Voice Services
Making the move
from ISDN to SIP
Enable your customers to improve the flexibility and reliability of their
communications infrastructure while reducing costs by moving from
ISDN to SIP.
www.gamma.co.uk
Making the move
from ISDN to SIP
Enable your customers to improve the flexibility and reliability of their
communications infrastructure while reducing costs by moving from
ISDN to SIP.
The next generation
ISDN lines have served businesses well for many years. Their introduction meant better call quality,
increased flexibility and higher capacity. As happens with most technologies though, ISDN lines are
beginning to seem antiquated. As business grows, accounting departments demand lower costs and
workforces require greater flexibility, many companies are finding out that ISDN lines are no longer able
to accommodate their requirements. Today’s providers offer SIP trunking services to replace ISDN lines.
Replacing a fully-built voice infrastructure is no small task but with some careful planning, moving your
customers to the next generation of phone networking can be hassle-free.
Step by step
Now that your customer’s voice infrastructure will be running
over a standard IP network, it should be treated as would
any other network deployment. Any IT department veteran
will tell you that the key to a successful network deployment
is to plan it out ahead of time. The steps for migrating from
ISDN to SIP services are similar to that of a larger IP network
deployment, with a few phone-specific twists thrown in:
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What makes it tick?
The first step in any migration is to document the
requirements. What existing business processes do
the customer’s SIP trunks have to support? What
new processes do they need to enable their staff to
accomplish? Have your customers document the
answers to these questions in detail, as they will
need them later. A few example items that need to be
considered include:
•
How many phone numbers/DDIs does the customer have now, what are they and where are they
directed to? Many companies have freephone and local numbers directed to a main receptionist or
auto attendant, with additional numbers allocated directly to specific departments, top management
and executives.
•
How are inbound calls handled? Are there any call queues, recordings that give out information or
IVRs/touch tone button response systems?
•
Which users have a voicemail system and how do they access it?
•
Can departments or individual users divert calls to another number or location now? If so, how do
they configure this?
•
What are the extensions of every user in your system?
In essence, the first step of the migration process is to map out
the customer’s existing phone network. Ask the customer to find
out how calls are handled for every department and document
that call flow. The customer should create a detailed network
map for their phone network and a complete end to end call flow
diagram for each type of call that their company handles. This
documentation will not only assist with their decision-making
process for new equipment but also serves as the basis for the
testing plan that will be used after implementation is complete.
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Out with the old
Now that they have a map of what their existing phone
network looks like and diagrams for how calls are handled by
their business, ask the customer to try and find opportunities
for change. Frequently, companies have procedures and
processes for call flows that were implemented many years
ago, sometimes decades in the past. They will reflect neither
the current telephony options available to the customer, nor
the current requirements of their business. Ask the customer
to query their staff for their communication pain points
and investigate possible solutions using SIP technology.
Common frustrations that SIP can solve include:
•
High costs. SIP trunks provide significant savings over ISDN lines. If a company struggles with
capacity issues, SIP trunks will enable more active calls for lower cost.
•
Lack of resilience to failure. Power outages, high staff absenteeism or other unexpected disasters
need not result in an unsatisfied customer. Ask your customer to create a plan to redirect calls to
other offices, staff cell phones or automated attendants to solve these problems before they occur.
•
Inflexible distribution of staff. Staff at any office location can now answer calls to any number that
your customer owns, providing the ability to easily move an employee between offices.
•
Disparate communication systems. Integration with unified communications systems (such as
Microsoft Lync) enables a single place for staff to check voice messages, instant messages, emails
and call records.
•
Inability to handle temporary call volume spikes. Many businesses experience seasonal influxes of
orders. SIP technologies can ensure that enough capacity is present to answer all customer calls when
your customer needs them, without having to run additional physical phone lines to your business.
Ask your customer to locate these types of problems with
their current technology, then modify their phone network
map and call flow diagrams to satisfy those deficiencies.
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Find your failures
With updated phone network maps and call flow diagrams
in hand, it is time for your customer to create a testing plan.
Ask them to document the processes that they will take to
verify that calls to each department are handled correctly.
Be sure that they include the testing of their newly available
resilience options.
Shopping spree
The customer now knows what their requirements
are for their new phone network. The next step is to
determine the equipment that will enable them to meet
those requirements. You may choose to approach this in
various ways, depending on the level of flexibility that the
customer requires and how they have decided to route
their calls. Equipment that requires consideration is:
The internet connectivity that will utilise SIP trunking.
