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What is SIP Trunking?

Why choose SIP?

Building a modern business requires investment in unified communication services. A return of that investment is possible with SIP Trunking’s significant cost savings. Yet, how SIP Trunking works and its requirements are usually ignored.

Summary


We will help you understand what SIP Trunking is, its benefits and its implementation process.

Definition of SIP Trunking


SIP Trunking is an optimized method of delivering unified communications over the Internet or any IP based network (e.g. dedicated line for voice). If you are looking for a more complex definition, SIP stands for Session Initiation Protocol.  SIP is a protocol that transports signaling packets between your PBX and it’s peer. And Trunks are the IP connections that enable voice and video calls transmissions.

Trunking is a method of sharing one line of communication to multiple users.

SIP is a protocol that transports data packets between your PBX and their destination.

PBX or Private Branch Exchange is the device (physical or virtual) responsible for managing your offices phone communication.

Main benefits of SIP Trunking

sip-trunking
There are numerous advantages associated with the use of SIP Trunking:

 

  1. Cost-effectiveness

SIP Trunking telephony is less expensive compared to traditional phone services. Due to the lightweight structure of SIP technology and the absence of a bulky, physical infrastructure.

SIP Trunking eliminates the mediators between telecom providers and their customers meaning less charging fees. Its technical simplicity significantly reduces all costs, related to the installation, configuration, maintenance, hardware and scalability.

 

  1. Fast ROI

Minimal initial investments and significant cost savings are the reasons why SIP Trunking is so attractive to businesses. In most cases the old phone system can remain in place, with no need for major changes in technical equipment. Cost transparency and lack of major investment needs, results in fast ROI. Companies report up to a 40% decrease in their communication expenses.

 

  1. Scalability and expansion made easy

Telephony services with Sip Trunking are highly adjustable. Lines can be added or removed without the need of physical restructuring within the limits of the available bandwidth. 

In times of high demand channels or other add-on, communication services can be easily scaled on. And when needed can be removed with no extra charges.

 

  1. Unified communications

Unified communications are easy to implement and with SIP Trunking. This simplifies the management of all the companies communications channels in one place.

 

  1. Mobility and Increased Productivity

Mobile VoIP applications allow employees to use the existing office numbers on their mobile devices. This constant connectivity between offices and field teams ensures smooth professional communication and increased productivity.

 

  1. Flexibility and Reliability

SIP Trunking is a trustful and reliable technology, unlike the traditional phone services that can easily experience connection interruptions. Should connection failure occur, SIP Trunking providers have the ability to redirect numbers in case of connection outages or according to the customers needs.

SIP features

sip trunk
Multiple Direct Phone Numbers

With SIP Trunking office phone numbers are no longer attached to the physical presence in a certain area. Phone numbers of different regions or countries can often be used regardless of your office location (This option is a subject of the regulation governing the phone numbers).

Remote Offices with Local Numbers

With SIP Trunking technology your organization can build virtual local presence anywhere around the globe. Employees who work remotely can keep their local phone numbers, related to your company’s headquarters.

Call Detail Records

Call Data Records (CDR) is a useful feature, that gives helpful insights. It allows tracking of business call history in a certain time frame. With SIP trunk they can be analyzed almost instantaneous instead of having to wait for the phone bill until the end of the month.

HD Call Quality

VoIP calls are crystal clear due to the possibility of SIP to integrate with protocols for efficient exchange of media data, such as RTP (Real-time Transport Protocol). Fast network connection speed and bandwidth ensure excellent call quality.

Automated fail-over Routing

In case of emergency (ex. internet or power outage), disaster recovery option will protect the communications flow. If the main communication channels are down, they could be redirected automatically. The incoming calls will be routed to other secure locations like mobile devices or home phone lines

Caller ID

SIP Trunking services provide personalization of the incoming and outgoing calls. The caller ID can be changed for additional exposure, branding or identification.

International Toll Fraud prevention

International toll fraud prevention is offered by most trusted SIP Trunking providers. Suspicious activity and call patterns can be recognized and acted upon. In such cases international call communication will be suspended to avoid the negative financial effects of fraudulent attacks.

SIP Trunk Monitoring

The benefits of well-monitored Sip Trunking are:

  • Detailed information about performance metrics
  • Active call monitoring and statistics
  • Full-time access to SIP signaling information for a call review
  • Monitoring of endpoint device and device registration. 

How does SIP Trunking work

SIP architecture
SIP Trunk Architecture
  • SIP Trunks connect your on-premises phone systems with the Internet Telephony Service Provider (ITSP).

