RespOrg: Toll-Free Carrier Diversity

RespOrg: Toll-Free Carrier Diversity

Sorell Slaymaker, May 02, 2010

A RespOrg refers to companies that have access to the database that controls routing on all toll-free telephone numbers.

Enterprises that would like to provide carrier diversity of their toll free numbers to increase reliability, disaster recovery, and carrier competition, should investigate becoming their own Responsible Organization (RespOrg).On Monday, January 4, 2010, AT&T received more toll-free calls than they could handle. About 25 percent of their toll-free traffic was blocked (giving callers a fast busy) for a good part of the business day. Enterprise call center staff sat idle while callers tried to reach them. This is not the first time AT&T’s or other carriers’ toll-free networks failed to deliver toll-free calls. Large toll-free outages occur every few years because of disasters, extremely high call volume, or human error (usually connected to software upgrades).

A RespOrg refers to companies that have access to the Service Management System (SMS), the database that controls routing on all toll-free telephone numbers. RespOrgs were established in 1993 as part of the FCC order to institute toll-free number portability. Every ten-digit toll-free telephone number is managed by a RespOrg. A RespOrg can be a telephone company, a very large enterprise, or an independent service provider that offers RespOrg services on behalf of an enterprise, such as

An example of RespOrg call flow (see corresponding diagram):

1) Customer dials a toll-free number.

2) Call goes to the customer’s phone provider–Local Exchange Carrier (LEC), IP service provider, or Mobile Service Provider.

3) The phone provider uses a Service Control Point (SCP), which is part of the SS7 signaling network, to identify which carrier to pass the call along using the Circuit Identification Code (CIC). Which carrier to send the call to can be based on percent allocation, least cost routing, or other rules.

4) The SMS database is used to update the all the SCPs that are distributed across the country

5) The SMS database is configured by an authorized RespOrg. Changes can be made in near real time and then it can take around 15 minutes for the changes to propagate to all the SCPs.

6) The call is passed to the IntereXchange Carrier (IXC) determined by the CIC.

7) The call then goes into the enterprise. In this example, the enterprise has all call center technology within the data centers. This model works with both traditional TDM/PRI and IP/SIP trunking.

8) The last step is the call is passed to the appropriate agent and the customer and agent begin a conversation.

Additionally, it is advantageous to use multiple carriers to deliver toll-free calls. Most enterprises use multiple ISPs for Internet connectivity to increase reliability, disaster recovery, and control costs; the same model should apply for toll-free voice traffic. Toll Free providers do not actively promote the use of RespOrg, because they stand to lose some of their traffic and it also drives down their margins. Being or using a RespOrg service provider is less risky and more convenient than porting toll-free numbers from one carrier to another.

When implementing toll-free SIP Trunking, an enterprise should use multiple SIP trunking providers and become their own RespOrg. This is SIP Trunking best practice #11. (For those of you interested in SIP Trunking best practices #1-10, these were presented at VoiceCon in Orlando in the “Implementing SIP Trunking” session, and are shown below:

Forgot password?

(*) Required fields

I agree with OptimaSales Terms & Privacy Policy