A line by line comparison between SIP and PRI - two popular voice delivery methods used by business today.

1. SIP vs. PRI

2. Definition:
 PRI - Primary Rate Interface.
 SIP - Session Initiation Protocol.

3. Allocation:
 PRI is sold per circuit. Each circuit provides 23 channels or
call paths.
 SIP is sold per call path.

4. Infrastructure:
 PRI is part of the Public Switched Telephone Network
(PSTN).
 SIP is Voice over IP and is delivered over an internet
connection.

5. Phone Numbers:
PRI utilizes Direct Inward Dialing (DID) phone numbers
that can be purchased in blocks of 20 and are local to the
area the service is terminated.
 SIP utilizes DID but can use local and out of area phone
numbers. With SIP, a company located in Philadelphia
could utilize Phoenix telephone numbers.


6. Disaster Recovery:
In the event of a natural disaster, SIP DIDs can be rerouted
from one office or call center to call centers or offices
untouched by the event.
 This can be accomplished more easily and seamlessly
than with PRI.


7. Utilization:
 Multiple users at a single or a networked location can share
PRI voice channels.
 SIP trunks can be centrally located and shared company
wide, maximizing economies of scale. This setup is
facilitated by the availability of out of area DIDs.

8. Scalability:
 PRIs provide 23 channels or voice paths. If a business
requires more than 23, they have to order another PRI, and
deployment requires 2 to 3 weeks time.
 SIP trunks can be ordered in any increment and
implementation can be completed in days, sometimes hours.

9. Resource Utilization:
 PRIs are static. When their channels aren’t use, they sit
stagnant.
 SIP is a dynamic service. When SIP trunks are not in
use, the bandwidth they require is freed up for other uses.

10. Availability:
 PRI requires a local loop, provided by a local phone
company or incumbent carrier (ILEC). PRI providers
must have agreements in place with ILECs to be able
to provide PRI.
 SIP only requires an internet connection, so there is a
smaller barrier to entry to become a SIP service
provider, leading to more competition and lower
prices.

11. Handoff:
 PRI requires the existence of a T1 card in a PBX or business
phone system.
 SIP can be engineered to work with any type of phone
system.

12. Cost:
 PRIs typically cost between 4 and 5 hundred dollars per
month. The cost is higher for more remote locations that
require a longer local loop.
 SIP trunks cost between 10 and 20 dollars per month. The
service can be made more economical when SIP trunks are
consolidated at a company’s head quarters and
shared, requiring fewer in number. With SIP there is a cost
of the added bandwidth necessary to support the service, but
the cost of bandwidth has dropped and should continue to do
so.

13. For More Information:
 John Gelhard
 CarrierBid Sales Director
 Toll free: 888-706-5656 x 701
 Direct: 609-921-3434
 Email: johngelhard@carrierbid.com