SIP Trunking – adding flexibility to Unified Communications


Consider this scenario: your company is growing at a fast rate and setting up branches at many locations. Employees are reaching out to each other using various modes of communication like e-mail, instant messaging, landlines and VoIP. Communication costs are spiralling upwards but employees are still complaining about the communication overhead with the distributed model. As the CTO, the onus is on you to arrive at the most optimal and productive way to connect your employees while keeping costs down. Do the parameters appear too many to balance? Not really, with Unified Communications and SIP trunking, you may have the answer.

What is Unified Communications?

Unified Communications (UC) is the bringing together of different modes of communication for seamless connectivity and collaboration. In the present day enterprise, where every stakeholder assumes smooth, uninterrupted communication, UC brings in flexibility to the workspace by integrating independent and unconnected channels of communication, thus allowing a consistent experience across multiple channels.

Here is how UC makes it happen: a person receiving an e-mail can place a call to the sender by clicking a call button without even exiting the email application. This will then invoke a softphone and place a call over VoIP to reach the sender of the e-mail over mobile phone. What makes this possible is the underlying communication platform where the contacts at various channels, both synchronous and asynchronous, such as e-mail, wireline, presence and mobile phone are unified.

Unified Communications is implemented by combining of components that integrate existing disparate communication systems. These could include:

Benefits of Unified Communications

Unified Communications offers benefits beyond the obvious. Let us examine what they are:

  • Improved connectivity within the enterprise: UC helps to connect multiple channels and provides seamless connectivity, thus enabling employees to conduct business effectively and painlessly. Companies report a savings of 20 minutes per employee daily by effectively escalating IM chats and e-mails into phone calls and web conferences.
  • Collaboration: Information can be easily shared and hence employees can be more productive. This can lead to faster decision making and go-to-market times for an organisation’s products and services. A Forrester study “Next Generation Communication” reveals 31% of the decision makers feel real-time communication would lead to faster and better decision making.
  • Cost savings: Organisations can realise travel cost savings by using voice and video conferencing and this can also lead to building flexible and productive organisations. On an average an organisation can save over 5 travel days per employee, annually.
  • Better customer experience: From a contact centre view point, Unified Communications provides immense improvement and a positive experience for an organisation’s customers. By implementing Unified Communications, customers have shorter wait times while enjoying a better quality of service. On an average, there is an increase of 6 to 10 % in first call resolution after Unified Communications deployment in contact centers.

SIP Trunking as the pivot of Unified Communications:

Now that we have seen how Unified Communications can connect employees and improve productivity, let us tackle the next important priority which is lowering the cost of connecting various offices

The traditional way to do it is to connect Private Branch Exchange (PBX) through trunks. These trunks connect a branch to the public telephone network (PSTN) which then connects to other branches. With the advent of VoIP this happened over the internet and all that was needed was a VoIP gateway. However, VoIP gateways and traditional trunks are limiting, with separate trunks needed for each branch office. Also, scaling up is very difficult and costly with only 30 lines available per standard trunk.

This problem can be alleviated by the use of SIP trunking. Session Initiation Protocol (SIP) is a communication protocol that governs messaging over various media streams. This adds flexibility to the delivery and future expansion of UC services. SIP trunking uses the Session Initiation Protocol to connect internal enterprise IP-PBX to traditional external PSTN network and enables communication over IP.

SIP trunking is superior to several other IP based trunking using protocols such as Media Gateway Control Protocol (MGCP) and H323. These protocols assign a fixed bandwidth for the trunking whereas SIP creates and maintains a session only when needed thus optimising the network usage and provides flexibility. So SIP trunking integrates an organisation’s communication network over the existing IP-PBX eliminating the need to maintain separate voice and data circuits.

SIP trunking can be deployed through IP-PBX or a mediation server and communication through these trunks is facilitated by means of “soft-switches”.

Benefits of SIP Trunking:

The main benefits of SIP trunking lie in operational cost savings and flexibility: Eliminates the need for more expensive Basic Rate Interfaces (BRI), Primary Rate Interfaces (PRI) and gateways to connect to the PSTN.

Very low incremental cost when adding additional lines. Moreover, an SIP trunk can provide 1500 lines which is much higher than traditional trunks. SIP trunking is thus cheaper per line than the traditional PSTN gateway. Though it may be argued that the initial cost and maintenance of aPSTN gateway is cheaper, it should be understood that the PSTN gateway is not as flexible and scalable in the long run and thus will lose its cost advantage.

Cost savings by effective routing. SIP trunking allows more control and can route calls to the cheapest service provider based on country codes. These routing rules can be built over the SIP edge devices.

SIP trunking delivers both voice and data over the same connection, hence optimising the bandwidth utilisation.

Hassle free maintenance. SIP trunking maintains a uniform IP based network for all communication needs rather than having separate networks and multiple service providers.

Better business continuity. SIP trunking allows configuring IP address forwarding in case the SIP trunk fails. Automatic failover and load balancing can be set up in case of multiple trunks for better manageability.

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