[VoiceOps] Call term misrouting?

[Mike Johnston]

I serve a rural area.  I do the technical "make it work" stuff.  I'm 
generally only involved in the business dealings insofar as determining 
technical incompatibilities (draw 7 red lines, all perpendicular, some 
with green ink and some with transparent).  That said, please forgive 
any errors in what I say, and feel free to correct me.

On 2023-07-26 08:28, Nathan Anderson via VoiceOps wrote:
> ...by which I mean, we send a call to a term provider via SIP, who then *seems* to terminate the call to the wrong callee entirely.
> 
> What the heck actually causes this?

A long distance carrier, generally an intermediate one, being shady. 
Here at my workplace, we call that carrier something like, "Bob's Shady 
Long Distance Shack."  Bob probably charges 1 cent per minutes, or less, 
as a flat rate.  When he gets calls for cellphones or urban areas, the 
calls might cost him 0.1 of a cent per minute, and Bob is doing good. 
But when Bob gets calls to rural areas that cost more than one 1 cent 
per minute, he doesn't like that.  It cuts into his profits.  So he does 
shady stuff.

> Whenever I have experienced it, it inevitably involves a rural carrier of some kind, one that likely charges a lot to accept traffic.

"Charges a lot to accept traffic," makes it seem like a troll under a 
bridge, making up whatever rate they want to pass.  My understanding is 
that these rates were set by a process that involved distance, to help 
cover fixed infrastructure costs.  Thus, rural areas cost more to call.

> Over the course of a few days, we just went through twelve rounds of having a wholesale term provider blacklist various carriers from their LCRs for calls headed to this particular exchange, before the problem stopped happening.

It seems that Bob's Shady Long Distance Shack is popular.  Either that, 
or there are multiple intermediate carriers in play.  For example, if 
you route a call to carrier A, they route the call to carrier I, who 
routes the call to carrier BOB.  If you try a different carrier, they 
might also send the call to carrier I, who will still send the call to 
carrier BOB.

> "Is it working yet?"  "Nope."  "How about now?"  "Still nope."  And it's random and sporadic enough that I have to place a lot of test calls (as well as continue to field feedback from our end-users) before I can be sure that the problem is actually fixed.  It's aggravating...

I try to find numbers that go to IVRs, fax numbers, automated airport 
weather numbers, etc.  Anything that doesn't involve bothering a human 
over and over.  It has to be with the same OCN though, and generally 
needs to be in the same NPA-NXX too.

We have a test number with an announcement in every one of our assigned 
blocks.  It is the last number, such as 9999 or 2999.  If you want to 
test, look up OCN 1505 and OCN 194F.  If you would like an exhaustive 
list of those numbers, email me off list.

> It doesn't seem to be the final destination carrier that's screwing up the call routing after having received the call: I can call the same number over and over again through a "reputable" carrier, or via my personal cell (but I repeat myself), and get connected to the right destination every time.  Based on my experiences, I highly doubt the misdirected calls are even getting as far as the CO's switch for that exchange.

Correct.  If I had received the call, I would have routed the call.  I 
can't imagine why any rural telephone company would route calls to fake 
voicemails, fake announcements, static noises, etc.

I've even worked with my upstream on some calls, and they don't receive 
them either.  If they received the call, they would have sent it to me.

> So I have to hypothesize that some sketch carrier getting is picked from an LCR table, one who just doesn't like sending the call to a rural carrier who either charges that much

The FCC has a page about this, by the way.

https://www.fcc.gov/general/rural-call-completion-problems-long-distance-or-wireless-calling-rural-areas

When working with your carriers, using the exact phrase "Rural Call 
Completion" should help.  And please, file reports with the FCC!  There 
isn't much the rural telephone companies can do at the receiving end, 
since we don't know about the calls we don't receive.

> or that they suspect is engaging in fraud.

It's possible you are referring to this:
https://en.wikipedia.org/wiki/Traffic_pumping
Is that a thing that some rural telcos are still doing?

> But...WHY *misroute* it?  I'd rather you just reject the call if you don't want to carry it.

I also want to know!  Don't offer to route calls you can't complete, right?

> The misrouted calls in this latest case more often than not seemed to be hitting a foreign voicemail system that sounded an awful lot like AT&T Mobility's default voicemail greeting.

These are generally fake voicemails.  Just a recording of some voicemail 
intro, to make you think you hit a voicemail box.  The call hasn't 
actually been mis-routed.  It hasn't been "routed" anywhere, other than 
to an audio file.

> But we have definitely had calls just end up ringing the absolute wrong phone...in one case a few months back, I tried ringing the public library branch in this one rural town, and ended up getting the answering machine for some random business

Are you sure it actually rang a line at some business?  Or maybe it was, 
again, just an audio file?  Some wav file on a server at Bob's Shady 
Long Distance Shack?

> (...and also the call quality was *abysmal* on top of that).  (Never did manage to figure out where that business whose answering machine I got was actually located.  It was a generic-enough name for a business in their industry, but what I can tell you is that there was no business by that name in the rate centers covered by that rural carrier.

Yup, that's common.  More stuff to fake a person out.  Make you think it 
must be a problem at the far end.

> And also that my CDRs back up the fact that I did *not* mis-dial that call.)

Bob's Shady Long Distance Shack still wants to collect his money on that 
call, though.

> About the only theory I can come up with that makes a lick of sense is that these cut-rate carriers in these LCRs decide to throw to a rando number if they get asked to term to a high-cost exchange, so that they can record a call completion and charge the caller for it anyway.  Which would be a form of fraud itself, if that's actually happening.

I would argue it is fraud.  But again, prove to me they are actually 
"routing" to any number, and not some audio file.

I am currently struggling with one where an alarm monitoring company 
serving an alarm system at a facility can not call a Sheriff's office.. 
The alarm system can call the monitoring company, but the monitoring 
company can not call into our rural area.  I have no way of 
troubleshooting this issue at the receiving end.  I have no idea who the 
call center is using for long distance.  I can only assume the 
monitoring company is actively working with their long distance carrier.

I liken it to ordering something online, where the shipping method is 
labeled as "Best Method Ground" or something generic.  And the online 
store dumps all their boxed up items off at a shipping center who does 
the actual shipping out.  Some packages go out UPS, some FedEx, some 
USPS, some DHL, and so on.  Sometimes those carriers outsource to 
another carrier, who might only get it as far as your regional USPS 
office.  Then your regional USPS office hires a truck to bring it to 
your local USPS office.  A mail carrier brings it to your office 
building.  A guy in your office brings it to your department.  Your 
cubicle-mate brings it to your desk.