SIP Trunking Fact Sheet

SIP Trunking BasicsSIP Trunking is a Voice over Internet Protocol (VoIP) service based on the Session Initiation Protocol (SIP) by which Next Generation (Next Gen) providers deliver telephone services and unified communications to customers with SIP capable Private Branch Exchanges (PBX) – the equipment that sites on your site controlling your phones. SIP Trunking can provide voice, video, and other streaming media applications such as desktop sharing, web conferencing and shared whiteboard.

In Europe and US SIP Trunking is a high growth technology past being leading edge. An Acme packet survey showed over 60% of the 100 medium to large organisations questioned were moving to SIP (Jan 2013).

So what? SIP Trunking is the replacement technology for ISDN (Integrated Services Digital Network) or traditional telephone services. ISDN generally runs over the copper in the ground, from a Telephony Service Provider to your premises. The step between ISDN and SIP Trunking is like a change between analogue and digital or AM and FM radio. The differences are inherently in how SIP Trunking operates – using Internet type language, rather than electrical signalling. Unlike in traditional telephony, where bundles of physical wires were once delivered from the Service Provider to a business, a SIP trunk allows a company to replace these traditional fixed lines with Ethernet based access like fibre.

SIP trunks can offer significant cost savings for business, as they eliminate the need for costly ISDN BRIs (Basic Rate Interfaces) or PRIs (Primary Rate Interfaces). But there is much more to it than that.

The Benefits - why you should adopt itThe main benefits are:1. Eliminates costly ISDN type services such as BRIs and PRIs; 2. No need to invest in PSTN gateways and additional line cards as you grow;3. Optimal utilization of bandwidth by delivering both data and voice in the same connection; 4. Maximum flexibility in dimensioning and usage of lines as you avoid having to buy capacity in chunks other than single lines;5. Calls can be routed to other carriers (nationally and around the world) as IP; calls to anywhere worldwide can be made for the cost of a local one;6. Redundancy is created across multiple access circuits (and even access providers).

Cost effectivenessYes the main driver is costs. Unlike ISDN, the network created to support SIP trunking uses servers and soft switches, not banks of hardware based switching gear. It is like looking at how far your home PC has come (and the price has also gone down) – why wouldn’t this be true for telephony services? In addition the SIP Trunk is provided over a converged network. That means it uses the same connection as your Internet – sharing this cost. In New Zealand the cost of broadband access has been steadily declining, whilst bandwidth improves. The Government’s UFB programme is yet another example of reducing prices in this area. Note: whilst we talk about using Internet Protocol and even sharing access circuits that are also being used for your Internet traffic – your SIP Trunk should not go across the Internet. The SIP Trunk itself is pointed away from the general web, meaning call quality can be maintained, even during peak times.

Business customers can save up to 40% on their fixed line and calling costs.

FlexibilityUnlike traditional ISDN circuits which have a 12 month contract and take 21 business days to implement (due to physical wires in the ground having to be enlivened and connected) SIP trunking can flex with your business requirements. Once installed, a SIP Trunking can change the number of calls that it can hold with a change in the software that runs the trunk – rather than any hardware requirement. SIP Trunking are actually only limited by the size of the physical access circuit going into a premise. This is particularly useful for growth periods and allowing for seasonalities or call spikes.

Indeed there are some Next Gen Providers that allow customers to burst up and down, meaning a call is never missed without having to have in place latent call capacity.

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Resiliency & RedundancyDue to SIP Trunks being a software based communication protocol, rules and services can be layered around the SIP Trunk. For redundancy this means that a single SIP Trunk can have multiple end points in a hierarchical structure. For instance a SIP Trunk can be terminated in your Hamilton office for Waikato based calls, with an automatic overflow to Wellington and then Dunedin. This means if for whatever reason calls cannot be presented to the 1st priority, it will automatically overflow – without human intervention – to the next priority and so on. This example can be enhanced by using your business’s own LAN/WAN to then route the call back to the appropriate person. If you use different access providers to support different end points this enhances the resiliency of your telephony network even further with minimal cost.

