Lost
2. Downstream 1536
3. Upstream 512
4. Only at One remote sometimes it comes to Max. Power!
i. All remotes are with iDirect 3100
ii. That remote settings are Initial Power: -12 & Max. Power: -9
iii. Down C/N: 13-12 dB, Up C/N: 9-8 dB
Back to top
 

Gomes&&
WWW  
IP Logged
 
TDMAMike
Senior Member
★★★
Offline



Posts: 826
Reply #8 - Oct 31st, 2007 at 10:50am  
Everything looks good. Not seeing anything odd (with what you told me).  When the CRCs are present is the remote maxed out in power (at the exact time you note it)?
Back to top
 

Regards, &&&&M
 
IP Logged
 
Gomes
Member
★★
Offline



Posts: 12
Bangladesh
Reply #9 - Oct 31st, 2007 at 11:09am  
When the CRCs are present is the remote maxed out in power (at the exact time you note it)?  
Ans: NO, not at the same time - gradually
Back to top
« Last Edit: Nov 6th, 2007 at 7:16am by Gomes »  

Gomes&&
WWW  
IP Logged
 
techtest
Member
★★
Offline



Posts: 42
Reply #10 - Jul 24th, 2009 at 8:47am  
Hi  All ,
What are the telnet commands to  check current usage in i Direct modem... ie  by typing that command in telnet session
can we check  what is uplink and downlink usage going on right now ...
Back to top
 
 
IP Logged
 
techtest
Member
★★
Offline



Posts: 42
Reply #11 - Jul 24th, 2009 at 8:50am  
Hi  All ,
What are the telnet commands to  check current usage in i Direct modem... ie  by typing that command in telnet session
can we check  what is uplink and downlink usage going on right now ...
Back to top
 
 
IP Logged
 
TDMAMike
Senior Member
★★★
Offline



Posts: 826
Reply #12 - Jul 24th, 2009 at 12:03pm  
Usage?  You want throughputs or RF statistics?  iSite is a better alternative than command line.
Back to top
 

Regards, &&&&M
 
IP Logged
 
Pages: 1