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ThaiGuy

join:2008-05-10
Thailand

Help me understand DID's

I have never concerned myself with the inner workings of DID's, but now I need to learn how they work. I have a DID with CallCentric, so let me ask this:

If the CallCentric network were to go down completely, is there any way to build in failover so that incoming calls from the PSTN get routed elsewhere?

Would any other VoIP provider DID's work any differently?

Mango
What router are you using?
Premium
join:2008-12-25
www.toao.net
kudos:15
Reviews:
·Callcentric
·AcroVoice
·Anveo
Unfortunately no. DIDs are a single point of failure, no matter who your service provider is.

You may be interested in reading this thread: »VOIP disaster question - technical

Stewart

join:2005-07-13
kudos:29
reply to ThaiGuy
If you have a toll-free DID with a provider (such as CallCentric) that is their own RespOrg, they can reroute your traffic via another carrier in case of an outage. Unfortunately, there is AFAIK no way to do this with a US geographic DID.

Next most reliable is a service directly from a CLEC. Although you are still out of luck if their facility in that rate center goes down, you can provide two or more (presumably geographically redundant) destinations where they will attempt to send calls. In the case of CallCentric, if you have a DID served by Telengy (same company), they can also send you calls via their TDM network, if their Internet connectivity is lost.

MartinM
VoIP.ms
Premium,VIP
join:2008-07-21
kudos:4
reply to ThaiGuy
Our 2 main Toll-Free providers are also their own RespOrg and have switched traffic during downtime previously in at least one occasion a remember. And it was transparent.

CLEC's do not usually deal with end-users, most with providers. However, they are usually quick in resolving their issues.

If your VoIP provider has their equipment or network go down in a specific location and they have redundant equipment in another location (For example, VoIP.ms), they can re-route traffic to that server, like we did during the Sandy storm (we made our New York customers connect to another location via a DNS Update) or when we had a DDoS to our Tampa IP Address.

So points of failure:

- Data Center Network or Equipment failure of your VoIP provider (This Point of failure can be eliminated if they have another location_

- CLEC Providing the DID, Don't usually deal with end users, anyway, if they fail with your VOIP provider or if you were the customer, it's the same downtime. It's in their best interest to resolve issue quickly has they usually provide thousands of numbers.

- Your Equipment or Internet: Program a failover to ring a cell phone. Worst case scenario: Voicemail
--
Martin - VoiP.ms


ThaiGuy

join:2008-05-10
Thailand
Thank you Gentlemen. Luckily it is programmable equipment that will be making calls to the DID numbers and not humans, so rather than worry about failover for a single DID, I'm thinking the best approach might be to get two DID's and have the equipment dial the backup DID if the primary DID is down.

I am a fan of both CC and voip.ms, so my preference would be to use them if possible. Am I correct in thinking that they use different CLEC's thereby giving me the redundancy I require?

I'm not clear on what a RespOrg or CLEC is, so I have some work to do on that side of things. If anyone can provide a simple overview of RespOrg/CLEC's that relates to what I am trying to do, then I'd appreciate it.


Gershom 1624

@optonline.net
said by ThaiGuy:

I am a fan of both CC and voip.ms, so my preference would be to use them if possible. Am I correct in thinking that they use different CLEC's thereby giving me the redundancy I require?

Probably a good idea to use different retail VoIP providers but there is no guarantee that they'll use different CLEC's in any given community (rate centre).

Many CLEC's have merged, reducing the choices.

By the way, it seems that Voip.MS uses Vitelity (also called Sixtel or EXGN) for many/most of their US phone numbers (DID) and also tollfree numbers, but surely they use others too.

Local phone numbers (DID's) are provisioned by Local Exchange Carriers (LEC).

The original LEC in a community---essentially the POTS company---is the Incumbent Local Exchange Carrier (ILEC).