Most Next Gen Service providers will be able to place an endpoint back in use without intervention – meaning the restoration of links is automatic. This is handy in the light of taking a branch or call centre out of action for maintenance or upgrades.

Note: calls in and out of a business are no longer tied to your local exchange. This means that calls made in say, Wellington can be presented directly to your PBX in Christchurch. Building on this, moving to 2 or 3 ‘gateways’ for each SIP Trunk can drive further efficiencies. By using your own internal network you can remove wider costly and underutilised access links across your branch network.

Future-proofedAlthough New Zealand is using SIP Trunking largely for voice, the service goes wider than this. This is because the trunk is simply a connection for the movement of data packets – whatever this might be. This included the next round of service likely to come to market – in particular video and video conferencing. The reduction of video to another ‘call’ reduces cost and improves reliability.

IntelligenceBeyond the simple SIP Trunking is the next layer of feature services. This tends to be specific to the Next Gen provider, and is ideally tailored to a specific business need or issue, and relies on different elements within their network, including their OSS/BSS and CRM. Some examples of additional service provided across SIP Trunks:

Real time access to call records; Portals allowing self-management of numbers (including toll free numbers for call centres) and endpoints; Complete flexibility on the number of channels on a trunk – including ‘pay for what you use’ systems; Pooling channels across multiple SIP Trunks; Active/ Passive DDIs.

So the first step? Given there is a considerable ground swell for SIP – and overseas is no longer even remotely leading edge, the first step is to talk to a Next Gen provider to outline a network plan and cost profile for your business.

Want more information? There are 3 other articles available:1. SIP Trunk Readiness Assessment for your Business2. Transferring to SIP Trunks: how to go about it and the pitfalls3. Codecs, Security and QoS: Some Technical aspects

Please contact us for these – they will be available on this website shortly.

SIP Trunking BasicsSIP Trunking is a Voice over Internet Protocol (VoIP) service based on the Session Initiation Protocol (SIP) by which Next Generation (Next Gen) providers deliver telephone services and unified communications to customers with SIP capable Private Branch Exchanges (PBX) – the equipment that sites on your site controlling your phones. SIP Trunking can provide voice, video, and other streaming media applications such as desktop sharing, web conferencing and shared whiteboard.

In Europe and US SIP Trunking is a high growth technology past being leading edge. An Acme packet survey showed over 60% of the 100 medium to large organisations questioned were moving to SIP (Jan 2013).

So what? SIP Trunking is the replacement technology for ISDN (Integrated Services Digital Network) or traditional telephone services. ISDN generally runs over the copper in the ground, from a Telephony Service Provider to your premises. The step between ISDN and SIP Trunking is like a change between analogue and digital or AM and FM radio. The differences are inherently in how SIP Trunking operates – using Internet type language, rather than electrical signalling. Unlike in traditional telephony, where bundles of physical wires were once delivered from the Service Provider to a business, a SIP trunk allows a company to replace these traditional fixed lines with Ethernet based access like fibre.

SIP trunks can offer significant cost savings for business, as they eliminate the need for costly ISDN BRIs (Basic Rate Interfaces) or PRIs (Primary Rate Interfaces). But there is much more to it than that.

The Benefits - why you should adopt itThe main benefits are:1. Eliminates costly ISDN type services such as BRIs and PRIs; 2. No need to invest in PSTN gateways and additional line cards as you grow;3. Optimal utilization of bandwidth by delivering both data and voice in the same connection; 4. Maximum flexibility in dimensioning and usage of lines as you avoid having to buy capacity in chunks other than single lines;5. Calls can be routed to other carriers (nationally and around the world) as IP; calls to anywhere worldwide can be made for the cost of a local one;6. Redundancy is created across multiple access circuits (and even access providers).

