wow thanks for the detail, I will work with the boss and the fiber provider to try to address some of those problems.
On Thu, Jan 25, 2024 at 10:14 AM <[email protected]> wrote: > As an OTDR trace it looks really good, but your problem might be at event > 18 and/or 19. I don’t know how much you wanted to know so I apologize if > I’m starting too far towards the beginning. > > > > #18 is around 100m from the end and has reflectance of -21.36. That’s > crappy. > > The -15 below it is even crappier. > > > > A UPC connector should be -40 to -50 dB > > An APC connector should be better than -55 or -60 depending on who you > believe. > > > > If the distance is correct then maybe #18 is a cross connect panel? #19 > should be your Arista. Start with re-cleaning those connectors. One-click > cleaners are fast and cheap. They only shot this in one direction, so we > don’t know about the connectors on the other end. I’d clean it on both > sides. > > > > The line graph is showing you attenuation over distance. You’re averaging > under 0.2dB per Km so that’s really good. The table below is showing you > 19 events. An event is any point along the graph where attenuation > suddenly increased. Events are either “reflective” or “non-reflective”. > In the first column of the table they’re showing you a /R or /N for > reflective or non-reflective. You can also tell that in the line graph > because reflective events will have a spike before the dip. You don’t want > reflections. Reflections are given in a -dB and you want it farther from > zero (i.e.: -55 reflectance is better than -40 reflectance). > > > > (And side comment: reflectance is the same thing as return loss, but in > optics people seem to prefer the term “reflectance”. The only difference > is return loss should be indicated with a positive number and reflectance > is negative. > > Return Loss = 10*log(incident power/reflected power) in +dB > > Reflectance = 10*log(reflected power/incident power) in -dB > > ) > > > > Non-reflective events are things adding attenuation but not adding > reflectance. Those would be fusion splices, coils, and bends. > > > > Reflective events mean there’s an exposed face of glass. Those would be > mechanical splices or connectors. Reflective events could also be a fault > in the fiber like a bubbled fusion splice. > > > > All that noise at the end of the line shows where the dead end is. > > > > On that test result the only event I don’t like along the middle of the > run is #9. 4dB is a lot for one event. It might be a less than perfect > splice, a tight bend in a splice tray, a slack coil that’s too tight, or > whatever. It’s not enough to ruin this link, and it’s probably ok if it > stays at 4dB forever. There are some underground cases where I’ve seen the > same high attenuation events for years, but they’re not hurting us and it’s > too much trouble to access the case to fix something that isn’t currently a > problem. > > > > If nobody ever said this before: you should clean connectors every time > they are handled. No matter what anybody tells you, the caps they come > with are not “dust caps” and they won’t keep it clean; the caps are there > so the glass face doesn’t get scratched. When I’m plugging things in I > clean the jack, clean the plug, and then treat it like I’m playing the old > Operation game: If the ferrule touches anything before it goes into the > hole then it’s “Bzzzzzt!” and reclean it. > > > > The dispersion thing is a new concept for me, and I don’t think you could > diagnose it from this one trace. From what I’m gathering in this thread, I > think you’d have to shoot it on multiple wavelengths and compare the > differences. This trace is only at 1550nm. > > > > -Adam > > > > > > > > *From:* AF <[email protected]> *On Behalf Of *Zach Underwood > *Sent:* Wednesday, January 24, 2024 7:41 PM > *To:* AnimalFarm Microwave Users Group <[email protected]> > *Subject:* Re: [AFMUG] optical TX power levels > > > > Ok we got the report back from the fiber supplier. This is new to me so > anyone can offer insight into it? > > > > PDF > https://drive.google.com/file/d/1KeIuWHFsiKZHxcmpPiY8PX_-PABl55Sz/view?usp=sharing > > > > > On Wed, Jan 24, 2024 at 