Hello,
I assume your referring to SIP trunk providers.
Here is a recent thread for inbound DID providers;
As for outbound traffic, it entirely depends on;
* Which countries you wish to target
* Where your own server is located
* What service level you are trying to achieve
* How much you have to spend
* Are you looking or ingress (inbound) or egress (outbound)
From the perspective of the UK, here is a brief breakdown of the
categories (from best to worst);
* Direct with a state/national telecoms company (such as BT or Kingston)
- usually come with minimum commitment levels and very high set up/monthly
costs, suitable only for large existing customer bases
* Through a wholesaler that uses only the above routes (such as Simwood)
- they give lower traffic customers the ability to use these high quality
routes without the cost.. yes they are reselling, but it's one of the rare
occasions where reselling it is justified, as you will save a lot of money in
several circumstances
* Through a reseller of a reseller of the above (always ask the company
what routes they use, and try to cut out the useless middleman)
* Through a reseller of a reseller of a reseller of a reseller of a
reseller that is using grey routes (seriously, this really does happen a
lot)
It is also worth noting that providers are known to lie about the quality
and sources of their routes, so rely heavily on community reviews to figure
out if a company is good. And, even if a company is reselling wholesaler
routes, you must make sure you perform inter-op right from the beginning, else
you might hit some fun surprises along the way (we have been stung
by this before).
Remember, crappy cheap SIP trunk providers are 10 a penny these days, and
it really depends on what you are trying to achieve. If you want to build say
an automated phone alerting system that calls people with an automated
electronic voice (such as PagerDuty), then using crappy routes might be
acceptable for your business case. However, if you are trying to build an
enterprise product for voice, then you need to make careful choices about what
sacrifices (if any) you're going to make on quality vs cost.
On a last note, we have trialed several "reputable" providers over the
last 6 months, and most of them ended in tears - be weary.
I hope this helps.
Cal