 

  • Simply put, Session Initiation Protocol (SIP) establishes the telephony connection to the World. This could be a standard voice call between two clients or conference calling involving several participants with different phone phone systems.

 

  • The company’s PBX system, could be connected to one or more communication channels, according to the organization’s needs.

 

 

 SIP Trunking using an existing PBX

SIP Trunking Implementation can utilize a company’s existing PBX infrastructure. Some small technical adjustments are necessary to make it compatible with the traditional communication system.

Switching over to VoIP does not necessarily mean buying new phones for all employees. The standard analog phones can be modified for VoIP telephony with adapters and IP network gateways.

Instead of buying both desktop and mobile phones, the business can opt only for new mobile devices. Business numbers can be used on personal cell phones. Traditional communication lines could also support video transmission, instant messaging or other IP-based communication services.

What about SIP Trunking technical equipment requirements

*The needed hardware involves a SIP compatible PBX (be it Cloud PBX or IP PBX) and IP phones.

*Computers and mobile phones with the software installed and be used as IP phones.

*Conventional desk phones can serve with the help of VoIP modems.

SIP Trunking and the business

Business communications
Why businesses are switching to SIP Trunk service

Companies move to SIP technology because it meets their business needs. It is reliable, flexible and agile. It becomes the core of the organization’s integrated system of communication.

SIP Trunking eases the communication flow among employees, clients, and partners. This streamlines the team’s collaboration and boosts business productivity

How does SIP help businesses?cost-saving

 

  • Cost savings 
  • Unified communications
  • Flexibility 

Those are the big three answers to this question.

Immediate cost-saving effect makes more companies to choose SIP technology. The business growth is supported by unifying rich communication capabilities into a single network that scales with ease. Fast adjustments to that network according to the company needs, enable the company’s resources optimization.

SIP Trunking also helps enterprises take advantage in the business environment by providing:

  • High mobility across locations
  • Full-time availability of the teams
  • No investment in physical infrastructure
  • No investments on costly hardware
  • Reliability and simple management
  • Disaster recovery

SIP Trunking associated costs

business costs

Direct costs associated with SIP Trunks fall into two main groups. Initial costs like set up fees and monthly expenses for maintenance and support.

          Configuration fees

Usually, the setup fee is predetermined and is not related to the number of channels a company needs.

          Monthly trunk charges

This variable fee depends on the number of purchased channels within a company. Based on the call records history and future plans for development, the needed channels can be calculated.

          Call charges

Unlimited plans or metered calling option are the two alternatives. The first one refers to the unlimited number of inbound and outbound long distance and international calls. The metered calling option includes paying for each minute that a call is performed.  

Number porting and new numbers 

Transferring the phone numbers or buying new ones is fast and easy. Numbers porting normally means a one-time fee while buying new phone numbers is bound to ongoing monthly costs.

Toll-free numbers

Paying for toll-free numbers can be associated with the recurring monthly costs. The charges can vary significantly depending on the pricing plan offered by the SIP Provider.

VoIP gateways

Old PBX that doesn’t support SIP Trunking might have to be replaced.  With a cheaper alternative being Cloud PBX solutions. If your conventional PBX supports SIP Trunking, VoIP gateways have to be bought to allow conversion between traditional and SIP calls.

Internet bandwidth

Additional Internet bandwidth might have to be bought depending on the concurrent call channels.

SIP Trunking vs. PRI (Primary Rate Interface)

SIP Trunking vs. PRI

What are the differences between both phone systems?

Connection and Transmission

SIP interface uses the virtual connection through data network – internet

PRI technology uses a physical hardwired connection – copper cables

 

Hardware

SIP solutions require minimal hardware and upkeep. The PBX can be Cloud hosted or on-site.  No additional cabling or other technical equipment is needed. The number of channels can be changed on demand.

For PRI the existence of physical connections is a must. The signal is transmitted via actual cables and PBX installed on-site. There is an upper limit on the number of channels a single connection can handle.

 

Data backup and redundancy

With SIP Trunking the business communications flow will not be affected in case of force majeure events. All the calls can be easily rerouted to predetermined safe destinations.

PRI technology does not support call redirection. The only solution is to buy additional PRI circuits to cover up your communications if the system goes down.

 

Scalability

With SIP Trunking service the upscale of phone lines is related to the Internet bandwidth. The SIP Trunk provider can add or remove more lines fast and easy.

In PRI technology the number of available physical phone lines is limited to 30. In case of increased communications flow, a new set of 30 channels has to be purchased. The physical installment could be costly and time-consuming.

 

Costs

SIP Trunking is cheaper in almost any aspect. Ongoing costs depend on the monthly fees of your VoIP provider and small maintenance fees. International calls cost a lot less than PRI.