In the majority of the US that was covered by the Bell System pre-1984, the ILEC is often called the Regional Bell Operating Company (RBOC or Baby Bell). Seven RBOC were created after the 1984 government breakup, but after lots of re-mergers we are left with Verizon, a resurrected AT&T, and CenturyLink (as successor to the ill-fated USWest RBOC).

Newer competitors that have entered the market are allowed access to a pool of phone numbers, and are allowed to connect to the national network, because the government mandated it. These are Competitive Local Exchange Carriers or CLEC's.

No type of LEC provides 800-type tollfree numbers, because the L in LEC stands for Local, and these are not local.

Rather, toll-free numbers are in a pool run by an organization called SMS/800 that traces back to the former Bell System and then became jointly owned by the RBOC's.

Only certain companies are allowed to access the pool of TF numbers operated by SMS/800.

Those companies are called Responsible Organisations, hence RespOrgs.

So directly or indirectly, any TF number comes from a RespOrg (pronounced "resborg", not to be confused with Starfleet's team assigned to research the borg).

josephf

join:2009-04-26
It is easy to determine which CLEC your VoSP is using for your DID.

ILEC/RBOCs have always offered toll-free (800) service. Even during the years that they were regulated to providing only Intra-LATA service.


ThaiGuy

join:2008-05-10
Thailand
reply to Gershom 1624
Thanks Gershom for that clear overview

In this particular case, I'm not looking for toll free numbers so hopefully that will make things a little easier when trying get DID's from different CLEC's.

I know it's not common, but does anyone know if any DID provider can support SIP INFO?


Gershom 1624

@optonline.net
said by ThaiGuy:

I know it's not common, but does anyone know if any DID provider can support SIP INFO?

FWIW, I just set my Gigaset A580IP phone to use [SIP INFO] exclusively.

I then made some calls on CallCentric, Voip.MS, and CallWithUs.

All the calls went through.

(Interestingly, CC website says they do not currently support SIP INFO.)

------------------------------

Clarification:

In an earlier post on this page, it might have sounded like I was saying that Vitelity is a CLEC.

In fact, while Vitelity is a RespOrg for TF numbers, they are not themselves a CLEC for DID's. Vitelity uses many different CLEC's for their local number supply.

Stewart

join:2005-07-13
kudos:29
said by Gershom 1624 :

said by ThaiGuy:

I know it's not common, but does anyone know if any DID provider can support SIP INFO?

FWIW, I just set my Gigaset A580IP phone to use [SIP INFO] exclusively.

I then made some calls on CallCentric, Voip.MS, and CallWithUs.

All the calls went through.

But that's not what the OP is asking. He wants to know whether on an incoming call to his DID, when the caller sends DTMF, the proper SIP INFO request will be sent to his server.

You can't test that with an IP phone, because they are designed to send DTMF, but not receive. However, an ATA supporting SIP INFO should play a DTMF tone in response to incoming requests.


ThaiGuy

join:2008-05-10
Thailand
Stewart has correctly pointed out that I forgot to mention my question was in relation to incoming calls. I think it's highly unlikely that SIP INFO will be supported as many think it is unreliable, but it may be worth running some tests - just in case.


ThaiGuy

join:2008-05-10
Thailand
reply to ThaiGuy
Sorry to bump this thread but it saves me repeating myself

I scrapped the idea of SIP INFO and have spent the last month building RFC4733(2833) support into our IP PBX.

Testing with my Callcentric DID has gone well and I've worked out that regardless of the codec or DTMF setting a VoIP caller uses to make calls to the DID number, the CC equipment generates and sends RFC4733 to our IP PBX. The same applies to calls from at least 1 GSM network and I assume PSTN too (yet to test).

So, as I am going to need multiple DID's from multiple providers I have to gain an understanding of what hardware equipment or software is responsible for generating and forwarding RFC4733 at CallCentric.

Then I can try to find out what is used by voip.ms, Voxbeam and other candidates for the supply of RFC4733 compliant DID's.

Stewart: I know you have a lot of experience in this area and I'd especially appreciate your guidance - as always.