Cost effectivenessYes the main driver is costs. Unlike ISDN, the network created to support SIP trunking uses servers and soft switches, not banks of hardware based switching gear. It is like looking at how far your home PC has come (and the price has also gone down) – why wouldn’t this be true for telephony services? In addition the SIP Trunk is provided over a converged network. That means it uses the same connection as your Internet – sharing this cost. In New Zealand the cost of broadband access has been steadily declining, whilst bandwidth improves. The Government’s UFB programme is yet another example of reducing prices in this area. Note: whilst we talk about using Internet Protocol and even sharing access circuits that are also being used for your Internet traffic – your SIP Trunk should not go across the Internet. The SIP Trunk itself is pointed away from the general web, meaning call quality can be maintained, even during peak times.

Business customers can save up to 40% on their fixed line and calling costs.

FlexibilityUnlike traditional ISDN circuits which have a 12 month contract and take 21 business days to implement (due to physical wires in the ground having to be enlivened and connected) SIP trunking can flex with your business requirements. Once installed, a SIP Trunking can change the number of calls that it can hold with a change in the software that runs the trunk – rather than any hardware requirement. SIP Trunking are actually only limited by the size of the physical access circuit going into a premise. This is particularly useful for growth periods and allowing for seasonalities or call spikes.

Indeed there are some Next Gen Providers that allow customers to burst up and down, meaning a call is never missed without having to have in place latent call capacity.

Page 2

Resiliency & RedundancyDue to SIP Trunks being a software based communication protocol, rules and services can be layered around the SIP Trunk. For redundancy this means that a single SIP Trunk can have multiple end points in a hierarchical structure. For instance a SIP Trunk can be terminated in your Hamilton office for Waikato based calls, with an automatic overflow to Wellington and then Dunedin. This means if for whatever reason calls cannot be presented to the 1st priority, it will automatically overflow – without human intervention – to the next priority and so on. This example can be enhanced by using your business’s own LAN/WAN to then route the call back to the appropriate person. If you use different access providers to support different end points this enhances the resiliency of your telephony network even further with minimal cost.

Most Next Gen Service providers will be able to place an endpoint back in use without intervention – meaning the restoration of links is automatic. This is handy in the light of taking a branch or call centre out of action for maintenance or upgrades.

Note: calls in and out of a business are no longer tied to your local exchange. This means that calls made in say, Wellington can be presented directly to your PBX in Christchurch. Building on this, moving to 2 or 3 ‘gateways’ for each SIP Trunk can drive further efficiencies. By using your own internal network you can remove wider costly and underutilised access links across your branch network.

Future-proofedAlthough New Zealand is using SIP Trunking largely for voice, the service goes wider than this. This is because the trunk is simply a connection for the movement of data packets – whatever this might be. This included the next round of service likely to come to market – in particular video and video conferencing. The reduction of video to another ‘call’ reduces cost and improves reliability.

IntelligenceBeyond the simple SIP Trunking is the next layer of feature services. This tends to be specific to the Next Gen provider, and is ideally tailored to a specific business need or issue, and relies on different elements within their network, including their OSS/BSS and CRM. Some examples of additional service provided across SIP Trunks:

Real time access to call records; Portals allowing self-management of numbers (including toll free numbers for call centres) and endpoints; Complete flexibility on the number of channels on a trunk – including ‘pay for what you use’ systems; Pooling channels across multiple SIP Trunks; Active/ Passive DDIs.

So the first step? Given there is a considerable ground swell for SIP – and overseas is no longer even remotely leading edge, the first step is to talk to a Next Gen provider to outline a network plan and cost profile for your business.

Want more information? There are 3 other articles available:1. SIP Trunk Readiness Assessment for your Business2. Transferring to SIP Trunks: how to go about it and the pitfalls3. Codecs, Security and QoS: Some Technical aspects

Please contact us for these – they will be available on this website shortly.

SIP Trunking Fact Sheet