Stumble It!
(Part 3 of a 6 Part Series)
Part 1 of this series provided some tips to help you create a solid and credible business justification for an IP Telephony migration. Part 2 focused on the Human Factor of an IP Telephony implementation.
Part 3 of this series will provide some guidance to assist you in
choosing between a Premise-based or Hosted IP Telephony solution.
For the purpose of clarity, the following terms and definitions will be used in this article:
A
premise based IP Telephony solution. Most or all of the components of
the solution are located at the customer premise. The components are
usually purchased by the organization. The product is usually designed
to serve a single company. In some instances, a vendor may own and
manage the IP-PBX as part of a managed service.
IP-Centrex:
Similar
to regular Centrex, an IP-Centrex solution is hosted by a service
provider. The components that deliver the service are designed to serve
hundreds or thousands of customers. With the exception of telephones
(which are located at the client), most of the functional components
are located in a secure environment at the service provider’s location.
IP-Centrex or IP-PBX ?
The
first question that should be answered is whether your organization
will even consider outsourcing a vital service such as voice
communication services. For some organizations, corporate policy or
culture will not permit outsourcing services that are considered
mission-critical. In those cases, the choice is clear: IP-PBX.
What follows is high-level comparison of the two service delivery models. It should be noted that the comparisons are not absolute. There are of course exceptions and the suitability of the service type will be dependent on the particular circumstances within your organization.
| | IP-Centrex | IP-PBX |
| Service Availability | IP-Centrex service availability is limited in | |
| Small vs. Large Business | IP-Centrex
services are best suited for small to medium organizations (10 to 200)
users. IP-Centrex can offer a rich set of features and functionality
that small organizations cannot typically afford to build on their own.
In addition, many small companies lack the staff and expertise to
implement IP Telephony on their own. | IP-PBX solutions are available for the smallest to largest organizations. |
| Capital vs. Operational Expenditures | IP-Centrex
will require less initial capital expenditures and may offer more
predictable operational spending. However, typically the two most
costly factors in an IP Telephony solution are network upgrades and
telephones. These two elements may necessitate a significant initial
capital investment. A service provider may be willing to bundle these
costs into the monthly fee. Operations of the internal infrastructure
may also result in increased operational expenses above the recurring
cost of the service. | An
IP-PBX is subject to the same potential costly network upgrade costs as
IP-Centrex. These, and all other solution costs, will require a greater
initial investment than IP-Centrex. Operational costs should be lower than IP-Centrex but these may be more difficult to predict and control. |
| Customization | In
general, service providers build their solutions so that they can be
reliably replicated, delivered and managed across their customer base.
This is important since customization for thousands of customers could
result in an operation that would be impractical to manage and operate.
Your organization will likely be limited to a specific set of features
and products that are predefined in the IP-Centrex service. This may
result in less flexibility and ability to adapt to new business
requirements. I am not aware of an IP-Centrex solution that offers an
API to individual end-customers. | IP-PBX
solutions will offer more customization options. In addition, an IP-PBX
solution may have APIs that allow the integration with external
business processes and applications. |
| Company Staff, Expertise and History | Organizations
that are currently Centrex customers may not have the experience
required to install and operate an IP-PBX solution. However, it is
important to note, that unless you also outsource the network
infrastructure, your company will still be required to manage and
operate the infrastructure required to deliver the IP-Centrex service
within your organization. | Designing,
installing and operating an IP-PBX solution requires skills not
typically found in either Telecom or IT. An IP-PBX solution will
necessitate associated training and may require the use of external
expertise during the design, implementation and early stages of
operations. |
| E911 | Enhanced
911 capabilities vary among service providers. Most will be able to
deal effectively with locations that are directly connected to the
IP-Centrex service. However, if your organization has other locations
where IP-Centrex is being delivered across your network from a central
service-provider connection point, the IP-Centrex solution may not be
able to identify the location of the 911 caller. | Enterprise-class
IP-PBX solutions from the major vendors can be engineered to provide
reliable E911 services to users located within a predefined geographic
network boundary. |
| Integrated Applications | Integrated
applications such as Call Centres, Instant Messaging, Presence and
Meet-Me Conferencing may not be available from an IP-Centrex based
solution. Additional monthly or usage charges may apply if these types
of services are available. | Integrated
applications are available with IP-PBX solutions. They may be included
in the core software or they may require a one-time purchase and follow
up maintenance charges. |
| Admission Control | Unless
the IP-Centrex solution supports RSVP (I’m not aware of any that do so)
it will likely be unaware of bandwidth utilization conditions inside
your network and will therefore be incapable of rejecting a call
attempt, even if insufficient network resources are available to
support the call. | Some
IP-PBX vendor solutions incorporate devices distributed at key
locations within your network or support RSVP to allow the system to
determine if sufficient network resources exist to allow a call and
ensure voice quality. |
| Disaster Recovery & Survivability | With
a typical IP-Centrex solution, if part or all of your organization’s
network was non-functional, incoming calls could still be handled by
the IP-Centrex system, in a couple of different ways:
The
circuit connection(s) from your organization’s data network to the
service provider can potentially be a single point of failure. The
survivability aspects already discussed, and the addition of redundant
circuits and components, can mitigate the risk. | Some
IP-PBX solutions can compensate (at least partially) for data network
circuit failures with some form of local (on-site) backup systems. At a
minimum, these backup systems will allow extension-to-extension calling
and will allow outgoing calls, including 911 calls. Distributed call control and PSTN connectivity or additional data network redundancy can mitigate the risk. Primary
call control system failure would result in the inability to process
incoming calls unless some form of alternate call routing had been
previously arranged with the telephone company. It would also be
necessary for the associated supporting systems and processes to have
been in place prior to the failure event. |
- Ensure that the service provider is financially stable and that you trust them to provide a reliable service over the long term.
- Negotiate an acceptable
- Attain a service commitment for the term of the contract and a “not-to-exceed” increase upon renewal.
- Ensure that the service can scale to accommodate your expected growth.
Conclusion
In
general, IP-Centrex service is best suited for small to medium
business. Large organizations will typically require more
functionality, customization and service control than is available from
IP-Centrex. Hybrid models that combine IP-PBX and IP-Centrex may be a
viable model. For example, large organizations with many geographic
locations may choose an IP-PBX for larger buildings and IP-Centrex for
remote and lower user-density branch locations.
RIC
has extensive experience with both service models from both the service
provider and enterprise perspectives and we can assist you in
determining what is best suited for your organization.
Rick McCharles
www.ric.ca
