SatSig topic:

TDM Lost

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Oct 12^th, 2008 at 1:04pm

TDM Lost.
Sometimes it appears with low numbers but it does appear

what is it? why does it happen?

i never saw it happen on my 3100.
on the x3 however it does appaer

pls advise.

Oct 12^th, 2008 at 2:41pm

That value is indicative of lost data in your TDMA upstreams (as observed by the NMS at the Hub). It can be the result of interference, someone walking in front of your dish, etc. It is normal to lose some TDM on entry into the usptreams (just after you get your framestart into the returns). Unless you are losing TDM constantly, there is no cause for alarm.

Oct 12^th, 2008 at 3:47pm

ya but thats the thing i never had it happen on my 3100. 0

now during a 1 day uptime period i can see 1 or 2 showing up.

there is no interference that wasnt there when the 3100 was. same place.

only difference in the chain now is the PLL lnb and the BUC + the x3 modem.

so let me get another thing straight... when a tdm gets lost the modem has to retry sending the frame again... how much delay am i gonna see with a retry?

[edit: update]
one odd thing to add ::
i did the rmtstat command and it shows the following:

> Remote Status: t:000118964943 SNR=11.20 TxPower=-22.00 dBm RxPower=-43.06 dBm DigitalRxPower=0.00 Temp=36.5 COF= 2000 TDM(NCR)_Lost=0 PL_Lost=0 LocalFOCorrection = 99 FastFadeCorrection = 90 FllDac=31138 delta_scpc_errors=0
CRC8Errors = 0 CRC32Errors = 0 Raw AGC=115
LAN Port: 100 Mbps Full Duplex(AutoNegotiation: Complete) on phy 0

it says TDM Lost=0.
hmm. i wonder if this is a new bug from the new iSite? it even shows my BUC as "Fail or unavailable".

Oct 15^th, 2008 at 9:14pm

anybody wanna take a shot at this?

in 2 days now isite shows 2 TDM's lost.

i wonder what to believe now...

Oct 16^th, 2008 at 2:52am

Its an interruption in your upstream (TDMA). Nothing more. A value of 2 is nothing to be concerned with. A bird landing on your system can cause more TDM loss than what you are observing.

Oct 16^th, 2008 at 7:48am

Mike

The problem is with my old 3100 i've never ever ever had a TDM lost

The only thing different this time is the 3100+PLL LNB but you're saying its a Transmit issue. i dont know how that can be...

getting VERY VERY VERY sick and tired of these problems. maybe i'll get a hughes system Sad

Oct 16^th, 2008 at 10:17am

"getting VERY VERY VERY sick and tired of these problems." is an over reaction. You have lost a couple of uplink packets, say a couple of mouse clicks.

Maybe a bird, aeroplane or noise burst from somewhere. Not significant.

Best regards, Eric.

Oct 16^th, 2008 at 10:44am

ok so check this out

same satellite W6, hub: skylogic

idirect 3100 modem.

isite shows tdm-lost 6

rmtstat: [RMT:xxxxx] admin@telnet:xx.xx.xx.xx;1617
> Remote Status: t:000846562444 SNR=8.70 TxPower=-13.50 dBm RxPower=-30.86 dBm D
igitalRxPower=24.46 Temp=46.6 COF= -4769 TDM_Lost=6 FllDac=2622 delta_scpc_erro
rs=0
LAN Port: 100 Mbps Full Duplex(AutoNegotiation: Complete) on phy 0

weird?

well at least for the 3100 both isite and rmtstat showed the same thing

on the x3 isite showed 1 or 2 while rmtstat showed 0

something is very funny.
these are two different sites.
when i was on am22 i had 0 all the time.

Oct 16^th, 2008 at 12:00pm

I wouldnt worry a lot about that value unless it achieves double digits. That value of 2 is not constant loss, it is letting you know that over the last X amount of hours you have had a brief interruption in your upstreams. That could be someone poking energy from the cross-POL, some object (manmande, natural, ie a bird, aircraft, etc) traversed your link (teleport or remote side), or weather (on either side of the link) has attentuated the RF to the point where TDM was dropped. It is nothing to be alarmed about at a value of 2. Now if that counter was climbing (2, 4, 12, etc), then it would be worth looking into.

It is your choice to move to Hughes, but limit your expectations now. You are sending signal through the atmosphere, there are going to be some bumps here and there. Hughes, iDirect, Viasat, none of them are immune.

Oct 16^th, 2008 at 12:16pm

thanks for the reply

i am assuming your experience with the x3 and the new isite is limited?

i would call iDirect and ask them why isite shows something and rmtstat shows another.

i knows hughes, idirect or whoever all are the same in theory... i was just upset. thanks again Mike.

Oct 16^th, 2008 at 12:34pm

It will be some time before I cross paths with the X3. I am going to let it mature a little. Plus, I do not deal with the lower grade (inexpensive) boxes (i.e. the 3100, X3, etc).

Oct 16^th, 2008 at 1:29pm

Quote:

I do not deal with the lower grade (inexpensive) boxes (i.e. the 3100, X3, etc).

ouch. that hurt :-|

Oct 16^th, 2008 at 9:28pm

It is perfect for your application and that is all that matters:)

Nov 26^th, 2008 at 4:46pm

I was bored at work and came across this site. I just wanted to chime in that the TDM lost stat does not have anything to do with your transmit. This is a receive side statistic. Specifically, it increments by one anytime your modem loses RX lock. However, this counter is reset to 0 anytime the modem is reset. So, if you show a value of two here, it just means the modem lost rx lock twice since the last time it was reset.

Over time, you'll certainly have times when the modem loses RX lock (i.e. local weather, weather at the hub, RFI on the satellite). In any case, as long as this number is not constantly incrementing, then I wouldn't worry about it. If it was constantly incrementing (meaning your modem was constantly losing RX lock), I'd check with your network operator to make sure there wasn't a network issue. If no network problems, then troubleshoot your RX chain.