SIP is a network service and will use a considerable portion of the customer’s available
bandwidth when many people are on the phone. It is common for businesses to
implement a secondary connection that is dedicated to SIP services. If the customer
chooses to do this, they should be made aware of the option of dedicated, non-public connectivity. By
implementing a link of this type, security is greatly improved and call quality can be better protected.
Whichever choice the customer makes, ensure that adequate bandwidth is available for their expected
volume of calls or call quality will suffer.
Phones.
If the customer is implementing an IPPBX, they can choose to make use of existing
analogue handsets with analogue telephone adaptors or to replace all handsets with
IP phones.
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Security equipment.
Ideally, the customer should use a Session Border Controller (SBC) to control all calls
into and out of their network. An SBC is similar to a VPN concentrator device. The SBC
acts as a demarcation point for a particular type of network traffic (SIP traffic, in this
case) and SBCs are purpose-built to quickly and securely handle large volumes of SIP traffic. If the use
of an SBC is not possible, a SIP-aware firewall should be implemented to ensure that the customer’s
security equipment is capable of understanding what suspicious SIP traffic looks like.
IPPBX or SIP gateway.
This is one of the main decision points for a SIP migration. If the customer is already
using an IPPBX, there is likely no reason for them to make any changes. If they are
using a standard PBX with analogue phones they will need to consider their options.
Replacing an older PBX with an IPPBX can provide greater functionality and flexibility but can be
costly. It will also require that a member of the customer’s staff be trained on the implementation and
maintenance of an IPPBX. If the customer wishes to continue to use their existing analogue PBX, they
can implement a SIP gateway that will convert SIP trunks into a format that the PBX is able to use.
Switching equipment.
Complete physical separation of voice and data traffic is recommended. If possible, the
customer should implement a separate set of switches and cabling for SIP phones and
trunking equipment. If this is not possible, they should implement VLANs to segregate
traffic. In either case, ensure that the customer has enough network ports in their switching infrastructure
to handle the number of new telephones that will be plugged in. If they are using
an existing analogue PBX with analogue phones, this will not be a concern.
Ask the customer to select the equipment that can handle their
requirements and place the order to get it in their hands.
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Freedom of choice
Your customer now has their phone network requirements,
a testing plan and some brand new telephony equipment
ready to be configured. The next step is to choose a
provider who will supply the necessary SIP trunks. A few
factors come into play when making this decision:
•
Can the provider port the customer’s numbers? Some providers operate at a very small scale and
only offer phone numbers in specific cities or regions. Ensure that you choose a provider who can
port all of the customer’s existing numbers to their service.
•
Does the provider run their own network? Many SIP trunking providers base their business entirely
on reselling the SIP services of other companies. Make sure the selected provider has control over
their network to prevent being told that an issue is outside of their control if your customer does need
support.
•
Does the provider have anti-fraud measures? Find a provider that cares about security as much as
you and your customers do. The right provider will limit your customer’s exposure to fraudulent call
charges should a hacker breach their security.
•
Cost. Every company wishes for lower costs but try not to choose a provider based on the lowest price
you can find. If a provider can offer service for a small fraction of the price of each of their competitors,
there are likely some key elements missing from their offering.
Select the right provider for your customer’s SIP trunks carefully and create an account with them.
We have the technology
By now, your customer should have everything needed to
run a SIP-based phone network. Get them to install their
equipment and configure it to work with their new SIP
phone service. When everything is up and running, assign
a few test numbers to their SIP service and get them to
run through their test plan. Be sure that they test out any
resiliency options by simulating failures.
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Portal
So long as everything works during testing, your customer
can safely cut over their infrastructure to use their new
SIP trunks. Ask them to submit a porting request for all of
their phone numbers. Be sure that the customer provides
all required information to avoid their port request being
rejected. Encourage your customer not to cancel their ISDN
lines just yet; porting numbers can take several weeks to
complete. Ensure that all numbers have been successfully
ported and that the customer confirms all numbers are
working correctly before moving to the next step.
The long goodbye
It is finally time for your customer to cut off service to their ISDN
lines. Ask the customer to contact their provider to cancel their ISDN
accounts. They should also shutdown and decommission any ISDNspecific equipment. By this point, your customer should be running
entirely on a modern SIP trunking network, ready to expand and
adapt their communications infrastructure as they grow.
Discover how Gamma can provide
you with the solutions that you need:
Why Gamma is the perfect
fit for Telecoms resellers
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