[asterisk-biz] How are phone calls routed and who is responsiblefor what?

[Jim Dalton]

> Who is responsible for this routing and how does one go about 
> protecting the route to your phone number.

In the US Public Switched Telephone Network all routing is defined by two
databases.  The Telcordia Local Exchange Routing Guide (LERG) defines the
telephone number owned by each local telephone company.  However, with
number portability, telephone numbers can be ported to other carriers.
Therefore a dip into the Local Number Portability (LNP) database is required
to get final PSTN routing to the called party.  NeuStar manages the (LNP)
database, but it can be accessed via RBOCs and other entities.

There is no numbering infrastructure, analagous to the PSTN, for VoIP.

Jim Dalton
VoIP Routing, Accounting, Security
1.404.526.6053
www.TransNexus.com
 

> -----Original Message-----
> From: asterisk-biz-bounces at lists.digium.com 
> [mailto:asterisk-biz-bounces at lists.digium.com] On Behalf Of 
> John Schmerold
> Sent: Tuesday, March 06, 2007 9:14 PM
> To: asterisk-biz at lists.digium.com
> Subject: [asterisk-biz] How are phone calls routed and who is 
> responsiblefor what?
> 
> The VOIPJet note reminded me of an issue that has been 
> bugging me for some time. How are phone calls routed and who 
> is responsible for what?
> 
> I understand what happens when I plug www.google.com into my 
> web browser, my computer connects to a name server, it 
> contacts its name server until the IP address is determined. 
> Then my router contacts its router until I'm connected to google.
> 
> When it comes to phone calls I'm baffled. When I pick up the 
> handset at the house to call my brother's house across the 
> street, they may or may not both be in the same switch, 
> handled by the same carrier, delivered via the same physical 
> connections.
> 
> Who is responsible for this routing and how does one go about 
> protecting the route to your phone number.
> 
> The point of this exercise is performance and security.
> 1. Performance
>     When we get VOIP service from a supplier, how can we 
> determine their ability to perform. On a simple level, we can 
> ping their SIP server. 
> Fast, consistent ping may mean good service. However we don't 
> know if we just connecting to a sip server that connects to 
> another sip server that may or may not have a good connection.
> 
> 2. Security.
>      What if our supplier goes out of business (Remember 
> Enron, Worldcom or even NorVergence)? How do we get our 
> number? How long does it take? 
> etc etc  Most resellers go through XO or Level 3. Is anyone 
> aware of their policies relative to number ports when one of 
> their resellers goes broke or refuses to return your number to you?
>