6:00 PM Daniel Pautz via AF <[email protected]> > wrote: > > Dispersion compensation module - https://www.fs.com/products/65783.html > > > > *From:* AF <[email protected]> *On Behalf Of *Ken Hohhof > *Sent:* Wednesday, January 24, 2024 3:53 PM > *To:* 'AnimalFarm Microwave Users Group' <[email protected]> > *Subject:* Re: [AFMUG] optical TX power levels > > > > I spent a few minutes searching on the term DCM and came up with “chirped > fiber Bragg grating”. > > https://en.wikipedia.org/wiki/Fiber_Bragg_grating > > > > OK, I’m out of my depth now. > > > > > > *From:* AF <[email protected]> *On Behalf Of *Daniel Pautz via AF > *Sent:* Wednesday, January 24, 2024 4:40 PM > *To:* AnimalFarm Microwave Users Group <[email protected]> > *Cc:* Daniel Pautz <[email protected]> > *Subject:* Re: [AFMUG] optical TX power levels > > > > Perhaps pick up a used cheap DCM and see if it helps, adjustable > preferred if not as close to the fiber distance. Our newest 100G dwdm > build (dozen 100G optics) very much needed a DCM on it. > > > > *From:* AF <[email protected]> *On Behalf Of *Chuck McCown via AF > *Sent:* Wednesday, January 24, 2024 3:36 PM > *To:* 'AnimalFarm Microwave Users Group' <[email protected]> > *Cc:* [email protected] > *Subject:* Re: [AFMUG] optical TX power levels > > > > Gotta think of the Fourier series of the pulse. Yes group velocities or > group delay of the whole enchalada. It is all kinda the same thing. They > were doing some kind of soliton fiber development. Haven’t heard much for > some time about that. No idea how frequency pure/coherent the tx is. I > imagine phase coherency is a big deal. > > > > > > > > *From:* Ken Hohhof > > *Sent:* Wednesday, January 24, 2024 4:12 PM > > *To:* 'AnimalFarm Microwave Users Group' > > *Subject:* Re: [AFMUG] optical TX power levels > > > > Looks like different wavelengths have different group velocities, so > compensation is possible (but probably not cheap?). > > > > Is this because the transmitter doesn’t generate literally a single > wavelength? Or is this a WDM issue? Chuck says the pulses get smeared out > in time, that sounds like the first one. > > > > *From:* AF <[email protected]> *On Behalf Of *Chuck McCown via AF > *Sent:* Wednesday, January 24, 2024 3:56 PM > *To:* AnimalFarm Microwave Users Group <[email protected]> > *Cc:* [email protected] > *Subject:* Re: [AFMUG] optical TX power levels > > > > Yeah, the pulses tend to get smeared out in time if there is too much > dispersion. Similar to trying to use too high level of QAM with SNR > issues. > > > > *From:* Josh Luthman > > *Sent:* Wednesday, January 24, 2024 12:26 PM > > *To:* AnimalFarm Microwave Users Group > > *Subject:* Re: [AFMUG] optical TX power levels > > > > Even if the RX level is good? > > > rx was within 0.3dBm on all 4 lanes on both sides > > > > On Wed, Jan 24, 2024 at 1:22 PM Daniel Pautz via AF <[email protected]> > wrote: > > Yeah makes me think the two paths have different loss. We have had that > on mirrored paths, or even single paths with crappy splices on one of the > strands. > > > > *From:* AF <[email protected]> *On Behalf Of *Chuck McCown via AF > *Sent:* Wednesday, January 24, 2024 11:12 AM > *To:* AnimalFarm Microwave Users Group <[email protected]> > *Cc:* [email protected] > *Subject:* Re: [AFMUG] optical TX power levels > > > > Did anyone do dispersion testing on the fiber? > > > > Chuck McCown > McCown Technology Corporation > 8401 N Commerce Dr > Lake Point, Utah 84074 > 801-250-9503 > 435-830-4306 cell > www.mccowntech.com > www.microtrench-blades.com > www.terabitnetworks.com > > > > *From:* Zach Underwood > > *Sent:* Wednesday, January 24, 2024 12:07 PM > > *To:* AnimalFarm Microwave Users Group > > *Subject:* Re: [AFMUG] optical TX power levels > > > > tired again this morning and still no link. rx was within 0.3dBm on all 4 > lanes on both sides. We got 10gb 80km to link up. This will do for now. We > will be looking at getting 40gb 80km single lane optics or adding another > site to fiber loop to shorten the footage to under 40km. > > > > On Wed, Jan 24, 2024 at 11:14 AM Colin Stanners <[email protected]> > wrote: > > So both of those SFPs are within the tx power range. > > > > 