PRI technology requires much more investment in hardware installation and maintenance.  Physical lines and International calls cost a lot more.

 

Installation and Maintenance

SIP with a Cloud PBX can be set up in one day.  Its maintenance can be done remotely, meaning cheaper and faster support

PRI requires on-site PBX and cabling which can take time. On-site maintenance is recommended for fast troubleshooting.

 

Quality of service

SIP transmissions of voice calls are in high definition. The connection quality is dependent on the network bandwidth and backup internet line is recommended.

PRI connection relies on the dedicated phone lines to transmit voice calls. The sound can be good or poor depending on the hardware and cables used. The signal is conducted with a low range of frequency which can further lower call quality.

Deploying SIP trunking

connections
Are the up-front costs steep?

SIP Trunking deployment requires minimal up-front costs. Cloud PBX can be rented and the price of IP phones is not too high.

 

Is the network ready for SIP Trunking?

Having enough bandwidth available:  The required bandwidth can be calculated according to the number of expected simultaneous calls

Having the right Private Branch Exchange: Cloud PBX can be rented or existing on-premise IP-PBX can be used

 

What kind of equipment is needed for SIP Trunking?

The equipment necessary for SIP Trunking consists of 3 major components:

 

IP or Cloud PBX – the PBX grants communication flow between two or more endpoints over an IP network. It switches calls between local lines and VoIP users

ITSP – it provides connectivity to the Public Switched Telephone Network from an IP network for fixed communications or mobile devices.

Border element – ensures the connectivity between an organization’s internal IP network, the PSTN and the external IP-carrier network. This component can be a SIP capable firewall, SIP enabling edge device connected to firewall or a switch.

 

Calculating SIP’s bandwidth needs

The amount of SIP’s bandwidth needed for smooth communication depends on three main factors

  1. Determine the number of expected simultaneous calls at any given point of time. This can vary depending on the company’s organizational structure and calls intensity
  2. The voice codec used by the SIP provider defines the IP bandwidth needed to support each separate call. Usually, 120 kbps upload and download speed is required for each call.
  3. It is simple to calculate the necessary IP bandwidth. Multiply the expected number of concurrent calls by the consumption of bandwidth (given from your SIP provider) per call. After that add a margin of 10% for technical reasons.

sip phone calls

100 kb per second for single call means that a cheap 20 Mbps
internet connection is enough for 150 concurrent calls 

Finding the right SIP Trunking provider

Several features should be considered when an organization searches for the right SIP service provider. We recommend that these questions are answered before signing a contract:

  • Voice call quality – IP voice calls use a portion of the internet connection. Choose a provider that also offers internet as a service.
  • Reliability – Good infrastructure guarantees consistency in voice calls. Choose a vendor that also provides PBX services.
  • Security – fundamental security principles should be followed to protect the company’s communication networks from fraud and attacks.
  • Scalability – How easy is to scale up or down and how the price packages change.
  • Compatibility – make sure the provider can adjust its solutions to client’s needs
  • Costs – look for SIP Trunk providers that offer flexible pricing options
  • Simplicity – the right service provider should make configuration and upkeep rather simple from a both technological and administrative standpoint.
  • Flexibility – investigate if there are flexible in terms of phone numbers changes, IP addresses access, phone system adjustment or softphones configuration
  • Expertise in customer support – make sure the provider is an expert when it comes to complicated installations, scaling, unexpected troubleshooting and more.
  • Contract length – it is common that SIP providers offer short term contracts

 

Migrating from PSTN to SIP Trunking

Switching from PSTN to SIP Trunking services is executed in 4 steps

 

  • SIP Trunking vendors change

            – Check if there is an option for phone numbers transfer and how long it takes.

           – Research terms and conditions of providers’ offerings and prices, since this is an unregulated service and the package features can vary.

          – Discuss issues like troubleshooting methods, SIP trunk status monitoring calls rerouting etc.

 

  • Deployment of SIP Trunk solution  

       – Consider geographical phases for the deployment schedule, the regional differences in costs and provider’s connectivity capabilities

 

  • Designing SIP Trunking Network

     – Is the data network protected from denial of service attacks?

     – How are the troubleshooting problems resolved?

     – Are the tools for the call management and status monitoring provided?

     – What kind of SIP Trunk it is – centralized or distributed?

 

  • SIP Trunking service security

      – The SIP Trunk system and the PBX type, determine the level of security planned for the business network. Smaller organizations usually rely on either firewalls or NAT devices as security border devices. Big companies’ data networks often opt for a Layer 7 SBC device for additional protection.