The TaraSpan Blog

Mar 29

PRI or SIP Trunking Services : Which one to Choose and Why?

Posted on March 29th, by Pratibha Gubrani 0 Comments

Today, enterprises are looking for transforming ways in Unified Communications so that communication and collaboration become all the more simplified, effective and cost efficient. SIP trunking services and PRI are two new techniques that are storming businesses and paving a way towards a more consolidated network in Unified Communications. Let us study in detail each of this technology:

What is SIP Trunking?

1. SIP stands for Session Initiation Protocol which enables users to engage in integrated and consolidated communications instead of physically separated voice and data networks, anywhere and anytime, irrespective of the network infrastructure employed.

2. SIP has come up as the universal standard for Voice over Internet Protocol (VoIP) services.

3. SIP trunking is a service offered by Internet Telephony Service Provider (ITSP) that connects a private business-class phone system with a VoIP service network. 

4. Certainly, SIP Trunking Services offer technological and operational benefits of VoIP to the organizations while communicating with the branch offices or with the world outside. 

What is PRI?

1. PRI stands for Primary Rate Interface.

2. A PRI line is an end to end digital circuit and is a form of ISDN (Integrated Services Digital Network) line which enables traditional phone lines to carry voice, data and video traffic.

3. Physically, there is only one line connecting the customer PBX to the service provider but that one PRI line can send/receive 30 calls at the same time.

4. By deploying multiplexing/de-multiplexing techniques, a PRI line can carry more than one channel in a single circuit.

5. E1 and T1 are two common forms of PRI lines. E1 is most commonly used in Europe and India to carry 30 channels in 2 pairs of copper lines. T1 is used to carry 23/24 channels and is used in US.  

Advantages of PRI Trunking :

1. Cost Savings : As discussed earlier, a PRI line can send/receive 30 lines at the same time. Therefore, instead of 30 analog trunks and 30 rentals to be paid, a consolidated, converged PRI network ensures lower rental. 

2. Inward dialing is simplified : Many customers do not like to go through an auto-attendant as it consumes time. Therefore, the outsiders can call the extension directly as the service provider provides around 100-500 numbers, for each PRI line which avoids the trouble of going through the PBX auto-attendant.

3. Voice and Data Transmission : Both voice and data transmission is possible with PRI line. There is data transmission on all the channels that are free and not occupied by voice. 

4. PRI lines can prove to be much economical for small enterprises as there are some service providers which offer flexible plans as well. For instance, if an organization needs 20 channels, so it will be charged according to that only.  

5. It is a consolidated network which implies that it enables voice and data connectivity, video conferencing, faxing and all can be done at the same time across different channels. 

6. Call Hunting : If a customer dials a number and the channel is busy, with PRI lines, it is possible that the call lands to another channel that is free. Without the customer’s need to dial another number manually. 

Advantages of SIP Trunking over PRI

1. First of all, unlike physical connection in PRI, SIP trunking works on virtual connections.

2. In case of PRI, if an enterprise needs to scale up, installation of new circuits with additional termination hardware is needed. If your business needs to make more calls, you may have to purchase additional PRI line, that gives 23 additional calls, simultaneously. 

In case of SIP trunking services, you just need to increase your data connection’s bandwidth to have more SIP trunk virtual connections.Software configuration change offers on demand and automation scale up and scale down services. 

3. Additional Capacity Planning : For PRI, you need to plan well in advance, as installation of new circuits and termination hardware may need some time. In case of SIP trunking, you don’t need to think much of capacity planning as this is as simple as a software change. 

4. Disaster Recovery : In case of a disaster, with PRI lines, diverting calls to some other location would be quite complicated as well as expensive. Cost factor would definitely pose an interference in this case. If we talk about SIP trunking, since connections are virtual, there is automate call re-routing to pre-defined locations. This proves a huge benefit in case of business continuity. 

5. Cost Efficiency : With PRI lines, cost is per circuit per month. If your business needs more than the fixed voice channels, the balance of cost-efficiency may become shaky. SIP trunking services work on pricing models that depend upon the utility and on-demand capacity. With no need of supporting hardware, SIP trunking costs are relatively lower. 

6. Backup and Redundancy : Providing backup circuits to remote sites in IPT distributed architecture can affect ROI adversely. The only way to compensate the loss of hardware is by building-in excess capacity. On the other hand, backup with SIP is not that complicated because of automatic IP-rerouting capabilities. With SIP trunking services, network can be designed to retain PSTN, reachability and capacity in case the terminating hardware or an entire office location is lost/destroyed. There is no need to build in excess capacity and hence cost efficiency is maintained. 

In the points above, we learnt the pros of SIP trunking over PRI but which one you should choose solely depends on your business needs. VoIP with SIP Trunking service may have been proved the best technology but you must also envisage that it is compatible with your business requirements.

Pratibha Gubrani
Written by Pratibha Gubrani
Pratibha Gubrani is the Content Writer at TaraSpan. She likes to keep herself updated with the latest technologies so that she is able to provide deep domain knowledge to the wider audience through her writings.

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