100G may not work on a link that long unless you have dispersion > compensation fiber on the path or in a huge loop in a box style at one end. > > > > You likely cannot change tx power levels on those SFPs, they will run at > the max they can do for that specific unit. > > > > On Wed, Jan 24, 2024, 7:46 a.m. Zach Underwood <[email protected]> > wrote: > > > *TX Power* 2~6.5dBm > > > > I am struggling to get this 100gb link up. In the field this link is > quoted at 31 miles. The rx levels are -22 and -20 on both sides but I can't > get it to link. I take the same optics to the lab and add 20dbm of attenuator > to get almost the same rx levels as the field and it will link up. > > I have added error-correction encoding reed-solomon per the user guide for > links over 40km. > > So far I have not found a way to change the TX levels in arista, the > options are in the CLI but they dont seem to change the outcome. For me > this is the first time dealing with 80km optics or 100gb optics over 10km. > > switch is Arista DCS-7060SX2-48YC6-R > > > > https://resource.fs.com/mall/doc/20230531114903y4ljxw.pdf > https://www.fs.com/products/115818.html?attribute=29032&id=3462585 > > > > On Wed, Jan 24, 2024 at 8:35 AM Colin Stanners <[email protected]> > wrote: > > There should be. What does their datasheey indicate for tx power range? > > > > On Wed, Jan 24, 2024, 7:31 a.m. Zach Underwood <[email protected]> > wrote: > > Yep labels identical but there is a difference in default power levels. > > > > On Wed, Jan 24, 2024, 8:13 AM Mike Hammett <[email protected]> wrote: > > Oh, meaning the variance between the two, otherwise identical models? > > > > ----- > Mike Hammett > Intelligent Computing Solutions <http://www.ics-il.com/> > > Midwest Internet Exchange > > The Brothers WISP > > > > > <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > ------------------------------ > <https://www.facebook.com/ICSIL> > > > > > > > > > > > *From: "Zach Underwood" <[email protected]>To: "AnimalFarm Microwave > Users Group" <[email protected]>Sent: Tuesday, January 23, 2024 12:51:39 > PMSubject: [AFMUG] optical TX power levels <https://www.facebook.com/ICSIL>* > > I got 2x 100gb 80km optics from FS that run difficult default TX power > levels one is 3.81dBm and the other 2.63dBm, the config on the arista > devices hosting the optics is the same. <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > > Has anyone seen much difference between optic like this? My sample size is > small due to the optices costing $4k each <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > > -- <https://www.facebook.com/ICSIL> > > Zach Underwood (RHCE,RHCSA,RHCT,UACA) <https://www.facebook.com/ICSIL> > > *My website <https://www.facebook.com/ICSIL>* > > *advance-networking.com <https://www.facebook.com/ICSIL>* > > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > > > <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > > -- <https://www.facebook.com/ICSIL> > > Zach Underwood (RHCE,RHCSA,RHCT,UACA) <https://www.facebook.com/ICSIL> > > My website <https://www.facebook.com/ICSIL> > > advance-networking.com <https://www.facebook.com/ICSIL> > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > > -- <https://www.facebook.com/ICSIL> > > Zach Underwood (RHCE,RHCSA,RHCT,UACA) <https://www.facebook.com/ICSIL> > > My website <https://www.facebook.com/ICSIL> > > advance-networking.com <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > ------------------------------ > <https://www.facebook.com/ICSIL> > > > > > > > > > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > <https://www.facebook.com/ICSIL> > ------------------------------ > <https://www.facebook.com/ICSIL> > > > > > > > > > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <https://www.facebook.com/ICSIL> > > ------------------------------ > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > > > > -- > > Zach Underwood (RHCE,RHCSA,RHCT,UACA) > > My website <http://zachunderwood.me> > > advance-networking.com > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- Zach Underwood (RHCE,RHCSA,RHCT,UACA) My website <http://zachunderwood.me> advance-networking.com
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